Association of 29C>T polymorphism in the transforming growth factor-β1 gene with lean body mass in community-dwelling Japanese population

Aim: Sarcopenia is the significant degenerative loss of skeletal muscle mass and strength associated with aging, and it is one of the components of frailty. We previously reported an association between the 29C>T polymorphism in the transforming growth factor-β1 gene (rs1800470) and the prevalence of vertebral fractures in subjects with postmenopausal osteoporosis. The association was not attributable to bone mineral density, which suggests that polymorphism influences some aspects of bone quality that affects strength and/or frailty rather than bone strength itself. Thus, we examined the relationship between genetic polymorphism and lean body mass in a Japanese population. Methods: A total of 479 adults comprising 143 men and 336 women, age 23 to 85years, participated in the present study. Fat-free mass was measured by dual energy X-ray absorptiometry, and the relative skeletal muscle index was calculated as the ratio of appendicular (sum of arms and legs) fat-free mass to the square of height. Results: Total, leg, and appendicular fat-free mass as well as the relative skeletal muscle index were significantly lower in male subjects with CT/TT genotypes compared to those with CC genotype. Female subjects did not show any genotype-dependent differences when analyzed as a group, but when those without menstruation (postmenopausal women) were analyzed, arm fat-free mass was significantly lower in the CT/TT genotypes than in the CC genotype. Conclusions: T allele of the 29C>T polymorphism in the transforming growth factor-β1 gene might be a risk factor of sarcopenia in a Japanese population.