G1359A Variant of the Cannabinoid Receptor Gene (rs1049353) and Obesity-Related Traits and Related Endophenotypes: A Meta-Analysis.

Background: This study aimed to investigate the comparison of G1359A variant of cannabinoid receptor gene (rs1049353) with obesity-related traits including body mass index (BMI), fat mass (FM), fat-free mass (FFM), food-related traits, and leptin among healthy and non-healthy adults.

Methods: We searched PubMed, Cochrane, Scopus, Web of Science, and EMBASE until December 2016 for observational studies assessing each of the anthropometric measurements, food-related traits, and leptin of 1359 G/A polymorphism of CNR1 gene. A total of 22 studies were included in the meta-analysis comparing mean and SD differences of the anthropometric measurements, leptin, and dietary intake between GA/AA and GG genotypes.

Results: The results showed that subjects with GA/AA genotype had significantly lower BMI (weighted mean difference = -0.59 kg/m2, p < 0.001) compared to those with the GG genotype. Dietary intake of fat, carbohydrate, and protein as well as serum levels of leptin was not significantly different between GA/AA and GG genotypes.

Conclusion: It was revealed that subjects with mutant polymorphism (GA/AA) of CNR1, compared to the wild-type group (GG), had lower BMI (although there was unexplained heterogeneity).