Predictors of physical activity at 1 year in a randomized controlled trial of family members of patients with cardiovascular disease

Abstract

Background and objective: Recommendations for physical activity to lower risk of cardiovascular disease (CVD) are widely known but not often followed. The purpose of this study was to determine the demographic, lifestyle, and psychosocial variables that predict improved physical activity among participants in a CVD prevention lifestyle intervention trial.

Subjects and methods: Adult family members (N = 501; 66% female; 36% nonwhite; mean age, 48 years) of cardiac patients were randomized to a 1-year special intervention that received education on physical activity or to a control intervention. Demographics, physical activity, stage of change, and CVD risk factors were measured systematically at baseline and 1 year (94% follow-up). Lipids were analyzed in a core laboratory. Linear regression models were adjusted for confounders.

Results: At baseline, 21% of participants reported exercising more than 3 d/wk, which did not differ by group assignment. The special intervention and control intervention experienced significant increases in physical activity at 1 year with mean physical activity days per week in the special intervention significantly greater than the control intervention (2.5 vs 2.0 d/wk, P = .03). Significant predictors of increased physical activity at 1 year were group assignment (P = .03), female sex (P = .04), nonminority status (P <.01), greater readiness to change (P <.01), and baseline measurements of lower body mass index (P <.01) and waist size (P <.01), greater diet adherence (P <.01), higher high-density lipoprotein cholesterol (P <.01), lower high-sensitivity C-reactive protein (P = .02), less depression (P <.01), and higher social support (P = .03). In multiple regression models, group assignment, female, and nonminority status remained independent predictors of higher physical activity levels at 1 year.

Conclusion: Several predictors of improved physical activity levels at 1 year were documented among clinical trial participants. Racial/ethnic minorities and men were significantly less likely to make positive changes and may need more targeted efforts to improve physical activity levels.