Evening chronotype is associated with hormonal and metabolic disorders in polycystic ovary syndrome

Despite current treatments for polycystic ovary syndrome (PCOS), a considerable number of women with this syndrome do not reach the treatment goal, suggesting the presence of other probable misdiagnosed features of this syndrome that are not taken into account in the assessment and therefore in the therapeutical approach. The aim of this study was to investigate the prevalence of chronotype categories in women with PCOS and their role in determining hormonal and metabolic aspects of PCOS. This observational case-control study was conducted on 112 women with PCOS and 112 healthy women matched for age and body mass index (BMI). At baseline anthropometric parameters such as weight, height, BMI and waist circumference, clinical parameters such as Ferriman-Gallwey (FG) score, biochemical parameters such as fasting plasma glucose, insulin levels and assessment of the homeostasis model of insulin resistance (HoMA-IR), inflammatory parameters such as C-reactive protein (CRP) and hormonal parameters such as testosterone levels were evaluated. Women with PCOS had a lower chronotype score (p < .001) which indicates a higher prevalence of evening chronotype (EC) category (p = .037) compared to controls. After adjustment for BMI, chronotype score was significantly negatively correlated with CRP levels (r = -0.418, p < .001), testosterone levels (r = -0.543, p < .001) and FG score (r = -0.514, p < .001). Linear regression analysis showed that high testosterone levels were among the factors most associated with a lower chronotype score (p < .001), followed by BMI (p < .001) and HoMA-IR (p < .05). In conclusion, there is a higher prevalence of EC in women with PCOS than in women without the condition, which in turn was associated with a worse hormonal and metabolic profile. These findings provide support for the relevance of including chronotype assessment in the treatment of women with PCOS.