Circadian rhythms in women with polycystic ovarian syndromeand their role in determining metabolic dysfunction

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age for which a lifestyle approach is an integral part of treatment. Despite modern therapies for this syndrome, a significant number of women with this condition do not achieve treatment goals, suggesting that there are other features of this syndrome that are not taken into account in the assessment and therefore choice of therapeutic approach. Chronotype is known to play a role in determining dietary preferences and the risk of developing endocrine-metabolic diseases, including those of PCOS. Aim : to study differences in circadian rhythms in women with PCOS and to evaluate their role in determining metabolic aspects of the disease. Materials and methods : 109 women aged 18–36 years (mean age 26.3±4.3 years) with a confirmed diagnosis of PCOS were included in the study and divided into 3 groups according to chronotype: Group 1 (evening chronotype) – 19 (17.4 %) subjects, Group 2 (intermediate chronotype) – 38 (34.9%) subjects and Group 3 (morning chronotype) – 52 (47.7%) subjects. All patients underwent standard clinical, laboratory and instrumental examinations to determine the status of PCOS, as well as a medical history and physical examination with assessment of anthropometric parameters. Results : patients with the evening chronotype exercised less regularly and were significantly less physically active, and had higher rates of smoking and arterial hypertension than patients with other types of circadian rhythm. The evening chronotype was associated with higher body mass index (BMI; p=0.001), waist and hip circumference (WC and HC; p=0.004 and p=0.003, respectively), WC/HC ratio (p=0.017), neck circumference (NC; p=0.013), and Deurenberg fat mass percentage (p=0.001), as well as lower prolactin and 25(OH)D levels (p=0.046 and p=0.037, respectively) compared to the mid-phase phenotype. And compared to the morning phenotype, women with the PCOS and evening phenotypes had significantly higher BMI (p<0.001), WC (p<0.001), HC (p<0.001), OB (p<0.001), WC/HC (p=0.009), NC (p<0.001), Deurenberg fat mass percentage (p<0.001) and levels of very low density lipoproteins (p=0.042), ApoA1 (p=0.042), insulin (p=0.020), HOMA-IR index (p=0.035) and lower 25(OH)D (p=0.004). Low-density lipoproteinemia was more common in the morning circadian variant compared to the evening PCOS group (p=0.042), and isolated lipid abnormalities were less common compared to the intermediate chronotype (p=0.028). Conclusions : women with PCOS and evening chronotype have worse anthropometric indices, more severe degree of IR and in general are less likely to lead a healthy lifestyle, suffer more often from arterial hypertension compared to women with PCOS and other types of chronotypes. Further study of circadian rhythm abnormalities in PCOS has significant potential and may help to develop effective treatment strategies for this disease.