Association of metabolically healthy obesity with depressive symptoms: pooled analysis of eight studies

The hypothesis of metabolically healthy obesity posits that adverse health effects of obesity are largely avoided when obesity is accompanied by a favorable metabolic profile. We tested this hypothesis with depressive symptoms as the outcome using cross-sectional data on obesity, metabolic health and depressive symptoms. Data were extracted from eight studies and pooled for individual-participant meta-analysis with 30 337 men and women aged 15-105 years (mean age = 46.1). Clinic measures included height, weight and metabolic risk factors (high blood pressure, high triglycerides, low high-density lipoprotein cholesterol, high C-reactive protein and high glycated hemoglobin). Depressive symptoms were assessed using clinical interview or standardized rating scales. The pooled sample comprised 7673 (25%) obese participants (body mass index >= 30 kg m(-2)). Compared to all non-obese individuals, the OR for depressive symptoms was higher in metabolically unhealthy obese individuals with two or more metabolic risk factors (1.45; 95% confidence interval (CI) = 1.30, 1.61) and for metabolically healthy obese with <= 1 metabolic risk factor (1.19; 95% CI = 1.03, 1.37), adjusted for sex, age and race/ethnicity. Metabolically unhealthy obesity was associated with higher depression risk (OR = 1.23; 95% CI = 1.05, 1.45) compared with metabolically healthy obesity. These associations were consistent across studies with no evidence for heterogeneity in estimates (all l(2)-values < 4%). In conclusion, obese persons with a favorable metabolic profile have a slightly increased risk of depressive symptoms compared with non-obese, but the risk is greater when obesity is combined with an adverse metabolic profile. These findings suggest that metabolically healthy obesity is not a completely benign condition in relation to depression risk.