Abnormal Glucose Metabolism and Infertility
Background: Several studies have suggested that abnormal glucose metabolism, caused by the easy availability of calories and an increasingly sedentary lifestyle, is a cause of infertility. Indeed, specific foods have been shown to affect fertility by influencing related signaling pathways. Excess insulin has been shown to induce hormonal imbalances, which in turn can disrupt ovulation, egg quality, and conception, and women exhibiting insulin resistance often develop polycystic ovarian syndrome (PCOS). Similarly, a majority of diabetic individuals also suffer from infertility. Recently, our understanding of the relationship between glucose metabolism and fertility has greatly improved.
Methods: The published literature was systematically reviewed for case-controlled and cohort studies investigating infertility and glucose metabolism. A meta-analysis was then performed on all studies meeting well-defined selection criteria, as determined by two independent reviewers. The studies were critically evaluated using the Newcastle-Ottawa scale for non-randomized studies, before data were pooled and analyzed.
Main findings: Twenty-one articles were included in the final analysis, all of which provided the age, BMI, and ovulatory status of the subjects. A significant association between impaired glucose metabolism and infertility was observed. Additionally, impaired glucose metabolism was significantly more likely to occur where subjects were over 30 years of age, had a BMI of over 25 kg/m2, or had metabolic syndrome. Impaired glucose metabolism was also associated with PCOS and infertility in women.
Conclusion: We have systematically pooled the available evidence, and we find a convincing causative link between altered glucose metabolism and serious fertility complications.