Study on the relationship between collagen type Ⅰ alpha 2, osteocalcin genes polymorphisms, serum calciotropic hormone levels and dental fluorosis / 中国地方病学杂志

ABSTRACT

Objectives To investigate the relationship between fluorosis polymorphisms in collagen type Ⅰ alpha 2 (COL1A2) and osteocalcin (OC) gene, and serum calciotropic hormone levels. Methods The children between 8 and 12 years of age in Kaifeng and Tongxu cities of Henan Province were chosen to be the object of observation. Accoding to situation of dental fluorosis, they were divided into three groups dental fluorosis group, non-dental fluorosis group from high fluoride areas, and control group form the control areas. The Pvu Ⅱ and Rsa Ⅰ markers of COL1A2 gene as well as HindⅢ marker of OC gene were genotyped by PCR-RFLP procedure. Calcitonin and osteocalcin levels in serum were measured using radioimmunassays. Results The frequency distribution of COL1A2 PvuⅡ genotype was pp 49.3%(37/75), Pp 32.0%(24/75), PP 18.7%(14/75) in children with fluorosis; pp 43.5% (30/69), Pp 52.2% (36/69), PP 4.3%(3/69) in children without fluorosis from high fluoride areas; and pp 43.8% (42/96), Pp 40.6% (39/96), PP 15.6% (15/96) in the children without fluorosis from control areas respectively. Childrens with the homozygous genotype PP of COL1A2 Pvu Ⅱ had a significantly increased risk of dental fluorosis(OR=4.85, 95%CI 1.22-19.32) compared to children with the homozygous genotype pp in anendemic fluorosis area. The frequency distribution of COLIA2 Rsa Ⅰ genotype was rr 50.7% (38/75), Rr 36.0% (27/75), RR 13.3%(10/75) in children with fluorosis; rr 46.4%(32/69), Rr 46.4%(32/69), RR 7.2%(5/69) in children without fluorosis from high fluoride areas, and rr 45.8% (44/96), Rr 45.8% (44/96), RR 8.3% (8/96) in the children without fluorosis from control areas respectively. There were no significant differences in the three groups (P>0.05). The frequency distribution of OC Hind Ⅲ genotype was hh 48.0% (36/75), Hh 34.7% (26/75), HH 17.3% (13/75) in children with fluorosis; hh 43.5% (30/69), Hh 43.5% (30/69), HH 13.0% (9/69) in children without fluorosis from high fluoride areas, and hh 47.9%(46/96), Hh 40.6%(39/96), HH 11.5%(11/96) in children without fluorosis from control areas respectively. There were no significant differences in the three groups (P>0.05). Additionally, fluoride levels in urine and OC levels inserum were found to be significantly lower in controls from non-endemic areas compared to cases(P<0.05). However, the differences in urine fluoride and serum OC levels were not observed when cases were compared to controls from high fluoride areas(P>0.05). Conehlsions This study provides the evidence of an association between polymorphisms in the COL1A2 gene with dental fluorosis in populations exposed to high fluoride. There were no correlation between OC Hind Ⅲ genotype and the dental fluorosis.