BMI, weight stability and mortality among adults without clinical co-morbidities: a 22-year mortality follow-up in the Finnish twin cohort.

AIM AND METHOD

Cause-specific mortality was studied in relation to body mass index (BMI) and weight stability (defined as less than 1 BMI unit change during a 6-year period) in 15,424 initially healthy twin subjects from the Finnish Twin Cohort, first examined in 1975, re-examined in 1981, and then followed over 22 years (1982-2003). Additionally, death discordant twin pairs were studied to assess whether body weight differences are associated with mortality independent of childhood factors and genetic background. Deaths and cause of death were ascertained from national registries. Associations with mortality were estimated by Cox proportional hazards model for all individuals and conditional logistic regression analysis for pairwise analyses.

RESULTS

Mortality increased with increasing BMI for all causes and coronary heart disease (CHD) in men, and there were no associations for all natural causes, cerebrovascular disease, and violent deaths. After adjustment for multiple co-variates and changes in co-variates between 1975 and 1981, BMI was associated with CHD mortality in all men (hazard ratio (HR) = 1.22, 95% CI 1.06-1.41) and in men with stable weight between 1975 and 1981 (HR = 1.26, 95% CI 1.03-1.55). Overall risk of death and cause-specific mortality was not associated with BMI in women.

CONCLUSION

Among clinically healthy subjects at low risk of death, BMI appears to be associated with CHD risk in men.