Affective disorders, weight change, and patient engagement in a rural behavioral weight loss trial

Background: Adults in rural areas have a higher prevalence of obesity and some mental health conditions. The degree to which mental health influences weight loss among rural residents remains unclear. This study evaluated changes in body weight, physical activity, diet, and program engagement outcomes in a cohort of participants with vs. without an affective disorder in a behavioral weight loss trial. Methods: A sample of 1407 adults with obesity were recruited from rural U.S. primary care practices to participate in a weight loss trial. In this secondary analysis, participants were stratified by those with vs. without an affective disorder at baseline. Mixed models were used to estimate changes in outcomes over 24 months. Results: One-third of participants (n = 468) had an affective disorder. After covariate adjustment, both groups experienced significant weight loss over 24 months, but weight loss was significantly less among those with an affective disorder at all follow-up times (all p's < 0.001; 24-month weight loss -2.7 +/- 0.4 vs. -4.8 +/- 0.3 kg). Compared to those without an affective disorder, participants with an affective disorder also had significantly less improvement in physical activity and fruit/vegetable consumption, lower attendance at weight loss sessions, and less engagement in setting weight loss goals and strategies. Conclusion: Participants with an affective disorder lost less body weight and less improvement in lifestyle measures over 24 months. These trends paralleled reduced engagement in critical intervention activities such as weight loss session attendance. Future interventions should consider additional methods to minimize disengagement in adults with underlying affective disorders.