Relation between obesity, lipid profile, leptin and atopic disorders in children

Background: Obesity has become a disease of great importance affecting children and adolescents. Obesity can cause atopy or inflammation, where there are some common factors that predispose to both obesity and atopy. Objective: To study the factors contributing to allergic disorders in obese children, the role of leptin in obesity related atopic disorders and the relation of birth weight and breast feeding to both obesity and atopy. Methods: Forty seven obese children and adolescents and 45 healthy children (control group) were included in the study. The obese children were divided into 2 groups (based on the history of nasal allergy, bronchial asthma, skin, eye or food allergy), group I (n=21) atopic and group II (n=26) non atopic. All obese children were subjected to complete blood count, serum triglycerides and cholesterol, serum leptin (for control group also) and serum total immunoglobulin E (IgE) measurement. Results: Body mass index (BMI) was significantly higher in group I than group II (33.35±9.93 vs. 23.70±9.7IU/L, p=0.000), also serum total IgE was significantly higher in group I than in group II (510.476±366.407 IU/L vs. 114.577±120.940 IU/L, p=0.000). Group II showed higher serum leptin level than group I (185.115±105.912 vs. 133.048±100.718 ng/ml), a difference not statistically significant (p = 0.092), yet, both were higher than the control group (7.24±5.98 ng/ml). Significant positive correlation was found between serum leptin level and age (p=0.000, r = 0.60) and BMI (p=0.000, r = 0.720), while negative correlation was found between serum leptin and IgE (r= 0.289, P=0.049). Significant positive correlation was found between obesity (BMI) and family history of obesity (r = 4.672, p = 0.036). Conclusion: There is a strong positive association between obesity and atopy: Serum leptin was higher in obese children when compared to control group more in non atopic than atopic group yet not statistically significant. Family history of obesity is an important predisposing factor for obesity in children. The frequency of atopy was higher in artificial than in breast fed obese children. Therefore efforts should focus on weight reduction as a part of treatment of asthma in obese children, also serum leptin assay is important in all obese children and further studies are needed to know more details about leptin hormone and its relation to both atopy and obesity. Keywords: Obesity, Leptin hormone, Atopy, Total IgE, Allergic disorders Egypt J Pediatr Allergy Immunol 2008; 6(1): 27-34.