Anahita Hamidi, Abdolhamid Bagheri, Hossein Fakkhrzadeh, Ramin Heshmat, Alireza Moayyeri, Mohammad Jafar Mahmoudi, Rasoul Pourebrahim, Ozra Tabatabaee, Bagher Larijani,
Volume 4, Issue 2 (17 2004)
Abstract
Background: Leptin is an adipocyte- derived hormone that plays an important role in the pathogenesis of obesity. Obesity is associated with insulin resistance and hyperinsulinemia. Insulin resistance is one of the factors which have been suggested to affect leptin serum levels. There are few studies evaluating the relation between leptin level and insulin resistance in childhood and adolescence obesity. The aim of the present study is to investigate this relationship in Iranian obese children.
Methods: We screened 13089 primary school students aged 7-12 years. Children were divided to overweight and normal based on the recently published National Center for Health Statistics growth charts. The number of children which were overweight was 498, of whom 347 subjects particiated in the study. Fasting blood glucose, insulin and leptin levels were measured and homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) and fasting glucose to insulin ratio (FGIR) were calculated and compared between two groups.
Results: Serum leptin levels were significantly higher in overweight compared to normal group. (11.58±8.1 and 8.1±5.2 respectively p<0.05). Before adjustment for BMI, there was a significant correlation between leptin and fasting insulin, HOMA –IR index and FGIR. (r=0.1, p< 0.05, r=0.1 , p<0.01, r=0.07, p<0.05 respectively). After adjustment for BMI, no significant correlation was found (r=0.097, p=0.20).
Conclusion: The relation between leptin and insulin resistance was weak and disappeared after adjustment for BMI. It seems that many other factors including BMI and total fat amount may affect this relationship. Further studies in this field are required.
Hossein Fakhrzadeh, Maryam Ghodsi, Anahita Hamidi, Alireza Moayyeri, Ramin Heshmat, Rasool Poorebrahim, Masoumeh Noori, Bagher Larijani,
Volume 5, Issue 1 (18 2005)
Abstract
Background: It is well recognized that an increased body weight is often associated with increased blood pressure. Moreover, leptin an adipocyte-derived hormone is strongly suggested to have an important role in pathogenesis of the obesity. We aimed to evaluate the levels of serum leptin in association with obesity and hypertension in a sample of Iranian obese children.
Methods: Children from all the primary schools of a distinct of Tehran were screened for obesity. Children with a waist circumference equal to or above 90th percentile for their age and height were invited for the study. Anthropometric measurements were done and blood samples for fasting serum leptin levels were collected from 563 enrolled obese children. Multivariate linear regression analysis was used to evaluate relationship of various factors with obesity.
Results: Mean Serum leptin levels were 8.65 ±2.18 (ng/ml). Serum Leptin levels were higher in girls than boys (P=0.009). There were significant correlations between body mass index (BMI) and serum Leptin levels, child age, systolic and diastolic blood pressure. Systolic blood pressure and diastolic blood pressure lost their association with serum Leptin level in multivariate linear regression analysis.
Conclusion: BMI is independently associated with Leptin levels among obese children. This may affirm a role for this hormone in the pathogenesis of childhood obesity. It seems unlikely that plasma Leptin be a major mediator of association between obesity and hypertension. However, severe hyperleptinemia may act as a risk factor for increased blood pressure.
