Importance of ethnic base standard references for the diagnosis of osteoporosis in Thai women

Different reference BMDs affect the prevalence of osteoporosis

The T score represents the degree of deviation from the peak bone mineral density (BMD) (reference standard) in a population. Little has been investigated concerning the age at which the BMD reaches the peak value and how we should define the reference standard BMD in terms of age ranges. BMDs of 9,800 participants were analyzed from the Korean National Health and Nutrition Examination Survey database. Five reference standards were defined: (1) the reference standard of Japanese young adults provided by the dual-energy X-ray absorptiometry machine manufacturer, (2) peak BMD of the Korean population evaluated by statistical analysis (second-order polynomial regression models), (3) BMD of subjects aged 20-29 years, (4) BMD of subjects aged 20-39 years, and (5) BMD of subjects aged 30-39 years. T-scores from the five reference standards were calculated, and the prevalence of osteoporosis was evaluated and compared for males and females separately. The peak BMD in the polynomial regression model was achieved at 26 years in males and 36 years in females in the total hip, at 20 years in males and 27 years in females in the femoral neck, and at 20 years in males and 30 years in females in the lumbar spine. The prevalence of osteoporosis over the age of 50 years showed significant variation of up to two fold depending on the reference standards adopted. The age at which peak BMD was achieved was variable according to the gender and body sites. A consistent definition of peak BMD needs to be established in terms of age ranges because this could affect the prevalence of osteoporosis and healthcare policies.

Aging and bone health in Singaporean Chinese pre-menopausal and postmenopausal women

OBJECTIVE

The study evaluated relationships between menopausal statuses, hormone replacement therapy (HRT), body mass index (BMI), percent body fat (PBF), and exercise with osteoporosis and bone mineral density (BMD) in Singaporean women.

STUDY DESIGN

This is a cross-sectional study.

MAIN OUTCOME MEASURES

The spine BMD, and femoral neck BMD as well as the prevalence of osteoporosis are the main outcome measures studied.

RESULTS

Age, BMI, PBF and exercise intensity were independently associated with spine and femoral neck BMD. Women with higher BMI and lower PBF had higher BMD and lower prevalence of osteoporosis. Postmenopausal women without HRT had lower BMD and higher prevalence of osteoporosis while those on HRT had similar BMD and prevalence of osteoporosis as premenopausal women.

CONCLUSION

This study shows that BMI and PBF are powerful predictors of BMD. Osteoporosis is site-specific in the Singapore population, being higher in the femoral neck than in the lumbar spine. The bone status after menopause may not be worse than that dictated by age alone and both ERT and E/PRT could sustain the BMD to levels corresponding to those of women a decade younger. A strategy to improve bone health should include dieting and physical exercise program that focuses on selectively reducing fat mass and increasing lean mass.

Reference values of bone mineral density and prevalence of osteoporosis in Chinese adults

We pooled bone mineral density (BMD) data published in 91 articles including 139,912 Chinese adults and then established a national-wide BMD reference database at the lumbar spine and femur neck for Chinese adults. The prevalence of osteoporosis in the middle-aged and elderly Chinese population was also estimated.

INTRODUCTION

Well-accepted reference value of BMD is lacking in Chinese. We established the reference database and assessed osteoporosis prevalence based on published literature conducted in the Mainland China, Taiwan, and Hong Kong Chinese.

METHODS

We searched for all published articles indexed in MEDLINE, PubMed, CNKI, and SinoMed up to January 2013. We included cross-sectional studies that examined BMD using a dual-energy X-ray absorptiometry at the femur neck (FN) and/or lumbar spine (LS) in healthy adults. Overall age-specific mean (SD) BMD were pooled after standardization.

RESULTS

Ninety-one studies including 51,906 males and 88,006 females (≥ 20 years) in 38 cities in China were included in this pooling study. Gender- and age-specific reference curves of standardized BMD (sBMD) at the LS and FN were constructed. The sBMD cutoffs for osteoporosis classification were 0.746 and 0.549 in women, and 0.680 and 0.568 g/cm(2) in men; age-standardized prevalence of osteoporosis was 23.9 % and 12.5 % in women and 3.2 % and 5.3 % in men aged ≥ 50 years at the LS and FN, respectively. Meta-regression analysis showed that greater age and altitude, lower latitude, smaller city size, earlier detection time, and random sample were correlated to lower sBMD in at least one gender-specific bone sites; the Hologic DXA produced a higher value of FN sBMD than the other two devices (Lunar and Norland).

CONCLUSION

We have established a national-wide BMD reference database at the LS and FN for Chinese adults and estimated the prevalence of osteoporosis in the middle-aged and elderly Chinese population.