Participation in a US community-based cardiovascular health study: investigating nonrandom selection effects related to employment, perceived stress, work-related stress, and family caregiving.

Purpose: Participation in health studies may be inversely associated with employment and stress. We investigated whether employment, perceived stress, work-related stress, and family caregiving were related to participation in a longitudinal US community-based health study of black and white men and women aged ≥45 years.

Methods: Prevalence ratios and confidence intervals were estimated for completion of the second stage (S2) of a two-stage enrollment process by employment (status, type), and stress (perceived stress, work-related stress, caregiving), adjusting for age, sex, race, region, income, and education. Eligibility and consent for a follow-up occupational survey were similarly evaluated.

Results: Wage- but not self-employed participants were less likely than the unemployed to complete S2. Among the employed, S2 completion did not vary by stress; however, family caregivers with a short time burden of care (<2 hour/d) were more likely to complete S2, compared to noncaregivers. Eligibility and participation in the follow-up occupational survey were higher among those employed (vs. unemployed) at enrollment but were not associated with enrollment stress levels.

Conclusions: Limited evidence of selection bias was seen by employment and stress within a large US community-based cohort, but findings suggest the need for enrollment procedures to consider possible barriers to participation among wage-employed individuals.