The study of the role of insulin resistance as etiological factor in polycystic ovarian syndrome: a case control study

OBJECTIVES: The relationship between insulin resistance (IR) and polycystic ovary syndrome (PCOS) has been consistently shown by several studies but what is the cause and what is the effect remained an unsolved issue. In recent years, IR has been suggested to be a key etiological factor which contributes to the severity of metabolic and reproductive features in PCOS. The aim of the present study is to determine the etiological role of IR in PCOS. METHODS: This is an analytical case control study where 30 newly diagnosed normoglycemic cases of PCOS (according to Rotterdam revised criteria 2003) between the age group of 15 and 35 years were enrolled. A total of 30 age matched, apparently healthy women were selected from volunteers as controls. Fasting glucose was analysed by spectrophotometry and fasting insulin by chemiluminescence immunoassay. HOMA-IR, Log HOMA-IR, QUICKI, G/I ratio and FIRI were calculated using standard formulae. RESULTS: The anthropometric parameters and markers of IR were high and QUICKI & G/I ratio were low in cases as compared to controls (p<0.05). Cases with BMI≥25 showed significantly higher IR markers and lower QUICKI & G/I ratio than BMI<25 cases and BMI matched controls. No significant difference was present in IR markers between high and low central obesity cases. CONCLUSIONS: The findings of our study suggest that in normoglycemic PCOS women, raised IR markers in obese patients cannot be attributed to obesity or central obesity alone. Presence of IR in newly diagnosed cases at such an early stage i.e., even before development of hyperglycemia and hyperinsulinemia suggest IR to be a causative factor in development of PCOS.