What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Depression. Intervention: Severe obesity (BMI ≥40) vs. Normal-weight (BMI 18.5-24.9). Primary outcome: Past-month depression (OR 4.98, 95% CI 2.07-11.99).

December 2, 2003Open Access

Is Obesity Associated with Major Depression? Results from the Third National Health and Nutrition Examination Survey

Key Result

Severe obesity (BMI ≥40) was strongly associated with past-month depression (OR 4.98; 95% CI 2.07-11.99), with the association remaining strong after adjusting for multiple confounders.

Study Design

Type

Cross-Sectional

Multicenter

Yes

Structured PICO

Is obesity associated with major depression in the general population?

Population

Participants from the Third National Health and Nutrition Examination Survey (1988-1994) evaluated for the association between obesity and past-month depression.

Exposure

Obesity (body mass index ≥ 30) and severe obesity (body mass index ≥ 40)

Comparator

Normal-weight persons (body mass index 18.5-24.9)

Outcome

Past-month depression defined using DSM-III criteria and measured with the Diagnostic Interview Schedule

Severe obesity is strongly associated with major depression, highlighting a significant comorbidity that warrants clinical attention and further prospective investigation.

Main Result

Odds Ratio: 4.98 (95% CI 2.07–11.99)

Limitations

Prospective studies are necessary to clarify the obesity-depression relation

Abstract

Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used to examine the relation between obesity and depression. Past-month depression was defined using criteria from the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, and was measured with the Diagnostic Interview Schedule. Obesity was defined as a body mass index (weight (kg)/height (m)2) of 30 or higher. The authors compared risks of depression in obese and normal-weight (body mass index 18.5-24.9) persons. Obesity was associated with past-month depression in women (odds ratio (OR)=1.82, 95% confidence interval (CI): 1.01, 3.3) but was not significantly associated in men (OR=1.73, 95% CI: 0.56, 5.37). When obesity was stratified by severity, heterogeneity in the association with depression was observed. Class 3 (severe) obesity (body mass index > or =40) was associated with past-month depression in unadjusted analyses (OR=4.98, 95% CI: 2.07, 11.99); the association remained strong after results were controlled for age, education, marital status, physician's health rating, dieting for medical reasons, use of psychiatric medicines, cigarette smoking, and use of alcohol, marijuana, and cocaine. These findings suggest that obesity is associated with depression mainly among persons with severe obesity. Prospective studies will be necessary to clarify the obesity-depression relation but await the identification of potential risk factors for depression in the obese.