Effect of a nutrition supplement and physical activity program on pneumonia and walking capacity in Chilean older people: a factorial cluster randomized trial

Background

Ageing is associated with increased risk of poor health and functionaldecline. Uncertainties about the health-related benefits of nutrition andphysical activity for older people have precluded their widespreadimplementation. We investigated the effectiveness and cost-effectiveness ofa national nutritional supplementation program and/or a physical activityintervention among older people in Chile.

Methods and Findings

We conducted a cluster randomized factorial trial among low to middlesocioeconomic status adults aged 65–67.9 years living in Santiago,Chile. We randomized 28 clusters (health centers) into the study andrecruited 2,799 individuals in 2005 (∼100 per cluster). Theinterventions were a daily micronutrient-rich nutritional supplement, or two1-hour physical activity classes per week, or both interventions, orneither, for 24 months. The primary outcomes, assessed blind to allocation,were incidence of pneumonia over 24 months, and physical function assessedby walking capacity 24 months after enrolment. Adherence was good for thenutritional supplement (∼75%), and moderate for the physicalactivity intervention (∼43%). Over 24 months the incidence rateof pneumonia did not differ between intervention and control clusters (32.5versus 32.6 per 1,000 person years respectively; riskratio = 1.00; 95% confidence interval0.61–1.63; p = 0.99). Inintention-to-treat analysis, after 24 months there was a significantdifference in walking capacity between the intervention and control clusters(mean difference 33.8 meters; 95% confidence interval13.9–53.8; p = 0.001). Theoverall cost of the physical activity intervention over 24 months wasUS$164/participant; equivalent to US$4.84/extra meter walked.The number of falls and fractures was balanced across physical activityintervention arms and no serious adverse events were reported for eitherintervention.

Conclusions

Chile''s nutritional supplementation program for older people is noteffective in reducing the incidence of pneumonia. This trial suggests thatthe provision of locally accessible physical activity classes in atransition economy population can be a cost-effective means of enhancingphysical function in later life.

Trial registration

Current Controlled Trials ISRCTN 48153354Please see later in the article for the Editors'' Summary