Relation of Bone Mineral Density to Vitamin D Receptor Gene Polymorphism and Lifestyle Factors in Japanese Female Workers Aged 22-44 Years: A Cross-Sectional Study

Abstract

Summary Bone mineral density (BMD) reflects both genetic and lifestyle factors. The aim of this cross-sectional study was to investigate the influence of vitamin D receptor ( VDR ) gene polymorphism and lifestyle factors on BMD in premenopausal female workers. The subjects were 162 premenopausal female employees aged 22-44 y who worked at a large-scale integrated manufacturing facility in Japan. BMD was measured at the nondominant radius by dual energy X-ray absorptiometry. Lifestyle information was obtained by a questionnaire at the same time and genomic DNA was isolated from peripheral leukocytes. BMD was positively correlated with age, weight, and body mass index (BMI). The genotype frequencies of VDR gene polymorphism detected by Taq I analysis were 77.2, 22.8, and 0.0% for TT , Tt , and tt , respectively. Analysis of covariance with adjustment for age and BMI showed that the mean BMD was significantly lower in subjects with the Tt genotype than in those with the TT genotype. Subjects who drank alcohol also showed a significantly lower BMD if they had the Tt genotype than if they had the TT genotype. According to multiple linear regression analysis, the independent determinants of BMD were age, BMI, and VDR gene polymorphism. Our data show that BMD is negatively correlated with the Tt genotype of the VDR gene, but positively correlated with age and BMI. These findings suggest that analysis of VDR gene polymorphism may be useful for identifying individuals who are susceptible to osteoporosis so that early preventive measures can be provided. Key Words bone mineral density, gene polymorphism, lifestyle factors, vitamin D receptor In Japan, prevention of osteoporosis is a high-priority issue because osteoporotic fracture is one of the primary causes of elderly persons becoming bedridden ( 1 ). Measurement of bone mineral density (BMD) is the best tool available to assess osteoporotic fracture risk, since low BMD is an important risk factor for osteoporotic fracture ( 2 ). The peak BMD of Japanese women is reached around 35-40 y of age, and it falls rapidly during the first 10 y after menopause and then decreases gradually ( 3 ). Because a decrease of BMD is inevitable after menopause, it is necessary to identify and manage any premenopausal decrease of BMD. BMD can be influenced by various lifestyle factors, such as smoking, alcohol intake, exercise, and nutrition ( 4 ). Among the genes that may be associated with the development of osteoporosis, polymorphism of the vitamin D receptor ( VDR ) gene has been most widely studied ( 5 ), and a meta-analysis ( 6 ) suggested that BMD is influenced by VDR gene polymorphism. BMD is affected by both genetic and lifestyle factors ( 5 ), but most studies have separately investigated the effects of VDR gene polymorphism or lifestyle factors on BMD. Better understanding of this combined effect may allow us to identify a highrisk group for osteoporosis and lead to more effective osteoporosis prevention and to improvement of public health. A few previous studies ( 7-10 ) have ...

Relation of Bone Mass to Vitamin D Receptor Gene Polymorphism and Lifestyle Factors in Japanese Female College Students

“…Of the 317 subjects, 247, 68, and 2 had the TT, TC, and CC polymorphisms (77.9%, 21.5%, and 0.6%), respectively. This distribution was consistent with the reported data on the Japanese population 20,21) . No significant difference in the bone mass (OSI) was observed between the VDR gene polymorphism (rs731236) (TT versus TC + CC).…”

“…One problem inherent in these studies is that they tend to focus solely on gene polymorphisms while disregarding the impact of lifestyle habits, such as the intake of nutrients and impact of exercise. In particular, regarding Japanese women, little data is available on the correlation between VDR polymorphisms and lifestyle habits: the intake of nutrients and impact of exercise 21) . Therefore, the aim of the present study was to identify VDR gene polymorphism and lifestyle factors associated with bone mass in Japanese female college students.…”

Genetic variants in vitamin D metabolism-related genes and body mass index: analysis of genome-wide scan data of approximately 7000 Chinese women

“…5,6 Studies have found associations between vitamin D pathway gene polymorphisms and circulating 25(OH)D level. 7–9 Genetic variants in vitamin D pathway genes, namely in the vitamin D nuclear receptor ( VDR ) gene, have been associated with obesity in some, 10–13 but not all studies. 14,15 Studies of other genes in the vitamin D pathway, including vitamin D binding protein ( DBP ) or group-specific component ( GC ) or CYP27B1 and BMI, have also produced inconsistent results.…”

Relationship Between Vitamin D Receptor Gene polymorphisms (BsmI, TaqI, ApaI, and FokI) and Calcium Intake on Bone Mass in Young Japanese Women

“…However, the effects of the BsmI AA and TaqI CC genotypes on bone mass in Japanese women have rarely been examined because these genotypes are present at a relatively lower proportion than that seen in European countries; e.g., the respective allelic frequencies for the BsmI genotype G and A in the European population were 59% and 41%, respectively, compared to 88% and 12% in the Japanese population, (25,30), indicating a clear racial difference. In previous studies, less than 200 Japanese women participants were observed, a few of whom expressed the BsmI AA and TaqI CC genotypes (n = 0-2); hence, the relevant data could not be included in the analyses (20,21,(31)(32)(33). However, in the present study involving 499 participants, these genotypes were recognized (n = 8 for both) and included in the analysis.…”

“…In contrast, there are relatively fewer studies that assessed the relationship among bone mass, VDR gene polymorphisms, and environmental factors in premenopausal Japanese women. In these studies, the number of participants was low, and their age range was relatively wide (18-44 years) (19)(20)(21). Estrogen levels and lifestyle factors among participants can vary if a wide age range is considered in a study.…”