Combined healthy lifestyle behaviours and incident disability in an elderly population: the Ohsaki Cohort 2006 Study.

BACKGROUND

The joint impact of healthy lifestyle behaviours (HLBs) on incident disability among elderly populations is still uncertain. This cohort study was conducted to estimate the population-attributable fraction (PAF) of combined HLBs for disability reduction in elderly Japanese.

METHODS

We analysed 10-year follow-up data for 9910 community-dwelling elderly people (≥65 years) in a prospective cohort study. Information on lifestyle behaviours and food consumption was collected via a questionnaire in 2006. The exposure variable was defined as a healthy lifestyle index (HLI), which represented the summed number of HLBs ('never or former smoker', 'time spent walking ≥0.5 hour/day' and 'vegetable and fruit consumption volume ≥median'). Data on incident disability were retrieved from the public Long term Care Insurance database. HRs and 95% CIs were estimated by Cox proportional regression and the PAFs and their 95% CIs were estimated with the multivariate-adjusted model.

RESULTS

The 10-year incidence of disability was 35.7%. An inverse dose-response relationship was observed (HR (95% CI): 0.85(0.81 to 0.90) for each one-point increase of the HLI score, p-trend <0.001). Based on multivariate-adjustment, adherence to each one additional HLB gives PAF of 10.5%(95% CI 9.0% to 12.0%) for disability reduction. The PAF would have been 25.9%(14.2% to 36.0%) if all subjects had adhered to all three HLBs.

CONCLUSION

Combined HLBs may have a substantial impact on reducing the risk of incident disability among elderly people. Even having one more healthy lifestyle habit may bring considerable benefit.