Prevalence and magnitude of osteopenia in patients with prolactinoma.

1. The association between hypogonadism and osteoporosis has been reported. We conducted a study to establish the prevalence and magnitude of osteopenia in patients with prolactinoma and the relationship of bone loss with the duration of hypogonadism. 2. We measured the bone mineral density (BMD) of spine and femur (a site that has not been analyzed earlier) in 35 patients with prolactinoma using a dual-energy X-ray absorptiometer. The patients were classified as normal BMD and low BMD (osteopenics). 3. Seventeen patients (48%) showed osteopenia. The mean bone loss in the different regions was: spine, 13%; femoral neck, 15%; trochanter, 11%; Ward's, 22%. This difference was only significant when the spine and Ward's region were compared. The duration of hypogonadism was significantly greater in the low-BMD group (11.3 vs 4.9 years) when compared to the normal BMD group. There was a positive relationship between the duration of hypogonadism and magnitude of bone loss in both spine and femur (P = 0.04; r = 0.6). 4. A high prevalence of osteopenia in both spine and femur was found in patients with prolactinoma, and was highly associated with the duration of hypogonadism. Early treatment of this condition seems important to prevent bone loss.