Association of transforming growth factor beta 1 genotype with spinal osteophytosis in Japanese women

Objective. To examine the possible relationship between a T-->C polymorphis m at nucleotide position 29 of the transforming growth factor beta 1 (TGF b eta 1) gene and genetic susceptibility to radiographic spinal osteophytosis , Methods, A total of 540 postmenopausal Japanese women were subjected to rad iography of the spine and determination of bone mineral density (BMD) for t he lumbar spine and total body. Changes in lumbar intervertebral discs were examined in 67 individuals with either osteoporosis or spinal osteophytosi s by magnetic resonance imaging (MRT), TGF beta 1 genotype was determined w ith an allele-specific polymerase chain reaction assay. The serum concentra tion of TGF beta 1 was measured in 29 control subjects and in 36 patients w ith spinal osteophytosis. Results. Among all study subjects, the prevalence of radiographic spinal os teophytosis in individuals with the CC genotype was greater than that in th ose with the TC or TT genotype, Logistic regression analysis, adjusted for age, height, body weight, time since menopause, smoking status, body fat, l ean mass, and either lumbar spine or total body BMD, demonstrated that the frequency of the C allele in subjects with spinal osteophytosis was signifi cantly greater than that in those without this condition. Comparison among control, osteoporosis, and spinal osteophytosis groups also revealed that t he C allele was more prevalent in subjects with osteophytosis than in contr ols, even after adjustment for BMD, In contrast, as previously shown, the f requency of the C allele was lower in osteoporosis patients than in control s. The intervertebral disc area and the ratio of disc area to vertebral bod y area, as determined by MRI, were also lowest in subjects with the CC geno type, The serum concentration of TGFP1 increased with the number of C allel es in both controls and patients with spinal osteophytosis. Conclusion. The T-29-->C polymorphism of the TGF beta 1 gene exhibited inve rse patterns of association with genetic susceptibility to spinal osteophyt osis and with osteoporosis. Although radiographic evaluation of osteophytes might not reflect the actual disease severity, the C allele, which protect s against osteoporosis, may be a risk factor for genetic susceptibility to spinal osteophytosis.