Association between anemia and depression: The 2014, 2016, and 2018 Korea National Health and Nutrition Examination Survey

Several studies have reported an association between anemia and depression. However, whether anemia is independently associated with depression remains controversial. The current study aimed to investigate the association between anemia and depression according to sex in a large national sample population.Data from the 2014, 2016, and 2018 Korean National Health and Nutrition Examination Survey were analyzed, and 15,472 participants were included in this study. Anemia was defined as a hemoglobin level <13 g/dL in men and <12 g/dL in women. We defined a Patient Health Questionnaire-9 score ≥10 as depression and ≥5 as mild depressive symptoms.The prevalence of depression was significantly higher in women with anemia than in women without anemia (8.9 % vs. 7.0 %, P = 0.036). In women, anemia was significantly associated with depression after adjusting all covariates in multilevel logistic regression analysis (odds ratio, 1.37; 95 % confidence interval, 1.08-1.75; P = 0.011). However, no significant association was observed in men.There is a limit to explaining the causal direction, and several factors may not have been considered as confounders. Also, patients with severe diseases were excluded from data acquisition. A structured diagnostic interview, other than the self-report method, was not conducted.The findings of this study suggest that anemia is associated with depression in women but not in men. A decrease in tissue oxygenation, deterioration of physical performance due to anemia, and altered monoamine synthesis due to malnutrition may have an effect on depression.