Collagen type I alpha1 Sp1 polymorphism, osteoporosis, and intervertebral disc degeneration in older men and women.
OBJECTIVE
To examine whether collagen type I alpha1 (COLIA1) Sp1 polymorphism is associated with osteoporosis and/or intervertebral disc degeneration in older people.


METHODS
COLIA1 genotype was determined in 966 men and women (>/=65 years) of the Longitudinal Aging Study Amsterdam. The guanine (G) to thymidine (T) polymorphism in the first intron of the COLIA1 gene was detected by PCR and MscI digestion. In the total sample, quantitative ultrasound (QUS) measurements, serum osteocalcin (OC), and urine deoxypyridinoline (DPD/Cr(urine)) were assessed. A follow up of fractures was done every three months. In a subsample, total body bone mineral content (n = 485) and bone mineral density (BMD) of the hip and lumbar spine (n = 512) were measured by dual energy x ray absorptiometry (DXA). Prevalent vertebral deformities and intervertebral disc degeneration were identified on radiographs (n = 517).


RESULTS
People with the TT genotype had a higher risk of disc degeneration than those with the GG and GT genotypes (OR = 3.6; 95% CI 1.3 to 10). For men, higher levels of OC were found in those with the T allele than in those without it (GG v (GT+TT) 1.96 (0.06) nmol/l v 2.19 (0.09) nmol/l). COLIA1 polymorphism was not significantly associated with other measures of osteoporosis in either men or women.


CONCLUSIONS
COLIA1 Sp1 polymorphism may be a genetic risk factor related to intervertebral disc degeneration in older people. Previously reported associations between the COLIAI Sp1 genotype and lower BMD or QUS values, higher levels of DPD/Cr, and an increased fracture risk in either men or women could not be confirmed.
Pluijm
S M F
SM
Institute for Research in Extramural Medicine (EMGO Institute), VU University Medical Centre, Amsterdam, The Netherlands.
van Essen
H W
HW
Bravenboer
N
N
Uitterlinden
A G
AG
Smit
J H
JH
Pols
H A P
HA
Lips
P
P
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000235:genetics; D024042:Collagen Type I / Q000235:genetics*; D005260:Female; D050723:Fractures, Bone / Q000235:genetics; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007403:Intervertebral Disc; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010024:Osteoporosis / Q000235:genetics*; D015663:Osteoporosis, Postmenopausal / Q000235:genetics; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D012307:Risk Factors; D013122:Spinal Diseases / Q000235:genetics*
D024042:Collagen Type I