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The Mendelian randomization approach is an epidemiological study design incorporating genetic information into traditional epidemiological studies to infer causality of biomarkers, risk factors, or lifestyle factors on disease risk. Mendelian randomization studies often draw on novel information generated in genome-wide association studies on causal associations between genetic variants and a risk factor or lifestyle factor. Such information can then be used in a largely unconfounded study design free of reverse causation to understand if and how risk factors and lifestyle factors cause cardiovascular disease. If causation is demonstrated, an opportunity for prevention of disease is identified; importantly however, before prevention or treatment can be implemented, randomized intervention trials altering risk factor levels or improving deleterious lifestyle factors needs to document reductions in cardiovascular disease in a safe and side-effect sparse manner. Documentation of causality can also inform on potential drug targets, more likely to be successful than prior approaches often relying on animal or cell studies mainly. The present review summarizes the history and background of Mendelian randomization, the study design, assumptions for using the design, and the most common caveats, followed by a discussion on advantages and disadvantages of different types of Mendelian randomization studies using one or more samples and different levels of information on study participants. The review also provides an overview of results on many of the risk factors and lifestyle factors for cardiovascular disease examined to date using the Mendelian randomization study design. [ABSTRACT FROM AUTHOR]

Aims Treatment with sodium-glucose co-transporter 2 (SGLT2)-inhibitors reduces the risk of cardiovascular disease and mortality, but the mechanism is unclear. We hypothesized that a functional genetic variant in solute carrier family 5 member 2 (SLC5A2), known to be associated with familial renal glucosuria, would mimic pharmacological SGLT2-inhibition, and thus provide an opportunity to examine potential mediators of the effects on lower risk of cardiovascular disease and mortality. Methods and results We examined 112 712 individuals from the Copenhagen City Heart Study and Copenhagen General Population Study (CCHS + CGPS), 488 687 from the UK Biobank, and 342 499 from FinnGen, genotyped for SLC5A2 rs61742739, c.1961A > G; p.(Asn654Ser). The 2.0% heterozygotes and 0.01% homozygotes were pooled as carriers and compared with the 98% non-carriers. First, we examined the risk of cardiovascular disease and mortality; second, whether carrying the variant was associated with potential mediators of the effect; and third, whether identified potential mediators could explain the observed reduced risk of cardiovascular disease and mortality. In the CCHS + CGPS, carriers vs. non-carries had a 31% lower risk of heart failure, 21% lower risk of myocardial infarction, 16% lower risk of ischaemic heart disease, and 22% lower risk of all-cause mortality. Corresponding values in meta-analyses of the three studies combined were lower risk by 10%, 6%, 6%, and 10%, respectively. The SLC5A2 rs61742739 variant was not associated with a risk of ischaemic stroke or cardiovascular mortality. Of the lower risks observed in CCHS + CGPS, lower plasma glucose mediated 2.0%(P = 0.004) on heart failure, 3.1%(P = 0.09) on myocardial infarction, 4.1%(P = 0.02) on ischaemic heart disease, and 6.0%(P = 0.39) on all-cause mortality; corresponding values in the UK Biobank were 2.9%(P = 0.70), 1.5%(P = 0.77), 4.1%(P = 0.23), and 3.1%(P = 0.21), respectively. Conclusion A functional genetic variant in SLC5A2 , mimicking SGLT2-inhibition, was associated with a lower risk of heart failure, myocardial infarction, ischaemic heart disease, and all-cause mortality. These effects were at most minimally mediated through lower plasma glucose. [ABSTRACT FROM AUTHOR]

Background: Increasing evidence suggests that smoking influences mental health negatively. This study investigated whether high tobacco consumption is causally related to psychological distress in a Mendelian randomization design, using a variant in the nicotine acetylcholine receptor gene CHRNA3-known to influence individual tobacco consumption-as instrumental variable for tobacco consumption.Methods: Data from 90 108 participants in the Copenhagen General Population Study was used. Exposures included self-reported cigarettes/day and pack years and the CHRNA3 rs1051730 genotype as instrumental variable for tobacco consumption. Three dimensions of psychological distress were studied: Stress, fatigue, and hopelessness. Analyses with the CHRNA3 genotype were stratified by smoking status.Results: Self-reported amount of smoking was associated with all three dimensions of psychological distress. For instance among participants smoking 30 cigarettes/day or more, the odds ratio (OR) for stress was 1.67 (95% confidence interval [CI] 1.47-1.89) compared to never-smokers. Corresponding ORs for fatigue and hopelessness were 2.18 (95% CI 1.92-2.47) and 3.08 (95% CI 2.62-3.62). Among current smokers, homozygotes and heterozygotes for the CHRNA3 genotype had higher tobacco consumption than noncarriers. Nevertheless, the CHRNA3 genotype was not associated with psychological distress neither in current nor in former or never-smokers. For instance among current smokers, the OR for stress was 1.02 (95% CI 0.91-1.15) among homozygotes compared to noncarriers of the CHRNA3 genotype.Conclusions: Though a strong association between tobacco consumption and psychological distress was found, there was no clear evidence that high tobacco consumption was causally related to psychological distress.Implications: Smoking is associated with several mental health outcomes and smoking cessation is associated with improved mental health. Causality in the association between smoking and mental health is difficult to establish using observational data. Using a genotype known to influence tobacco consumption as instrumental variable for amount of smoking, we found no clear evidence of a direct causal path between high tobacco consumption and psychological distress. Whatever causes the strong association between tobacco consumption and psychological distress, the co-occurrence is important to consider both in interventions for smoking prevention and cessation. [ABSTRACT FROM AUTHOR]

Background: Results regarding telomere length and cancer risk are conflicting. We tested the hypothesis that long telomeres are associated with increased risk of any cancer and specific cancer types in genetic and observational analyses.Methods: Individuals (N = 95 568) from the Copenhagen City Heart Study and the Copenhagen General Population Study had the telomere length-associated genotypes rs7726159 (TERT), rs1317082 (TERC), and rs2487999 (OBFC1) determined, and 65 176 had telomere length measured. A total of 10 895 individuals had had a cancer diagnosis. Endpoints were any cancer and 25 specific cancer types. We conducted Cox regression analyses and logistic regression analyses. The three genotypes were combined as an allele sum.Results: Telomere length increased 67 base-pairs [95% confidence interval (CI) 61-74] per allele. In logistic regression models, the per-allele odds ratio (OR) for cancer was 1.05 (95% CI 1.03-1.07) for the allele sum, 1.05 (1.02-1.09) for rs7726159, 1.05 (1.02-1.08) for rs1317082 and 1.07 (1.02-1.12) for rs2487999. In contrast, the hazard ratio for any cancer was 1.01 (1.00-1.01) per 200-base-pair increase in telomere length in multivariable adjusted observational analysis. In genetic analyses according to specific cancer types, the per-allele odds ratio was 1.19 (1.12-1.27) for melanoma and 1.14 (1.06-1.22) for lung cancer.Conclusions: Genetic determinants of long telomeres are associated with increased cancer risk, particularly melanoma and lung cancer. This genetic predisposition to enhanced telomere maintenance may represent a survival advantage for pre-cancerous cells, allowing for multiple cell divisions leading to cancer development. [ABSTRACT FROM AUTHOR]

Background: Short telomeres in peripheral blood leukocytes are associated with older age and age-related diseases. We tested the hypotheses that short telomeres are associated with both increased cancer mortality and all-cause mortality. Methods: Individuals (n = 64 637) were recruited from 1991 onwards from two Danish prospective cohort studies: the Copenhagen City Heart Study and the Copenhagen General Population Study. All had telomere length measured by quantitative polymerase chain reaction and the genotypes rs1317082 (TERC), rs7726159 (TERT), and rs2487999 (OBFC1) determined. The sum of telomere-shortening alleles from these three genotypes was calculated. We conducted Cox regression analyses and instrumental variable analyses using the allele sum as an instrument. All statistical tests were two-sided. Results: Among 7607 individuals who died during follow-up (0-22 years, median = 7 years), 2420 had cancer and 2633 had cardiovascular disease as causes of death. Decreasing telomere length deciles were associated with increasing allcause mortality (Ptrend = 2*10-15). The multivariable-adjusted hazard ratio of all-cause mortality was 1.40 (95% confidence interval [CI] = 1.25 to 1.57) for individuals in the shortest vs the longest decile. Results were similar for cancer mortality and cardiovascular mortality. Telomere length decreased 69 base pairs (95% CI = 61 to 76) per allele for the allele sum, and the per-allele hazard ratio for cancer mortality was 0.95 (95% CI = 0.91 to 0.99). Allele sum was not associated with cardiovascular, other, or all-cause mortality. Conclusion: Short telomeres in peripheral blood leukocytes were associated with high mortality in association analyses. In contrast, genetically determined short telomeres were associated with low cancer mortality but not with all-cause mortality. [ABSTRACT FROM AUTHOR]

Background: Observationally, reports on the association between milk intake and risk of ischaemic heart disease (IHD) and myocardial infarction (MI) have produced conflicting results; and no previous large-scale study using the lactase persistent/non-persistent LCT-13910 C/T genotype as a largely unconfounded proxy for milk intake free of reverse causation has been conducted. We tested the hypothesis that milk intake observationally and genetically through the LCT-13910 C/T genotype is associated with risk of IHD and MI in a Mendelian randomization design. Methods: We included 98 529 White individuals of Danish descent, aged 20-100 years, from three studies of the general population. Information on IHD (N=10 372) and MI (N=4188) were obtained from national Danish registries. First, we investigated observational associations between milk intake and incident IHD and MI. Second, we confirmed the association between the rs4988235 genetic variant LCT-13910 C/T, associated with lactase persistence/non-persistence, and milk intake. Finally, we tested whether LCT-13910 C/T genotype was associated with risk of IHD and MI as well as with cardiovascular risk factors. Results: During a mean follow-up time of 5.4 years, the observational hazard ratio for a 1 glass/week higher milk intake was 1.00 [95% confidence interval (CI): 1.00,1.01] for both IHD and MI. Median milk intake was 3 glasses/week (interquartile range: 0-7) in lactase CC non-persistent individuals compared with 5 glasses/week (0-10) in lactase TC/TT persistent individuals (P=3*10-60). In the dominant genetic model comparing lactase TC/TT persistent individuals with lactase CC non-persistent individuals, the odds ratio was 1.00 (0.92,1.09) for IHD and 0.96 (0.84,1.09) for MI. Finally, in the dominant genetic model genotype was not associated convincingly with plasma levels of total cholesterol, low density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides or glucose, nor with blood pressure. Conclusion: Milk intake was not associated with risk of IHD or MI, observationally orgenetically [ABSTRACT FROM AUTHOR]

Background Sun exposure is the single most important risk factor for skin cancer, but sun exposure may also have beneficial effects on health. We tested the hypothesis that individuals with skin cancer (non-melanoma skin cancer and cutaneous malignant melanoma) have less myocardial infarction, hip fracture and death from any cause, compared with general population controls.Methods We examined the entire Danish population above age 40 years from 1980 through 2006, comprising 4.4 million individuals. Diagnoses of non-melanoma skin cancer (n = 129 206), cutaneous malignant melanoma (n = 22107), myocardial infarction (n = 327 856), hip fracture (n = 129 419), and deaths from any cause (n = 1 629 519) were drawn from national registries.Results In individuals with vs without non-melanoma skin cancer, multifactorially adjusted odds ratios were 0.96 (95% confidence interval: 0.94–0.98) for myocardial infarction and 1.15 (1.12–1.18) for hip fracture, and the multifactorially adjusted hazard ratio was 0.52 (0.52–0.53) for death from any cause. Risk of hip fracture was reduced (odds ratios were below 1.0) in individuals below age 90 years. In individuals with vs without cutaneous malignant melanoma, corresponding odds ratios were 0.79 (0.74–0.84) for myocardial infarction and 0.84 (0.76–0.93) for hip fracture, and the corresponding hazard ratio for death from any cause was 0.89 (0.87–0.91); however, cutaneous malignant melanoma was associated positively with death from any cause in some individuals.Conclusions In this nationwide study, having a diagnosis of skin cancer was associated with less myocardial infarction, less hip fracture in those below age 90 years and less death from any cause. Causal conclusions cannot be made from our data. A beneficial effect of sun exposure per se needs to be examined in other studies. [ABSTRACT FROM AUTHOR]

Background Recent meta-analyses have suggested that short telomere length was associated with increased risk of cancer. We therefore tested the hypotheses that short telomere length was associated with increased risk of cancer and with increased risk of early death after cancer. Methods We measured leukocyte telomere length in a prospective study of 47 102 Danish general population participants from the Copenhagen City Heart Study and the Copenhagen General Population Study. Participants were followed for up to 20 years for cancer diagnosis and death. Follow-up was 100% complete. All statistical tests were two-sided. Results Telomere length decreased linearly with increasing age (P <.001). During follow-up, we observed 3142 first cancers and, among these individuals, 1730 deaths. Decreasing quartiles of telomere length were associated with decreasing survival after cancer (log-rank P <.001). Multivariable-adjusted hazard ratios of early death were 1.31 (95% confidence interval [CI] = 1.14 to 1.52) in individuals in the quartile and 1.43 (95% CI = 1.13 to 1.80) in individuals in the decile with the shortest telomeres vs the longest. Unadjusted hazard ratios of cancer risk were 1.74 (95% CI = 1.58 to 1.93) and 2.00 (95% CI = 1.70 to 2.35) in individuals in the quartile and decile with the shortest vs longest telomeres; however, multivariable adjustment changed these hazard ratios to 0.98 (95% CI = 0.88 to 1.08) and 0.95 (95% CI = 0.80 to 1.11), mainly because of age adjustment. Conclusions Short telomere length is associated with reduced survival after cancer but not with cancer risk. The latter contrasts with findings from recent meta-analyses. [ABSTRACT FROM AUTHOR]

Elevated plasma levels of C-reactive protein (CRP), a marker of inflammation, are associated with an increased risk of cancer, but it is unclear whether this association is causal. We examined whether four common single-nucleotide polymorphisms (SNPs) in the CRP gene that are associated with altered plasma CRP levels are causally associated with an increased risk of cancer. The study population included participants in a prospective study (n = 10 215) and a cross-sectional study (n = 36 403) of the adult general population in Denmark, all of whom were genotyped for the CRP SNPs. The association between plasma CRP levels measured by a high-sensitivity turbidimetry assay and the risk of cancer was examined for 8224 participants in the prospective study. The hazard ratio of cancer for a doubling of the plasma CRP level was 1.09 (95% confidence interval [CI] = 1.03 to 1.14). The nine most common genotype combinations of the four CRP SNPs were associated with up to a 72% increase (95% CI = 58% to 87%) in CRP levels but not with an increased risk of cancer. The estimated causal odds ratio for cancer associated with a genetically induced doubling in CRP level was 0.94 (95% CI = 0.81 to 1.08). This finding suggests that elevated CRP levels do not cause cancer. [ABSTRACT FROM PUBLISHER]

Background The long-term pulmonary sequelae of mild coronavirus disease 2019 (COVID-19) remains unknown. In this study, we aimed to characterize lung function trajectories in individuals with mild COVID-19 from preinfection to 2 years postinfection. Methods We reinvited participants 2 years after infection from our matched cohort study of the Copenhagen General Population who had initially been examined 5.4 months after infection. We repeated lung tests and questionnaires. Linear mixed models were used to estimate dynamics in lung volumes in individuals with COVID-19 patients versus uninfected controls over two intervals: from pre-infection to 6 months postinfection and 6 months postinfection to 2 years postinfection. Results 52 individuals (48.6%) attended the 2-year examination at median 1.9 years (interquartile range, 1.8–2.4) after COVID-19, all with mild infection. Individuals with COVID-19 had an adjusted excess decline in forced expiratory volume in 1 second (FEV1) of 13.0 mL per year (95% confidence interval [CI], −23.5 to −2.5; P =.02) from before infection to 6 months after infection compared to uninfected controls. From 6 to 24 months after infection, they had an excess decline of 7.5 mL per year (95% CI, −25.6–9.6; P =.40). A similar pattern was observed for forced vital capacity (FVC). Participants had a mean increase in diffusing capacity for carbon monoxide (DLco) of 3.33 (SD 7.97) between the 6- and 24-month examination. Conclusions Our results indicate that mild COVID-19 infection affects lung function at the time of infection with limited recovery 2 years after infection. [ABSTRACT FROM AUTHOR]

A response from the authors of the article "Short telomere length, cancer survival, and cancer risk in 47102 individuals" in the 2013 issue is presented.

Objective Gout is the most common form of inflammatory arthritis and is caused by hyperuricaemia. Some studies have found a reduction in plasma urate with vitamin C supplementation. We tested the hypothesis that high plasma vitamin C is causally associated with low plasma urate and low risk of hyperuricaemia, using a Mendelian randomization approach. Methods We measured plasma urate and genotyped for the SLC23A1 rs33972313 vitamin C variant in 106 147 individuals from the Copenhagen General Population Study, of which 24 099 had hyperuricaemia. We measured plasma vitamin C in 9234 individuals and genotyped for the SLC2A9 rs7442295 urate variant in 102 345 individuals. Results Each 10 µmol/l higher plasma vitamin C was associated with a −2.3(95%CI: −0.69 to −3.9) µmol/l lower plasma urate after multivariable adjustments. The SLC23A1 rs33972313 GG genotype was associated with a 9% (5.6%, 11.9%) higher plasma vitamin C compared with AA and AG combined but was not associated with plasma urate (P = 0.31). Likewise, for each 10 µmol/l higher plasma vitamin C the odds ratios for hyperuricaemia were 0.92 (0.86, 0.98) observationally after multivariable adjustments, but 1.01 (0.84, 1.23) genetically. Conclusion High plasma vitamin C was associated with low plasma urate and with low risk of hyperuricaemia. However, the SLC23A1 genetic variant causing lifelong high plasma vitamin C was not associated with plasma urate levels or with risk of hyperuricaemia. Thus, our data do not support a causal relationship between high plasma vitamin C and low plasma urate. [ABSTRACT FROM AUTHOR]

The author comments on the article "Thirty-Five-Year Trends in Cardiovascular Risk Factors in Finland" by E. Vartiainen and colleagues. He relates a study which describes the common lifestyle of individuals living in Finland, Scandinavia and most of Northern Europe. He highlights the results of the study in Finland. He emphasizes the need to address the increasing cardiovascular mortality rates.

Aims Low levels of HDL cholesterol have been associated with increased risk of infectious disease morbidity and mortality. Nuclear magnetic resonance (NMR) spectroscopy permits the measurement of HDL particle count and allows further subclassification according to particle size. We tested the hypothesis that low number of different HDL subfractions is associated with increased infectious disease morbidity and mortality. Methods and results HDL particle counts were measured using NMR spectroscopy in 30 195 individuals aged 22–99 years from the Copenhagen General Population Study. Using multiple-event Cox regression and cause-specific hazard models, we assessed risk of hospitalizations due to infection and infectious disease-related death, from 2003 through 2018. During follow-up, 9303 individuals had one or more infectious disease events, and 1558 experienced infectious disease-related death. In multifactorial adjusted analyses, low number of small and medium HDL particles was associated with increased risk of any infection and infectious disease-related death, whereas low number of large and extra-large HDL particles was not. A very high number of small and medium HDL particles was also associated with increased risk of any infection, but not with infectious disease-related death. For small and medium HDL particles and compared to individuals in the 91–95th percentile, hazard ratios (HRs) in individuals in the lowest percentile were 2.31 (95% confidence interval: 1.75, 3.05) for any infection and 3.23 (2.08, 5.02) for infectious disease-related death. For the highest percentile, corresponding HRs were 1.36 (1.07, 1.74) and 1.06 (0.57, 1.98), respectively. Individuals in the lowest percentile had increased risk of pneumonia (HR: 1.86; 95% confidence interval: 1.30, 2.65), sepsis (2.17; 1.37, 3.35), urinary tract infection (1.76; 1.17, 2.63), skin infection (1.87; 1.24, 2.81), gastroenteritis (1.78; 1.01, 3.16), and other infections (2.57; 1.28, 5.16). Conclusion Low number of the small HDL particles was associated with increased infectious disease morbidity and mortality. [ABSTRACT FROM AUTHOR]

Aims Whether high body mass index (BMI) causally influences development and prognosis of heart failure has implications for clinical practice. We tested the hypotheses that high BMI causally influences heart failure incidence and mortality. Methods and results Using observational and Mendelian randomization causal, genetic analyses, we studied 106 121 individuals from the Copenhagen General Population Study, 18 407 from the Copenhagen City Heart Study, and 977 323 from publicly available databases. In observational analyses in the Copenhagen studies with 10 years of median follow-up, multivariable adjusted hazard ratios per 1 kg/m2 increment of BMI were 1.06 (95% confidence interval: 1.05–1.07; P < 0.001; n = 124 528; events = 6589) for heart failure incidence, 1.04 (1.03–1.06; P < 0.001; n = 124 528; events = 1237) for heart failure mortality, and 1.01 (1.00–1.01; P < 0.001; n = 124 528; events = 24 144) for all-cause mortality. In genetic analyses in the Copenhagen studies, the age and sex adjusted causal risk ratios per 1 kg/m2 increment of BMI were 1.19 (1.05–1.36; P = 0.008; n = 118 200; events = 6541) for heart failure incidence, 1.27 (0.82–1.98; P = 0.28; n = 118 200; events = 889) for heart failure mortality, and 1.11 (1.02–1.22; P = 0.022; n = 118 200; events = 16 814) for all-cause mortality. Finally, combining genetic data from the Copenhagen studies, the Genetic Investigation of ANthropometric Traits, the Heart Failure Molecular Epidemiology for Therapeutic Targets, and the UK Biobank, the unadjusted causal risk ratios per 1 kg/m2 increment of BMI were 1.39 (1.27–1.52; P < 0.001; n = 1 095 523; events = 53 850) for heart failure incidence, 1.18 (1.00–1.38; P = 0.05; n = 576 853; events = 2373) for heart failure mortality, and 1.02 (1.00–1.04; P = 0.03; n = 576 853; events = 44 734) for all-cause mortality. Conclusion High BMI causally increases the risk of both heart failure incidence and mortality. [ABSTRACT FROM AUTHOR]

Background Studies on the pulmonary consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are impeded by limited access to pre–SARS-CoV-2 examinations. Methods We invited Copenhagen General Population Study participants with a confirmed SARS-CoV-2 polymerase chain reaction (PCR) test during the first and second coronavirus disease 2019 waves in Denmark for a repeat chest computed tomography (CT) scan. Paired CT scans were independently assessed for interstitial and noninterstitial abnormalities by 2 trained radiologists. A semiquantitative CT score (ranging from 0 to 20) was used to quantify the extent of interstitial abnormalities. Results Of 111 SARS-CoV-2–infected individuals, 102 (91.2%) experienced symptoms and 12 (11.2%) were hospitalized. Follow-up examination was performed at median of 5.4 (interquartile range, 4.1–7.8) months after a positive SARS-CoV-2 PCR test. Of 67 individuals with paired CT scans, ground glass opacities and reticulation were present in 31 (46.3%) individuals post–SARS-CoV-2 compared to 23 (34.1%) pre–SARS-CoV-2 (mean CT score, 3.0 vs 1.3; P =.011). Results were similar for nonhospitalized individuals. We did not detect development of bronchiectasis, emphysema, or nodules. Conclusions SARS-CoV-2 infection in predominantly nonhospitalized individuals with mild disease was associated with a small increase in only interstitial lung abnormalities. [ABSTRACT FROM AUTHOR]

Background Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease and represents a wide spectrum ranging from mild steatosis to non-alcoholic steatohepatitis with or without fibrosis to overt cirrhosis. Patients with NAFLD have a high risk of developing cardiovascular disease and chronic kidney disease (CKD). So far there has been scarce evidence of the prevalence of NAFLD among patients with CKD. We investigated the prevalence of moderate–severe hepatic steatosis graded according to the definition of NAFLD in a cohort of patients with CKD. Methods Hepatic liver fat content was evaluated by computed tomography (CT) scan in 291 patients from the Copenhagen CKD Cohort Study and in 866 age- and sex-matched individuals with normal kidney function from the Copenhagen General Population Study. Liver attenuation density <48 HU was used as a cut-off value for moderate–severe hepatic steatosis. Results The prevalence of moderate–severe hepatic steatosis was 7.9 and 10.7% (P = 0.177) among patients with CKD and controls, respectively. No association between liver fat content and CKD stage was found. In the pooled dataset from both cohorts, adjusted odds ratios for moderate–severe hepatic steatosis among persons with diabetes, overweight and obesity were 3.1 [95% confidence interval (CI) 1.6–5.9], 14.8 (95% CI 4.6–47.9) and 42.0 (95% CI 12.9–136.6), respectively. Conclusions In a cohort of 291 patients with CKD, kidney function was not associated with the prevalence of moderate–severe hepatic steatosis as assessed by CT scan. [ABSTRACT FROM AUTHOR]

Background: Conflicting evidence has been found regarding the association between high tobacco consumption and body weight among smokers. We tested the hypothesis that high tobacco consumption is causally associated with low body weight. Methods: We conducted a Mendelian randomization study with a genetic variant in CHRNA3 (rs1051730) as proxy for high tobacco consumption. The cohort consisted of 80 342 participants from the Copenhagen General Population Study, with details on body weight, smoking habits and CHRNA3 genotype, including 15 220 current smokers. Results: In observational analyses, high tobacco consumption was associated with high body weight, body mass index, waist circumference, hip circumference and waist-hip ratio. In multivariable adjusted models a 1-cigarette/day higher tobacco consumption was associated with 0.05 kg (95% confidence interval 0.02; 0.08) higher body weight, 0.02 kg/m² (0.01; 0.02) higher body mass index, 0.10cm (0.07; 0.12) higher waist circumference and 0.02cm (0.001; 0.03) higher hip circumference. In contrast, the per-allele increase inCHRNA3 rs1051730 associated with high tobacco consumption was associated with 0.59 kg (0.96; 0.22) lower body weight, 0.23 kg/m² (0.33; 0.13) lower body mass index, 0.32cm (0.74; 0.003) lower waist circumference and 0.45cm (0.66; 0.24) lower hip circumference. No association was found between tobacco consumption and waist-hip ratio in genetic analysis, or among CHRNA3 genotype and any of the outcome variables in former or never smokers. Conclusions: High tobacco consumption causes lower body weight among current smokers. However, smoking does not seem to affect body shape or fat distribution causally. The lack of association between CHRNA3 genotype and body weight among former smokers and never smokers favours smoking as the causal factor for the observed associations. [ABSTRACT FROM AUTHOR]

Background To quantify the potential decline in dynamic lung volumes following coronavirus disease 2019 (COVID-19) in the general population. Methods A prospective matched cohort study of adult Copenhagen General Population Study (CGPS) participants with a prepandemic spirometry available. CGPS individuals with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) test performed repeat spirometry, a questionnaire regarding respiratory symptoms, and diffusing capacity test for carbon monoxide. A matched uninfected CGPS control sample was used, and simple regression and linear mixed effect models were computed to study lung function decline. Results A total of 606 individuals were included; 92/107 (85.9%) with positive SARS-CoV-2 PCR test experienced coronavirus disease 2019 (COVID-19) symptoms and 12 (11.2%) were hospitalized. Spirometry was performed at median 5.6 months (interquartile range, 3.9–12.8) after positive SARS-CoV-2 PCR test. COVID-19 was associated with adjusted 7.3 mL (95% confidence interval [CI],.3–14.3) and 22.6 mL (95% CI, 13.1–32.0) steeper decline in annual forced expiratory volume in first second (FEV1) and FVC or total 113.8 and 301.3 mL lower FEV1 and FVC from baseline to follow-up. Results were robust in analyses restricted to individuals not requiring hospitalization. Conclusions COVID-19–related declines of dynamic lung volume in the general population not requiring hospitalization were small but measurable. [ABSTRACT FROM AUTHOR]

Aims The association of plasma high-density lipoprotein (HDL) cholesterol with risk of dementia is unclear. We, therefore, tested the hypothesis that high levels of plasma HDL cholesterol are associated with increased risk of dementia and whether a potential association is of a causal nature. Methods and results In two prospective population-based studies, the Copenhagen General Population Study and the Copenhagen City Heart Study (N  = 111 984 individuals), we first tested whether high plasma HDL cholesterol is associated with increased risk of any dementia and its subtypes. These analyses in men and women separately were adjusted multifactorially for other risk factors including apolipoprotein E (APOE) genotype. Second, taking advantage of two-sample Mendelian randomization, we tested whether genetically elevated HDL cholesterol was causally associated with Alzheimer's disease using publicly available consortia data on 643 836 individuals. Observationally, multifactorially adjusted Cox regression restricted cubic spline models showed that both men and women with extreme high HDL cholesterol concentrations had increased risk of any dementia and of Alzheimer's disease. Men in the 96th–99th and 100th vs. the 41st–60th percentiles of HDL cholesterol had multifactorially including APOE genotype adjusted hazard ratios of 1.66 (95% confidence interval 1.30–2.11) and 2.00 (1.35–2.98) for any dementia and 1.59 (1.16–2.20) and 1.87 (1.11–3.16) for Alzheimer's disease. Corresponding estimates for women were 0.94 (0.74–1.18) and 1.45 (1.03–2.05) for any dementia and 0.94 (0.70–1.26) and 1.69 (1.13–2.53) for Alzheimer's disease. Genetically, the two-sample Mendelian randomization odds ratio for Alzheimer's disease per 1 SD increase in HDL cholesterol was 0.92 (0.74–1.10) in the IGAP2019 consortium and 0.98 (0.95–1.00) in the ADSP/IGAP/PGC-ALZ/UKB consortium. Similar estimates were observed in sex stratified analyses. Conclusion High plasma HDL cholesterol was observationally associated with increased risk of any dementia and Alzheimer's disease, suggesting that HDL cholesterol can be used as an easily accessible plasma biomarker for individual risk assessment. [ABSTRACT FROM AUTHOR]

Background: Increased tumor cell expression of integrins containing the beta3 subunit is associated with increased progression to invasive tumors, whereas inhibition of beta3 integrin expression and/or function may reduce tumor growth and metastasis. The Leu33Pro polymorphism of the beta3 subunit modulates the function of alpha(IIb)beta3 integrin. We examined whether this polymorphism influences cancer risk.Methods: Using participants (n = 9242) from the Copenhagen City Heart Study with 24 years of follow-up and endpoints from the Danish Cancer Registry, we assessed the risk of all cancers and of 27 cancer types in individuals who carry the Leu33Pro polymorphism (heterozygotes and homozygotes) relative to those without the polymorphism (non-carriers). Relative risks (RRs) of cancer and 95% confidence intervals (CIs) were calculated by Cox proportional hazards regression analysis. Differences in cumulative cancer incidence (per 10 000 person-years) were tested using log-rank statistics. Statistical tests were two-sided.Results: Among the participants, 70.0% were non-carriers, 27.3% were heterozygotes, and 2.7% were homozygotes. We detected 1296 participants with a first cancer. Cumulative incidences in non-carriers, heterozygotes, and homozygotes were 81, 83, and 112, respectively (homozygotes versus non-carriers, P =.02). The age-adjusted RR of all cancers in homozygotes relative to non-carriers was 1.4 (95% CI = 1.1 to 1.9). Incidences in non-carriers, heterozygotes, and homozygotes were 3, 4, and 16 for ovarian cancer; 19, 24, and 36 for breast cancer; and 2, 3, and 7 for melanoma (homozygotes versus non-carriers; P =.002, P =.06, and P =.03, respectively). The age-adjusted RR in homozygotes relative to non-carriers was 4.7 (95% CI = 1.6 to 14) for ovarian cancer, 1.9 (95% CI = 1.0 to 3.7) for breast cancer, and 3.5 (95% CI = 1.1 to 12) for melanoma. Adjustment for other cancer risk factors did not alter these results. Heterozygotes did not differ from non-carriers with respect to cancer risk.Conclusion: Individuals homozygous for the Leu33Pro polymorphism of the beta3 integrin subunit have an increased cancer risk. [ABSTRACT FROM AUTHOR]

Studies the relationship between the risk of cancer and the homozygosity of the Leu33Pro polymorphism of the integrin beta[sub 3]. Genotyping by restriction fragment length polymorphism; Study population; Statistical analysis.

Background Increased risk of asthma and chronic obstructive pulmonary disease has been reported in people living with human immunodeficiency virus (PLWH). Fraction of exhaled nitric oxide (FeNO) is a marker of eosinophilic airway inflammation. We assessed FeNO levels in PLWH and matched uninfected controls and investigated whether human immunodeficiency virus (HIV) status is independently associated with elevated FeNO. Methods FeNO was quantified by NIOX Vero and pulmonary function was assessed by spirometry in 432 PLWH from the Copenhagen Comorbidity in HIV Infection Study and in 1618 age- and sex-matched uninfected controls from the Copenhagen General Population Study. Elevated FeNO was defined as ≥25 parts per billion. Associations between FeNO and HIV status were adjusted for known potential confounders. Results Mean age of PLWH was 50.7 (standard deviation [SD], 11.1) years and 97.4% received combination antiretroviral therapy. PLWH had higher FeNO than uninfected controls (median, 17.0 [interquartile range {IQR}, 11.0–26.0] vs 13.0 [IQR, 9.0–19.0]; P  < .001). Also, PLWH had a higher prevalence of elevated FeNO than uninfected controls (27.5% vs 12.3%; P  < .001). This association remained after adjusting for age, sex, height, smoking status, use of airway medication, blood eosinophils, and immunoglobulin E (adjusted OR [aOR], 3.56 [95% CI, 2.51–5.04]; P  < .001). Elevated FeNO was associated with self-reported asthma (aOR, 2.65 [95% CI, 1.66–4.24]; P  < .001) but not with airflow limitation (aOR, 1.07 [95% CI,.71–1.62]; P  = .745). Conclusions HIV status was independently associated with elevated FeNO, suggesting increased eosinophilic airway inflammation. The potential impact on chronic lung disease pathogenesis needs further investigation. [ABSTRACT FROM AUTHOR]

Background: People with human immunodeficiency virus (PWH) may be at risk of nonalcoholic fatty liver disease. We compared the prevalence of moderate-to-severe hepatic steatosis (M-HS) in PWH with human immunodeficiency virus (HIV)-uninfected controls and determined risk factors for M-HS in PWH.Methods: The Copenhagen Co-Morbidity in HIV Infection study included 453 participants, and the Copenhagen General Population Study included 765 participants. None had prior or current viral hepatitis or excessive alcohol intake. Moderate-to-severe hepatic steatosis was assessed by unenhanced computed tomography liver scan defined by liver attenuation ≤48 Hounsfield units. Adjusted odds ratios (aORs) were computed by adjusted logistic regression.Results: The prevalence of M-HS was lower in PWH compared with uninfected controls (8.6% vs 14.2%, P < .01). In multivariable analyses, HIV (aOR, 0.44; P < .01), female sex (aOR, 0.08; P = .03), physical activity level (aOR, 0.09; very active vs inactive; P < .01), and alcohol (aOR, 0.89 per unit/week; P = .02) were protective factors, whereas body mass index (BMI) (aOR, 1.58 per 1 kg/m2; P < .01), alanine transaminase (ALT) (aOR, 1.76 per 10 U/L; P < .01), and exposure to integrase inhibitors (aOR, 1.28 per year; P = .02) were associated with higher odds of M-HS.Conclusions: Moderate-to-severe hepatic steatosis is less common in PWH compared with demographically comparable uninfected controls. Besides BMI and ALT, integrase inhibitor exposure was associated with higher prevalence of steatosis in PWH. [ABSTRACT FROM AUTHOR]

Background Increased pericardial adipose tissue is associated with higher risk of cardiovascular disease. We aimed to determine whether human immunodeficiency virus (HIV) status was independently associated with larger pericardial adipose tissue volume and to explore possible HIV-specific risk factors. Methods Persons with HIV (PWH) were recruited from the Copenhagen Comorbidity in HIV Infection (COCOMO) Study and matched 1:1 on age and sex to uninfected controls. Pericardial adipose tissue volume was measured using cardiac computed tomography. Results A total of 587 PWH and 587 controls were included. Median age was 52 years, and 88% were male. Human immunodeficiency virus status was independently associated with 17 mL (95% confidence interval [CI], 10–23; P < .001) larger pericardial adipose tissue volume. Larger pericardial adipose tissue volume was associated with low CD4+ nadir and prior use of stavudine, didanosine, and indinavir. Among PWH without thymidine analogue or didanosine exposure, time since initiating combination antiretroviral treatment (per 5-year use) was associated with l6 mL (95% CI, −6 to −25; P  = .002) lower pericardial adipose tissue volume. Conclusions Human immunodeficiency virus status was independently associated with larger pericardial adipose tissue volume. Severe immunodeficiency, stavudine, didanosine, and indinavir were associated with larger pericardial adipose tissue volume. Persons with HIV with prior exposure to these drugs may constitute a distinct cardiovascular risk population. [ABSTRACT FROM AUTHOR]

Background: Increased pericardial adipose tissue is associated with higher risk of cardiovascular disease. We aimed to determine whether human immunodeficiency virus (HIV) status was independently associated with larger pericardial adipose tissue volume and to explore possible HIV-specific risk factors.Methods: Persons with HIV (PWH) were recruited from the Copenhagen Comorbidity in HIV Infection (COCOMO) Study and matched 1:1 on age and sex to uninfected controls. Pericardial adipose tissue volume was measured using cardiac computed tomography.Results: A total of 587 PWH and 587 controls were included. Median age was 52 years, and 88% were male. Human immunodeficiency virus status was independently associated with 17 mL (95% confidence interval [CI], 10-23; P < .001) larger pericardial adipose tissue volume. Larger pericardial adipose tissue volume was associated with low CD4+ nadir and prior use of stavudine, didanosine, and indinavir. Among PWH without thymidine analogue or didanosine exposure, time since initiating combination antiretroviral treatment (per 5-year use) was associated with l6 mL (95% CI, -6 to -25; P = .002) lower pericardial adipose tissue volume.Conclusions: Human immunodeficiency virus status was independently associated with larger pericardial adipose tissue volume. Severe immunodeficiency, stavudine, didanosine, and indinavir were associated with larger pericardial adipose tissue volume. Persons with HIV with prior exposure to these drugs may constitute a distinct cardiovascular risk population. [ABSTRACT FROM AUTHOR]

Background: Chest computed tomography (CT) findings in well-treated people with HIV infection (PWH) remain poorly characterized.Methods: Cross-sectional analysis examining interstitial chest CT findings in PWH (n = 754) and uninfected controls (n = 470).Results: HIV infection was independently associated with 1.82 (95% CI, 1.18-2.88) and 5.15 (95% CI, 1.72-22.2) higher adjusted odds of any interstitial lung abnormality and findings suspicious for interstitial lung disease, respectively.Conclusions: HIV infection was independently associated with interstitial lung abnormalities and findings suspicious for interstitial lung disease. Whether these abnormalities develop into more recognizable disease states over time is unknown but warrants further investigation. [ABSTRACT FROM AUTHOR]

Introduction: Observational studies have found lower concentrations of plasma bilirubin in current smokers compared with former and never smokers. However, whether there is a causal relationship between smoking and bilirubin is unknown. In a Mendelian randomization analysis, we tested the hypothesis that higher tobacco consumption is causally associated with lower concentrations of plasma bilirubin.Methods: We genotyped 103 557 individuals aged 20-100 years from the Copenhagen General Population Study for the CHRNA3 rs1051730 genotype, known to be associated with higher tobacco consumption. Tobacco consumption was defined as daily and cumulative tobacco consumption.Results: In observational multivariable-adjusted analyses, a 10 g/day higher daily tobacco consumption was associated with a 0.28 µmol/L (95% confidence interval = 0.20 to 0.35) lower concentration of plasma bilirubin in current smokers, and a 10 pack-year higher cumulative tobacco consumption was associated with a 0.19 µmol/L (0.17 to 0.21) lower concentration of plasma bilirubin in former and current smokers. Using the CHRNA3 rs1051730 genotype as a proxy for daily and cumulative tobacco consumption, the difference in plasma bilirubin per T-allele was -0.12 µmol/L (-0.23 to -0.002) in current smokers and -0.09 µmol/L (-0.15 to -0.01) in current and former smokers combined. Furthermore, observationally bilirubin concentrations increased with time from smoking cessation in former smokers.Conclusion: Higher daily and cumulative tobacco consumption were associated with lower concentrations of plasma bilirubin in observational and genetic analyses, suggesting that the association is causal.Implications: Our results are compatible with two possible interpretations of previous observational studies, either that bilirubin is a mediator of smoking-induced respiratory disease or that the association between plasma bilirubin and respiratory disease stems from residual confounding because of smoking. Future studies should examine whether bilirubin is a causal risk factor for respiratory disease, or merely a marker of smoking status. [ABSTRACT FROM AUTHOR]

Background Prior to the introduction of combination antiretroviral therapy (cART), cytopenias were common in people with human immunodeficiency virus (PWH), but it is unknown if well-controlled HIV infection is a risk factor for cytopenia. In this study we aimed to determine if HIV infection is an independent risk factor for anemia, neutropenia, lymphocytopenia, and thrombocytopenia. Methods PWH with undetectable viral replication and absence of chronic hepatitis infection (n = 796) were recruited from the Copenhagen Comorbidity in HIV Infection (COCOMO) study and matched uninfected controls from the Copenhagen General Population Study (n = 2388). Hematology was analyzed in venous blood samples. Logistic regression analyses adjusted for age, sex, ethnicity, smoking status, alcohol, and high-sensitivity C-reactive protein were performed to determine possible associations between HIV and cytopenias. Results PWH had a higher prevalence of anemia (6.9% vs 3.4%, P <.001), neutropenia (1.3% vs 0.2%, P <.001), and thrombocytopenia (5.5% vs 2.7%, P <.001) compared with uninfected controls. HIV was independently associated with anemia-adjusted odds ratio (aOR) of 2.0 (95% confidence interval [CI], 1.4–3.0); neutropenia aOR, 6.3 (95% CI, 2.0–19.6); and thrombocytopenia aOR, 2.7 (95% CI, 1.8–4.2). No association was found between HIV and lymphocytopenia. Conclusions Cytopenia is rare in people with well-controlled HIV, but HIV remains a risk factor for anemia, neutropenia, and thrombocytopenia and requires ongoing attention and monitoring. [ABSTRACT FROM AUTHOR]

Background: DNA methylation changes in peripheral blood have recently been identified in relation to lung cancer risk. Some of these changes have been suggested to mediate part of the effect of smoking on lung cancer. However, limitations with conventional mediation analyses mean that the causal nature of these methylation changes has yet to be fully elucidated.Methods: We first performed a meta-analysis of four epigenome-wide association studies (EWAS) of lung cancer (918 cases, 918 controls). Next, we conducted a two-sample Mendelian randomization analysis, using genetic instruments for methylation at CpG sites identified in the EWAS meta-analysis, and 29 863 cases and 55 586 controls from the TRICL-ILCCO lung cancer consortium, to appraise the possible causal role of methylation at these sites on lung cancer.Results: Sixteen CpG sites were identified from the EWAS meta-analysis [false discovery rate (FDR) < 0.05], for 14 of which we could identify genetic instruments. Mendelian randomization provided little evidence that DNA methylation in peripheral blood at the 14 CpG sites plays a causal role in lung cancer development (FDR > 0.05), including for cg05575921-AHRR where methylation is strongly associated with both smoke exposure and lung cancer risk.Conclusions: The results contrast with previous observational and mediation analysis, which have made strong claims regarding the causal role of DNA methylation. Thus, previous suggestions of a mediating role of methylation at sites identified in peripheral blood, such as cg05575921-AHRR, could be unfounded. However, this study does not preclude the possibility that differential DNA methylation at other sites is causally involved in lung cancer development, especially within lung tissue. [ABSTRACT FROM AUTHOR]

Introduction: Smoking is associated with systemic and local inflammation in the lungs. Furthermore, in chronic obstructive pulmonary disease, which is often caused by smoking, there is often systemic inflammation that is linked to lung function impairment. However, the causal pathways linking smoking, systemic inflammation, and airflow limitation are still unknown. We tested whether higher tobacco consumption is associated with higher systemic inflammation, observationally and genetically and whether genetically higher systemic inflammation is associated with airflow limitation.Methods: We included 98 085 individuals aged 20-100 years from the Copenhagen General Population Study; 36589 were former smokers and 16172 were current smokers. CHRNA3 rs1051730 genotype was used as a proxy for higher tobacco consumption and the IL6R rs2228145 genotype was used for higher systemic inflammation. Airflow limitation was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <70%.Results: Difference in plasma level of C-reactive protein was 4.8% (95% CI = 4.4% to 5.2%) per 10 pack-year increase and 1.6% (95% CI = 0.4% to 2.8%) per T allele. Corresponding differences were 1.2% (95% CI = 1.1% to 1.3%) and 0.5% (95% CI = 0.3% to 0.8%) for fibrinogen, 1.2% (95% CI = 1.2% to 1.3%) and 0.7% (95% CI = 0.5% to 1.0%) for α1-antitrypsin, 2.0% (95% CI = 1.8% to 2.1%) and 0.7% (95% CI = 0.4% to 1.1%) for leukocytes, 1.9% (95% CI = 1.8% to 2.1%) and 0.8% (95% CI = 0.4% to 1.2%) for neutrophils, and 0.8% (95% CI = 0.7% to 1.0%) and 0.4% (95% CI = 0.1% to 0.7%) for thrombocytes. The differences in these levels were lower for former smokers compared with current smokers. The IL6R rs2228145 genotype was associated with higher plasma acute-phase reactants but not with airflow limitation. Compared with the C/C genotype, the odds ratio for airflow limitation was 0.95 (95% CI = 0.89 to 1.02) for A/C genotype and 0.94 (95% CI = 0.87 to 1.01) for A/A genotype.Conclusions: Higher tobacco consumption is associated with higher systemic inflammation both genetically and observationally, whereas systemic inflammation was not associated with airflow limitation genetically.Implications: The association between higher tobacco consumption and higher systemic inflammation may be causal, and the association is stronger among current smokers compared to former smokers, indicating that smoking cessation may reduce the effects of smoking on systemic inflammation. Systemic inflammation does not seem to be a causal driver in development of airflow limitation. These findings can help to understand the pathogenic effects of smoking and the interplay between smoking, systemic inflammation, and airflow limitation and hence development and progression of chronic obstructive pulmonary disease. [ABSTRACT FROM AUTHOR]

Motivation The use of single nucleotide polymorphism (SNP) interactions to predict complex diseases is getting more attention during the past decade, but related statistical methods are still immature. We previously proposed the SNP Interaction Pattern Identifier (SIPI) approach to evaluate 45 SNP interaction patterns/patterns. SIPI is statistically powerful but suffers from a large computation burden. For large-scale studies, it is necessary to use a powerful and computation-efficient method. The objective of this study is to develop an evidence-based mini-version of SIPI as the screening tool or solitary use and to evaluate the impact of inheritance mode and model structure on detecting SNP–SNP interactions. Results We tested two candidate approaches: the 'Five-Full' and 'AA9int' method. The Five-Full approach is composed of the five full interaction models considering three inheritance modes (additive, dominant and recessive). The AA9int approach is composed of nine interaction models by considering non-hierarchical model structure and the additive mode. Our simulation results show that AA9int has similar statistical power compared to SIPI and is superior to the Five-Full approach, and the impact of the non-hierarchical model structure is greater than that of the inheritance mode in detecting SNP–SNP interactions. In summary, it is recommended that AA9int is a powerful tool to be used either alone or as the screening stage of a two-stage approach (AA9int+SIPI) for detecting SNP–SNP interactions in large-scale studies. Availability and implementation The 'AA9int' and 'parAA9int' functions (standard and parallel computing version) are added in the SIPI R package, which is freely available at https://linhuiyi.github.io/LinHY%5fSoftware/. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Background: Observational studies have shown that tobacco and alcohol use co-occur, but it is not clear whether this relationship is causal.Methods: Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK Biobank, we used observational methods to test the hypothesis that smoking heaviness increases alcohol consumption. Mendelian randomization (MR) analyses were then used to test the causal relationship between smoking heaviness and alcohol consumption using 55 967 smokers from four European studies [ALSPAC, The Nord-Trøndelag Health Study (HUNT), the Copenhagen General Population Study (CGPS) and UK Biobank]. MR analyses used rs1051730/rs16969968 as a genetic proxy for smoking heaviness.Results: Observational results provided evidence of an association between cigarettes per day and weekly alcohol consumption (increase in units of alcohol per additional cigarette smoked per day = 0.10, 95% confidence interval (CI) 0.05 to 0.15, P ≤ 0.001 in ALSPAC; and 0.48, 95% CI 0.45 to 0.52, P ≤ 0.001 in UK Biobank). However, there was little evidence for an association between rs1051730/rs16969968 and units of alcohol consumed per week across ALSPAC, HUNT, CGPS and UK Biobank (standard deviation increase in units of alcohol per additional copy of the risk allele = -0.004, 95% CI -0.023 to 0.016, P=0.708, I2 = 51.9%). We had 99% and 88% power to detect a change of 0.03 and 0.02 standard deviation units of alcohol per additional copy of the risk allele, respectively.Conclusions: Previously reported associations between smoking and alcohol are unlikely to be causal, and may be the result of confounding and/or reverse causation. This has implications for public health research and intervention research. [ABSTRACT FROM AUTHOR]

Background: Results from randomized controlled trials (RCTs) have raised concern that the cholesterol-lowering drug ezetimibe might increase the risk of cancer. We tested the hypothesis that genetic variation in NPC1L1, mimicking treatment with ezetimibe, was associated with an increased risk of cancer.Methods: We included 67 257 individuals from the general population. Of these, 8333 developed cancer and 2057 died of cancer from 1968 to 2011. To mimic the effect of ezetimibe, we calculated weighted allele scores based on the low-density lipoprotein (LDL) cholesterol-lowering(= NPC1L1-inhibitory) effect of each variant. We tested the associations of the NPC1L1 allele scores with LDL cholesterol and with risk of any cancer, death from any cancer and 27 site-specific cancers. As a positive control, we tested the association of the NPC1L1 allele scores with risk of ischaemic vascular disease (IVD).Results: The NPC1L1 allele scores did not associate with risk of any cancer, death from any cancer or with any of 27 site-specific cancers. Hazard ratios (HRs) for a 1-unit increase in internally weighted allele scores were 1.00 (95% confidence interval: 0.98-1.02) for any cancer, and 1.02 (0.98-1.06) for cancer death. The corresponding HR for IVD was 0.97 (0.94-0.99). Results were similar for an externally weighted allele score and for a simple allele count. Finally, the null association with cancer was robust in sensitivity analyses.Conclusions: Lifelong, genetic inhibition of NPC1L1, mimicking treatment with ezetimibe, does not associate with risk of cancer. These results suggest that long-term treatment with ezetimibe is unlikely to increase the risk of cancer, in agreement with the overall evidence from ezetimibe RCTs. [ABSTRACT FROM AUTHOR]

The added value of incorporating information from repeated blood pressure and cholesterol measurements to predict cardiovascular disease (CVD) risk has not been rigorously assessed. We used data on 191,445 adults from the Emerging Risk Factors Collaboration (38 cohorts from 17 countries with data encompassing 1962-2014) with more than 1 million measurements of systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol. Over a median 12 years of follow-up, 21,170 CVD events occurred. Risk prediction models using cumulative mean values of repeated measurements and summary measures from longitudinal modeling of the repeated measurements were compared with models using measurements from a single time point. Risk discrimination (C-index) and net reclassification were calculated, and changes in C-indices were meta-analyzed across studies. Compared with the single-time-point model, the cumulative means and longitudinal models increased the C-index by 0.0040 (95% confidence interval (CI): 0.0023, 0.0057) and 0.0023 (95% CI: 0.0005, 0.0042), respectively. Reclassification was also improved in both models; compared with the single-time-point model, overall net reclassi- fication improvements were 0.0369 (95% CI: 0.0303, 0.0436) for the cumulative-means model and 0.0177 (95% CI: 0.0110, 0.0243) for the longitudinal model. In conclusion, incorporating repeated measurements of blood pressure and cholesterol into CVD risk prediction models slightly improves risk prediction. [ABSTRACT FROM AUTHOR]

Background: In the clinic, the combination of obesity and chronic obstructive pulmonary disease (COPD) has been increasing. However, whether high body mass index (BMI) affects the risk of exacerbations and pneumonias in individuals with COPD is presently unknown. Genetics can be used to assess the causal role of high BMI in exacerbations and pneumonias in individuals with COPD. We tested the hypothesis that high BMI is associated with an increased risk of exacerbations and pneumonias in individuals with COPD, both observationally and genetically.Methods: We genotyped 93 894 individuals of Danish descent, aged 20-100 years, from the Copenhagen General Population Study, for FTO (rs9939609), MC4R (rs17782313) and TMEM18 (rs6548238), and created an allele score. A total of 10 883 individuals had spirometric COPD with forced expiratory volume in 1 s (FEV1) / forced vital capacity (FVC) < lower limit of normal (LLN). In these individuals, we observed 1453 exacerbations and 3390 pneumonias during 4.7 years of follow-up.Results: For each increase in allele score, BMI was 0.28 kg/m2 [95% confidence interval (CI): 0.25-0.30) higher. Age- and sex-adjusted genetic hazard ratios (HRs) per one allele score increase in individuals with COPD were 1.13 (1.01-1.27) for exacerbations, 1.10 (1.03-1.19) for pneumonias and 1.12 (1.04-1.21) for exacerbations and/or pneumonias. Corresponding multivariable adjusted observational HRs per unit (kg/m2) BMI increase were 0.98 (0.95-1.01), 0.99 (0.96-1.03) and 0.99 (0.96-1.01), respectively.Conclusions: Genetically determined high BMI was associated with an increased risk of recurrent exacerbations and pneumonias in individuals with COPD, whereas this was not the case for observationally determined high BMI. The genetic data are compatible with the notion that high BMI leads to increased risk of exacerbations and pneumonias in individuals with COPD. [ABSTRACT FROM AUTHOR]

Background: Epidemiological studies have linked adult height with breast cancer risk in women. However, the magnitude of the association, particularly by subtypes of breast cancer, has not been established. Furthermore, the mechanisms of the association remain unclear.Methods: We performed a meta-analysis to investigate associations between height and breast cancer risk using data from 159 prospective cohorts totaling 5216302 women, including 113178 events. In a consortium with individual-level data from 46325 case patients and 42482 control patients, we conducted a Mendelian randomization analysis using a genetic score that comprised 168 height-associated variants as an instrument. This association was further evaluated in a second consortium using summary statistics data from 16003 case patients and 41335 control patients.Results: The pooled relative risk of breast cancer was 1.17 (95% confidence interval [CI] = 1.15 to 1.19) per 10cm increase in height in the meta-analysis of prospective studies. In Mendelian randomization analysis, the odds ratio of breast cancer per 10cm increase in genetically predicted height was 1.22 (95% CI = 1.13 to 1.32) in the first consortium and 1.21 (95% CI = 1.05 to 1.39) in the second consortium. The association was found in both premenopausal and postmenopausal women but restricted to hormone receptor-positive breast cancer. Analyses of height-associated variants identified eight new loci associated with breast cancer risk after adjusting for multiple comparisons, including three loci at 1q21.2, DNAJC27, and CCDC91 at genome-wide significance level P < 5×10(-8).Conclusions: Our study provides strong evidence that adult height is a risk factor for breast cancer in women and certain genetic factors and biological pathways affecting adult height have an important role in the etiology of breast cancer. [ABSTRACT FROM AUTHOR]

Background: Data for multiple common susceptibility alleles for breast cancer may be combined to identify women at different levels of breast cancer risk. Such stratification could guide preventive and screening strategies. However, empirical evidence for genetic risk stratification is lacking. Methods: We investigated the value of using 77 breast cancer-associated single nucleotide polymorphisms (SNPs) for risk stratification, in a study of 33 673 breast cancer cases and 33 381 control women of European origin. We tested all possible pair-wise multiplicative interactions and constructed a 77-SNP polygenic risk score (PRS) for breast cancer overall and by estrogen receptor (ER) status. Absolute risks of breast cancer by PRS were derived from relative risk estimates and UK incidence and mortality rates. Results: There was no strong evidence for departure from a multiplicative model for any SNP pair. Women in the highest 1% of the PRS had a three-fold increased risk of developing breast cancer compared with women in the middle quintile (odds ratio [OR] = 3.36, 95% confidence interval [CI] = 2.95 to 3.83). The ORs for ER-positive and ER-negative disease were 3.73 (95% CI = 3.24 to 4.30) and 2.80 (95% CI = 2.26 to 3.46), respectively. Lifetime risk of breast cancer for women in the lowest and highest quintiles of the PRS were 5.2% and 16.6% for a woman without family history, and 8.6% and 24.4% for a woman with a first-degree family history of breast cancer. Conclusions: The PRS stratifies breast cancer risk in women both with and without a family history of breast cancer. The observed level of risk discrimination could inform targeted screening and prevention strategies. Further discrimination may be achievable through combining the PRS with lifestyle/environmental factors, although these were not considered in this report. [ABSTRACT FROM AUTHOR]

Background. Human immunodeficiency virus-infected individuals have increased risk of myocardial infarction (MI); however, the contribution from smoking and potentiating effects of HIV are controversial. Methods. From the Danish HIV Cohort Study and the Copenhagen General Population Study, we identified 3251 HIV-infected individuals and 13 004 population controls matched on age and gender. Data on MI were obtained from the National Hospital Registry and the National Registry of Causes of Death.We calculated adjusted incidence rate ratios (aIRR) for risk of MI and population-attributable fractions (PAF) of MI associated with smoking. Results. In never smokers, HIV was not associated with an increased risk ofMI (aIRR, 1.01; 95% confidence interval [CI], .41-2.54). In previous and current smokers, HIV was associated with a substantially increased risk of MI (aIRR, 1.78; 95% CI, .75-4.24 and aIRR, 2.83; 95% CI, 1.71-4.70). The PAF associated with ever smoking (previous or current) was 72% (95% CI, 55%-82%) for HIV-infected individuals and 24% (95% CI, 3%-40%) for population controls. If all current smokers stopped smoking, 42% (95% CI, 21%-57%) and 21% (95% CI, 12%-28%) of all MIs could potentially be avoided in these 2 populations. Conclusions. Smoking is associated with a higher risk of MI in the HIV-infected population than in the general population. Approximately 3 of 4 MIs among HIV-infected individuals are associated with ever smoking compared with only 1 of 4 MIs among population controls. Smoking cessation could potentially prevent more than 40% of MIs among HIV-infected individuals, and smoking cessation should be a primary focus in modern HIV care. [ABSTRACT FROM AUTHOR]

Background: Low plasma 25-hydroxyvitamin D [p-25(OH)D] is associated with increased risk of ischaemic heart disease and with the subgroup myocardial infarction. However, whether this association is causal or due to confounding or reverse causation is presently unknown. We tested the hypothesis that genetically reduced plasma 25(OH)D is associated with increased risk of ischaemic heart disease and myocardial infarction.Methods: We used a Mendelian randomization design in the Copenhagen City Heart Study, the Copenhagen General Population Study, and the Copenhagen Ischaemic Heart Disease Study. Two 25(OH)D reducing genetic variants in the DCHR7 gene (rs7944926 and rs11234027) and two in the CYP2R1 gene (rs10741657 and rs12794714) were genotyped in 92 416 participants of Danish descent, of whom 14 455 developed ischaemic heart disease (ICD-8:410-414; ICD-10:I20-I25) and 7061 myocardial infarction (ICD-8:410: ICD-10:I21-I22) from 1977 through 2011. P-25(OH)D was measured in 36,089 participants. APOE genotype was included as a positive control for risk of ischaemic heart disease.Results: The multivariable adjusted hazard ratios for lowest vs highest quartile of 25(OH)D were 1.82 [95% confidence interval (CI): 1.42-2.32] for ischaemic heart disease. Each allele increase in a combined allele score was associated with a 1.9-nmol/l decrease in p-25(OH)D (P = 7 × 10(-55); R(2) = 0.9%). The genetic variants were, however, not associated with increased risk of ischaemic heart disease. In instrumental variable analysis, the odds ratio for ischaemic heart disease for a genetically 25-nmol/l decrease in p-25(OH)D was 0.98 (95% CI: 0.76-1.26), with a corresponding observational hazard ratio by Cox regression of 1.07 (1.01-1.13). Similarly, with myocardial infarction as the outcome, observational analyses suggested an increased risk with lower 25(OH)D, whereas genetic analyses suggested no causal effect. For APOE genotype, the odds ratio for ischaemic heart disease for a 1-mmol/l genetic increase in plasma total cholesterol concentrations was 1.23 (1.08-1.41), with a corresponding observational hazard ratio of 1.08 (1.04-1.14).Conclusion: We found no evidence to suggest that genetically reduced p-25(OH)D is associated with increased risk of ischaemic heart disease or myocardial infarction. [ABSTRACT FROM AUTHOR]

Background The aetiology of ischaemic heart disease (IHD) is complex and is influenced by a spectrum of environmental factors and susceptibility genes. Traditional statistical modelling considers such factors to act independently in an additive manner. The Patient Rule-Induction Method (PRIM) is a multi-model building strategy for evaluating risk attributable to context-dependent gene and environmental effects.Methods PRIM was applied to 9073 participants from the prospective Copenhagen City Heart Study (CCHS). Gender-specific cumulative incidences were estimated for subgroups defined by categories of age, smoking, hypertension, diabetes, body mass index, total cholesterol, high-density lipoprotein cholesterol and triglycerides and by 94 single nucleotide variants (SNVs).Cumulative incidences for subgroups were validated using an independently ascertained sample of 58 240 participants from the Copenhagen General Population Study (CGPS).Results In the CCHS the overall cumulative incidences were 0.17 in women and 0.21 in men. PRIM identified six and four mutually exclusive subgroups in women and men, respectively, with cumulative incidences of IHD ranging from 0.02 to 0.34. Cumulative incidences of IHD generated by PRIM in the CCHS were validated in four of the six subgroups of women and two of the four subgroups of men in the CGPS.Conclusions PRIM identified high-risk subgroups characterized by specific contexts of selected values of traditional risk factors and genetic variants. These subgroups were validated in an independently ascertained cohort study. Thus, a multi-model strategy may identify groups of individuals with substantially higher risk of IHD than the overall risk for the general population. [ABSTRACT FROM PUBLISHER]

This is the first study investigating the contribution of inherited variants in core genes of the chromosomal passenger complex to breast cancer susceptibility. It was found that several INCENP variants are associated with the risk of ER-negative breast cancer in the European population.The chromosomal passenger complex (CPC) plays a pivotal role in the regulation of cell division. Therefore, inherited CPC variability could influence tumor development. The present candidate gene approach investigates the relationship between single nucleotide polymorphisms (SNPs) in genes encoding key CPC components and breast cancer risk. Fifteen SNPs in four CPC genes (INCENP, AURKB, BIRC5 and CDCA8) were genotyped in 88 911 European women from 39 case-control studies of the Breast Cancer Association Consortium. Possible associations were investigated in fixed-effects meta-analyses. The synonymous SNP rs1675126 in exon 7 of INCENP was associated with overall breast cancer risk [per A allele odds ratio (OR) 0.95, 95% confidence interval (CI) 0.92–0.98, P = 0.007] and particularly with estrogen receptor (ER)-negative breast tumors (per A allele OR 0.89, 95% CI 0.83–0.95, P = 0.0005). SNPs not directly genotyped were imputed based on 1000 Genomes. The SNPs rs1047739 in the 3ʹ untranslated region and rs144045115 downstream of INCENP showed the strongest association signals for overall (per T allele OR 1.03, 95% CI 1.00–1.06, P = 0.0009) and ER-negative breast cancer risk (per A allele OR 1.06, 95% CI 1.02–1.10, P = 0.0002). Two genotyped SNPs in BIRC5 were associated with familial breast cancer risk (top SNP rs2071214: per G allele OR 1.12, 95% CI 1.04–1.21, P = 0.002). The data suggest that INCENP in the CPC pathway contributes to ER-negative breast cancer susceptibility in the European population. In spite of a modest contribution of CPC-inherited variants to the total burden of sporadic and familial breast cancer, their potential as novel targets for breast cancer treatment should be further investigated. [ABSTRACT FROM AUTHOR]