Association between vitamin D receptor gene FokI polymorphism and skeletal fluorosis of the brick-tea type fluorosis: a cross sectional, case control study.
Brick-tea type fluorosis is a public health concern in the north west area of China. The vitamin D receptor (VDR)-FokI polymorphism is considered to be a regulator of bone metabolism and calcium resorption. However, the association of VDR-FokI polymorphism with the risk of brick-tea type fluorosis has not been reported.



A cross sectional, case control study was conducted in three provinces (Inner Mongolia, Qinghai and Sinkiang) in China. The fluoride content of Brick-tea water and urine was tested using the standards GB 1996-2005 and WS/T89-2006 (China), respectively. Skeletal fluorosis was diagnosed using the standard WS/192-2008 (China). The VDR-FokI polymorphism was detected by the Sequenom MassARRAY system.



Compared with carriers of the CC genotype, participants with the CT/TT genotype had a significantly decreased risk of skeletal fluorosis (OR=0.761 (95% CI 0.580 to 0.997)), after adjustment for risk factors. When investigated among ethnic groups, the protective effect of the CT/TT genotype was limited in the Mongolian participants (OR=0.525 (95% CI 0.278 to 0.991)). Moreover, the interaction of VDR-FokI with risk factors was only found in Mongolian participants: the protective effect of the CT/TT genotype was limited to participants with >7.0 mg/day daily intake of tea fluoride (OR=0.085 (95% CI 0.009 to 0.851), participants with >3.2 mg/L urine fluoride (OR=0.103 (95% CI 0.017 to 0.633)) or participants aged 46-65 years (OR=0.404 (95% CI 0.177 to 0.922).



Our data suggest that the CT/TT genotype of VDR-FokI may be a protective factor for brick-tea type skeletal fluorosis, and this effect is pronounced in Mongolian participants.
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.|Chongqing Blood Centre, Chongqing, China.
Dan
D
Yang
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Yang
Y
Liu
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Yanru
Y
Chu
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Qing
Q
Yang
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Wei
W
Jiang
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Fuxun
F
Chen
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Dandan
D
Li
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Ming
M
Qin
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Dianjun
D
Sun
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Yanmei
Y
Yang
Centre for Endemic Disease Control, Chinese Centre for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang, China.|Key Laboratory of Aetiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health, Harbin, Heilongjiang, China.
Yanhui
Y
Gao
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001847:Bone Diseases / Q000208:ethnology / Q000235:genetics*; D016022:Case-Control Studies; D002681:China; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005459:Fluorides / Q000633:toxicity*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008986:Mongolia; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000235:genetics*; D012307:Risk Factors; D013662:Tea / Q000009:adverse effects; D055815:Young Adult
D018167:Receptors, Calcitriol; D013662:Tea; C579457:VDR protein, human; D005459:Fluorides
EPIDEMIOLOGY; GENETICS