The association between depressive symptoms and high-sensitivity C-reactive protein: Is body mass index a moderator?

Depression and obesity are highly comorbid conditions with shared biological mechanisms. It remains unclear how depressive symptoms and body mass index (BMI) interact in relation to inflammation. This cross-sectional study investigated the independent associations of depressive symptoms and BMI with high sensitivity C-reactive protein (hs-CRP), as well as the moderating role of BMI on the depressive symptoms-hs-CRP association. Participants (n = 8827) from the 2015–2018 National Health and Nutrition Examination Surveys were aged ≥20 with a BMI ≥18.5 kg/m2, completed the Depression Screener, and had hs-CRP data. Multivariable linear regression was used to analyze hs-CRP in relation to depressive symptoms and BMI. An interaction term was included to examine whether the depressive symptoms-hs-CRP relationship differs depending on BMI. There was a slight, albeit non-significant, increase in hs-CRP levels with each one-point increase in depressive symptoms (aCoef.Estm. = 0.01, 95% CI = −0.05, 0.06, p = 0.754). Participants with overweight (aCoef.Estm. = 1.07, 95% CI = 0.61, 1.53, p