Association of serum leptin and ghrelin with depressive symptoms in a Japanese working population: a cross-sectional study

Background: Leptin and ghrelin have been implicated in the pathogenesis of major depression. However, evidence is lacking among apparently healthy people. This study examined the relationship of these appetite hormones to depressive symptoms in a Japanese working population. Methods: A cross-sectional study was conducted in 2009 among 497 Japanese employees (287 men and 210 women) aged 20-68 years. Fasting serum leptin and ghrelin levels were measured using a Luminex suspension bead-based multiplexed array. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression analysis was performed to estimate odds ratio (OR) and 95% confidence interval (CI) for depressive symptoms with adjustment for potential confounders. Results: The prevalence of depressive symptoms (CES-D >= 16) was 26.5% and 33.3% among men and women, respectively. Women in the middle and highest tertiles of leptin levels showed lower odds for depressive symptoms compared with those in the lowest level, although the trend association was not statistically significant (P-trend = 0.14). Higher ghrelin levels were associated with increased odds for depressive symptoms in women (P-trend = 0.02). The multivariable adjusted OR (95% CI) of having depressive symptoms for the lowest through highest tertiles of ghrelin levels were 1.00 (reference), 1.71 (0.76 - 3.86), and 2.69 (1.16 - 6.28), respectively. Neither leptin nor ghrelin was associated with depressive symptoms in men. Conclusions: Results suggest that lower leptin and higher ghrelin levels may be related to higher prevalence of depressive status among Japanese women.