Parity and bone mineral density in middle-aged women

A retrospective study was carried out to determine the relationship between parity and bone mineral density (BMD) in middle-aged women. Eight hundred and twenty-five woman aged 41–76 years were recruited from four general practice registers in Cambridge. Subjects were unselected as to their health status. Each subject completed a detailed health questionnaire. Participation rate was 50%. The main outcome measure was BMD measured at the spine (L2–4,n=825) and hip (neck, intertrochanter and Ward's triangle;n=817) by dual-energy X-ray absorptiometry (DXA) using the Hologic QDR-1000 densitometer. It was found that the unadjusted mean BMD was significantly higher at all sites among the parous women (p=0.031 to <0.00001), and remained significantly higher at the femoral neck (p=0.025), intertrochanter (p=0.001) and Ward's triangle (p=0.045) after adjusting for age and body mass index (BMI). Similar findings were seen after stratifying for potential confounding variables. There was a consistent upward trend of BMD with increasing parity at all sites. Parity remained a significant independent predictor of BMD at all sites after controlling for age, BMI, menopausal status, oral contraceptive and hormone replacement therapy use, smoking status and breast-feeding status in multiple linear regression analyses. There was, on average, a 1.0% increase in BMD per live birth. Our findings therefore suggest a positive relationship between parity and bone mass.     

When should bone density measurements be repeated?

We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement.     

Determination of bone mineral density by dual x-ray absorptiometry in patients with uncemented total hip arthroplasty.

Bone remodeling is an expected sequela with total hip arthroplasty (THA). Although there are several methods of estimating bone response in THA patients from radiographs, there are no accurate and generally accepted methods for quantitative determinations in vivo. In this study, we describe an application of dual x-ray absorptiometry (DXA) for measuring bone mineral content and bone mineral density in the proximal femur following THA. DXA is a noninvasive technique with minimal radiation exposure (< 5 mrem). Various aspects of measurement error (accuracy and reliability) of this application of DXA were determined in a series of studies reported here. Accuracy error (how similar are the measured and actual values) was < 1% determined in bone phantoms of four densities. Precision error (how reproducible are the measurements) was also < 1% at all four densities in the phantoms and was only slightly elevated (0.9-1.5%) in repeated measurements of implanted cadaver femora. Precision error in vivo, determined both from multiple replicates on five patients and from duplicate scans on 30 patients, was further elevated but remained < 5%. Contributions to precision error, rotation of the leg, and interoperator variability were assessed; none was found to elevate precision error appreciably. We suggest that DXA is a feasible method for quantifying bone response following THA, and will allow discrimination of small changes (> 5%) not previously measurable.     

Correlations between bone mineral density and demographic, lifestyle, and biochemical variables in community-dwelling Japanese women 69 years of age and over

Introduction A few epidemiologic studies have comprehensively attempted to identify risk factors for low bone mineral density (BMD) in elderly Asian women. The purpose of this study was to identify demographic, lifestyle, and biochemical factors correlated with BMD in elderly Japanese women 69 years of age and over.Methods The study design was cross-sectional. The subjects were 583 ambulatory women aged 69 years and over, and their average age was 74.3 (SD 4.4) years. Predictor variables were age, reproductive history, anthropometric indices, grip strength, calcium intake, lifestyle information, and serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D (1,25(OH)₂D), osteocalcin (OC), and undercarboxylated osteocalcin (ucOC) values. The outcome variable was forearm BMD measured with a DTX-200 osteometer.Results Simple linear regression analyses showed that BMD was significantly positively associated with body height, weight, body mass index, grip strength, serum albumin concentration, and “housework,” and negatively associated with age, years since menopause, age at menarche, number of children, serum 1,25(OH)₂D concentration, serum OC concentration, and ucOC concentration. The stepwise multiple regression analysis showed that weight (β=0.00316, SE=0.00028, R²=0.180), age (β=−0.00321, SE=0.00050, R²=0.108), log-transformed serum OC (β=−0.0445, SE=0.0064, R²=0.053), log-transformed serum 1,25(OH)₂D (β=−0.0401, SE=0.0074, R²=0.050), “farmwork” (β=0.00904, SE=0.00426, R²=0.005), and serum 25(OH)D concentration (β=0.000281, SE=0.000120, R²=0.003) were significantly associated with BMD.Conclusion It was concluded that body weight is a major predictor of forearm BMD among the factors measured in this study in independent Japanese women 69 years of age and over and that serum 1,25(OH)₂D concentration may be associated with cortical BMD. Maintenance of body weight is very important for maintaining BMD in this population, unless a large weight aggravates obesity-related diseases. A follow-up study is needed to confirm these findings.     

微血管密度测定在子宫内膜癌病变发展中的价值

目的　探讨血管生成活性在子宫内膜癌发展中的价值。方法　采用Ⅷ因子相关抗原为标志物 ,以免疫组化技术对正常子宫内膜、不典型增生内膜 ,子宫内膜癌组织进行微血管密度 (MVD)测定。结果　①正常组与内膜癌组比较 (P <0 .0 1) ,正常组与不典型增生组比较 (P <0 .0 5 ) ;从正常内膜、不典型增生到内膜癌组织内MVD逐渐增多 (P <0 .0 5 )。②内膜癌组织内MVD与肿瘤细胞分化程度有关 (P <0 .0 5 )。结论　临床采用MVD测定对子宫内膜增生病变发展和追随检查具有重要价值 ,同时MVD测定可作为判断子宫内膜癌预后的指标之一。     

Effect of adiposity on plasma lipid transfer protein activities: a possible link between insulin resistance and high density lipoprotein metabolism

Abstract. The mechanisms responsible for the decreased high density lipoprotein (HDL) cholesterol levels associated with obesity and insulin resistance are not well understood. Lecithin: cholesterol acyltransferase (LCAT) and cholesterol ester transfer protein (CETP) are key factors in the esterification of cholesterol in HDL and the subsequent transfer of cholesteryl ester towards apolipoprotein B-containing lipoproteins. Phospholipid transfer protein (PLTP) may be involved in the regulation of HDL particle size. We therefore measured the activities of LCAT, CETP and PLTP using exogenous substrate assays, as well as lipids, lipoproteins, insulin and C-peptide in fasting plasma from eight healthy obese men (body mass index >27 kg m^-2) and 24 non-obese subjects. The obese men had lower levels of HDL cholesterol (P<0·05) and higher levels of plasma triglycerides (P<0·05), insulin (P<0·05) and C-peptide (P<0·01), as compared to the quartile of subjects with the lowest body mass index (BMI <22·4 kg m^-2). CETP and PLTP activities were elevated in the obese men by 35% (P<0·01) and by 15% (P<0·05), respectively. LCAT activity was comparable among the quartiles. Linear regression analysis showed that CETP activity was positively correlated with body mass index (P<0·02), fasting blood glucose (P7lt;0·05) and plasma C-peptide (P<0·05). PLTP activity was positively related to body mass index (P<0·01), waist to hip circumference ratio (P<0·001), as well as to fasting blood glucose (P<0·05) and plasma C-peptide (P<0·05) It is concluded that the activities of CETP and PLTP are influenced by adiposity and possibly by insulin resistance. Elevated lipid transfer protein activities may provide a mechanism that contributes to alterations in HDL in insulin resistant states.     

北京市房山区绝经前后妇女骨代谢情况报告

测定北京房山区１４４例绝经前后妇女桡骨骨密度值及４３例绝经妇女血清钙、雌激素、降钙素、甲状旁腺素值。结果表明：随着年龄和绝经年限的增加，骨密度值显著下降。血清钙各年龄组变化不大。雌激素、降钙素绝经后逐渐降低，甲状旁腺素明显增加，多因素回归分析提示，年龄、绝经年限、孕次、人工流产次数、服用营养补品、经济水平、雌激素、甲状旁腺素是影响骨密度的主要因素。     

补肾密骨片结合骨髓移植对桡骨延迟愈合的实验研究

[目的]观察补肾密骨片结合经皮自体骨髓移植对骨折延迟愈合治疗后的骨密度和生物力学性能影响。[方法]预制新西兰大耳白兔骨延迟愈合模型，将75只兔随机分为四组：A组20只，饲料中加入补肾密骨片，骨延迟愈合区注入自体红骨髓2ml；B组20只，饲料中加入补肾密骨片，骨延迟愈合区不注入自体红骨髓；C组20只，饲料中不加补肾密骨片，骨延迟愈合区注入自体红骨髓；D组15只，造成骨延迟愈合模型后，饲料中不加补肾密骨片，骨延迟愈合区不注人自体红骨髓。治疗后12周处死动物取材，行骨密度及生物力学测试。[结果]骨密度及生物力学测试均显示A组骨愈合优于B、C、D组。[结论]补肾密骨片结合经皮自体骨髓移植治疗骨折延迟愈合的骨组织的骨密度及生物力学强度优于单一骨髓移植或中药治疗。     

老年2型糖尿病患者骨密度及临床相关因素分析

目的 了解老年2型糖尿病患者骨密度的变化，初步探讨临床相关因素对骨密度变化的影响。方法 采用双能X线骨密度仪测定65例老年2型糖尿病患者及80例年龄、性别匹配的正常对照者腰椎及髋部骨密度，同时测定前者空腹血糖（FBG）、餐后2h血糖（PBG）、空腹C肽、餐后2hC肽、果糖胺（FA）、糖化血红蛋白（HBAle）、胆固醇（chol）、甘油三酯（TG）。结果 65例糖尿病患者各部位骨密度值均低于正常对照者，但仅腰椎降低有统计学意义（P〈0．05）；糖尿病组30例（45％）合并骨质疏松（OP）。OP与非0P组病程有显著性差异（P〈0．05）。结论 2型糖尿病会导致骨矿密度减低，并与糖尿病病程密切相关。