Diet, Genes, or Both? Coffee Consumption, Snacking, and BDNF and TCF7L2 Genotypes in Relation to Cardiometabolic Traits: A Cross-Sectional Study in Polish Adults

Background/Objectives: Coffee consumption and snacking are common dietary behaviours linked to cardiometabolic risk, and variants in BDNF and TCF7L2 have been associated with obesity and type 2 diabetes (T2DM). We examined whether glycaemic, adiposity, and lipid traits reflect these behaviours, these genotypes, or both, and whether BDNF (rs10501087) and TCF7L2 (rs4506565, rs7901695, rs7903146) genotypes modify the behavioural associations.

Methods

In a cross-sectional study of Polish adults (NCT03792685; analytic cohort n = 1227), coffee consumption (never, weekly, daily) and snacking frequency (rare, frequent) were assessed by questionnaire (n = 905); outcomes were glucose and insulin area under the curve (AUC) from a 2-h 75 g oral glucose tolerance test (OGTT), glycated haemoglobin (HbA1c), fasting lipids, and bioimpedance body composition. Multivariable models were adjusted for age, sex, daily energy intake, and physical inactivity; all analyses, including gene × behaviour interaction tests, were exploratory, with false discovery rate (FDR) correction for multiple testing.