Obesity and Type 2 Diabetes Markers and Their Association with Fat-mass and Obesity-associated Gene (FTO) Variants in Some Selected Ethnic Populations in Niger Delta, Nigeria

Aim: To assess the levels of some glycemic parameters and their association with fat-mass and obesity-associated gene (FTO) variants in some selected ethnic populations in Niger Delta, Nigeria.

Study Design: Case-controlled observational study.

Place and Duration of Study: Federal Medical Centre, Asaba, Delta State and Safety Molecular Pathology Laboratory, Enugu, Nigeria, between March 2020 and February 2022.

Methodology: The association between sixteen (16) Single Nucleotide Polymorphisms in the FTO gene and some biomarkers of obesity and type 2 diabetes (fasting blood glucose, HbA1c, adiponectin, insulin, C-peptide, Homeostatic model assessment (HOMA) of β-cell function and insulin resistance (HOMA-IR) and body mass index) was studied in ninety-eight (98) type 2 diabetes (T2D) subjects (78 cases and 20 controls) from four different tribes in the Niger Delta region, Nigeria. Multistage sampling method was employed in the subject selection. The subjects were first separated into two groups – new cases (less than a year of diagnosis as Diabetic) and old cases (one year & above). Equal number of samples was then randomly collected from each of the cluster groups. 10mls of blood was collected into EDTA and plain bottles for the assay of the above-named markers, and were assayed using spectrophotometric and ELISA methods. The data were analyzed using GraphPad Prism, version 8.0.2 and p values less than .05 were considered statistically significant.

Results: Significant association between rs9939609 variant genotype (A) allele of FTO gene with BMI (p<.01), HOMA-IR (p<.01), and Insulin (p<.01) were observed in obese subjects, but only BMI (p<.01) with obese and T2D subjects combined. The results also found a moderate to strong correlation between variants rs201041270 (GA/AA) with adiponectin (p<.05) and with Insulin (p<.05), rs531215275 (CA/AA), mild with C-peptide p<.05), rs1410999299 (AG/GG) with C-peptide (p<.05), rs145884431 (GA/GG) with HbA1c (p<.05), rs146138389 (CT/CC) with insulin (p<.05) and rs886052102 (AG/AA) with FBS (p<.05) and strongly with HbA1c (p<.01).

Conclusion: Knowledge of the dominant SNPs that are consistent with some specific biomarkers in some ethnic groups, may provide platform for prevention of its expression through informed wise choice of lifestyle change and proper dieting.