The Risks of Cardiovascular Disease, Death and Diabetes in Twin Pairs with Discrepant Aerobic Fitness : A Nationwide Cohort Study

• Background: In observational studies, low physical fitness has been a strong risk factor for cardiovascular disease (CVD), diabetes and mortality. As physical fitness is under strong genetic control, genetic confounding may have influenced these associations.Methods: The study population comprised 5,710 male twin pairs that took part in mandatory Swedish conscription during the years 1972–1996. All pairs (mean age, 18.2 years) were discordant for physical fitness. The primary endpoint of CVD (stroke or myocardial infarction), or mortality and the secondary endpoint of diabetes during follow up was compared between more-fit and less-fit twin pairs using a co-twin stratified conditional logistic regression models.Results: During a mean follow-up period of 30 years, 74 cases of CVD and 150 deaths occurred among less-fit twins, and 76 cases of CVD and 152 deaths occurred among more-fit twins. Accordingly, the more-fit twins did not have a lower risk CVD or death (multi-adjusted odds ratio [OR] 1.11, 95% confidence interval [CI] 0.88–1.40). These results remained similar when the risks of CVD and death were compared in twin pairs with at least 50 Watt difference in physical fitness (OR, 1.09; 95% CI, 0.56–2.12). In contrast, during follow up the risk of diabetes was significantly lower in more-fit twins compared to in less-fit twins (OR 0.74, 95% CI 0.55–0.98). The effect with respect to diabetes was significantly different than the risk associated with the main outcome (P = 0.032 by testing heterogeneity). Conclusions: In twin pairs discordant for physical fitness, higher fitness was not associated with a decreased risk of CVD or death, but it was associated with the onset of diabetes. These results suggest that lifestyle-obtained fitness may not be effective in reducing the risk CVD and death. 

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Public Health, Global Health, Social Medicine and Epidemiology (hsv//eng)

Publication and Content Type

vet (subject category)

ovr (subject category)