Physical activity and all-cause mortality among older Brazilian adults: 11-year follow-up of the Bambuí Health and Aging Study.

OBJECTIVE

To investigate the association between physical activity (eg, energy expenditure) and survival over 11 years of follow-up in a large representative community sample of older Brazilian adults with a low level of education. Furthermore, we assessed sex as a potential effect modifier of this association.

MATERIALS AND METHODS

A population-based prospective cohort study was conducted on all the ≥60-year-old residents in Bambuí city (Brazil). A total of 1,606 subjects (92.2% of the population) enrolled, and 1,378 (85.8%) were included in this study. Type, frequency, and duration of physical activity were assessed in the baseline survey questionnaire, and the metabolic equivalent task tertiles were estimated. The follow-up time was 11 years (1997-2007), and the end point was mortality. Deaths were reported by next of kin during the annual follow-up interview and ascertained through the Brazilian System of Information on Mortality, Brazilian Ministry of Health. Hazard ratios (95% confidence intervals [CIs]) were estimated by Cox proportional-hazard models, and potential confounders were considered.

RESULTS

A statistically significant interaction (P<0.03) was found between sex and energy expenditure. Among older men, increases in levels of physical activity were associated with reduced mortality risk. The hazard ratios were 0.59 (95% CI 0.43-0.81) and 0.47 (95% CI 0.34-0.66) for the second and third tertiles, respectively. Among older women, there was no significant association between physical activity and mortality.

CONCLUSION

It was possible to observe the effect of physical activity in reducing mortality risk, and there was a significant interaction between sex and energy expenditure, which should be considered in the analysis of this association in different populations.