The lactase −13910C>T polymorphism (rs4988235) is associated with overweight/obesity and obesity-related variables in a population sample of Portuguese young adults

Background/Objectives: Several studies reported associations of the lactase gene ( LCT ) polymorphism −13910C>T (rs4988235) with obesity-related variables and obesity in adults. This study aimed to replicate previously reported associations in a population sample of Portuguese young adults. Subjects/Methods: We genotyped 447 subjects from central and northern regions of Portugal (mean age 20.81±4.24 years) for the lactase variant −13910C>T (rs4988235), using TaqMan probes. Anthropometric variables (weight, height and body fat) were measured using standardized procedures and body mass index (BMI) (kg/m 2 ) was calculated. Results: Frequency of genotypes was 35.8% CC (lactase nonpersistent, LNP), 48.1% CT and 16.1% TT, consistent with Hardy–Weinberg equilibrium ( P =1). The frequency for the minor −13910 T allele was 0.402. Assuming a dominance model for the lactase persistence (LP) minor T-allele, linear regression models showed statistically significant associations between the LP genotype CT/TT and BMI, fat mass and weight ( β =1.114, P =0.003; β =1.309, P =0.007 and β =2.67, P =0.021, respectively) after adjustment for age and sex. In concordance, logistic regression showed significant association between LP genotype CT/TT and overweight/obesity (OR=1.77; CI 1.08–2.92; P =0.023), as well as with high fat percentage ranges (OR=1.58; CI 1.01–2.46; P =0.041), when adjusting for age and sex. No significant interaction was obtained between the LCT polymorphism and physical activity for BMI ( P int =0.454) or FAT % ( P int =0.421). Conclusions: In the Portuguese sample of young adults, the lactase −13910C>T polymorphism revealed significant associations with the obesity-related anthropometric variables BMI, fat mass and weight, and previously observed associations with the obesity risk were also confirmed.