Association between gonadal hormones and osteoporosis in schizophrenia patients undergoing risperidone monotherapy: a cross-sectional study

OBJECTIVE: Patients with schizophrenia are at increased risk of osteoporosis. This study first determined the osteoporosis rate in patients with schizophrenia and then then explored the association between serum gonadal hormone levels and osteoporosis among these patients. METHODS: A total of 250 patients with schizophrenia and 288 healthy controls were recruited. Osteoporosis was defined by decreased bone mineral density (BMD) of the calcaneus. Serum fasting levels of gonadal hormones (prolactin, estradiol, testosterone, progesterone, follicle-stimulating hormone, luteinizing hormone) were determined. The relationship between osteoporosis and hormone levels was statistically analyzed by binary logistic regression analysis. RESULTS: Our results showed that patients with schizophrenia had a markedly higher rate of osteoporosis (24.4% vs. 10.1%) than healthy controls (P < 0.001). Patients with osteoporosis were older, had a longer disease course, and had a lower body mass index (BMI) than patients without osteoporosis (all P < 0.05). Regarding gonadal hormones, we found significantly higher prolactin, but lower estradiol, levels in patients with osteoporosis than in those without osteoporosis (both P < 0.05). The regression analysis revealed that PRL (OR = 1.1, 95% CI [1.08–1.15], P < 0.001) and E2 level (OR = 0.9, 95%CI [0.96–0.99], P = 0.011) were significantly associated with osteoporosis in patients with schizophrenia. CONCLUSION: Our results indicate that patients with schizophrenia who are being treated with risperidone have a high rate of osteoporosis. Increased prolactin and reduced estradiol levels are significantly associated with osteoporosis.