Weight change and mental health status in a behavioral weight loss trial

Obesity, depression, and anxiety often co-occur, but research on weight change and mental health status is limited. This analysis examined how the mental component score (MCS-12) from the Short Form health survey changed over 24 months in weight loss trial participants with vs. without treatment seeking for affective symptoms (TxASx) and by weight change quintiles.

Participants with complete data (n = 1163) were analyzed from enrollees in a cluster-randomized, behavioral weight loss trial in rural U.S. Midwestern primary care practices. Participants received a lifestyle intervention with different delivery models, including in-clinic individual, in-clinic group, or telephone group counseling visits. Participants were stratified by baseline TxASx status and 24-month weight change quintiles. Mixed models were used to estimate MCS-12 scores.

There was a significant group-by-time interaction at the 24-month follow-up. The largest 0-24 month increase in MCS-12 scores (+5.3 points [12 %]) was observed in participants with TxASx who lost the most weight during the trial, while the largest decrease in MCS-12 scores (-1.8 points [-3 %]) was observed in participants without TxASx who gained the most weight (p < 0.001).

Notable limitations included self-reported mental health, the observational analytical design, and a largely homogenous source population, as well as the possibility of reverse causation biasing some findings.

Mental health status generally improved, particularly among participants with TxASx who experienced significant weight loss. Those without TxASx who gained weight, however, had a decline in mental health status over 24 months. Replication of these findings is warranted.