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Background Data about the clinical benefit from initial low-density lipoprotein cholesterol (LDL-C) reduction with lipid lowering treatment for secondary prevention and risk of major vascular events amongst older as compared with younger individuals treated during routine clinical care are limited. We investigated this in a nationwide cohort. Methods Individuals aged ≥ 50 years with a first-time hospitalisation for a cardiovascular event (index event, including acute coronary syndrome, non-haemorrhagic stroke, transient ischaemic attack and coronary revascularisation), 1 January 2008 to 31 October 2018, who subsequently used lipid lowering treatment, and had an LDL-C measurement before and after the event were included. Hazard ratios (HRs) for major vascular events per 1 mmol/L reduction in LDL-C were estimated for the included 21,751 older and 22,681 younger individuals (≥/<70 years old) using Cox regression. Results LDL-C lowering was associated with a 12% lower risk of major vascular events in older individuals per 1 mmol/L reduction in LDL-C (HR 0.88, 95% confidence interval [CI] 0.84–0.93), with no significant difference compared with the risk reduction amongst younger individuals (HR 0.88, 95% CI 0.83–0.93; P -value for difference between age groups: 0.86). The risk reduction was more pronounced when post hoc restricting, as a proxy for compliance, to new users with an LDL-C reduction above the lowest decile for both older (0.81, 95% CI 0.73–0.90) and younger (0.81, 95% CI 0.72–0.91) individuals. Conclusions This study strongly supports a similar relative clinical benefit of LDL-C reduction with lipid lowering treatment for secondary prevention of major vascular events amongst individuals aged ≥70 and <70 years. [ABSTRACT FROM AUTHOR]

Background: High parity and extremes of age at first birth have been linked with increased dementia risk in women, with exposure to pregnancy-associated physiological changes proposed as an explanation. However, confounding by socioeconomic and lifestyle factors could also produce such associations, whereby men would share similar patterns of association. We investigated whether these associations hold for both sexes. Methods: In a cohort study including all women (N = 2,222,638) and men (N = 2,141,002) ≥ 40 years of age in 1994–2017 in Denmark, we used Cox regression to evaluate associations between number of children, age at first birth, and dementia risk separately for women and men. Results: During follow-up, 81,413 women and 53,568 men (median age at diagnosis, 83.3 and 80.3 years, respectively) developed dementia. Compared with having one child, having two or more children was associated with modest decreases in overall dementia risk in both sexes (hazard ratio [HR] range 0.82–0.91, Pdifference men vs. women = 0.07). Although the associations between childlessness and overall dementia risk differed statistically for men and women, the association magnitudes differed only slightly (HRmen 1.04, 95% confidence interval [CI] 1.01–1.06; HRwomen 0.99, 95% CI 0.97–1.01; P = 0.002). Associations between age at becoming a parent and overall dementia were also similar for women and men, with the exception of older (≥ 40 years) first-time parents (HRmen 1.00, 95% CI 0.96–1.05; HRwomen 0.92, 95% CI 0.86–0.98; P = 0.01). With few exceptions, sub-analyses by dementia subtype and timing of onset also revealed similar patterns and effect magnitudes for women and men. Conclusions: Associations between number of children, age at becoming a parent, and dementia risk were similar for both sexes. Lifestyle and socioeconomic factors are more likely to explain the observed associations than normal pregnancy-related physiological changes. [ABSTRACT FROM AUTHOR]

A woman's reproductive history is strongly associated with her risk of ovarian cancer. However, it is unclear how pregnancies of different duration impact a woman's ovarian cancer risk, and therefore, what part of a pregnancy explains the protective effect. Using a cohort of all Danish women followed from 1968 to 2018, with prospectively registered information on reproductive history (eg, gestational duration of pregnancies, tubal ligation and resection and hormonal pharmaceutical use), we investigated the effect of pregnancy duration on ovarian cancer risk. We adjusted for potential confounders, such as age at pregnancy and time since pregnancy, using log‐linear Poisson regression to isolate the effect of pregnancy duration on ovarian cancer risk. Among 2.5 million Danish women with 4.4 million pregnancies, a pregnancy was associated with a reduction of ovarian cancer risk of 21% (95% CI, 14%‐28%), 26% (95% CI, 21%‐31%), 12% (95% CI, 7%‐17%) and 3% (95% CI, −5% to 11%) compared to one less, for the first, second, third and fourth pregnancy, respectively (P <.001 for heterogeneity), with similar effects of induced abortions, spontaneous abortions and childbirths. Sensitivity analysis of age at pregnancy, time since pregnancy and other potential confounders did not change these findings. The reduced ovarian cancer risk associated with pregnancy is primarily driven by the first three pregnancies, with similar effects of induced abortion, spontaneous abortions and childbirth, suggesting that mainly exposure to early pregnancy factors, and not pregnancy duration, protect against ovarian cancer. [ABSTRACT FROM AUTHOR]

Risk of colorectal cancer (CRC) increases in relatives of patients with CRC. The extent to which this is attributable to genetic predisposition or shared environment is unclear. We explored this question using nationwide cohorts from Denmark, Finland and Sweden. From 1977 to 2013, we identified 359 879 individuals with a CRC diagnosis and 2 258 870 of their relatives who we followed for CRC incidence. We calculated standardized incidence ratios (SIR) and 95% confidence intervals (CI) for CRC in individuals with an affected relative. We used nationwide household and pedigree data along with national SIR estimates to calculate risk ratios (RR) for the contribution of shared household environment, childhood environment and genetic relationship to CRC risk in those with an affected relative. SIR of CRC was increased for individuals with an affected relative, across all countries and ages. For those with an affected parent, the SIR was 1.65 (95% CI: 1.61‐1.69), 1.98 (95% CI: 1.87‐2.09), for those with an affected sibling and 2.14 (95% CI: 1.84‐2.49) for those with an affected halfsibling. In those <65 years old, shared childhood (RR: 1.41, 95% CI: 1.26‐1.57) and household (RR: 2.08, 95% CI: 1.25‐3.46) environments were significantly greater contributors to familial risk of CRC than genetics (RR: 0.88, 95% CI: 0.53‐1.46). This large‐scale Nordic population‐based study of excess risk of CRC among relatives of those with CRC addresses the difficult disentangling of shared environment from genetic predisposition in the heritability of CRC. We found shared environment to be the most important contributor to CRC risk. [ABSTRACT FROM AUTHOR]

Background Prepregnancy diabetes, especially when severely dysregulated, is associated with an increased risk of congenital heart defects in offspring. This suggests that glucose plays a role in embryonic heart development. Objective The aim was to investigate the association between midpregnancy dietary glycemic index (GI), glycemic load (GL), and sugar-sweetened beverages and the risk of congenital heart defects in the offspring. Methods Offspring of mothers from the Danish National Birth Cohort who filled out a food-frequency questionnaire (FFQ) covering midpregnancy dietary intake were included. Individual-level information on GI and GL, offspring congenital heart defects, and health and lifestyle covariates was linked. The association between GI and GL and offspring congenital heart defects was estimated by logistic regression. Further, we evaluated whether maternal intake of sugar-sweetened drinks increased the risk of offspring congenital heart defects. Results In total, 66,387 offspring of women who responded to the FFQ were included; among offspring, 543 had a congenital heart defect. The adjusted OR (aOR) of congenital heart defects among offspring of mothers belonging to the highest versus the lowest GI quintile was 1.02 (95% CI: 0.78, 1.34; P -trend = 0.86). Results were similar for GL (aOR: 0.95; 95% CI: 0.72, 1.24). A high intake of sugar-sweetened carbonated beverages was associated with a statistically significant increased risk of offspring congenital heart defects (highest vs lowest intake—aOR: 2.41; 95% CI: 1.26, 4.64; P -trend = 0.03). No association was found with other types of beverages. Conclusions The study does not support an association between a high GI and GL in midpregnancy and increased offspring risk of congenital heart defects. Nevertheless, a statistically significant association between sugar-sweetened carbonated beverages and a moderately increased risk of offspring congenital heart defects was observed. [ABSTRACT FROM AUTHOR]

Background The present study aimed to investigate the long-term risk of hemorrhagic stroke (HS) in patients with infective endocarditis (IE). Methods Using a register-based nationwide cohort of 9 million Danes, we performed propensity score matching between patients with left-sided IE from 1977 to mid-2015 and IE-free individuals (1:10). Follow-up started 1 year after the IE diagnosis. Hazard ratios (HRs) for HS in patients with IE compared with the matched cohort were estimated using Cox regression. Results During follow-up of 5735 patients with left-sided IE from 1 year after IE diagnosis and up to 37.5 years (median, 6.3 years), 103 cases of HS were observed. Compared with the matched cohort, patients with IE had a higher long-term risk of HS (HR, 1.47; 95% confidence interval, 1.20–1.80; P <.001). The risk of HS was particularly increased in patients within the lowest propensity score quartile (HR, 2.60; 95% confidence interval, 1.89–3.58). Mediation analyses suggested that the increased HS risk could be explained by an indirect effect of mechanical heart valve insertion, atrial fibrillation, or treatment with anticoagulants. The cumulative risk of HS 30 years after start of follow-up was 3.0% in patients with IE. Conclusions IE does not directly increase the long-term risk of HS. The apparent excess risk of HS in patients with previous IE was explained by mediating factors, including mechanical heart valve insertion, atrial fibrillation, and anticoagulation medication. [ABSTRACT FROM AUTHOR]

Background Filaggrin gene ( FLG) mutations compromise skin barrier functions and increase risk of atopic dermatitis. We aimed to study effects on other skin diseases using unique data from the Danish registers. Methods FLG genotyping of a population-based sample of 1547 children with extracted DNA and information on skin diseases from the Danish National Birth Cohort and Health Register, with 18 years follow-up during years 1996-2013. Odds ratios (OR) and hazard ratios (HR) were estimated using logistic regression and Cox regression, respectively, and adjusted for physician-diagnosed atopic dermatitis. Results FLG mutations were associated with increased risk of dry skin (OR 1.9, CI 1.1-3.1), and a decreased risk of fungal skin infections at age <18 months (OR 0.2, CI 0.1-0.8). There was no association with wart treatments (HR 1.0, CI 0.6-1.7). FLG mutations were associated with an increased risk of atopic dermatitis (OR 3.3, CI 2.1-5.3), dermatology consultations for allergy or rash (HR 2.2, CI 1.4-3.5), basic dermatology consultations at age <5 years (HR 2.2, CI 1.7-2.9), urticaria at age <18 months (OR 2.9, CI 1.0-7.9), and other rash at age <18 months (OR 2.1, CI 1.2-3.8). Conclusions FLG mutations may predispose to skin disease in young children including urticaria, and rash not recognized as atopic dermatitis although equally frequent. In clinical practice, FLG genotyping may help indicate the use of moisturizers to reduce skin problems. [ABSTRACT FROM AUTHOR]

Background and Objectives: Existing data on pregnancy complications in inflammatory bowel disease (IBD) are inconsistent. To address these inconsistencies, we investigated potential associations between IBD, IBD-related medication use during pregnancy, and pregnancy loss, pre-eclampsia, preterm delivery, Apgar score, and congenital abnormalities. Methods: We conducted a cohort study in >85,000 Danish National Birth Cohort women who were pregnant in the period 1996-2002 and had information on IBD, IBD-related medication use (systemic or local corticosteroids, 5-aminosalicylates), pregnancy outcomes and potential confounders. We evaluated associations between IBD and adverse pregnancy/birth outcomes using Cox regression and log-linear binomial regression. Results: IBD was strongly and significantly associated with severe pre-eclampsia, preterm premature rupture of membranes and medically indicated preterm delivery in women using systemic corticosteroids during pregnancy (hazard ratios [HRs] >7). IBD was also associated with premature preterm rupture of membranes in women using local corticosteroid medications (HR 3.30, 95% confidence interval [CI] 1.33-8.20) and with medically indicated preterm delivery (HR 1.91, 95% CI 0.99-3.68) in non-medicated women. Furthermore, IBD was associated with low 5-minute Apgar score in term infants (risk ratio [RR] 2.19, 95% CI 1.03-4.66). Finally, Crohn’s disease (but not ulcerative colitis) was associated with major congenital abnormalities in the offspring (RR 1.85, 95% CI 1.06-3.21). No child with a congenital abnormality born to a woman with IBD was exposed to systemic corticosteroids in utero. Conclusion: Women with IBD are at increased risk of severe pre-eclampsia, medically indicated preterm delivery, preterm premature rupture of membranes, and delivering infants with low Apgar score and major congenital malformations. These associations are only partly explained by severe disease as reflected by systemic corticosteroid use. [ABSTRACT FROM AUTHOR]

OBJECTIVES:Estimates of familial risk of inflammatory bowel diseases (IBDs), Crohn's disease (CD), and ulcerative colitis (UC) are needed for counseling of patients and could be used to target future prevention. We aimed to provide comprehensive population-based estimates of familial risk of IBD.METHODS:The study encompassed the entire Danish population during 1977-2011 (N=8,295,773; 200 million person-years). From national registries, we obtained information on diagnosis date of IBD (N=45,780) and family ties. Using Poisson regression, we estimated incidence rate ratios (IRRs) of IBD in relatives of IBD cases compared with individuals with relatives of the same type without IBD.RESULTS:The risk of CD was significantly increased in first-degree (IRR, 7.77; 95% confidence interval (CI), 7.05-8.56), second-degree (IRR, 2.44; 95% CI, 2.01-2.96), and third-degree relatives (IRR, 1.88; 95% CI, 1.30-2.71) to patients with CD, and was less pronounced in relatives to UC cases. Likewise, the risk of UC was increased in first-degree (IRR, 4.08; 95% CI, 3.81-4.38), second-degree (IRR, 1.85; 95% CI, 1.60-2.13), and third-degree relatives (IRR, 1.51; 95% CI, 1.07-2.12) of UC cases, and less pronounced in relatives of CD cases. IRRs increased with two or more IBD-affected relatives and were modified by age, with the highest family-related IRR observed in early life.CONCLUSIONS:The risk of IBD is significantly increased in first -, second-, and third-degree relatives of IBD-affected cases, with up to 12% of all IBD cases being family cases. The risk is particularly pronounced in young individuals. [ABSTRACT FROM AUTHOR]

Greenland remains a highly endemic area for hepatitis B virus (HBV) infection. This is in sharp contrast to other modern societies, such as Denmark. To address this discrepancy, we investigated the natural history of HBV infection in Greenland by estimating the age-specific incidence of HBV infection, the proportion of chronic carriers, and the rates of hepatitis B surface antigen seroclearance. In total, 8,879 Greenlanders (16% of the population) from population-based surveys conducted in 1987 and 1998 were followed through March 2010. Data on HBV status were supplemented by HBV test results from all available HBV registries in Greenland to determine changes in HBV status over time. Incidence rates of HBV infection and hepatitis B surface antigen seroclearance were estimated after taking into account interval censoring. The incidence of HBV infection in 5–14-year-old subjects was less than 1 per 100 person-years and peaked at 5 per 100 person-years in persons 15–24 years of age. Overall, 17.5% of persons infected in adulthood were estimated to become chronic carriers. HBV is primarily transmitted in adolescence and adulthood in Greenland. In contrast to what is observed in most other populations, HBV-infected adults in Greenland have a high risk of progressing to chronic HBV carriage. This phenomenon might explain how the high rate of infection is maintained in Greenland. [ABSTRACT FROM PUBLISHER]

Background: Although, divorce is considered to have a negative impact on morbidity, very little is known concerning exposure to divorce and risk of infectious diseases. We aimed to investigate the association between divorce and subsequent hospital contacts with infectious diseases. Methods: We performed a nation-wide cohort study, including all Danish men and women (n≈5.6 million) alive on the 1 January 1982 or later, and followed them for infectious disease diagnosed in hospital settings from 1982 to 2010. The association between divorce and risk of infectious diseases was evaluated through rate ratios (RRs) comparing incidence rates of infectious diseases between divorced and married pesons. Results: Compared with married persons, divorced persons were overall at a 1.48 fold (RR=1.48 (95% CI: 1.47–1.50)) increased risk of hospital-diagnosed infectious diseases (RR adjusted for sex, age, period, income and education). The risk of infectious diseases was slightly more pronounced for divorced women (RR=1.54 (1.52–1.56)) than divorced men ((RR=1.42 (1.41–1.44)). The increased risk remained almost unchanged even more than 15 years after the divorce. Young age at divorce, short duration of marriage and number of divorces further increased the risk of infectious diseases, whereas number of children at time of divorce had no impact on risk of hospital-diagnosed infectious diseases following the divorce. Conclusions: Divorce appears to have a moderate but long lasting impact on the risk of infectious diseases. The underlying mechanism is unknown but shared risk factors predicting divorce and infectious diseases could contribute to our findings. [ABSTRACT FROM PUBLISHER]

Background: Present understanding of increased risk of Epstein-Barr virus (EBV)-related infectious mononucleosis among children of low birth order or small sibships is mainly based on old and indirect evidence. Societal changes and methodological limitations of previous studies call for new data.Methods: We used data from the Danish Civil Registration System and the Danish National Hospital Discharge Register to study incidence rates of inpatient hospitalizations for infectious mononucleosis before the age of 20 years in a cohort of 2 543 225 Danes born between 1971 and 2008, taking individual sibship structure into account.Results: A total of 12 872 cases of infectious mononucleosis were observed during 35.3 million person-years of follow-up. Statistical modelling showed that increasing sibship size was associated with a reduced risk of infectious mononucleosis and that younger siblings conferred more protection from infectious mononucleosis than older siblings. In addition to this general association with younger and older siblings, children aged less than 4 years transiently increased their siblings’ infectious mononucleosis risk. Our results were confirmed in an independent sample of blood donors followed up retrospectively for self-reported infectious mononucleosis.Conclusions: Younger siblings, and to a lesser degree older siblings, seem to be important in the transmission of EBV within families. Apparently the dogma of low birth order in a sibship as being at the highest risk of infectious mononucleosis is no longer valid. [ABSTRACT FROM AUTHOR]

Background: A possible aetiological link between obesity and certain autoimmune diseases (ADs) has been suggested. We investigated the associations between body mass index (BMI, kg/m2) and 43 ADs.Methods: 75 008 women participating in the Danish National Birth Cohort were followed during a median time of 11 years. Diagnoses on ADs were retrieved from the Danish National Patient Register. Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated adjusting for potential confounders (smoking, alcohol, parity and socio-occupational status).Results: During follow-up, 2430 women (3.2%) developed a total of 2607 new-onset ADs. Risk of any autoimmune disease was increased in obese women (HR, 1.27; 95% CI, 1.11 to 1.46) compared with normal weight women (18.5–≤25 kg/m2). Obese women (BMI ≥30 kg/m2) were at increased risk of sarcoidosis (HR 3.59; 95% CI, 2.31 to 5.57) and type 1 diabetes mellitus (HR 2.67; 95% CI, 1.71 to 4.17). Risk of dermatitis herpetiformis increased by 14% (95% CI, 1% to 30%) per BMI unit. Conversely, risk of celiac disease and Raynaud’s phenomenon decreased by 7% (95% CI, 1% to 13%) and 12% (95% CI, 4% to 19%) per BMI unit, respectively. Further associations between BMI and risk of psoriasis, rheumatoid arthritis and Crohn’s disease were suggested.Conclusions: BMI was found to be associated with several Ads. This was most pronounced between obesity and risk of sarcoidosis and and risk of type 1 diabetes mellitus. These novel findings need confirmation and the possible role of adipose tissue-derived immunological changes in the development of autoimmune reactions needs consideration. [ABSTRACT FROM PUBLISHER]

Pyloric stenosis occurs with a nearly 5-fold male predominance. To what extent this is due to environmental factors is unknown. In a cohort of all children born in Denmark, 1977–2008, the authors examined the association between pre- and perinatal exposures and pyloric stenosis and investigated whether these factors modified the male predominance. Information on pre- and perinatal factors and pyloric stenosis was obtained from national registers. Poisson regression models were used to estimate rate ratios. Among 1,925,313 children, 3,174 had surgery for pyloric stenosis. The authors found pyloric stenosis to be significantly associated with male sex, age between 2 and 7 weeks, early study period, being first born, maternal smoking during pregnancy, preterm delivery, small weight for gestational age, cesarean section, and congenital malformations. Among cases, 2,595 were males and 579 were females. Lower male predominance was associated with age at diagnosis outside the peak ages, early study period, no maternal smoking during pregnancy, preterm delivery, and congenital malformations. The authors have previously found a strong familial aggregation of pyloric stenosis indicating a genetic influence. This study shows that environmental factors during and shortly after pregnancy also play a role and that several of these modify the strong male predominance. [ABSTRACT FROM PUBLISHER]

Background & Aims: Parasitic helminth infections can suppress symptoms of allergy, type 1 diabetes, arthritis, and inflammatory bowel disease in animal models. We analyzed data from a large, population-based cohort study to determine whether common childhood enterobiasis protects against these diseases. Methods: We collected information on individual prescriptions filled for the drug Mebendazole against Enterobius vermicularis for all children born in Denmark 1995–2008 from the National Register of Medicinal Product Statistics (n = 924,749; age 0–14 years); 132,383 of these children (14%) filled a prescription for Mebendazole, 102,482 of the children (11%) had a household peer who was registered with a filled Mebendazole prescription, and the remaining 689,884 children (75%) comprised the reference group. Children diagnosed with asthma, type 1 diabetes, juvenile arthritis, ulcerative colitis, or Crohn''s disease were identified from the National Patient Registry. We used Poisson regression to estimate confounder-adjusted incidence rate ratios for first in- or outpatient hospital diagnosis of chronic inflammatory disease according to history of Mebendazole treatment prescribed to children in the study. Results: Chronic inflammatory disease was diagnosed in 10,352 children during 6.4 million person-years of follow-up. The incidence rate ratios was 1.07 for asthma (95% confidence interval [CI]: 1.00–1.13), 1.05 for type 1 diabetes (95% CI: 0.79–1.12), 1.13 for juvenile arthritis (95% CI: 0.94–1.37), 0.77 for ulcerative colitis (95% CI: 0.41–1.46), and 1.44 for Crohn''s disease (95% CI: 0.82–2.53). Results were not modified by number of treatments or age at treatment. Conclusions: Based on a population-based analysis, enterobiasis does not reduce risk for asthma, type 1 diabetes, arthritis, or inflammatory bowel disease. [Copyright &y& Elsevier]

In a prospective, population-based cohort study, the authors investigated the effect of in-utero exposure to maternal smoking and consumption of alcohol, coffee, and tea on the risk of strabismus. They reviewed medical records for children in the Danish National Birth Cohort identified through national registers as possibly having strabismus. Relative risk estimates were adjusted for year of birth, social class, maternal smoking, maternal age at birth, and maternal coffee and tea consumption. The authors identified 1,321 cases of strabismus in a cohort of 96,842 Danish children born between 1996 and 2003. Maternal smoking was associated with a significantly elevated risk of strabismus in the child, increasing with number of cigarettes smoked per day (<5 cigarettes/day: relative risk (RR) = 0.95, 95% confidence interval (CI): 0.80, 1.14; 5–<10 cigarettes/day: RR = 1.38, 95% CI: 1.12, 1.70; ≥10 cigarettes/day: RR = 1.90, 95% CI: 1.57, 2.30). Nicotine replacement therapy was not associated with strabismus risk (RR = 1.22, 95% CI: 0.92, 1.61). Light maternal alcohol consumption was inversely associated with strabismus risk, whereas maternal coffee and tea drinking were not associated with strabismus risk. In conclusion, smoking during pregnancy is associated with an increased risk of strabismus in the offspring. Conversely, light alcohol consumption is associated with decreased risk. [ABSTRACT FROM PUBLISHER]

In a study of 2,978 Danish children aged 5 years from two suburban counties of Copenhagen, carried out in 1998, the authors compared risk factor profiles for wheeze and recurrent cough without wheeze by using polytomous logistic regression to clarify whether the two conditions are likely to have the same etiology. Data were obtained 1) by a mailed parental questionnaire (International Study of Asthma and Allergies in Childhood questions and supplementary questions on cough, sociodemography, perinatal factors, and environmental exposure); 2) through general practitioners (familial allergic disease); and 3) from the National Medical Birth Register (birth weight). Wheeze (WH) was defined as more than one episode of wheeze within the last 12 months (irrespective of cough status) and recurrent cough without WH (RC) as cough occurring outside colds and usually lasting for periods of more than 1 week in children with no more than one attack of wheeze within the last 12 months. Risk factors for comparison were selected as those that, after repeated stepwise logistic regression, remained significant for children with WH or RC. Significant differences were found for gender (p = 0.003), gestational age (p = 0.0002), maternal history of asthma (p = 0.0008), and standard of housing condition (p = 0.04)—all risk factors for WH but not RC. Results may suggest that the two conditions have different etiologies. [ABSTRACT FROM AUTHOR]

Studying associations between sibship characteristics and allergic diseases in detail may contribute clues to their etiology. The authors studied associations between sibship characteristics and risk of self-reported allergic rhinitis and asthma among 31,145 pregnant women participating in a nationwide study in Denmark during 1997–2000. Increasing sibship size was associated with a decreased risk of allergic rhinitis and asthma with allergic rhinitis but not with asthma without allergic rhinitis. The protective effect of having older siblings was stronger than the protective effect of having younger siblings for both allergic rhinitis and asthma with allergic rhinitis. There was no association between interval to closest older or younger sibling and risk of allergic rhinitis or asthma with allergic rhinitis, while the risk of asthma without allergic rhinitis increased with intervals of 2 or more years compared with less than 2 years to the nearest older sibling. The protective effect of having siblings on the risk of asthma with allergic rhinitis could be explained by a protective effect of siblings on the risk of allergic rhinitis alone. In conclusion, our findings suggest that different etiologic mechanisms are involved for allergic rhinitis and asthma with respect to the effect of sibship characteristics. Furthermore, the findings that allergic rhinitis was associated with the number of younger siblings but not with the age interval to younger siblings support the hypothesis of an influence of postnatal mechanisms and suggest that these mechanisms may not necessarily be operating only in early life. [ABSTRACT FROM AUTHOR]

To examine the importance of intensity of exposure for the outcome of the poliomyelitis infection 429 polio cases were identified belonging to families with 2, 3 or 4 polio cases, all hospitalized in Copenhagen from 1919 to 1953. Furthermore, 87 pairs of polio cases living on the same stairway, but not in the same household, were identified. Severity among multiple cases in families analysed according to time of appearance showed a U-shaped curve. Initial cases had a higher risk of developing paralysis [relative risk (RR) = 1.5, 95% confidence interval (CI) 1.2–1.9] and of dying (RR =2.5, 95% CI 0.9–6.9). Decreased severity was observed among subsequent cases appearing within 11 d after the initial case (RR =1.0); however, severity increased again, with higher mortality for cases likely to have been infected by the initial case (cases appearing more than 11 d later) (RR = 5.7, 95% CI 1.8–17.8). The pattern described among multiple family cases was not found among cases from the same stairway. Since family cases appearing within 11 d were probably infected simultaneously, a short incubation period is associated with severe disease and a prolonged incubation period with milder infections. Furthermore, intensive exposure from being infected in the household increased severity. These observations therefore suggest that intensity of exposure and dose of infection are important factors in the severity of poliomyelitis. [ABSTRACT FROM AUTHOR]

The article discusses a nationwide cohort study in Denmark on the link between the use of macrolides in mother and child, and the risk of infantile hypertrophic pyloric stenosis (IHPS). The study assessed the link between macrolide use and IHPS for the categories of maternal use during pregnancy, maternal use after birth and use in infants after birth. It also informs that macrolide use in infants during the first two weeks after birth has been associated with an increased risk of IHPS.

Background: Maternal diabetes mellitus is associated with an increased risk of offspring congenital heart defects (CHD); however, the causal mechanism is poorly understood. We further investigated this association in a Danish nationwide cohort.Methods and Results: In a national cohort study, we identified 2 025 727 persons born from 1978 to 2011; among them were 7296 (0.36%) persons exposed to maternal pregestational diabetes mellitus. Pregestational diabetes mellitus was identified by using the National Patient Register and individual-level information on all prescriptions filled in Danish pharmacies. Persons with CHD (n=16 325) were assigned to embryologically related cardiac phenotypes. The CHD prevalence in the offspring of mothers with pregestational diabetes mellitus was 318 per 10 000 live births (n=232) in comparison with a baseline risk of 80 per 10 000; the adjusted relative risk for CHD was 4.00 (95% confidence interval, 3.51-4.53). The association was not modified by year of birth, maternal age at diabetes onset, or diabetes duration, and CHD risks associated with type 1 (insulin-dependent) and type 2 (insulin-independent) diabetes mellitus did not differ significantly. Persons born to women with previous acute diabetes complications had a higher CHD risk than those exposed to maternal diabetes mellitus without complications (relative risk, 7.62; 95% confidence interval, 5.23-10.6, and relative risk, 3.49; 95% confidence interval, 2.91-4.13, respectively; P=0.0004). All specific CHD phenotypes were associated with maternal pregestational diabetes mellitus (relative risk range, 2.74-13.8).Conclusions: The profoundly increased CHD risk conferred by maternal pregestational diabetes mellitus neither changed over time nor differed by diabetes subtype. The association with acute pregestational diabetes complications was particularly strong, suggesting a role for glucose in the causal pathway. [ABSTRACT FROM AUTHOR]

Objective To examine the risk factors for Mycobacterium tuberculosis infection (MTI) among Greenlandic children for the purpose of identifying those at highest risk of infection. Methods Between 2005 and 2007, 1797 Greenlandic schoolchildren in five different areas were tested for MTI with an interferon gamma release assay (IGRA) and a tuberculin skin test (TST). Parents or guardians were surveyed using a standardized self-administered questionnaire to obtain data on crowding in the household, parents' educational level and the child's health status. Demographic data for each child - i.e. parents' place of birth, number of siblings, distance between siblings (next younger and next older), birth order and mother's age when the child was born - were also extracted from a public registry. Logistic regression was used to check for associations between these variables and MTI, and all results were expressed as odds ratios (ORs) and 95% confidence intervals (CIs). Children were considered to have MTI if they tested positive on both the IGRA assay and the TST. Findings The overall prevalence of MTI was 8.5% (152/1797). MTI was diagnosed in 26.7% of the children with a known TB contact, as opposed to 6.4% of the children without such contact. Overall, the MTI rate was higher among Inuit children (OR: 4.22; 95% CI: 1.55--11.5) and among children born less than one year after the birth of the next older sibling (OR: 2.48; 95% CI: 1.33--4.63). Self-reported TB contact modified the profile to include household crowding and low mother's education. Children who had an older MTI-positive sibling were much more likely to test positive for MTI themselves (OR: 14.2; 95% CI: 5.75--35.0) than children without an infected older sibling. Conclusion Ethnicity, sibling relations, number of household residents and maternal level of education are factors associated with the risk of TB infection among children in Greenland. The strong household clustering of MTI suggests that family sources of exposure are important. [ABSTRACT FROM AUTHOR]