The Association between People’s Chronotype and Hormones Related to Appetite

Recently, it has been suggested that people’s chronotype is involved in regulating food intake and obesity. This study aimed to investigate the association between chronotypes with hormones related to appetite in adults in Tehran. Methods: This cross-sectional study was conducted on 353 men and women aged 18-60 years using convenience sampling in Tehran municipality community centers. Information on morningness-eveningness choronotype and physical activity (PA) level were collected by validated questionnaires. The data for anthropometric measurements and 3-day food recalls were also collected. ELISA method was used to assess Neuropeptide Y (NPY) and leptin serum level.  Results: The prevalence of eveningness, intermediate, and morningness chronotypes was 11%, 47.6%, and 41.4%, respectively. The participants with eveningness type were significantly younger (P = 0.001). The percentage of men with eveningness type was significantly higher than women (P = 0.001). The mean values of height, weight, body mass index (BMI), waist circumference, total calorie intake, protein, carbohydrate, fat, and calorie intake from each of the main meals and snacks, were not different among three chronotypes. Leptin and NPY did not show any significant association with chronotypes. Conclusion: Individual’s chronotype was not associated with NPY and leptin serum level. Further studies on a population with more varied work shifts are suggested