Lipoproteins: from A to B and maybe C-III

Endocrine and metabolic characteristics of polycystic ovary syndrome in Chinese women with different phenotypes

OBJECTIVE

The aim of this study was to describe the endocrine and metabolic characteristics of Chinese women with polycystic ovarian syndrome (PCOS) according to different phenotypes, including menstrual cycle pattern and body mass index (BMI).

DESIGN

Retrospective study.

PATIENT(S)

  A total of 3539 patients with PCOS and 590 controls were recruited from the Centre for Reproductive Medicine. Patients with PCOS were divided into three groups according to the characteristics of the menstrual cycle (amenorrhoea, oligomenorrhea and eumenorrhea) and the BMI (<25 kg/m(2) ; 25 ≤ and ≤ 30 kg/m(2) ; and BMI > 30 kg/m(2) ).

MEASUREMENTS

Waist circumference, hip circumference, weight, height, Ferriman-Gallwey score, and endocrine and metabolic variables were measured.

RESULTS

  The serum testosterone, luteinizing hormone (LH) and oral glucose tolerance test 2 h-glucose levels were increased in the amenorrhoea group (P < 0·05). The triglycerides (TG) and low-density lipoprotein-cholesterol (LDL) levels were the highest in the amenorrhoea group (P < 0·05). The same trend existed in total cholesterol and non- high-density lipoprotein-cholesterol (HDL) levels, although there was no statistical significance (P > 0·05). Subjects with a BMI<25 kg/m(2) had higher values of follicle stimulating hormone (FSH), LH, LH/FSH and prolactin (P < 0·001) than the other two groups. The levels of TG, LDL and non-HDL and the indices of glucose and insulin metabolism increased with the change in BMI (P < 0·001).

CONCLUSIONS

  The amenorrhoea group had severe endocrine and metabolic abnormalities, which appeared to be related to latent long-term complications and higher morbidity. The degree of dysbolism was positively associated with the change in BMI.

Milder forms of atherogenic dyslipidemia in ovulatory versus anovulatory polycystic ovary syndrome phenotype

BACKGROUND

Dyslipidemia is common in women with polycystic ovary syndrome (PCOS) but its prevalence in different PCOS phenotypes is still largely unknown.

METHODS

We measured plasma lipids and lipoproteins in 35 anovulatory PCOS (age: 25 +/- 6 years, BMI: 28 +/- 6 kg/m(2)), 15 ovulatory PCOS (age: 30 +/- 6 years, BMI: 25 +/- 3 kg/m(2)) and 27 healthy women (controls) age- and BMI-matched with ovulatory PCOS. PCOS was diagnosed by the presence of clinical or biologic hyperandrogenism associated with chronic anovulation and/or polycystic ovaries at ultrasound. In women with normal menses chronic anovulation was indicated by low serum progesterone levels (<9.54 nmol/l) during midluteal phase (days 21-24) in two consecutive menstrual cycles.

RESULTS

Total cholesterol, triglycerides and low-density lipoprotein (LDL)-cholesterol levels increased and high-density lipoprotein (HDL)-cholesterol decreased from controls to ovulatory and then to anovulatory PCOS (all P < 0.05). Levels of lipoprotein(a) (Lp(a)) and small, dense LDL increased (P < 0.0001 for both) and LDL size reduced (P < 0.005) between groups. Insulin resistance (by HOMA) showed a positive correlation with triglycerides and small, dense LDL and an inverse correlation with HDL-cholesterol and LDL size (P < 0.05 for all) in both PCOS phenotypes. No significant correlations were found with testosterone levels. At multivariate analysis, insulin resistance was independently associated with HDL-cholesterol and small, dense LDL in both PCOS phenotypes and with triglyceride concentrations in ovulatory PCOS only.

CONCLUSIONS

Women with ovulatory PCOS showed milder forms of atherogenic dyslipidemia than anovulatory PCOS and this seemed to be related to the extent of insulin resistance. Future prospective studies are needed to assess the relative contribution of such alterations on cardiovascular risk.

Atherogenic forms of dyslipidaemia in women with polycystic ovary syndrome

OBJECTIVE

Dyslipidaemia is very common in patients with polycystic ovary syndrome (PCOS) but, beyond plasma lipids, atherogenic lipoprotein (Lp) and apolipoprotein (apo) alterations are still ill defined.

DESIGN

We measured concentrations of apoB, Lp(a) and small, dense low-density lipoprotein (LDL) in 42 patients with PCOS [age: 28 +/- 7 years, body mass index (BMI): 27 +/- 5 kg/m(2)] vs. 37 age- and BMI-matched healthy controls.

METHODS

Elevated Lp(a) levels considered were those > 30 mg/dl while elevated apoB concentrations were those > 100 g/l.

RESULTS

Polycystic ovary syndrome showed increased triglycerides levels (p = 0.0011) and lower high-density lipoprotein (HDL)-cholesterol concentrations (p = 0.0131) while total- and LDL cholesterol were similar. PCOS also showed smaller LDL size (p = 0.0005), higher levels of total small, dense LDL (p < 0.0001), higher concentrations of Lp(a), as considered as absolute values (p = 0.0143) and log-transformed (p = 0.0014), while no differences were found in apoB levels. Elevated Lp(a) concentrations were found in 24% of PCOS, while elevated apoB levels were relatively uncommon (14%). Spearman correlation analysis revealed that Lp(a) concentrations were weakly correlated only with HDL-cholesterol levels (r = -0.378, p = 0.0431). In addition, 36% of patients with PCOS with normal plasma lipid profile showed elevated levels of Lp(a), apoB or small, dense LDL.

CONCLUSIONS

Atherogenic Lp abnormalities may be found in one-third of women with PCOS who have a normal lipid pattern. Future prospective studies are needed to test to which extent such atherogenic forms of dyslipidaemia may contribute to the increased cardiovascular risk in young women with PCOS.