Insulin resistance and dyslipidaemia in obese premenopausal and postmenopausal women matched for leg/trunk fat mass ratio

Objectives To investigate the influence of age, menopausal stage and selected hormonal factors on insulin resistance and dyslipidaemia in obese (BMI30 kg/m2) pre- and postmenopausal women. Material and methods: Thirty- eight pre- and postmenopausal women were matched one by one for leg/trunk fat mass (FM) ratio. Body composition and regional FM by dual X- ray absorptiometry (DXA), fasting glucose, insulin and C- peptide, insulin resistance by homeostasis model assessment (HOMA- IR), insulin sensitivity by quantitative insulin sensitivity check index (QUICKI) and metabolic clearance rate (MCRestOGTT), insulin secretion (HOMAsecr), serum lipids, oestradiol, SHBG, testosterone and testosterone index (total testosterone/SHBG), free thyroxine, free triiodothyronine, cortisol and IGF- 1 were assessed. Results: HDL- cholesterol was higher (p=0.025) and total cholesterol/HDL- cholesterol ratio lower (p=0.026) in post- than in premenopausal women. No differences in parameters of insulin resistance or hormonal factors except oestradiol were found. In forward stepwise multiple regression analysis, cholesterol/HDL- cholesterol ratio was negatively predicted by age (R2=0.25, p=0.02) and HDL- cholesterol negatively (R2=0.16, p=0.013) predicted by belonging to the premenopausal group. MCRestOGTT was unfavourably predicted by IGF- 1 (R2=0.28, p=0.005) and testosterone (R2=0.36, p=0.048). Because of the relatively small number of subjects studied, interpretation of the results may to some extent have limited general validity. Conclusion: FM distribution is the major determinant of insulin resistance and dyslipidaemia, with only minor roles for menopausal status, age as such and age- related changes in hormonal factors in the regulation of glucose and lipid metabolism.