Overweight and obese type 2 diabetes patients who followed an intensive lifestyle intervention had a lower risk of incident depression and attained better physical function than those who received diabetes support and education….
Thomas A. Wadden, Ph.D., from the University of Pennsylvania in Philadelphia, and colleagues compared the effects of an intensive lifestyle intervention (ILI) with a diabetes support and education (DSE) control intervention on long-term changes in depression symptoms, antidepressant medication use, and health-related quality of life. Participants included 5,145 overweight/obese individuals with type 2 diabetes who were followed for a median of 9.6 years. They administered the Beck Depression Inventory (BDI) at baseline, annually at years one to four, and at year eight. The researchers found that, compared with DSE, ILI correlated with a significant reduction in the incidence of mild or greater depression symptoms (BDI scores ≥10; hazard ratio, 0.85; P= 0.0145). Both groups experienced a worsening of Medical Outcome Study Short Form 36 (SF-36) physical component summary scores over time, but throughout the first eight years the ILI participants reported better physical function than DSE participants (all P values < 0.01). No significant between-group differences were seen in the proportion of participants who used antidepressant medications or in SF-36 mental component summary scores.
This study found that a lifestyle intervention, designed to induce weight loss, reduced the risk of progressing to mild or greater symptoms of depression by an average of 15% over 8 years of follow-up, relative to DSE. The present findings confirm the results of previous studies of shorter duration and provide the strongest evidence to date that ILI protects overweight/obese individuals from depression rather than precipitating it. The ILI’s benefit was not attributable to differential use of ADMs in the two treatment arms during the course of the trial.
In addition to its protective effects in nondepressed individuals, the ILI did not appear to harm individuals who had depression symptoms at the trial’s outset. Subgroup analyses showed that in participants who at baseline had mild depression symptoms (BDI score of 10–18), the lifestyle intervention did not increase the risk of progressing to moderate or greater depression symptoms (BDI score ≥19). Instead, at the end of the first year, ILI participants who began the trial with mild or greater depression symptoms (BDI score >10) experienced substantial improvements in mood, with reductions in mean BDI scores from 14.1 to 8.8. Part of the improvement likely was attributable to the spontaneous remission of depression, typically observed in 3 to 12 months (29). A similar (though more modest) pattern of improvement was observed the first year in comparable DSE participants, in whom mean BDI scores fell from 13.2 to 9.6.
The ILI’s prevention of mild or greater depression symptoms has important public health implications, particularly for people with type 2 diabetes. According to the World Health Organization, unipolar depression was the third most important cause of disease burden worldwide in 2004 and the most important in middle- and high-income countries. Depression is more prevalent among people with diabetes than it is in the general population. A study that included national samples reported that 6.1% of individuals without diabetes, and 9.3% of those with the condition, were currently depressed. The combination of depression and diabetes leads to negative effects on self-care behaviors and glycemic control and ultimately increases morbidity, mortality, and health care costs. Reducing the risk of developing depression over 8 years in individuals with diabetes could thus have an important health impact.
"These findings should be considered when evaluating the potential benefits of ILIs," the authors write.
- Depression is more prevalent among people with diabetes than it is in the general population.
- A lifestyle intervention, designed to induce weight loss, reduced the risk of progressing to mild or greater symptoms of depression by an average of 15% over 8 years
Diabetes Care June 2014vol. 37 no. 6 1544-1553