Does persistent hyperprolactinemia contribute to bone loss independently of estrogen deficiency in postmenopausal women?

OBJECTIVE

To evaluate bone mineral density (BMD) in postmenopausal women with prolactinoma diagnosed during the premenopausal period and to compare skeletal outcomes according to prolactin status during drug-free follow-up.

METHODS

This retrospective cross-sectional single-center study included 42 postmenopausal women with prolactinoma. Patients were classified as hyperprolactinemic or normoprolactinemic based on serum prolactin levels at the last follow-up visit. BMD was assessed by dual-energy X-ray absorptiometry at the lumbar spine and femoral neck. Clinical variables were compared between groups. Correlation analysis, receiver operating characteristic (ROC) analysis, and multivariable logistic regression were performed.

RESULTS

Lumbar spine BMD was significantly lower in hyperprolactinemic patients than in normoprolactinemic patients (0.861 ± 0.124 vs. 0.960 ± 0.129 g/cm², p = 0.022), whereas femoral neck BMD did not differ. Patients with hyperprolactinemia had longer cumulative exposure to hyperprolactinemia and required longer and higher-dose cabergoline treatment. Baseline prolactin levels were higher in patients with osteoporosis and showed potential discriminatory value for identifying osteoporosis (AUC = 0.861). Lumbar spine BMD and T-scores were inversely correlated with prolactin levels. In multivariable analysis, baseline prolactin level remained independently associated with low BMD.

CONCLUSION

Persistent hyperprolactinemia is associated with lower lumbar spine BMD in postmenopausal women with prolactinoma. Baseline prolactin level and cumulative exposure to prolactin excess appear to be important contributors to skeletal deterioration, supporting the need for routine bone health assessment during long-term follow-up.