Polymorphisms in the vitamin D receptor gene and bone mass, bone turnover and osteoporotic fractures.
BACKGROUND
Vitamin D is essential for normal bone metabolism. Polymorphisms in exon 2, intron 8 and exon 9 of the vitamin D receptor (VDR) gene have previously been found to be associated with bone mass and bone turnover.


METHODS
We examined the effect of these polymorphisms, separately and in combination, on bone mineral density (BMD), bone turnover, and the prevalence of osteoporotic fractures in 192 osteoporotic patients and 207 normal controls. The four polymorphisms were determined by RFLP using Fok I (T2-C), Bsm I (intron 8), Apa I (intron 8) and Taq I (T1055-C) after PCR.


RESULTS
We did not find any association between the Fok I polymorphism and bone mass, bone turnover or prevalence of osteoporotic fractures. We found that BB + Bb-genotypes were more frequent in patients with osteoporotic fractures (chi2 = 3.50, P = 0. 06). Furthermore, BMD of the intertrochanteric region (P < 0.0001, ANOVA) as well as the total hip (P < 0.01, ANOVA) were higher in individuals with the bb-genotype. The Apa I and the Taq I polymorphisms were not distributed differently among osteoporotic patients and normal controls. Apa I was not associated with differences in BMD. BMD of the intertrochanteric region was higher in individuals with the TT-genotype compared with individuals with the Tt- or tt-genotypes (P < 0.01, ANOVA), while no differences could be demonstrated in BMD of the lumbar spine, femoral neck, trochanter or Wards triangle. Combining the genotypes generally reflected the differences caused by the Bsm I polymorphism.


CONCLUSIONS
We have found that the B-allele of the Bsm I polymorphism in the 3' untranslated region of the VDR was associated with low BMD at the hip, and tended to be associated with osteoporotic fractures. The translation initiation polymorphism in the VDR does not affect BMD and is not associated with osteoporotic fractures in men or women.
Langdahl
B L
BL
Aarhus University Hospital, Aarhus Amtssygehus, Denmark. bente.langdahl@dadlnet.dk
Gravholt
C H
CH
Brixen
K
K
Eriksen
E F
EF
D000328:Adult; D000368:Aged; D015519:Bone Density; D002113:Calcification, Physiologic; D016022:Case-Control Studies; D015252:Deoxyribonucleases, Type II Site-Specific; D005260:Female; D005598:Fractures, Spontaneous / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005838:Genotype; D006239:Haplotypes; D006620:Hip Fractures / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D006801:Humans; D007438:Introns / Q000235:genetics; D008159:Lumbar Vertebrae / Q000293:injuries / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D018167:Receptors, Calcitriol / Q000235:genetics*; D016103:Spinal Fractures / Q000453:epidemiology / Q000235:genetics / Q000473:pathology
D018167:Receptors, Calcitriol; C053864:endodeoxyribonuclease BsmI; C035042:endodeoxyribonuclease FokI; D015252:Deoxyribonucleases, Type II Site-Specific; C038485:GGGCCC-specific type II deoxyribonucleases; C027046:TCGA-specific type II deoxyribonucleases