Relationships between hand-grip strength, socioeconomic status, and depressive symptoms in community-dwelling older adults

•Cross-sectional study including data from 3169 adults aged 60 years or older.•Hand-grip strength (HGS) was measured using a digital hand-grip dynamometer.•Association between HGS and depression was moderated by household income level.•Greater inverse correlation was observed between HGS and depression in older adults with low income.•Association between income and depression was mediated by HGS. Depressive symptoms have been found to be associated with decreased hand-grip strength (HGS) and low socioeconomic status (SES) in older adults. We aimed to investigate the potential moderating effect of SES on the association between HGS and depressive symptoms and the potential mediating effect of HGS on the association between SES and depressive symptoms using a nationally representative sample of older adults. Data from 3169 community-dwelling adults aged 60 years or older were acquired from the Korea National Health and Nutrition Examination Survey conducted in 2014 and 2016. HGS was measured using a digital hand-grip dynamometer. Depressive symptoms were evaluated using the 9-item version of the Patient Health Questionnaire-9 (PHQ-9). SES was assessed using equivalent monthly household income and education level. Older adults in the lowest tertile of HGS measures were more likely to have experienced depressive symptoms compared to those in the highest tertile (odds ratio = 1.95, 95% confidence interval = 1.25–2.74). A significant moderating effect of household income level was observed on the association between HGS and PHQ-9 score (P = 0.014). Older adults with a low income had a stronger inverse correlation between HGS and PHQ-9 score compared to those with a high income (low income: beta = −0.162, P