Prospective Associations of Serum Adiponectin, Leptin, and Leptin-Adiponectin Ratio with Incidence of Metabolic Syndrome: The Korean Genome and Epidemiology Study

Although the role of adiponectin and leptin in the etiology of metabolic syndrome (MetS) has been explored in various populations, limited knowledge is available on the prospective association of adiponectin and leptin with the risk of MetS development. The present study aimed to evaluate the associations of adiponectin, leptin, and the leptin-adiponectin (LA) ratio with the future risk of MetS in middle-aged and older Korean adults. Using a prospective, population-based Ansan-Ansung cohort of the Korean Genome and Epidemiology Study (KoGES), 2691 Korean adults (1317 men and 1374 women) were included in the present study. Serum adiponectin and leptin concentrations were measured using commonly available enzyme-linked immunosorbent assay kits. Multivariable Cox proportional hazard models were used to investigate the relationships of the different adiponectin and leptin concentrations and LA ratio with the incident MetS. During a mean follow-up of 6.75 years, a total of 359 (27.26%) men and 385 (28.02%) women were identified as developing new-onset MetS. After controlling for covariates, higher adiponectin levels were associated with lower incidence of MetS (hazard ratio (HR) for third vs. first tertile: 0.53, 95% confidence interval (CI): 0.40–0.70 for men and HR: 0.54, 95% CI: 0.42–0.71 for women), while higher leptin levels (HR for third vs. first tertile: 2.88, 95% CI: 2.01–4.13 for men and HR: 1.55, 95% CI: 1.13–2.13 for women) and LA ratio (HR for third vs. first tertile: 3.07, 95% CI: 2.13–4.44 for men and HR: 1.94, 95% CI: 1.41–2.66 for women) were associated with an increased incidence of MetS. Among men, in the fully adjusted models an increase by one standard deviation (SD) in adiponectin levels was associated with a 10% decrease in MetS risk (HR per SD: 0.90, 95% CI: 0.85–0.95) while leptin and LA ratio was associated with a 5% (HR per SD: 1.05, 95% CI: 1.01–1.08) and 40% (HR per SD: 1.40, 95% CI: 1.22–1.62) increase in MetS risk, respectively. Among women, a significant association with MetS risk was observed only in adiponectin levels (HR per SD: 0.91, 95% CI: 0.88–0.95). We found that higher adiponectin level was associated with a lower risk of MetS, while higher leptin level and LA ratio were associated with elevated MetS incidence, irrespective of body mass index at baseline in both Korean men and women. Adiponectin and leptin levels and LA ratio could play a role as a useful biomarker in the prediction of future MetS development among middle-aged and older Koreans.