Relationship between Rs1801282 polymorphism of peroxisome proliferator activated receptor γ gene and brick-tea type fluorosis

Abstract

Objective To investigate the relationship between single nucleotide polymorphism (SNP) of the peroxisome proliferator activated receptor γ (PPARγ) gene Rs1801282 and brick-tea type fluorosis. Methods From 2012 to 2013, this cross-sectional study was performed in 16 endemic fluorosis areas of brick-tea type in Inner Mongolia Autonomous Region, Qinghai and Xinjiang Uygur Autonomous Region of China, to select adults > 18 years old as subjects, who were diagnosed as skeletal fluorosis by X-ray. All of the subjects filled in demography survey questionnaire; the survey contents included general characteristics, and average daily brick tea intake. Drinking tea samples and urine samples of each subject were collected, and fluoride content of urine and brick-tea was determined via the ion selective electrode method (WS/T 89-2006). X-ray scintigraphy was used to diagnose skeletal fluorosis, according to the Diagnostic Criteria of Endemic Skeletal Fluorosis (WS/T 192-2007); the subjects were divided into skeletal fluorosis group (case group) and non-skeletal fluorosis group (control group). To collect venous blood 5 ml, whole blood DNA was extracted, and polymorphism at Rs1801282 of PPARγ was detected by MassARRAY time-of-flight mass spectrometry, to calculate odds ratio (OR) and 95% confidence interval (CI). Results There were 1 414 people included in this study, including 347 in case group and 1 067 in control group. By the Hardy-Weinberg balance test, the PPARγ gene Rs1801282 genotype was representative in case group, control group and each nationality (P > 0.05). The difference of PPARγ gene Rs1801282 genotype in case group and control group was not statistically significant (OR was 0.991, 95%CI: 0.704-1.395, the adjusted OR was 1.026, 95%CI: 0.707-1.489). The difference of PPARγ gene Rs1801282 genotype (CC, CG+ GG) in case group and control group in different nationality was not statistically significant (Tibetan: OR was 1.400, 95%CI: 0.576-3.404, the adjusted OR was 1.258, 95%CI: 0.474-3.340; Kazak: OR was 0.898, 95%CI: 0.516-1.562, the adjusted OR was 0.936, 95%CI: 0.532-1.648; Mongolia: OR was 1.148, 95%CI: 0.508-2.594, the adjusted OR was 1.644, 95%CI: 0.683-3.956; Han: OR was 1.058, 95%CI: 0.451-2.482, the adjusted OR was 0.959, 95%CI: 0.388-2.371; Russian: OR was 0.000, 95%CI: 0.000-0.000, the adjusted OR was 0.000, 95%CI: 0.000-0.000) with binary Logistic regression analysis. Conclusion We have found no association between SNP of PPARγ gene Rs1801282 and skeletal fluorosis of brick-tea type fluorosis in China. Key words: Fluorine; Polymorphism, single nucleotide; Peroxisome proliferative activation receptors