RESUMO
BACKGROUND: Physical inactivity is a significant risk factor for cardiovascular disease and remains highly prevalent in middle-aged women. OBJECTIVE: We hypothesized that an interventionist-led (IL), primary-care-based physical activity (PA) and weight loss intervention would increase PA levels and decrease weight to a greater degree than a self-guided (SG) program. DESIGN: We conducted a randomized trial. PARTICIPANTS: Ninety-nine inactive women aged 45-65 years and with BMI ≥ 25 kg/m(2) were recruited from three primary care clinics. INTERVENTIONS: The interventionist-led (IL) group (n = 49) had 12 weekly sessions of 30 min discussions with 30 min of moderate-intensity PA. The self-guided (SG) group (n = 50) received a manual for independent use. MAIN MEASURES: Assessments were conducted at 0, 3, and 12 months; PA and weight were primary outcomes. Weight was measured with a standardized protocol. Leisure PA levels were assessed using the Modifiable Activity Questionnaire. Differences in changes by group were analyzed with a t-test or Wilcoxon rank-sum test. Mixed models were used to analyze differences in changes of outcomes by group, using an intention-to-treat principle. KEY RESULTS: Data from 98 women were available for analysis. At baseline, mean (SD) age was 53.9 (5.4) years and 37 % were black. Mean weight was 92.3 (17.7) kg and mean BMI was 34.7 (5.9) kg/m(2). Median PA level was 2.8 metabolic equivalent hours per week (MET-hour/week) (IQR 0.0, 12.0). At 3 months, IL women had a significantly greater increase in PA levels (7.5 vs. 1.9 MET-hour/week; p = 0.02) than SG women; there was no significant difference in weight change. At 12 months, the difference between groups was no longer significant (4.7 vs. 0.7 MET-hour/week; p = 0.38). Mixed model analysis showed a significant (p = 0.048) difference in PA change between groups at 3 months only. CONCLUSIONS: The IL intervention was successful in increasing the physical activity levels of obese, inactive middle-aged women in the short-term. No significant changes in weight were observed.