A review article in “Human Reproduction Update” noted that polycystic ovary syndrome, or PCOS, affects between 4 and 8 percent of women that are of reproductive age. PCOS is associated with multiple cysts on the ovaries, hyperandrogenism, infertility, menstrual irregularities or cessation, metabolic abnormalities and psychological disorders.
Metabolic Complications
The metabolic complications of PCOS include insulin resistance, hyperglycemia, type 2 diabetes and metabolic syndrome. PCOS and metabolic syndrome are distinct disorders; however, women with PCOS are more likely to be affected by metabolic syndrome than women who do not have PCOS.
Metabolic Syndrome
The International Diabetes Federation defines metabolic syndrome as a cluster of disorders that include abdominal obesity, hypertension, high cholesterol, insulin resistance and diabetes. Besides abdominal obesity, not all of the disorders are required for a diagnosis of metabolic syndrome. The IDF also states that nearly 25 percent of the world’s population have metabolic syndrome, and they are three times more likely to have a heart attack or stroke and twice as likely to die from these events. Insulin resistance and abdominal obesity are the primary contributors to the symptoms and complications of metabolic syndrome. A study in the journal Metabolism reported that 46 percent of women with PCOS also have metabolic syndrome.
Insulin Resistance
Insulin resistance is common to both PCOS and metabolic syndrome. Insulin resistance is a condition that is defined by a decrease in the sensitivity of cells, like muscle and fat cells, to insulin. The decrease in insulin sensitivity causes cells in the pancreas to compensate by increasing insulin production and release. Therefore, persons with insulin resistance often have high levels of circulating insulin. A study in the journal Trends in Molecular Medicine stated that while some cells are insensitive to insulin in persons with insulin resistance, other cells are not. The increased levels of circulating insulin in women with PCOS stimulate ovarian cells to oversecrete androgens, which are male steroid hormones. Additionally, the high levels of insulin influence pituitary release of hormones that regulate androgen production. The insulin-stimulated increase in androgen production contributes to the virilization of women with PCOS, which manifests as increased facial hair growth, deepening of the voice, menstrual cessation and clitoral enlargement.
Obesity
A common characteristic of women with PCOS is obesity, especially increased abdominal fat. A review in the journal Obesity Facts reported that between 30 and 70 percent of women with PCOS are obese. Additionally, this review reported that obesity plays a central role in causing the symptoms of PCOS. Obesity is a diagnostic factor of metabolic syndrome, and research supports the idea that obesity is a requirement for the coexistence of PCOS and metabolic syndrome in women.
Hyperandrogenism
In women with PCOS, the ovaries secrete excess androgens, including the male sex hormone, testosterone. The high levels of insulin play a primary role in increasing the levels of circulating androgens in women with PCOS. The high levels of androgens actually exacerbate the metabolic symptoms of PCOS by further decreasing insulin sensitivity and promoting abdominal fat deposition. A study in the journal Human Reproduction found that when the ovaries were removed in women with PCOS, the levels of androgens decreased and insulin resistance was corrected. This study provides more evidence suggesting that androgens play a role in causing insulin resistance. The review in Obesity Facts cited much evidence to support that excess androgens increase abdominal fat deposition. Therefore in women with PCOS, a vicious cycle exists, where high insulin levels increase androgens, which increase obesity and insulin resistance, which increase insulin levels even more.
Treatment
Because obesity markedly exacerbates the symptoms and complications of PCOS and metabolic syndrome, weight loss substantially improves both the metabolic disorders and the symptoms of hyperandrogenism. In addition to lifestyle intervention, several drugs are available to treat the symptoms and complications of PCOS. A review of PCOS treatment strategies in Expert Opinion on Pharmacotherapy reported that oral contraceptive pills containing progestin are the drug of choice to treat the symptoms of hyperandrogenism. Oral antidiabetic drugs are effective in decreasing insulin resistance and the risk of cardiovascular complications in women with PCOS. Fertility problems are often managed with hormones that stimulate ovulation. In some cases, laparoscopic surgery on the ovaries may enhance fertility and improve pregnancy outcomes. Removal of one or both ovaries is not a standard method of treatment for PCOS.
References
- “Human Reproduction Update”; Metabolic Features of the Reproductive Phenotypes of Polycystic Ovary Syndrome
- International Diabetes Federation: The IDF Consensus worldwide definition of the Metabolic Syndrome
- PubMed: Incidence and Treatment of Metabolic Syndrome
- PubMed: Molecular Mechanisms of Insulin Resistance in Polycystic Ovary Syndrome
- “Obesity Facts”; Obesity and Polycystic Ovary Syndrome
