Mortality and disability: the effect of overweight and obesity.

CONTEXT

Prevalence of obesity is increasing globally. The effect of obesity on mortality and morbidity and its implication on the future prevalence of disability in the older population has not been conclusively analyzed.

OBJECTIVE

To determine the influence of overweight and obesity on mortality and disability by quantifying the effect in terms of disability-free life expectancy and years lost to disability (YLD) in the older people.

DESIGN, SETTING AND PARTICIPANTS: For 5980 participants from the Rotterdam Study cohort, regression techniques were used to estimate the association of body mass index (BMI) and waist circumference (WC) separately with mortality, incident disability and recovery from disability. Disability was assessed using the Stanford Health Assessment Questionnaire Disability Index, an activity of daily living scale. Multistate life table methodology was used to calculate life expectancies.

MAIN OUTCOME MEASURES

In total, 15-year mortality risk, 6-year disability incidence, total life expectancy, healthy life expectancy and years of disabled life expectancy.

RESULTS

We observed 2388 deaths. Our analysis revealed no association between body mass index, or WC and mortality in the healthy population. Body mass index and WC were related to disability ('overweight' 25 < or =BMI <30, odd ratio (OR)=1.33, 95% confidence interval (CI) (1.10; 1.61), 'obesity I' 30< or = BMI <35, OR=2.03, 95% CI (1.55; 2.65)) and negatively to recovery from disability. We observed an increase of years lost to disability with increasing weight for men ('normal weight'-4.69 years, 'overweight'-5.87 years and 'obesity I'-7.06 years) and for women ('normal weight'-10.95 years, 'overweight'-12.82 years, 'obesity I'-15.17 years and 'obesity II/III'-13.13 years).

CONCLUSION

Results do not support the hypothesis that an increased body weight reduces total life expectancy in the older people. Although increased body weight was associated with a higher risk of becoming and remaining disabled. These results remained using WC.