Efeito da melatonina na regulação da obesidade: estudo prospectivo longitudinal

Abstract

Introduction: Studies on the physiological role of melatonin have advanced in the treatment of diseases such as obesity and metabolic disorders. Objective: To evaluate the effect of melatonin supplementation in patients with overweight or obesity considering anthropometric profile (body weight, body mass index-BMI, abdominal circumference-AC, fat mass-FM and lean mass-LM) and biochemical(total cholesterol – TC and cholesterol fractions of low density lipoprotein - LDL-c, high density lipoprotein – HDL-c, non-HDL-c and triglycerides – TG, glycemia, insulin, C-reactive protein-CRP, and melatonin). Patients and Methods: A total of 67 patients were prospectively assessed: 54 with overweight or obesity (G1) and 13 eutrophic (G2). The analyzed variables included clinical, demographic, anthropometric and biochemical profiles, and life habits. Anthropometric and biochemical assessment was carried out before and after melatonin supplementation (5 mg) daily for 2 months. Results: There was predominance of females in both groups (G1=69%; G2=100%; P=0.019) with mean age of 40 ± 3 years in both groups. Diabetes mellitus (DM), systemic arterial hypertension (SAH), hypothyroidism, smoking and sedentarism were found only in G1 with prevalence in females (3%, 11%, 13%, 3%, 45%, respectively) compared to males (0%, 4%, 0%, 0%, 15%, respectively), while dyslipidemia was observed in both groups (2%). Melatonin administration in G1 decreased LDL-c (P<0.05) and non-HDL-c (P<0.001); in this group there was reduction both in males (TC and TG: P<0.001) as in females (glycemia: P<0.01; AC: P<0.001). In G1 females showed increase in HDL-c, TG, and TC (P<0.001). In G2 there was increase in TC and decrease in HDL-c (P<0.05) and AC (P<0.0001). Serum level of melatonin after supplementation increased significantly in both groups (P<0.001). Moreover, there was an increase in sleep hours in all groups, but significant in males and females with overweight or obesity (P<0,01). In G1 the correlation analysis in males revealed a significant negative correlation (P<0.05) between sleep hours and LDL-c (r=-0.630), non-HDL-c (r=-0.494), BMI (r=- 0.696), AC (r=-0.562) and FM (r=-0.703); and in females between insulin and HDL-c (r=-0.688). A significant positive correlation (P<0.05) was noted in G1 males and females, respectively, between insulin and body weight (r=0.586; r=0.470), AC (r=0.505; r= 0.491) and FM (r=0.490; r=0.527), and between CRP (r=0.368) and TG (r=0.488) only in females. In the eutrophic group there was a significant positive correlation (P<0.05) between BMI and TC (r=0.596), TG (r=0.695) and AC (r=0.698), AC and non-HDL-c (r=0.651), and insulin and CRP (r=0.680) observed in G1 females (r=0.368). Conclusions: It is worth mentioning the SAH, hypothyroidism, and sedentarism mainly in females with overweight or obesity. It also highlights the increase of serum level of melatonin and its impact as mediator of metabolic pathways, influencing the sleep time, and lipid and anthropometric profile including reduction of serum levels of TC, LDL-c, non-HDL-c, and TG, as well as AC, and increased of HDL-c; however, with variations according to the gender, BMI and possibly related to the comorbidities and life habits.