Inflammation, Obesity, and Metabolic Syndrome in Depression: Analysis of the 2009-2010 National Health and Nutrition Examination Survey (NHANES)

Objective: To describe the rates of elevated inflammation, obesity, and metabolic syndrome (MetS) within a large cohort of individuals with depression and to examine the interrelationships of inflammation and MetS in depressed individuals.

Method: Analyses were conducted on study participants from the 2009-2010 National Health and Nutrition Examination Survey (NHANES) with Patient Health Questionnaire (PHQ-9) depression scores ≥ 10 to (1) examine the relationship of inflammation (C-reactive protein; CRP) with demographic and clinical characteristics and (2) examine the prevalence of MetS criteria within CRP groups.

Results: 5,579 participants provided PHQ-9 data; of those, 606 had PHQ-9 scores ≥ 10 and were included in further analysis. Of the 606 depressed participants, 585 participants had valid CRP data; 275 participants (47.01%) had CRP levels ≥ 3.0 mg/L, while 170 (29.06%) had CRP levels ≥ 5.0 mg/L. Elevated inflammation was significantly correlated with body weight, waist circumference, body mass index, insulin, 2-hour glucose tolerance, and self-report general health (P values < .05). 112 subjects (41.18%) met American Heart Association/National Heart, Lung, and Blood Institute criteria for MetS. Those with elevated CRP were more likely to meet criteria for MetS (odds ratios of 2.81 for those with CRP levels ≥ 3.0 mg/L and 1.94 for those with CRP levels ≥ 5.0 mg/L).

Conclusions: Over 29% of depressed individuals had elevated levels of CRP, and 41% met criteria for MetS. Individuals with elevated inflammation are more likely to be obese and meet criteria for MetS. These results highlight the significant inflammatory and metabolic burden of individuals with depression.