These data indicate that moderate weight loss during long-term calorie restriction is associated with a marked clinical improvement which reflects the reduction in insulin concentrations and reciprocal changes in SHBG. The improvement in menstrual function and fertility may therefore be consequent upon an increase in insulin sensitivity which, directly or indirectly, affects ovarian function.

Insulin insensitivity in polycystic ovary syndrome occurs when there is oligo/amenorrhoea but not when the menstrual cycle is regular. This is consistent with PCO and insulin insensitivity being separate abnormalities which when combined are associated with anovulation.

Polycystic ovary syndrome is associated with biochemical risk factors for premature vascular disease, which cannot be explained by obesity alone.

Objectives-Despite improved nutrition and intensive treatment, subjects with cystic fibrosis have diYculty in maintaining anabolism during intercurrent infections, which can result in reduced body mass index and impaired skeletal growth. Insulin-like growth factor-I (IGF-I) and its binding protein IGFBP3 are sensitive to changes in nutritional status. The aim of this study was to determine the relation between circulating concentrations of these peptides, body mass index, and clinical status in cystic fibrosis. Methods-Serum concentrations of IGF-I and IGFBP3 were measured in 197 subjects (108 males, 89 females; mean age 9.69 years, range 0.41-17.9 years) and these data were analysed with respect to body mass index, pubertal stage, and clinical status as assessed by Shwachman score and forced expiratory volume in one second (FEV 1 ). Results-The mean height SD score of the children studied was −0.2 (SD 1.14) and the body mass index SD score −0.26 (1.4). The body mass index SD score declined with increasing age (r=−0.18) and paralleled changes in IGF-I concentrations, which also declined. The IGF-I SD score (calculated from control data) correlated with age (r=−0.53). The abnormalities were most obvious during late puberty, when IGF-I and IGFBP3 concentrations were significantly reduced compared with those in control subjects matched for pubertal stage. The IGF-I SD score correlated with height SD score (r=0.14) and the decline in IGF-I concentrations with the fall in body mass index SD score (r=0.42). IGF-I SD scores also correlated with the Shwachman score (r=0.33) and FEV 1 (r=0.17). Conclusions-The close relation between declining IGF-I and IGFBP3 concentrations and body mass index in patients with cystic fibrosis may simply reflect poor nutritional status and insulin hyposecretion. Nevertheless, IGF-I deficiency could also contribute towards the catabolism observed in these patients, and IGF-I SD scores correlated with other measures of clinical status such as the Shwachman score and FEV 1 .