Osteopenia occurs in a minority of patients with acromegaly and is predominant in the spine

Acromegaly may induce abnormalities in bone metabolism; however, there are limited data related to bone mineral density (BMD) in this condition. To evaluate the effects of an excess of growth hormone/ insulin-like growth fractor I (GH/IGF-I) in the skeleton, we measured the BMD in spine and femoral region, total body calcium and body composition in 45 patients (24 females and 21 males) aged 21-77 years (median 43 years) with acromegaly for 11.4 +/- 7.5 years (range 0.5-26 years) using a dual-energy X-ray absorptiometer (Lunar DPX). Thirty-four patients had had hypogonadism for 8.6 +/- 6.5 years (1-24 years). Mean serum GH and IGF-I levels were respectively 159 +/- 183 micrograms/l and 843 +/- 497 micrograms/l. Total body calcium was increased in the acromegalics (males: 1272 +/- 217 g, range 916-1816 g; females: 1041 +/- 223 g, range 739-1609 g) when compared with normal individuals (males: 1115 +/- 144 g, range 856-1398 g; females: 909 +/- 144 g, range 511-1311 g; p = 0.01). The lean body mass was significantly higher in acromegalic patients (p < 0.001) compared with normal individuals. There was a tendency for a lower fat percentage in the acromegalics; however, this difference was not significant. Osteopenia (1 Z-score below the mean) was found in the spine in 20% (n = 9) of the patients, while BMD was decreased in the femoral region in only 8.8% (n = 4). The group with osteopenia had a greater duration of hypogonadism than the normal BMD group (14 +/- 11 years vs 4.4 +/- 4.0 years; p = 0.01). A negative correlation was also found between the duration of hypogonadism and BMD in spine (r = -0.4; p = 0.003) and femoral region (r = -0.37; p = 0.013). The hypogonadal patients had a lower BMD in spine (p < 0.005), but not in other regions analyzed. No correlation was found between duration of hypersomatotropism, GH/IGF-I levels and BMD. We conclude that the majority of patients with acromegaly have preserved BMD despite the presence of hypogonadism.