Body composition in acromegaly.

Total body water (TBW) and potassium (TBK) were measured in untreated acromegalic patients seen between 1956 and 1984 and the results were compared to values predicted from height (BH), weight (BW), age and sex, using data from a large number of healthy subjects (n = 476). Normal body weight for each patient (BWnorm) was predicted from BH and sex, the regression equations being derived from a representative population sample (n = 4017). The BH for each patient was compared with data on BH in 15,000 Swedes. The patients were significantly taller than the control population (P less than 0.001). In 107 (70%) of the 156 patients BH was above the median. Patients with an early onset of the disease were taller than those with a later onset. TBK and TBW were significantly higher than predicted from observed BW (P less than 0.001) and so was the quotient extracellular water (ECW)/intracellular water (ICW). Body fat (BF), on the other hand, was lower than predicted (P less than 0.001). Observed BW in male acromegalics was 8.1 kg higher than predicted from healthy subjects of the same BH (BWnorm), a difference explained by an average increase of 4.7 kg in body cell mass (BCM) (P less than 0.001) and 7.1 kg in extracellular water (P less than 0.001) simultaneously with a mean decrease of 3.7 kg in BF (P less than 0.01). Female acromegalics weighed on average 6.4 kg more than healthy women, a difference explained by an increase in BCM of 3.3 kg (P less than 0.001) and in ECW of 4.6 kg (P less than 0.001) concomitantly with a decrease in BF of 1.5 kg. Mean hGH concentration at diagnosis correlated inversely with the quotients observed/predicted BF (P less than 0.01) and BW/BWnorm (P less than 0.05) but not with the quotients observed/predicted TBK, TBW or ECW/ICW.