How does lifestyle intervention affect depressive symptoms? Results from the Finnish Diabetes Prevention Study

To assess the effect of lifestyle intervention on depressive symptoms during a 36-month randomized clinical trial designed to prevent Type 2 diabetes.

A total of 522 middle-aged participants, who were overweight or obese and had impaired glucose tolerance, were randomized to the lifestyle intervention or control group in the Finnish Diabetes Prevention Study. The intervention group received individualized counselling aimed at reducing weight and increasing physical activity. Depressive symptoms were measured using the Beck Depression Inventory among a subgroup of 140 participants.

On study entry, the mean Beck Depression Inventory scores ± sd were 6.8 ± 5.6 in the intervention group and 6.7 ± 5.5 in the control group. Beck Depression Inventory scores reduced during the intervention study: the mean ± sd (95% CI) reduction was 0.90 ± 4.54 (-1.99 to -0.19) scores in the intervention group and 0.75 ± 4.47 (-1.80 to 0.31) in the control group, with no difference between the groups. In a stepwise linear multivariate regression analysis, the variables with the strongest associations with the change in Beck Depression Inventory scores were baseline Beck Depression Inventory scores, marital status, weight change and change of total energy intake (R(2) = 0.209, P < 0.001).

Participation in the study lowered depression scores, with no specific group effect. Among the lifestyle changes, particularly successful reduction of body weight was associated with the greater reduction of depressive symptoms. Thus, regardless of the intensity of the treatment, the success in executing alterations in one's lifestyle and behaviour is associated with beneficial changes in mood.