Depressive Symptoms Clusters and Insulin Resistance: Race/Ethnicity as a Moderator in 2005–2010 NHANES Data

BACKGROUND: Although depression has been linked to insulin resistance, few studies have examined depressive symptom clusters. PURPOSE: We examined whether certain depressive symptom clusters are more strongly associated with insulin resistance in a nationally representative sample, and we evaluated potential moderators and mediators. METHODS: Respondents were 4487 adults from NHANES 2005-2010. Depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9), and insulin resistance was indexed by the homeostatic model assessment (HOMA) score. RESULTS: Positive relationships between PHQ-9 total, somatic, and cognitive-affective scores and HOMA score were detected (ps <0.001). In a simultaneous model, the somatic (p = 0.017), but not the cognitive-affective (p = 0.071), score remained associated with HOMA score. We observed evidence of (a) moderation by race/ethnicity (relationships stronger in non-Hispanic Whites) and (b) mediation by body mass and inflammation. CONCLUSIONS: The depressive symptoms-insulin resistance link may be strongest among non-Hispanic Whites and may be driven slightly more by the somatic symptoms.