Search

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: 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 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]