Age and Body Mass Related Changes of Cardiovascular Risk Factors in Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is considered a metabolic disorder closely related to obesity, insulin resistance (IR), hyperinsulinemia and unfavorable lipid profile, all increasing the risk for the occurrence of cardiovascular diseases. The aim of this study was to assess age and body mass index (BMI) related changes of cardiovascular risk factors in 90 women with PCOS. The cut-off age point was 30 years and for BMI 27.8 kg/m. In all patients systolic and diastolic blood pressure (BP), metabolic parameters comprising values of glucose and insulin during oral glucose tolerance test (OGTT), and basal lipid values were determined. Significant increase in blood pressure (BP) indices, basal insulin values and insulin resistance (IR) assessed by HOMA model were observed with aging and the increase of BMI, while the parameters of glucose metabolism, total cholesterol and triglycerides were significantly elevated only with aging. However, the correlation between the indices of arterial blood pressure, and lipid and glucose metabolism parameters occurred only in patients over 30 years of age, pointing to the causative relation and the consequent deterioration of IR and lipid profile with aging, influencing cardiovascular function in women with PCOS.


Introduction
Polycystic ovary syndrome (PCOS) in women of reproductive age is defined as hyperandrogenism with chronic anovulation in the absence of adrenal or pituitary disorder.For years, following the first description of Stein and Leventhal in 1935, PCOS had been diagnosed on the basis of clinical manifestation featuring obesity, hirsutism, amenorrhea and enlarged ovaries (1).Nowadays, in diagnosing PCOS we mostly rely on far more sensitive diagnostic methods: increased levels of luteinizing hormone (LH), ratio LH:FSH (follicle stimulating hormone), free and bound testosterone, androstenedion or dehydroepiandrosteronesulfate (DHEA-S) and sex hormone binding globulin (SHBG).Today, PCOS is considered a metabolic disorder closely related to obesity, insulin resistance and hyperinsulinemia.The severe insulin resistance is associated with the alterations in β-cell function.Moreover, the prevalence of the impaired glucose tolerance and diabetes is increased in PCOS (2).It is postulated that the disorder begins at menarche, and its characteristics do not change with aging (1).Females with PCOS below 18 years of age have comparable clinical, neuroendocrine and ultrasonographic features as the adult women with PCOS (3).It was demonstrated that the adolescents with PCOS were severely insulin resistant (4) and that the adolescent PCOS group could represent a cohort with a potential of developing cardiovascular diseases in the adulthood due to the aggravation of dyslipidemia and fibrinolysis with aging (5, 6).
Studies of the lipid profiles in adult women with PCOS had shown the increase in total cholesterol, triglycerides and LDL-cholesterol decrease in Apo-A1 and HDLcholesterol levels (7, 8).Seemingly, the same pattern of changes within the lipid family had occurred in the adolescent patients with PCOS (6).These findings increased the overall risk for cardiovascular diseases and were positively correlated with the increased occurence of coronary artery disease (7, 9).Angiographic studies of coronary arteries in women discovered more significant atherosclerotic plaques in the subgroup of hyperandrogenic women, while women with PCOS were found to have a seven-fold increased risk for the acute myocardial infarction (AMI) (10, 11).Furthermore, the relationship between elevated plasma insulin levels and hypertension was shown (9).
The aim of our study was to assess glucose and lipid metabolism according to age and body mass index (BMI), and to determine possible associations between the investigated cardiovascular risk factors in women with PCOS.

Methods
This study was conducted at the Institute of Endocrinology, Diabetes and Diseases of Metabolism of the Clinical Center of Serbia, affiliated to the Belgrade University School of Medicine.In all the patients PCOS was diagnosed according to the standard criteria: hyperandrogenism, oligoamenorrhea and ultrasonographic findings of polycystic ovaries (1).Three months prior to the investigation patients had normal fasting glucose and did not take any medication.They were investigated in the follicular phase of the menstrual cycle, or randomly, if amenorrhoeic.
Within the anthropometric research patients' body mass index (BMI) and indices of arterial blood pressure (BP) -systolic and diastolic (mmHg) were assessed.Respective weights and heights [BMI: weight(kg)/height(m) 2 ] were used for the former.According to age, patients were divided into ones below 30 -group A (n=52) and ones aged 30 or older -group B (n=38).Regarding BMI, they were assessed at 27.8 kg/m 2 obesity cutt-off, being divided into ones with BMI below 27.8 kg/m 2 -group C (n=44) and ones with BMI of 27.8 kg/m 2 or higher -group D (n=46).
A 75g oral glucose tolerance test (OGTT) was performed on each patient after an overnight fast.Plasma glucose (mmol/l; normal value: 3.3−6.1)was determined by the glucose-oxidase method (Randox, UK) using auto-analyser (Beckman, Austria).Plasma insulin (mIU/l; normal value: <20) was measured by radioimmunoassay (RIA, INEP, Zemun).Coefficient of variation (CV) for intra-assay was 20.4,7.6 and 6.1% for the concentration of 9.4, 23.7 and 181.6 mIU/l; for inter-assay CV was 22.1, 10.6 and 16.8% for the concentration of 8.6, 33.8 and 153.9 mIU/l, respectively.For the measurement of glucose and insulin venous blood was drawn at 30 minute intervals over 2 hrs following glucose ingestion.The integrated area under the curve (AUC) analysis for glucose and insulin was determined according to the trapezoidal rule.Insulin sensitivity index (S I ) was calculated from fasting glucose-to-insulin ratio (FGIR), homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) (12 −14).
Data are presented as the mean value ± standard deviation (mean ± SD).Student's t-test was used for the assessment of respective parameters between groups.Correlation between the observed parameters was determined using Pearson's coefficient of correlation.The statistical level of significance was set at p<0.05.

Results
The results of respective anthropometric, glucose, insulin and lipid parameters according to the age and body mass index of the investigated patients are presented in Table 1 and Table 2, respectively.Regarding the age of the examined women with PCOS, older patients showed significantly higher values of systolic and diastolic BP, fasting glucose, glucose at the end of 2 hours-lasting OGTT, integrated glucose response (AUC for glucose) during OGTT, and total cholesterol and trygliceride levels (Table 1).Analyses of PCOS patients regarding respective BMI showed that only systolic and diastolic BP were significantly elevated in the obese group of patients with PCOS (Table 2).
The obtained significant correlations in respect to the age and BMI for the whole group of patients with PCOS are presented in Table 3.
The correlations presented in Table 4 for the subgroup of patients below 30 and in Table 5 for the subgroup of those aged 30 and over were obtained after the assessment of patients according to their respective age groups.

Discussion
In this study anthropometric and metabolic characteristics of the group of women with polycystic ovary syndrome admitted for further evaluation were examined at the Clinical Center of Serbia's Institute of Endocrinology, Diabetes and Diseases of Metabolism.The entire group of patients was further analyzed regarding their age and BMI.
Regarding the age at which patients were assessed and BMI-related, it was observed that there was a significant increase in systolic and diastolic blood pressure with aging, as well as the increase of body weight.Interestingly, women became hypertensive with aging in spite of the fact that there was no difference in their body mass, which was the case in the BMI-related analysis.Therefore, it was speculated that the deterioration of arterial blood pressure could be a consequence of PCOS independent of the body mass.It was previously shown that the obese women with PCOS had higher arterial blood pressure (7).Our results were in agreement with the data from previous studies, indicating that systolic and diastolic blood pressure elevated significantly in the groups over 35 years of age (5).
Significant increase in the fasting glucose, as well as global deterioration of glucose tolerance, was observed in the group of the assessed metabolic parameters.Namely, women with PCOS over than 30 years of age had impaired glucose tolerance after the glucose challenge as well as pronounced integral glucose response after OGTT expressed by the area under the glucose curve.However, basal insulin levels and integral insulin response after the glucose challenge were constantly high and did not differ between the respective age groups.This was in accordance with the view that insulin levels were higher in all PCOS age categories than in the respective controls (5).At the same time positive correlation between the age and basal glucose was observed for the whole group of PCOS patients, as well as positive correlation between both age and BMI and blood glucose after the glucose challenge test, total cholesterol and LDL-cholesterol levels, respectively.
Nestler indicated that approximately 75% of women with PCOS were insulin resistant and hyperinsulinemic, and demonstrated the increasing incidence of diabetes mellitus, hypertension, dyslipidemia and atherosclerosis (15).Impaired glucose tolerance and non-insulin dependent diabetes mellitus (NIDDM) was reported to be in range of 18−35% and 7.5−10%, respectively, in women with PCOS (12,16,17).Dunaif suggested that obese women with PCOS were at high risk of developing NIDDM in their 20s and 30s, compared to normal population, and proposed that non-obese women with PCOS were probably more likely to develop NIDDM if followed up to their 40s (16).Our results were in agreement with the above mentioned data, as we supposed that our group of women with PCOS developed hyperinsulinemia and insulin resistance already in the third decade of their life, Број 6

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Страна 597 even earlier (6, 16).Insulin resistance found in patients with PCOS was due to the defect in postreceptor signal transduction between receptor kinase and glucose transporters (18).At the same time, there was a speculation on the existence of a PCOS-specific adipocyte insulin resistance resulting in neutralisation of the stimulatory influence of hyperinsulinemia on insulin secretion (19).
According to the latter, our patients -even under 30 years of age -expressed the decreased insulin sensitivity assessed by the basal insulin value and HOMA model.Other indices of insulin action, as FGIR and QUICKI, seemed not specific and accurate in the assessment of insulin sensitivity in our group of women with PCOS.
Contrary to the results obtained in relation to their age, our group of women with PCOS did not show deterioration in glucose tolerance and integral glucose response regarding their BMI.In the non-obese group of women with PCOS, basal insulin level was over the upper limit of the normal range and was elevating with aging.Other parameters for the assessment of insulin sensitivity showed the same pattern of change as those obtained for age-related differences.
It was shown that traditional cardiovascular risk factors were more prevalent in hyperinsulinemic women with PCOS than in their normoinsulinemic counterparts.It was also shown that normoinsulinemic women with PCOS were under higher cardiovascular risk than unselected normal healthy controls (20).In spite of the non-significant difference in insulin levels between the examined subgroups of PCOS women, high levels of insulin with the advanced increase with aging and aggravation of BMI were obtained, which was in accordance with the previous results (6, 20).Furthermore, when the peripheral insulin effect was assessed with the indexes of insulin sensitivity, only HOMA model clearly showed the deterioration of insulin sensitivity with aging and the aggravation of BMI in our patients with PCOS.
The group of patients with PCOS showed an increase in all observed lipid parameters between the third and the fourth decade of life, which was significant for total cholesterol and triglycerides.The increase was observed for total cholesterol, LDL-cholesterol and triglycerides, after the assesment of the patients towards their BMI.Total cholesterol in the whole group of PCOS patients was in correlation with age and BMI.When the patients were analyzed in relation to their age, in patients younger than 30 years of age, correlation was observed between total cholesterol and triglycerides with BMI and glucose response after glucose challenge, while only triglycerides correlated significantly with BMI in patients older than 30 years of age.
It was shown that hyperinsulinemia in PCOS correlated with low HDL and high triglycerides' level (7), which was not found in our group of patients, in spite of the elevated insulin levels and insulin resistance present in all the analyzed groups.The dyslipidemia of the insulin resistance syndrome (i.e., increased triglyceride levels, decreased HDL, and compositional changes in LDL) appeared to be caused by characteristics of the insulin-resistant state itself, rather than by elevated insulin concentrations or obesity.Proved persistent defect of β-cells of the endocrine pancreas and their secretion was found in spite of significant improvement in insulin sensitivity, suggesting that it could represent a primary abnormality of the polycystic ovary syndrome (21).
The atherogenic potential of the decreased HDL levels is a well known fact.Unexpectedly, elevated LDL was not a characteristic of the dyslipidemia of insulin resistance.However, in the insulin-resistant state, the composition of LDL was altered.It was demonstrated that in women with PCOS there existed an elevation of LDL-cholesterol subfraction III (22).Recently, it was observed that in PCOS patients HDL and LDL-cholesterol concentrations remained within the range of the healthy population, and that there was a significant derangement within LDL/Apo-B related complex with aging.Also, a significant increase in triglycerides was verified in the same study, which, together with the derangement in LDL/Apo-B complex, pointed to the altered metabolism of very low-density lipoproteins (VLDL) in relation to aging (6) in PCOS women.

Conclusion
The results of this study demonstrated a deterioration of glucose and lipid metabolism presumably related to the age of the examined patients with PCOS.Consequently, a substantial degree of insulin resistance was shown, best assessed through the indices of insulin action as its basal insulin value and HOMA model.
A significant increase in systolic and diastolic arterial blood pressure with aging and the increase in body weight was noted in the examined group of PCOS patients.However, only in patients over 30 years of age correlation between the indices of arterial blood pressure and lipid and glucose metabolism parameters was found, pointing out their causative relation and consequent deterioration of insulin resistance and lipid profile with aging, influencing the cardiovascular function in women with PCOS.