Association of the European lactase persistence variant (LCT-13910 C>T polymorphism) with obesity in the Canary Islands

Abstract

Background: European lactose tolerance genotype (LCT -13910 C>T, rs4988234) has been positively associated to body mass indexes (BMI) in a meta-analysis of 31,720 individuals of northern and central European descent. A strong association of lactase persistence (LP) with BMI and obesity has also been traced in a Spanish Mediterranean population. The aim of this study was to analyze a potential association of LP compared to lactase non-persistence (LNP) with BMI in inhabitants of the Canary Islands of Spain using Mendelian randomization.

Methods: A representative, randomly sampled population of adults belonging to the Canary Islands Nutrition Survey (ENCA) in Spain, aged 18-75 years (n = 551), was genotyped for the LCT - 13910 C>T polymorphism. Milk consumption was assessed by a validated questionnaire. Anthropometric variables were directly measured. WHO classification of BMI was used.

Results: LP individuals were significantly more obese than LNP subjects (χ(2) = 10.59; p<0.005). LP showed in a multivariate linear regression analysis showed a positive association of LP with BMI compared to LNP, (β = 0.96; 95% CI: 0.08-1.85, p = 0.033). In a multinomial logistic regression analysis normal range weight LP subjects showed an odds ratio for obesity of 2.41; 95%CI 1.39-418, (p = 0.002) compared to LNP.

Conclusions: The T-13910 of the allele LCT-13910 C>T polymorphism is positively associated with BMI. LP increases significantly the risk to develop obesity in the studied population. The LCT-13910 C>T polymorphism stands proxy for the lifetime exposure pattern, milk intake, that may increase susceptibility to obesity and to obesity related pathologies.

Figure 1. BMI classification by LCT genotypes (LP: n = 330; LNP: n = 221) N = 13 individuals were underweight (n = 11 showed mild thinness and n = 2 moderate thinness; no subject showed severe thinness).

These subjects were included in the normal range column. Normal Range: LP = 119; LNP = 94, overweight: LP = 109; LNP = 88, obesity: LP = 84; LNP = 32; Missing BMI in 25 cases (N = 526).