Association of the FTO rs9939609 variant with glycemic control based on fasting glucose.
BACKGROUND Type 2 diabetes (T2D) affects 11.1% of the global population, underscoring the need for biomarkers that help characterize glycemic control status among treated individuals. We evaluated the association between the FTO variant rs9939609‑A and glycemic control in a Mexican population. METHODS A total of 174 individuals living with T2D from Mérida and Sisal, Yucatán, were included, of whom 85% were receiving oral hypoglycemic agents as main treatment. Glycemic control was defined cross‑sectionally as good (≤ 130 mg/dL, n = 63) or poor (> 130 mg/dL, n = 111) with fasting glucose. Linear mixed models incorporating relevant covariates and a family random intercept were used. Effect size estimates were transformed to logit odds ratios. RESULTS After adjustment for age, sex, BMI, years since T2D diagnosis, and treatment, the minor allele of rs9939609 (A) was associated with an increased risk of poorer glycemic control, reaching significance under both the additive (OR = 1.145 [1.003-1.307], p = 0.047) and recessive (OR = 1.514 [1.026-2.234], p = 0.038) models. In an alternative model adjusting for waist circumference instead of BMI, the effect of rs9939609‑A in the additive model was slightly attenuated (OR = 1.135 [0.994-1.297], p = 0.063), while the recessive model remained significant (OR = 1.486 [1.010-2.189], p = 0.046). CONCLUSIONS rs9939609-A was associated with poorer glycemic control in this exploratory cohort, but replication in larger and ancestrally characterized samples is required.