Population Reach and Recruitment Bias in a Maintenance RCT in Physically Active Older Adults

Abstract

Objective-To assess the representativeness of older adults recruited to a physical activity maintenance RCT by conducting sequential comparisons to characterize study sample composition changes occurring between sampling frame construction and study enrollment.Method-Study subjects (N=1,049) were 50-70 year old men and women who had increased physical activity within the past year recruited from a Midwestern managed care organization.Results-Those responding to an initial mailed screener differed on demographic, behavioral, and SES characteristics from those not responding. Compared to ineligibles, eligible individuals were significantly younger, more highly educated, and more likely to report improved health in the prior year. Compared to eligible individuals who did not enroll, enrollees had generally higher education and income.Conclusions-Physical activity promotion programs in older adults may have limited reach and substantial volunteer bias. Additional strategies to increase the reach of physical activity interventions into the target population are needed.

Socioeconomic differences in the benefits of structured physical activity compared with health education on the prevention of major mobility disability in older adults: the LIFE study

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Neighborhood walkability, physical activity, and walking for transportation: A cross-sectional study of older adults living on low income

“…Our recruitment rate was only 8%. This relatively low response rate likely reflects our focus upon a low SES population, a group that tends to not participate in research [55]. Self-selection bias may exist if active, healthy participants were more likely to participate.…”

The Long and Winding Road to Physical Activity Maintenance

“…23 Keep Active Minnesota (KAM) tested a PA maintenance intervention among active 50- to 70-year-old adults whose baseline level of activity represented an increase within the previous year. 11,37–38 Participants randomized into the KAM intervention were offered an interactive telephone and mail-based PA support program. In addition to assessing PA level at 6, 12, and 24 months after randomization, we assessed multiple theoretically grounded mediators of PA maintenance at each time point.…”