Depression risk fourfold higher in obese seniors

Depression and obesity appear to go hand in hand among community-dwelling older adults.

The prevalence of depression among men and women in their 60s, 70s, and 80s rises in tandem with body mass index (BMI) at about 17% for people with a BMI of 30 or greater (obese), compared with about 11% for those with a normal BMI (18.5-24.9), Dartmouth Medical School in Hanover, N.H., reported at the meeting.

The relative risk for depression among obese seniors receiving care from three different types of community-based settings was about fourfold higher than for seniors with normal weight.

“When depression and obesity co-occur, they may act synergistically to further reduce functioning and exacerbate outcomes from comorbid medical conditions. In older adults, the association between obesity and depression and the moderators of the relationship remain unclear.”

The investigators explored this relationship by analyzing three separate studies of older adults who were receiving prepared meals in their homes or in senior centers, and in publicly financed assisted living homes in the New York City borough of the Bronx.

Clinically significant depression was defined differently in each setting. In the home-meals setting, depression was defined as a score greater than 9 on the depression scale of the Patient Health Questionnaire. In the congregate-meal (senior center) setting, investigators used the Structural Clinical Interview for DSM-IV Disorders major depression scale. The assisted-living facilities, used the Basis-28 depressive symptoms scale, a modification of the 32-item Behavior and Symptom Identification Scale, which is a patient-reported measure of psychiatric symptoms.

They found that for women and whites of either sex, being overweight (BMI 25-29.9) was associated with a 20%-40% lower prevalence of depression, but being obese was associated with a relative risk of depression of 1.5 in the community center setting, and 2.4 in the assisted-living setting. Among all seniors 60-74 years old in the same settings, the relative risk of depression was 4.0 among those who were obese.

In analyses controlling for potential confounding factors, the association between obesity and depression was modified by sex, age, and race, but not by level of education attained.

The investigators acknowledged that the study could not address causality because of its cross-sectional design. In addition, the use of three separate definitions of significant depression limited the investigators’ ability to compare the three different populations.