Two adipocytokines, leptin and adiponectin, independently predict osteoporotic fracture risk at different bone sites in postmenopausal women

Although associations among obesity, adipocytokines, and bone mineral density have been reported, the influence of adipocytokines on osteoporotic fractures remains unclear. This study aimed to assess the impact of the adipocytokines leptin and adiponectin on the risk of incident vertebral and long-bone fractures in postmenopausal women. Clinical data were obtained from the retrospective Nagano Cohort Study of outpatients followed at a single primary care institute in Nagano Prefecture, Japan, between 1993 and 2018. The primary outcome was the occurrence of incident vertebral or long-bone fractures. In total, 1167 Japanese postmenopausal women (mean age: 65.9 years) completed the follow-up and the average observation period was 7.2 years. The subjects were divided into 4 groups (quartile 1 to 4) based respective leptin and adiponectin values. Kaplan-Meier analysis demonstrated a significantly lower incident long-bone fracture rate in the higher quartiles of serum leptin levels (p = 0.002). A significantly higher and more rapid occurrence of incident vertebral fractures, but not long-bone fractures, was found in the highest adiponectin quartile (p < 0.001). A Cox proportional hazards model adjusted for confounders including age, body weight, and either leptin or adiponectin revealed lower leptin levels and higher adiponectin levels as significant independent risk factors for incident long-bone fractures (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.50-0.96; p = 0.03) and vertebral fractures (HR 1.18, 95% CI 1.02-1.37; p = 0.02), respectively. Therefore, serum leptin and adiponectin may be independent risk factors for osteoporotic fractures affecting different bone types and sites. Determining patient adipocytokine levels may help predict the occurrence of specific osteoporotic fractures, thereby enabling optimal treatment for osteoporosis and improving quality of life.