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We analyzed 1,217 women to examine the effect of peroxisome proliferator-activated receptors gamma (PPARγ) C161 → T on bone status. Among 664 premenopausal women, the C161 → T is associated with low bone mineral density (BMD) at the total hip and femoral neck. Moreover, the odds ratio for osteopenia or osteoporosis at the femoral neck was 1.98 for premenopausal CT/TT genotypes. The impact of PPARγ on BMD has not been conclusively established. We examined if PPARγ C161T polymorphism is associated with BMD and its change. We conducted a baseline survey in 1996 and a 10-year follow-up survey, Japanese Population-based Osteoporosis Study, with a sample population representative of Japanese women. Of these, 1,217 participants in the 1996 survey were analyzed cross-sectionally, while longitudinal analysis was performed on 563 women. A P value < 0.0042 (=0.05/12 for three menstrual statuses and four skeletal sites) was considered statistically significant after Bonferroni correction in multiple testing for cross-sectional analysis. The total hip and femoral neck BMDs were significantly higher for CC genotype than for CT/TT genotypes among 664 premenopausal women ( P = 0.0020, P = 0.0022, respectively). Compared to the CC genotype, the odds ratio for osteopenia or osteoporosis (T-scores below −1) at the femoral neck was 1.98 for premenopausal CT/TT genotypes with statistical significance ( P = 0.0041). Change of BMD at either skeletal site during the follow-up period was not significantly different for either menstrual status. We conclude that the PPARγ C161T is associated with low peak bone mass. [ABSTRACT FROM AUTHOR]

Introduction: The predictive value of biochemical markers of bone turnover for subsequent change in bone density in a population sample of healthy women with a wide range of ages has not been fully established. Methods: We followed 1,283 women aged 15-79 years at baseline selected randomly from the inhabitants of three areas in Japan for 6 years, and examined 1,130 subjects with no disease or administration of drugs affecting bone metabolism. The annual change in bone density at the spine, total hip, and distal one third of the radius was determined during the follow-up period by dual xray absorptiometry and was compared among the groups using different levels of biochemical markers at baseline, including serum osteocalcin (OC) and bone-specific alkaline phosphatase (bone ALP), free and total (tDPD) forms of immunoreactive deoxypyridinoline, and type I collagen crosslinked C-terminal telopeptide (CTX) in urine. Results: Premenopausal women aged 45 years or older with elevated levels of OC, bone ALP, CTX, or tDPD showed significantly greater bone loss at most skeletal sites during the follow-up period than those with lower levels, after adjustment for the effects of age, height, weight, dietary calcium intake, regular exercise, and current smoking. The greatest coefficient of determination of the model was observed in the association between CTX and bone loss at the hip during the first 3 years of follow-up (42.8%). These subjects were pooled with perimenopausal women at baseline, and those who still menstruated at follow-up in this pooled group showed significant but more modest associations, whereas those who entered menopause during the follow-up period showed clear associations. However, early postmenopausal women with less than 5 or 10 years since menopause showed an association that was limited mostly to the distal radius, and other postmenopausal groups had virtually no association. Conclusion: Biochemical markers of bone turnover may predict bone loss in women undergoing menopausal transition but may not predict bone loss in postmenopausal women. [ABSTRACT FROM AUTHOR]

Using a large-scale representative sample of the Japanese female population, we examined the effects of a single nucleotide polymorphism within a binding site of Cdx-2 in the promoter region of the vitamin D receptor gene on bone mineral density (BMD), and the interactions between this polymorphism and lifestyle factors on BMD. Fifty women were randomly selected from each of the 5-year age-stratified populations (15-79 years) in each of three chosen municipalities as a part of the Japanese Population-based Osteoporosis Study. BMD at the lumbar spine, hip, and distal forearm was measured using dual-energy X-ray absorptiometry at baseline and again in a follow-up study conducted 3 years later. Information on lifestyle factors was collected in a questionnaire and followed up in interviews. The G-to-A polymorphism within the Cdx-2 binding site was determined by a TaqMan allelic discrimination assay. At baseline, 1,340 women were analyzed. The baseline BMD in the ultradistal forearm in premenopausal women with the GG genotype was significantly lower than in those with other genotypes. There was no association between the Cdx-2 genotype and the change in BMD at any of the skeletal sites. We found significant associations between daily milk consumption and baseline BMD at some skeletal sites but only in subjects with the GG genotype. In conclusion, the Cdx-2 polymorphism alone did not have a substantial effect on BMD in Japanese women. However, this polymorphism might have some effect in women with low calcium intake. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the ethnic difference in bone mass between Japanese and Inner Mongolian young premenopausal women and to assess the contribution of lifestyle related and anthropometric factors to bone mass. We studied 33 Japanese and 44 Inner Mongolian healthy young women, aged 20–34 years, in urban area. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) were measured at the calcaneus using quantitative ultrasound (QUS) analysis. Age at menarche, regularity of menstruation and lifestyle related factors were estimated by a self-reported questionnaire. There were no differences between the two groups in age, height, weight, BMI, regularity of menstruation, frequency of meat intake, frequency of yellow-green vegetable intake and exercise habit. Japanese women had significantly lower age at menarche and higher proportion of milk consumption habit at junior high school, senior school and present. Before adjustment, Japanese women had significantly higher SOS and SI than Inner Mongolian women. However, after adjustment for age at menarche and milk consumption habit at junior high school, both of which were significantly different between groups, no group-differences remained in either SOS or SI. These results suggest that the differences in age at menarche and milk consumption habit at junior high school, which relate to hormonal and nutritional status during puberty, may account for the differences in bone mass between Japanese and Inner Mongolian young women. [ABSTRACT FROM AUTHOR]

To establish the reference values of the quantitative ultrasound (QUS) indices in healthy Japanese women and to propose a diagnostic criterion for osteoporosis by means of the QUS indices, 659 healthy women aged 20–79 years recruited from a larger cohort study (JPOS study), were examined for bone mass measurements by QUS at the calcaneus (SAHARA, Hologic Inc., USA) and by dual-energy X-ray absorptiometry at the spine, hip, and distal forearm. We presented 10-year age-specific mean values and T-scores of the QUS indices. The pattern of decrease in the T-score appeared to be linear in the QUS indices and total hip BMD but not in BMD at the spine. The T-score of the QUS of indices of the subjects in their 70s were significantly higher than that of BMD at the spine. The prevalence rates of osteoporosis in the subjects aged 50 and older diagnosed by QUS (8.7% for SOS, 10.7% for BUA) were similar to that diagnosed by total hip BMD (11.5%) and significantly lower than that by the spine BMD (36.1%) when the WHO criteria were applied. We performed receiver-operating characteristic analysis to set a cutoff level of the QUS indices for the diagnosis of osteoporosis to accurately identify the subjects diagnosed by either the spine or total hip BMD. The highest likelihood ratios for SOS and BUA were obtained at the cutoff levels of 1,517.7 m/sec (T-score: -1.58) with the sensitivity of 0.65 and the specificity of 0.65 and 59.5 dB/MHz (T-score: -1.52) with 0.66 and 0.69, respectively. The diagnostic accuracy of QUS indices for osteoporosis was not superior to that of age. However, the QUS indices showed a significant contribution to forming the diagnosis of osteoporosis independently of age and body size in multivariate diagnostic models developed by the logistic regression analysis. Therefore, the cutoff values presented in this study may be used as a tentative criterion until the cutoff levels for the QUS indices are set according to the fracture risk. [ABSTRACT FROM AUTHOR]

: Osteoporosis is a major public health problem in Japan. The second decade is an important period in which to attain a high peak bone mass. However, normal values of forearm bone mineral density (BMD) are not well known in children and adolescents. BMD at one-third of forearm length proximal to the ulnar end plate (BMD1/3) and the ultradistal forearm (BMDud) was measured using dual-energy X-ray absorptiometry (DXA) in 1207 (631 males, 576 females) Japanese subjects aged 9–18 years. Puberty onset was assessed by questionnaire, by obtaining the time that pubic hair appeared in males and the time that menstruation started in females. BMD1/3 and BMDud increased steadily with age in males. In relation to puberty development, these parameters also increased after puberty onset although the increase in BMD1/3 was not statistically significant after the fifth year from puberty onset and that of BMDud was not significant after the sixth year from puberty onset. BMD1/3 and BMDud increased with age and then plateaued in females. The increase in BMD1/3 was not statistically significant after 15–16 years of age and that of BMDud was not significant after 13–14 years of age. In relation to puberty development, the increase in BMD1/3 leveled out after the fourth year from puberty onset and that of BMDud also plateaued after the third year from puberty onset. We provide reference values of forearm BMD in Japanese children and adolescents by DXA according to calendar age and puberty development. Peak bone mass of the forearm may be in the late second decade in Japanese females. [ABSTRACT FROM AUTHOR]