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Summary: This study evaluated racial differences in bone size and volumetric density at the spine and hip in pre- and postmenopausal Chinese American and White women. Compared with White women, Chinese American women have greater cortical volumetric bone density (vBMD) at the hip, congruent with the results at the peripheral skeleton. Introduction: Chinese American women have lower rates of fracture than White women despite lower areal bone density. At the forearm and tibia, however, Chinese American women have higher cortical vBMD as well as greater trabecular and cortical thickness, but smaller bone area as measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) compared with White women. Since HR-pQCT data are obtained at peripheral sites, it is unclear whether these differences are relevant to the clinically important lumbar spine and hip. This study assesses racial differences in bone size and vBMD at the spine and hip in Chinese American and White women. Methods: QCT of the spine and hip was measured to assess racial differences in bone size, structure, and vBMD in pre- ( n = 83) and postmenopausal ( n = 50) Chinese American and White women. Data were adjusted for weight, height, physical activity, total calcium intake, parathyroid hormone, and 25-hydroxyvitamin D levels. Results: Among premenopausal women, lumbar spine trabecular vBMD was 5.8% greater in Chinese American versus White women ( p = 0.01). At the hip, cortical vBMD was 3% greater at the femoral neck ( p = 0.05) and 3.6% greater at the total hip ( p = 0.01) in premenopausal Chinese American compared with White women. Among postmenopausal women, there was no difference in lumbar spine trabecular vBMD. Cortical vBMD was 4% greater at the total hip ( p = 0.02) and tended to be greater at the femoral neck ( p = 0.058) in Chinese American versus White women. Conclusions: Consistent with earlier findings in the peripheral skeleton, cortical vBMD is greater at the hip in Chinese American versus White women. [ABSTRACT FROM AUTHOR]

Summary: Few data are available regarding bone mineral density (BMD) and its determinants among Chinese Americans. We identified determinants of BMD among 359 Chinese-American women in order to identify risk factors for low BMD in this burgeoning population. BMD in Chinese-American women is influenced by a number of factors, including immigration., Introduction: Osteoporosis and low BMD are common among Chinese women, including Chinese Americans, who are a growing population at risk for osteoporosis in the US. Few data are available regarding BMD and its determinants among Chinese-American women., Methods: In this study, we examined predictors of BMD in 359 ambulatory Chinese-American women, ages 20-90, using stepwise multiple regression analysis. Variables in the model included age, weight, height, menarche age, years since menopause, immigration age, years in US, percentage of life in US, number of pregnancies, oral contraceptive use, family history of osteoporosis, family history of hip fracture, daily calcium intake, exercise, time outdoors, alcohol consumption and tobacco use., Results: Among premenopausal women, weight was the strongest predictor of BMD, accounting for 10.5% of the variance at the lumbar spine (LS), 15.2% at the total hip (TH) and 16.6% at the femoral neck (FN). Time outdoors was also a positive predictor of BMD (1.4% at LS, 2.8% at TH and 1.6% at FN), while family history of osteoporosis (1.4% at TH) and age (3.7% at FN) were negative predictors. Among postmenopausal women, greater BMD at the LS and TH was associated with greater weight and earlier immigration age. Weight accounted for 16.4% of the variance at the LS and 19.8% at the TH; immigration age accounted for 3.1% of the variance at the LS and 4.1% at the TH. At the FN, years since menopause and weight were predictors of BMD, accounting for 14.4% and 8.7% of the variance, respectively. While older age at immigration had a negative effect on BMD, years in and proportion of life in the United States were not significant predictors of BMD., Conclusions: Bone mineral density in Chinese-American women is influenced by a number of biological and lifestyle factors, including immigration. The results of this study provide new insights into risk factors for low bone density as they relate to environmental determinants in the growing population of Chinese-American women.

The Western world has been used to describing disease on its terms, as if it is a prototype for the same disease found anywhere else in the world. It is unusual that one can test the hypothesis that a common disease can present in markedly different ways, depending on the country in which it is studied. We have had the opportunity to compare and contrast primary hyperparathyroidism in the United States and in China as seen in New York City and in Beijing. The cohort of subjects in each case was well over 100, and the experience extends to well over a decade of observations. In the United States, primary hyperparathyroidism typically presents as asymptomatic hypercalcemia in women within 10 years of menopause. Most often, it is discovered accidentally in the course of a routine multichannel chemistry screening test. The serum calcium is 10.5 + 0.1 mg/dL, within 1 mg/dL above the upper limit of normal, 10.2; the serum parathyroid hormone level is 118 + 9 pg/mL (within 1.5-2-fold above the normal limit, 65). The average 25-hydroxyvitamin D level is 21 ng/mL, in the lower range of normal. The classical clinical manifestations of primary hyperparathyroidism, stone and bone disease, have become much less common than earlier descriptions of the disease in the United States through the 1950s. Overt radiological bone disease (osteitis fibrosa cystica) is almost never seen, whereas stone disease is reduced in incidence from a high of 60% in the 1940s to current estimates of 15-20% now. Most patients are asymptomatic; skeletal involvement is detected only by measuring skeletal calcium by bone densitometry. Primary hyperparathyroidism in China presents much differently. Patients are younger, with an average age of 37. The serum calcium level is much higher, averaging about 12 mg/dL. PTH is over 20 times the upper limits of normal. The average 25-hydroxyvitamin D concentration is much lower than in the United States population, 8.8 ng/mL. Radiological evidence for osteitis fibrosa cystica is seen in 60% of patients; virtually all patients have osteoporosis. Thirty-five percent of patients suffer pathological fractures, most often of the femur or humerus. Forty-two percent demonstrate kidney stones, with half showing bilateral disease. Constitutional features of weakness and easy fatigability are always present. There are both facile and rather subtle explanations for this dramatically different presentation of the same disease in the United States (New York City) and China (Beijing).