Polycystic ovary syndrome (PCOS) is the most common endocrine disease and metabolic disorder in adolescence and reproductive women, which is the first reason for female infertility, with the incidence of 5–10% in reproductive women [
PCOS is not only reproductive endocrine disease but also metabolic disorder. PCOS patients are often accompanied by obesity, insulin resistance, abnormal glucose metabolism, lipids disorder, hypertension, and other risk factors of cardiovascular disease (CVD) [
There is insulin resistance in about 70% of PCOS patients and 10% with diabetes mellitus [
The majority of those methods to evaluate insulin resistance are complicated to operate, expensive, and time-consuming. There is, therefore, an urgentneedto develop a simple, effective, and economic method to investigate insulin resistance in PCOS. The aim of this research was to study the correlation between serum lipoprotein ratios (TG/HDL-C, TC/HDL-C, and LDL-C/HDL-C) and insulin resistance in PCOS to provide new ideas for evaluation and treatment of PCOS with insulin resistance.
From February 2010 to October 2011, 105 patients diagnosed with PCOS in the Endocrinology Clinic in our hospital were enrolled in the PCOS group (according to PCOS diagnostic criteria revised in the 2003 Rotterdam meeting). This study was conducted in accordance with the declaration of Helsinki. This study was conducted with approval from the Ethics Committee ofthe Third Affiliated Hospital of Suzhou University. Written informed consent was obtained from all participants. The age of patients ranged from 17 to 36 years (average age: 24.8 years), who had no history of drugs affecting glucose and lipid metabolism. 109 healthy females (with normal menstrual cycle and sex hormone level, no evidence of polycystic ovary on ultrasound examination) were randomly selected as controls (control group) from the Medical Examination Center of our hospital. The age of the controls ranged from 18 to 35 years (an average age: 25.2 years).
Plasma samples were obtained in early follicular period from all participants after an overnight fasting to measure LH, FSH, E2, T, FBG, FINS, TG, TC, LDL-C, and HDL-C. Then, the ratio of TG/ HDL-C, TC/ HDL-C, and LDL-C/HDL-C was calculated. Their height, weight, waist circumference (WC), and blood pressure were measured, and the body mass index (BMI) was calculated.
Insulin resistance index was calculated with homeostasis model assessment (HOMA-IR), HOMA-IR = FBG (mmol/L) × FINS (mIU/L)/22.5. The diagnostic criterion of PCOS with insulin resistance (IR) was HOMA-IR > 2.77 [
Statistical analysis was performed by using SPSS15.0 statistical software. Quantitative data were expressed as mean ± SD. Groups' comparisons were made using independent sample
There was no difference in age between PCOS and control groups. BMI, WC, SBP, DBP, LH, T, FBG, FINS, HOMA-IR, TG, TC, LDL-C, TG/HDL-C, TC/HDL-C, and LDL-C/HDL-C were significantly higher in PCOS group than in control group. HDL-C was significantly lower in PCOS group than in control group. There was no significant difference between PCOS and control groups in terms of FSH and E2 (Table
Demographic data in PCOS and control groups (*
Groups | Control group | PCOS group |
---|---|---|
Age (years) | 25.2 ± 4.5 | 24.8 ± 4.8 |
BMI (Kg/m2) | 21.8 ± 3.2 | 24.2 ± 4.2* |
WC (cm) | 71.9 ± 6.9 | 77.2 ± 8.0* |
SBP (mmHg) | 111 ± 10 | 123 ± 11* |
DBP (mmHg) | 73 ± 8 | 76 ± 8* |
FBG (mmol/L) | 4.78 ± 0.43 | 5.57 ± 0.55* |
FINS (mIU/L) | 8.6 ± 2.6 | 21.5 ± 5.7* |
HOMA-IR | 1.83 ± 0.57 | 5.27 ± 1.04* |
TG (mmol/L) | 1.43 ± 1.28 | 2.64 ± 1.04* |
TC (mmol/L) | 3.69 ± 1.32 | 5.01 ± 0.69* |
LDL-C (mmol/L) | 2.10 ± 0.57 | 2.49 ± 0.29* |
HDL-C (mmol/L) | 1.27 ± 0.29 | 1.08 ± 0.16* |
TG/HDL-C | 1.10 ± 0.99 | 2.57 ± 1.26* |
TC/HDL-C | 2.84 ± 1.18 | 4.71 ± 0.88* |
LDL-C/HDL-C | 1.61 ± 0.60 | 2.34 ± 0.50* |
LH (mLU/mL) | 10.32 ± 2.05 | 15.69 ± 2.32* |
FSH (mLU/mL) | 6.06 ± 0.58 | 6.62 ± 0.75 |
T (ng/mL) | 0.51 ± 0.09 | 0.97 ± 0.11* |
E2 (pg/mL) | 64.11 ± 11.45 | 63.56 ± 12.28 |
There was a significant positive correlation between HOMA-IR and TG/HDL-C (
It was shown that TG/HDL-C, TC/HDL-C, and LDL-C/HDL-C were effective diagnostic markers for PCOS with insulin resistance, and the area under the ROC curve of TC/HDL-C was the biggest (Table
Serum lipoprotein ratios and the areas under ROC curve for the detection of PCOS with insulin resistance.
Serum lipoprotein ratios | Areas under ROC curve | 95% confidence interval |
|
---|---|---|---|
TG/HDL-C | 0.862 ± 0.026 | 0.811−0.912 | <0.001 |
TC/HDL-C | 0.913 ± 0.021 | 0.873–0.954 | <0.001 |
LDL-C/HDL-C | 0.853 ± 0.029 | 0.797–0.909 | <0.001 |
Serum lipoprotein ratios had high sensitivity and specificity for the detection of PCOS with insulin resistance.
PCOS is a common endocrine syndrome with a complex etiology and pathogenesis. Recent studies have considered PCOS as not only a reproductive endocrine disease but also metabolic disorder, which is related to hyperinsulinemia, hyperlipidemia, diabetes, and cardiovascular disease. Insulin resistance and concurrent hyperinsulinemia were reported to play a key role in its occurrence and pathophysiology [
Insulin resistance is defined clinically as the inability of a known quantity of exogenous or endogenous insulin to increase glucose uptake and utilization in an individual as much as it does in a normal population. There are many methods of evaluation of insulin resistance, among which the hyperinsulinemic euglycemic clamp technique is considered as the “gold standard” to assess insulin sensitivity; however, it was complicated to operate and time-consuming which, limited its use in clinical and epidemiological studies [
Abnormal lipid metabolism is one of the main metabolic characteristics of PCOS patients. The result of this study showed that PCOS patients had higher TC, LDL-C, and TG and lower HDL-C when compared with age-matched healthy females. These lipid abnormalities were closely related to insulin resistance independent of obesity [
The research showed that serum lipoprotein ratios had significant positive correlation with insulin resistance in PCOS patients, which could be used as a simple, reliable, and economic indicator to evaluate insulin resistance. Thus, it had important clinical significance for diagnosis and treatment options of PCOS.