Association between major dietary patterns and polycystic ovary syndrome: evidence from a case-control study

Polycystic ovary syndrome (PCOS) is a multifactorial endocrine disorder in women. Change in lifestyle, especially dietary pattern, might have a role in the prevalence of PCOS. The limited number of studies has made it difficult to draw any conclusion about the relationship of dietary patterns with PCOS. This study aimed to investigate the association between dietary patterns and PCOS. A case-control study was performed on 225 patients newly diagnosed with PCOS and 345 healthy women in Isfahan, Iran. The presence of PCOS was confirmed by expert gynecologists based on Rotterdam criteria. Usual dietary intake was assessed by a 168-item food frequency questionnaire. Dietary patterns were identified by principal component analysis. Three major dietary patterns including Western, plant-based, and mixed were identified that explained 53.93% of the variance in food intake. The top tertile of the Western dietary pattern significantly increased the odds of PCOS (odds ratio (OR), 2.03; 95% confidence interval (CI), 1.12-3.67), both before and after adjustments for covariates. After adjustments for potential confounders, the highest tertile of the plant-based dietary pattern was related to higher odds of PCOS than the lowest tertile (OR, 2.32; 95% CI, 1.23-4.37). In addition, those in the second tertile of the mixed dietary pattern were 66% less likely to have PCOS compared with those in the lowest tertile (OR, 0.34; 95% CI, 0.18-0.61). In conclusion, we found that Western and plant-based dietary patterns were associated with an increased risk of PCOS. Also, moderate adherence to the mixed dietary pattern was associated with a reduced risk of PCOS. Additional studies with a longitudinal design are required to confirm our findings.