Racial and sex differences in the polymorphisms of the endocannabinoid receptor genes in obesity.

Obesity is a global epidemic and prevalence of obesity is higher in African Americans (AAs) compared to Caucasians. The endocannabinoid system (EC) and polymorphims in the endocannabinoid receptor type 1 (CNR1) gene 3813A/G and 4895A/G and in the fatty acid amide hydrolase (FAAH) are associated with obesity. The objective was to explore racial and sex differences in these polymorphims and the biochemical abnormalities seen in obesity. A cross-sectional study of 667 subjects (53.67% female, 49.18% were AA; 69.72% were obese (body mass index [BMI] ≥30) were screened for CNR1 3813, 4895 and FAAH 385 polymorphisms using a real-time polymerase chain reaction (PCR) system. Subjects with FAAH 385 polymorphisms were more likely to be obese (75.14% vs. 67.81, P=0.046). There were no significant sex differences for CNR1 3813 and CNR1 4895; or between obese and control group. AAs had higher prevalence of CNR1 3813 (OR, 2.80, 95% CI, 1.95 – 4.04) and FAAH 385 (OR, 2.48, 95% CI, 1.82–3.38). Association between African American race and the three genotypes persisted after adjustment of all the variables (P<0.001). FAAH 385 polymorphism is more likely seen in obese and in older subjects. AAs had higher prevalence of CNR1 3813 and FAAH 385 polymorphims; and lower prevalence of CNR1 4895 polymorphisms. These findings may explain some of the racial differences, but not the sex differences in the clinical expression of obesity.

肥胖是一种全球性的流行病，与高加索人相比，非裔美国人（AA）的肥胖患病率更高。内源性大麻素系统（EC）以及内源性大麻素1型受体（CNR1）基因的3813A/G和4895A/G多态性以及脂肪酸酰胺水解酶（FAAH）与肥胖相关。目的是探究这些多态性中的种族和性别差异以及肥胖中出现的生化异常。 对667名受试者（53.67%为女性，49.18%为非裔美国人；69.72%肥胖（体重指数[BMI]≥30））进行了一项横断面研究，使用实时聚合酶链反应（PCR）系统对CNR1 3813、4895和FAAH 385多态性进行了筛查。 具有FAAH 385多态性的受试者更有可能肥胖（75.14%对67.81%，P = 0.046）。CNR1 3813和CNR1 4895在性别上无显著差异；肥胖组和对照组之间也无显著差异。非裔美国人CNR1 3813（比值比，2.80，95%置信区间，1.95 - 4.04）和FAAH 385（比值比，2.48，95%置信区间，1.82 - 3.38）的患病率更高。在对所有变量进行调整后，非裔美国人种族与这三种基因型之间的关联仍然存在（P<0.001）。 FAAH 385多态性更常见于肥胖者和年长者。非裔美国人CNR1 3813和FAAH 385多态性的患病率较高；CNR1 4895多态性的患病率较低。这些发现可能解释了肥胖临床表现中的一些种族差异，但不能解释性别差异。