Correlation of Gut Microbiota Profile with Body Mass Index Among School Age Children

[Background]The correlation between gut microbiota with body mass index is controversial. This study aimed to explore the correlation between gut microbiota profiles, Bacteroidetes and Firmicutes, with a body mass index in 7 - 12- year- old school aged children, Iran.[Methods]This cross-sectional study was carried out on school-age children. A total of 188 elementary school children were selected through cluster sampling frame. Data collection tool was the international physical activity questionnaire (IPAQ), therefore, we checked the anthropometric characteristics. Fecal sampling was obtained from all study samples, Langround, Iran. Obese (BMI = 25.8 ± 3.40 kg/m²), normal-weight (BMI = 15.54 ± 1.19 kg/m²), and lean (BMI = 12.79 ± 1.8 kg/m²) among langroud children aged 7 - 12 years. The total stool bacterial genomic DNA was extracted by quantitative real-time PCR (Q-PCR) to determine the colony forming units (CFU) of Bacteroidetes and Firmicutes. Q_PCR data were analyzed by using SPSS version 19.0, and analyzed interpreted statistical exams such as Spearman’s rank correlation coefficient and Kruskal Wallis test. Due to the fact that the data was not normal, P < 0.05 was set as a significant level.[Results]Gut microbiota, Firmicutes and Bacteroidetes CFU, and so bact/firm ratio were significantly different among the three group fecal samples (P < 0.0001, P = 0.025, P = 0.004). Bacteroidetes and bact/firm ratio had a significant difference among girls (P = 0.037, P = 0 0013); however, there is no significant difference among boys. The results indicate that there is a significant negative correlation between bact/firm ratio with BMI and waist circumference (r = -176, P = 0.016, r = -151, P = -0.3).[Conclusions]The amount of Bacteroidetes and so bact/firm ratio were decreased among obese children; however; Firmicutes increased. It was suggested that obesity in children might be associated with the imbalance of gut microbes.