Association between iron-deficiency anemia and depression: A web-based Japanese investigation

Aim: This web-based survey aimed to examine the relation between iron-deficiency anemia and depression in 11 876 Japanese participants. Methods: Participants consisted of 1000 individuals with self-reported history of depression (mean age, 41.4 +/- 12.3 years; 499 women) and 10 876 population-based controls (mean age, 45.1 +/- 13.6 years; 5185 women). The 6-item Kessler Scale (K6) score was used as a psychological distress scale. The design of the study was cross-sectional. Results: The rate of self-reported lifetime history of iron-deficiency anemia was higher in the depression group in both men (depression, 7.2%; control, 4.0%; P<0.001; odds ratio [OR], 1.86; 95% confidence interval [CI], 1.30-2.68) and women (depression, 33.4%; control, 25.8%; P<0.001; OR, 1.45; 95%CI, 1.19-1.76). The K6 score in participants with self-reported history of iron-deficiency anemia was higher in both the depression (P=0.004) and control (P<0.001) groups. In addition, in all participants, the rate of individuals who showed a K6 cut-off score of 13 or more was higher in those with a self-reported history of iron-deficiency anemia (P<0.001; OR, 1.47; 95%CI, 1.31-1.65). Logistic regression analyses revealed that self-reported history of depression and the K6 score were positively associated with self-reported history of iron-deficiency anemia (all P<0.01). Conclusion: Self-reported history of iron-deficiency anemia was associated with self-reported history of depression. Furthermore, self-reported history of iron-deficiency anemia was associated with higher psychological distress.