Association of vitamin D receptor gene polymorphisms with susceptibility to coal-burning borne fluorosis in Guizhou province

Abstract

Objective To observe the distribution of vitamin D receptor(VDR) gene polymorphisms in coal-burning borne fluorosis in Guizhou province and investigate the relationship between VDR gene polymorphisms and the susceptibility to coal-burning borne fluorosis.Methods One hundred and fifty villagers from non-improving cooking stove villages were selected as a non-intervention group in Bijie area,Guizhou province where coal-burning borne fluorosis was prevailing; 150 villagers were chosen from cooking stove improved villages as a intervention group; 150 villagers were selected from non-endemic area Changshun county as a control group.DNA was extracted from peripheral blood samples of these people.Genotype of VDR gene Bsm Ⅰ and Fok Ⅰ loci were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Results Distribution of Bsm Ⅰ polymorphism site of VDR gene of control group [AA:19.3％ (29/150),AG:39.3％ (59/150),GG:41.3％(62/150)],was compared with that[AA:4.7％(7/150),AG:14.0％(21/150),GG:81.3％(122/150)] of the non-intervention group and that[AA:7.3％(11/150),AG:23.3％(35/150),GG:69.3％(104/150)] of intervention group,and the difference was statistically significant(X2 =56.6,P ＜ 0.05).The frequency of VDR-Fok Ⅰ loci in non-intervention group [TT:29.3％(44/150),TC:55.3％(83/150),CC:15.3％(23/150)] and intervention group [TT:32.7％(49/150),TC:55.3％(83/150),CC:12.0％(18/150)] was compared with that [TT:45.3％(68/150),TC:48.7％(73/150),CC:6.0％(9/150)] of control group,and the difference was statistically significant(X2 =11.9,P ＜ 0.05).Univariate analysis showed that individuals carrying the GG genotype had increased risk of suffering fluorosis than individuals carrying the AA and AG genotypes(OR values were 6.2,3.2,all P ＜ 0.05),while carrying the TC and CC genotype had increased risk of suffering fluorosis than individuals carrying the TT genotype (OR values were 1.3,2.8,1.3,2.1,all P ＜ 0.05).Conclusion VDR gene polymorphisms may be one of the predisposing factors of coal-burning borne fluorosis. Key words: Vitamin D receptors; Fluoride poisoning; Polymorphism,restriction fragment length