The natural history of the metabolic syndrome in young women with the polycystic ovary syndrome and the effect of long-term oestrogen-progestagen treatment.

Abstract

Little is known about the natural history of polycystic ovary syndrome (PCOS), although preliminary data indicate that affected women are more susceptible than the general population to diabetes and cardiovascular diseases at post-menopausal ages. The aim of this study was to follow-up all main features of the metabolic syndrome in a group of young women with PCOS and to investigate the long-term effects on metabolism and body composition of oestrogen-progestagen (OP) compounds, which are frequently used in these women to treat hyperandrogenism and related clinical features. Long-term follow-up study. Thirty-seven women with PCOS were re-evaluated 10.3 +/- 0.8 years (range 6-18 years) after their first assessments (age: before 19.8 +/- 4.9 years; after 29.9 +/- 4.4 years). When first examined, women were instructed to follow a hypocaloric diet if they were obese plus OP, if they agreed to such treatment. Main anthropometric parameters, basal sex hormones and lipids, fasting and glucose-stimulated glucose and insulin levels and several clinical data were recorded before and after follow-up. In the whole group of women with PCOS we found no changes in body weight and fat mass, whereas both the waist-to-hip ratio and the waist-to-thigh ratio were significantly reduced. No significant changes occurred in mean fasting and glucose-stimulated glucose and insulin concentrations, whereas a significant increase in high-density lipoprotein-cholesterol was found. No significant changes occurred in testosterone levels. During the follow-up period 16 women took OP for an average of 97 +/- 18 months (range 12-180 months) (OP-users) whereas 21 women never took OP (non-OP-users). All OP-users were still taking OP when re-evaluated at the follow-up examination. With respect to baseline values, body mass index was higher in non-OP-users than in their counterparts. Waist circumference (P < 0.025), the waist-to-hip (P < 0.05) and the waist-to-thigh (P < 0.01) ratios decreased significantly only in the OP-users. In addition, percentage changes in waist circumference (P < 0.05) and waist-to-hip ratio (P < 0.05) during the follow-up period were significantly different between the groups. Glucose tolerance (as area under the curve (AUC)) improved (P < 0.05) in OP-users but not in non-OP-users. Moreover, compared to baseline values, basal insulin levels were significantly (P < 0.01) reduced in OP-users but not in non-OP-users. On the contrary, no significant change was found in insulinAUC in the former, whereas it significantly increased (P < 0.05) in the latter. Accordingly, fasting C-peptide decreased (P < 0.05) in OP-users, whereas both fasting (P < 0.01) and stimulated (P < 0.01) C-peptide significantly increased in non-OP-users. Changes in fasting or stimulated insulin and C-peptide in non-OP-users were not associated with parallel changes in testosterone levels. Total cholesterol and triglycerides did not change in either group, but HDL-cholesterol increased (P < 0.05) only in OP-users. Sex hormone-binding globulin concentrations increased significantly (P < 0.01) in OP-users, without any significant change in non-OP-users. Testosterone concentrations did not change significantly in either group, but the testosterone: SHBG ratio significantly decreased in OP-users (P < 0.05) but not in the non-OP-users. Among the clinical features, acanthosis nigricans significantly (P < 0.01) worsened in non-OP-users but not in the OP-users, without any significant change in the hirsutism and acne scores. Pregnancy rates during the follow-up were similar in both groups. These data indicate that hyperinsulinaemia and insulin resistance tended to worsen spontaneously in women with PCOS, without any worsening of the hyperandrogenism. Long-term oestrogen-progestagen treatment countered this tendency, probably because it improved the pattern of body fat distribution, by reducing abdominal fat depots.