Introduction
Polycystic ovary syndrome (PCOS) is a common and complex endocrine-metabolic disorder affecting 5-20% women of reproductive age worldwide.1 Patients with PCOS are at an increased risk of diverse reproductive and metabolic dysfunctions, such as obesity, insulin resistance, dyslipidemia, and metabolic syndrome.2 Using RNA sequencing techniques, our previous studies first revealed that monosaccharide biosynthesis is a novel marker for identifying patients with PCOS.3
Fructose is an important monosaccharide and fructose consumption is associated with the risk of developing dyslipidemia, fatty liver and insulin resistance,4 all of which are associated with PCOS. Recently, we first found that fructose metabolism of PCOS patients has significant differences from normal controls, and the abnormal fructose metabolism may be related to obese and insulin resistance in PCOS patients.5 Noteworthy, fructose is the only carbohydrate that generates uric acid during its metabolism6 and a synergistic effect of fructose on uric acid levels has been suggested.7 Fructose appears to mediate the metabolic disorders in part by raising uric acid8 and accumulating evidence indicates that fructose-induced hyperuricemia has a key role in the development of insulin resistance.7 Meanwhile, the importance of uric acid in reproductive diseases has been increasingly recognized, for example, serum uric acid levels are associated with increased odds of anovulation among young women.9 Despite these advances in knowledge, the relationship between serum fructose and uric acid in PCOS remains poorly understood and their relationship with PCOS-related metabolic disorders needs to be further explored. Thus, in this study, we measure and evaluate serum fructose and uric acid levels in a same cohort from PCOS patients and control subjects, and apply a flexible and powerful approach, restricted cubic splines, to analyze the association between fructose and uric acid in women with PCOS.