The prevalence of metabolic syndrome in women with polycystic ovary syndrome

Overview

Background and Aims:
Polycystic ovary syndrome (PCOS) affects between 4-10 % women of fertile age and is often connected with insulin resistance. We aimed to ascertain the prevalence of metabolic syndrome in Czech women with PCOS and to describe the connections of different features of metabolic syndrome with insulin sensititivity.

Methods and Results:
179 women with PCOS. Clinical examination was done and blood lipid spectrum was measured. Euglycaemic hyperinsulinaemic clamp was done in 114 subjects. Metabolic syndrome (according to ATP III criteria) was detected in 28,7 % women. The most frequent features were an increased waist circumference, decreased concentration of HDL – cholesterol (both in 96 %), and increased blood pressure (88 %). Increased triglycerides (49 %) and impaired fasting blood glucose or diabetes mellitus type 2 (37,3 %) were less common. The average insulin sensitivity described as corrected glucose disposal (Mk) was 34,9 ± 12,70 µmol/kg/min. The most tight correlations was that of Mk and waist circumference (r=-0,896), weight(r=-0,875) and BMI (r= -0,844).

Conclusion:
The increased risk of metabolic syndrome and the decreased insulin sensitivity in polycystic ovary syndrome is tightly connected with obesity, especially with its abdominal type

Key words:
polycystic ovary syndrome- obesity - metabolic syndrome – insulin sensitivity

Polycystic ovary syndrome (PCOS) is encountered as one of the most common endocrinopathies in women of fertile age, as it affects 4-10 % of these women (1-3). However, PCOS is not only a gynaecological affection. In last years, a great attention is given to so called late consequences, such as diabetes mellitus type 2 (DM2) or ischemic heart disease (IHD).

Some authors think that PCOS is another feature of metabolic syndrome (MetSy) (4). MetSy is significantly more common in American PCOS women than in their healthy counterparts (5, 6). The prevalence of MetSy reached 40% -50 %, however PCOS women were mostly obese with average BMI over 30 kg/m². A thorough metaanalysis concerning MetSy in PCOS was published recently and described approximately twice increased risk for MetSy in PCOS event hen compared with BMI matched women (7).

The aim of our work was to describe the prevalence of MetSy in Czech women with PCOS and to describe how are different features of this syndrome connected with insulin sensitivity measured by euglycaemic clamp.

Subjects and Methods:

The medical records of women with PCOS fulfilling European Society for Human Reproduction and Embryology (ESHRE) diagnostic criteria (n=179) were evaluated retrospectively using computerised medical record database. In 114 subjects, euglycaemic hyperinsulineamic clamp was also done.  Waist circumference was measured half way between lower ribs and spina iliaca anterior superior with precision to 0,5 cm Blood pressure was measured twice by mercury sphygmomanometer after 10 minutes of sitting. Blood glucose, total and HDL-cholesterol and triglycerides were measured in fasting serum sample by enzymatic method on analyser Cobas 6000 modul C (Roche Diagnostic GmbH Mannheim). Insulin and C peptide were measured by ECLIA on analyser Cobas 6000 modul E (Roche Diagnostic GmbH Mannheim). Steroid hormones, gonadotrophines and sex hormone binding globuline were measured as we have described previously (8). Euglyceamic hyperinsulinaemic clamp was done according to De Fronzo (9) in modification with empirical manual correction of velocity of glucose infusion as described previously (10). The diagnosis of MetSy was based on ATP III criteria (11). The relationships of different features of MetSy and insulin sensitivity were evaluated by multivariate regression with reduction of dimensionality using the method of orthogonal projections to latent structures (O2PLS).

Results

Metabolic syndrome was present in 28,7 % women with PCOS. The most common features were an increased waist circumference over 80 cm and decreased HDL – cholesterol concentrations (in 96 % of subjects), increased blood pressure (88 %), increased serum triglycerides levels (49 %) and less frequent were impaired fasting glucose or DM2 (37,3 %). Fifty three women (29,6%) were free of any metabolic syndrome feature and in 50 of them, BMI was below 25 kg/m² . The average insulin sensitivity described as corrected glucose disposal (Mk) was 34,9 ± 12,70 µmol/kg/min. The most tight correlations was that of Mk and waist circumference (factor loading-0,358; r=-0,896), weight(factor loading -0,349; r=-0,875) and BMI (factor loading -0,336; r= -0,844).The less tight was correlation between Mk and triglycerides (factor loading -0,243; r=-0,602), HDL cholesterol (factor loading 0,215; r= 0,533) or systolic blood pressure (factor loading -0,139; r= -0,344) –see table 1.

Discussion:

Metabolic syndrome was present in nearly 30 % of women affected with PCOS. The most common feature was an increased waist circumference and decreased HDL-cholesterol levels.

Obesity is one of the risk factors for IHD and DM 2. The prevalence of obesity in  PCOS varied from 20 % to 80 % in USA (12). Obesity could significantly modify also endocrine and gynaecologic features of PCOS. The increase on body weight could reveal the latent form of the disease (13). On the other hand, weight reduction could reverse reproductive abnormalities (14).

Our data are in accordance with others (15, 16) and are thrice as high as data from south Italy (17).However, we accord with all of these authors in the description of connection between MetSy and obesity (15, 17). Similar results were published recently also for adolescent girls with the risk of MetSy given by obesity and not increased by PCOS as such (18).

Insulin resistance is thought to be the central abnormality of MetSy. We have found that insulin sensitivity was most tightly connected with abdominal obesity and global adiposity. On the contrary, insulin sensitivity was not connected with diastolic blood pressure and was only slightly connected with systolic blood pressure. These data accord with others (19).

In conclusion, the occurrence of metabolic syndrome in PCOS is tightly connected with obesity, especially with abdominal adiposity.

Acknowledgement: The study was supported by grant NS/9831-4 of Interní grantová agentura MZ ČR (IGA).

The list of abbreviations:

• ATP III-Adult Treatment Panel III
• BMI-body mass index
• DM2-diabetes mellitus type 2
• ESHRE-European Society for Human Reproduction and Embryology
• HDL-cholesterol-high density cholesterol
• IHD-ischemic heart disease
• Mk-corrected glucose disposal
• PCOS-polycystic ovary syndrome

Address for correspondence:
Jana Vrbíková, MUDr., PhD.,
Endokrinologický ústav,
Národní 8, Praha 1, 116 94,
jvrbikova@endo.cz