Modifying Role of GSTP1 Polymorphism on the Association between Tea Fluoride Exposure and the Brick-Tea Type Fluorosis

PLoS One. 2015 Jun 5;10(6):e0128280. doi: 10.1371/journal.pone.0128280. eCollection 2015.

Abstract

Background: Brick tea type fluorosis is a public health concern in the north-west area of China. The association between SNPs of genes influencing bone mass and fluorosis has attracted attention, but the association of SNPs with the risk of brick-tea type of fluorosis has not been reported.

Objective: To investigate the modifying roles of GSTP1 rs1695 polymorphisms on this association.

Methods: A cross-sectional study was conducted. Brick-tea water was tested by the standard of GB1996-2005 (China). Urinary fluoride was tested by the standard of WS/T 89-2006 (China). Skeletal fluorosis was diagnosed by X-ray, the part we scheduled was forearm, shank, and pelvic, then diagnosed the skeletal fluorosis by the standard of WS/192-2008 (China). Gene polymorphism was tested by Sequenom MassARRAY system.

Result: The prevalence rate in different ethnical participants was different: Tibetan individuals had the highest prevalence rate of skeletal fluorosis. There were significant differences in genotype frequencies of GSTP1 Rs1695 among different ethnical participants (p<0.001): Tibetan, Mongolian and Han subjects with homozygous wild type (GSTP1-AA) genotype were numerically higher than Kazakh and Russian subjects (p<0.001). Compared to Tibetan participants who carried homozygous A allele of GSTP1 Rs1695, Tibetan participants who carried G allele had a significantly decreased risk of skeletal fluorosis (OR = 0.558 [95% CI, 0.326-0.955]). For Kazakh participants, a decreased risk of skeletal fluorosis among carriers of the G allele was limited to non high-loaded fluoride status (OR = 0. 166 [95% CI, 0.035-0.780] vs. OR = 1.478 [95% CI, 0.866-2.552] in participants with high-loaded fluoride status). Neither SNP-IF nor SNP-age for GSTP1 Rs1695 was observed.

Conclusion: The prevalence rate of the brick tea type fluorosis might have ethnic difference. For Tibetan individuals, who had the highest prevalence rate, G allele of GSTP1 Rs1695 might be a protective factor for brick tea type skeletal fluorosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Alleles
  • Bone Diseases, Metabolic / epidemiology
  • Bone Diseases, Metabolic / etiology
  • Bone Diseases, Metabolic / genetics*
  • China / epidemiology
  • Cross-Sectional Studies
  • Demography
  • Female
  • Fluorides / administration & dosage*
  • Fluorides / adverse effects
  • Fluorides / urine
  • Fluorosis, Dental / epidemiology
  • Fluorosis, Dental / etiology
  • Fluorosis, Dental / genetics*
  • Gene Frequency
  • Genotype
  • Glutathione S-Transferase pi / genetics*
  • Homozygote
  • Humans
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Prevalence
  • Tea / chemistry*
  • Tea / metabolism

Substances

  • Tea
  • Glutathione S-Transferase pi
  • Fluorides

Grant support

This study was supported by the National Natural Science Foundation of China (No.81172605 and 30800956).