Evaluating the Role of Diet ,Life Style , and Leptin Receptor (LEPR) Gln223Arg Gene Polymorphism as Risk Factors for Obesity among Secondary School Girls in Gaza Strip

Abstract

Introduction: Obesity is one of the most prevalent diseases worldwide today. It results from a combined effects of, environmental, lifestyle, and genetic factors. The leptin receptor gene plays a critical role in the regulation of body weight. Genetic variations of leptin receptor gene may play a role in the pathophysiology of human obesity. Dietary and lifestyle factors are also considered as a risk factors for obesity among adolescents. Our study aimed to evaluate the relation between these factors and obesity among adolescents in Gaza strip. Materials and methods: The present study is a cross sectional study included 409 secondary school adolescent females age (16-17) years (grades 10 and 11) selected randomly from 6 schools distributed all over the 6 governorates in Gaza strip-Palestine. weight was measured for the students and recorded in kilograms (Kg). Height (in meters)was measured. The participants were classified according to the current standard definitions of overweight and obesity used by the Center for Disease Control (CDC) and World Health Organization. BMI was determined using graphs or growth charts to find each adolescents BMI percentile-for-age. lipid profile of the study population was also determined. Genomic DNA was extracted and amplification of the LEPR gene was carried out using polymerase chain reaction restriction fragment length polymorphism(PCR-RFLP). The distribution of alleles frequency of the leptin receptor GLN223ARG polymorphism was determined and compared between normal weight and obese females. Results: Prevalence of overweight and obesity among study population was 27.9% and 6.6% respectively. Average body mass index of obese females(obese and overweight) was (27.3 ± 3.2) whereas that of normal weight females was (21.4 ± 1.8). Mean levels of triglycerides were (14.8 ± 27.6 mg\d) among obese and (109.11 ± 26.27 mg\d) among normal weight females with significant difference (P=0.039). The mean levels of total cholesterol, and LDL were increased in obese compared to normal weight (146 ± 30.3 mg/dl vs. 143.6 ± 28 mg\d, P=0.430) and (86.4 ± 29.0 mg/dl vs. 85 ± 29.9 mg\d, P=0.63) respectively but the differences were not significant. Sixty nine percent (69.3%) of the fathers of normal weight girls were employed compared to obese girls where (60.1%) of their fathers were employed (P=0.05). Twenty five percent (25.6%) of normal weight girls reported obesity among their relatives compared to (46.8%) of Obese girls ( P=0.000), and Twenty one percent (21.1%) of normal weight females reported that they had gone in diet compared to (54%) Of obese girls(P=0.000). Among obese girls, (56.2%) watch television more than one hour (>1 hour) daily compared to (45.3%) of normal weight girls (P=0.038). When comparing the frequency of the mutant genotype with that of wild type, the mutant genotype was higher (43.7%) among obese compared to normal weight females (35.6%) but the difference was not statistically significant (P=0.068). For normal weight females (74.2%) of them eat breakfast regularly compared to obese females (64.5%) (P=0.04).With regard to the frequency of homozygous(ARG-ARG) genotype there was a significant difference between obese (19.2%) and normal weight girls (10.9%)( P=0.05).When analyzing the effect of the genotype on triglyceride levels, females with the homozygous (ARG-ARG) genotype have higher mean triglyceride level (121.17 ± 32.43 mg\d) compared to those with wild type (GLN-GLN) (110.12 ± 24.22 mg\d) and heterozygous type(GLN-ARG) (109.86 ± 29.57 mg\d) (p=0.045). Conclusion: It is concluded that fathers job, family history of obesity, psychological factors, watching television more than one hour (>1 hour) daily, having breakfast and genetic polymorphisms (GLN223ARG) of Leptin receptor gene, represent potential risk factors for obesity among female adolescents in Gaza strip.