The non-linear associations of serum follicle-stimulating hormone levels with bone mineral density and the risk of osteoporosis during menopausal transition: an analysis of National Health and Nutrition Examination Survey data.

Non-linear associations of serum FSH levels with BMD at lumbar spine and femur neck were observed only in postmenopausal women. Meanwhile, serum FSH levels were non-linearly associated with the risk of osteoporosis in postmenopausal women.