The association of obesity and serum leptin levels with complete blood count and some serum biochemical parameters in Iranian overweight and obese individuals

Background: Obesity has been suggested to be well correlated with altered levels of complete blood count (CBC) parameters. In this study, the relationship of body mass index (BMI) and circulating leptin levels with CBC among obese and overweight adults was examined. Methods: CBC and biochemical parameters, WBC and hematological profiles, leptin levels, related factors to liver, and kidney and lipid profiles were measured among 184 obese and overweight people aged 18–60 years. Statistical analysis was performed using SPSS software. To assess the normality of data, the Kolmogorov–Smirnov test was used. Logarithmic transformation was performed for some variables with non-normal distribution. The association between 2 quantitative variables was measured using bivariate correlation (Pearson or Spearman). Pearson correlations and multiple regression analysis were performed to assess the correlation between variables. Simple and multiple regression analyses were performed to predict some variables. P- value <0.05 was considered significant. Results: Hematocrit, insulin, fasting blood sugar, uric acid, TG, LDL-C, VLDL-C, and ALT were positively correlated with BMI (p=0.041, r=0.149 for hematocrit; p≤0.001, r=0.520 for insulin; p≤0.001, r=0.363 for FBS; p≤0.001, r=0.309 for uric acid; p=0.015, r=0.189 for TG; p=0.030, r=161 for LDL-C; p=0.019, r=0.181 for VLDL-C; p≤0.001, r=0.299 for ALT), whereas urea and HDL-C were negatively correlated with BMI (p≤0.001, r=-0.368 for urea; p≤0.001, r=-0.297 for HDL-C). Moreover, LDL-C and insulin were positively correlated with leptin (P = 0.011, r = 0.194 for LDL-C, P = 0.013, r = 0.114 for insulin) and hematocrit, urea, creatinine, TG and VLDL-C were negatively correlated with leptin (p=0.040, r=-0.162 for hematocrit; p≤0.001, r=-0.305 for urea; p=0.007, r=-0.219 for creatinine; p=0.025, r=0.188 for TG; p=0.007, r=-0.218 for VLDL-C). Our analysis showed that white blood cell was positively correlated with leptin (β=17.36, p=0.048). Also, other CBC parameters had no significant correlations with BMI and leptin. Conclusion: According to the findings of this study, BMI had a negative association with urea and HDL-C, while BMI had a positive association with insulin, hematocrit, FBS, uric acid, TG, VLDL-C, LDL-C, and ALT. Furthermore, leptin had a negative association with hematocrit, creatinine, and urea, TG, VLDL-C and a positive association with LDL-C and insulin among the participants of this study.