Serum GH and IGF-I are significant determinants of bone turnover but not bone mineral density in active acromegaly: a prospective study of more than 70 consecutive patients

Abstract

Objective: Acromegaly is characterized by a persistent hypersecretion of GH and provides information on long-term effects of GH on bone metabolism. The aim of this study was to examine the effect of gonadal status and disease activity on bone metabolism in active acromegaly. Methods: Seventy-three consecutive patients with active acromegaly: 40 women and 33 men (50 ± 13 (mean ± s.d.) and 49 ± 10 years respectively) were evaluated and compared with age-, sex-, and body mass index (BMI)-matched controls by X-ray absorptiometry and biochemical analysis (markers of disease activity and bone turnover). Results: We found that bone turnover, as evaluated by biochemical bone markers, is coupled and markedly increased in relation to disease activity in active acromegaly. Acromegalic women, but not men, were characterized by an increased bone area and slightly decreased bone mineral content resulting in significantly decreased bone mineral density (BMD) in the ultradistal radius, proximal radius, and total body. No differences in bone turnover or BMD were found between eu-and hypogonadal subjects. Multivariate analysis identified age, BMI, and gender as independent predictors of total BMD in acromegaly. Conclusion: Our study demonstrates a decreased total body BMD in women, not men, with active acromegaly, regardless of gonadal status or disease activity. Bone turnover is markedly increased in relation to disease activity, possibly counteracting the anabolic effects of excess GH/IGF-I in these subjects. We suggest more focus on biomechanical analyses when investigating endocrine disorders affecting bone size and distribution between compartments.