Background: Type 2 diabetes mellitus (T2D) is the most frequent type of diabetes. It has a multifactorial etiology, affecting millions of people worldwide. Ghrelin gene (GHRL) encodes the ghrelin peptide, which promotes food intake, induces body weight and adipogenesis. Several single nucleotide polymorphisms (SNPs) in GHRL gene have been associated with metabolic diseases. A protective effect of the Leu72Met (rs696217) polymorphism has been described for T2D in some populations, but this effect seems to depend on the ethnicity of the patients studied.
Methods: The aim of this study was to investigate the association between the GHRL Leu72Met (rs696217) SNP with the development of T2D and serum ghrelin levels in a Western Mexican population. We performed a case-control study in which we included 284 subjects (159 with previous T2D diagnosis and 125 control subjects (CS)). Leu72Met SNP was genotyped by using PCR-RFLPs technique. Serum ghrelin levels were measured using a commercial enzyme immunoassay. Genotypic and allelic distributions were compared using Chi square test. Student T-test and Mann-Whitney U test were used to compare quantitative variables. Odds ratio (OR) was used to evaluate the association between alleles or genotypes and T2D. Multiple and logistic regression models were performed for adjustment. A two-tailed p-value ≤0.05 was considered statistically significant.
Results: Leu72Leu genotype was more frequent among T2D compared to CS (p < 0.05). After adjusting for age and body composition, there was a significant protective effect of the 72Met allele for T2D development (OR 0.40 IC 95% 0.23-0.70; p ≤ 0.001). Fasting serum ghrelin levels were lower in T2D than CS (p ≤ 0.0001) irrespective of age, body weight and BMI. No associations were found between genotypes and ghrelin serum levels in our population.
Conclusions: The GHRL 72Met allele decreases susceptibility for T2D development in a Western Mexican population. Serum ghrelin levels are lower in T2D independently of Leu72Met polymorphism genotype.
Keywords: Ghrelin; Leu72Met; Polymorphism; Type 2 diabetes mellitus.