Effect of estrogen replacement therapy on speed of sound at multiple skeletal sites

Bone density and frame size in adult women: Effects of body size, habitual use, and life history

OBJECTIVE

Bone mineral density (BMD) and frame size are important predictors of future bone health, with smaller frame size and lower BMD associated with higher risk of later fragility fractures. We test the effects of body size, habitual use, and life history on frame size and cortical BMD of the radius and tibia in sample of healthy adult premenopausal women.

METHODS

We used anthropometry and life history data from 123 women (age 18-46) from rural Poland. Standard techniques were used to measure height, weight, and body fat. Life history factors were recorded using surveys. Grip strength was measured as a proxy for habitual activity, wrist breadth for skeletal frame size. Cortical BMD was measured at the one-third distal point of the radius and mid-point of the tibia using quantitative ultrasound (reported as speed of sound, SoS).

RESULTS

Radial SoS was high (mean t-score 3.2 ± 1.6), but tibia SoS was average (mean t-score 0.35 ± 1.17). SoS was not associated with age, although wrist breadth was positively associated with age after adjusting for height. Radius SoS was not associated with measures of body size, habitual use, or life history factors. Wrist breadth was associated with body size (p < .05 for all), lean mass, and grip strength. Tibia SoS was associated with height. Life history factors were not associated with frame size or cortical SoS.

CONCLUSIONS

Habitual use and overall body size are more strongly associated with frame size and cortical SoS than life history factors in this sample of healthy adult women.

Multisite quantitative ultrasound for the prediction of fractures over 5 years of follow-up: the Canadian Multicentre Osteoporosis Study

This study assessed the ability of multisite quantitative ultrasound (mQUS) to predict fracture over a 5-year follow-up. Participants were a subset of the Canadian Multicentre Osteoporosis Study. mQUS-assessed speed of sound (SOS in m/s) at three sites (distal radius, tibia, and phalanx) and extensive questionnaires were completed, after which participants were followed for 5 years and incident fractures recorded. Two survival analyses were completed for each site--a univariate analysis and an adjusted multivariate analysis controlling for age, antiresorptive use, femoral neck bone mineral density, number of diseases, previous fractures, body mass index (BMI), parental history of hip fracture, current smoking, current alcoholic drinks >3 per day, current use of glucocorticoids, and rheumatoid arthritis diagnosis (variables from the FRAX 10-year fracture risk assessment tool). The unit of change for regression analyses was one standard deviation for all measurement sites, specific to site and sex. Separate analyses were completed for all clinical fractures, nonvertebral fractures, and hip fractures by sex. There were 2633 women and 1108 men included, and they experienced 204 incident fractures over 5 years (5.5% fractured). Univariate models revealed statistically significant (p < 0.05) predictive ability of mQUS for all three measurement sites for women alone for all three fracture types (one standard deviation decrease in SOS was associated with a 52% to 130% increase in the risk of fracture), but not for the men's group. The adjusted model found that measures at the distal radius and tibia in the women's group could significantly (p < 0.05) predict all clinical fractures and nonvertebral fractures within the next 5 years (one standard deviation decrease in SOS was associated with a 25% to 31% increase in the risk of fracture). mQUS provided significant 5-year clinical fracture prediction in women, independent of bone mineral density and other significant risk factors for fracture, when measured at the distal radius and tibia sites.

Relationship between risk factors and QUS in a European Population: The OPUS study

There are many risk factors associated with low bone mineral density. Quantitative ultrasound (QUS) is a generally accepted method for measurement of bone and has been shown to be strongly associated with future fracture risk. The Osteoporosis and Ultrasound Study (OPUS) is a multi-centre European wide study examining 5 different QUS scanners (4 calcaneal, 1 finger device). The aim of this paper was to examine the relationship between risk factors (as assessed by questionnaire) and QUS measurements. 449 younger women (aged 20 to 39 years) and 2283 older women (aged 55 to 79 years) were included in this analysis. As expected, those with a self-reported previous fracture had lower QUS measurements than those without (P < 0.001). However, no significant difference was seen between those reporting a maternal hip fracture and those who did not report such an event. Differences were found for smokers vs. non-smokers for SOS but not for BUA measurements. Weight was positively correlated with all BUA variables but only with some SOS variables. We determined which risk factors were most strongly associated with QUS measurements by using step-wise multiple regression. Models for each QUS measurement were calculated, and the R2 values ranged from 0.18 to 0.28 for SOS, 0.27 to 0.32 for BUA and 0.31 to 0.42 for the finger QUS device. The most common risk factors across all models were age, use of hormone replacement therapy, self-reported previous fracture, self-reported diagnosis of osteoporosis, current weight, pulse rate and self-reported estimated height at age 20 years. We analysed relationships across the 5 centres and detected some geographical differences in the prevalence of the risk factors. In conclusion, similar relationships are seen with QUS measurements as are found for bone mineral density. However, the strength of the association is dependent on the type of QUS device and variable measured.

Evaluation of skeletal status by quantitative ultrasonometry in postmenopausal women without known risk factors for osteoporosis

The objective of our study was to evaluate bone density in Italian postmenopausal women without clinical risk factors for osteoporosis resident in the Naples area using quantitative ultrasonometry of bone (QUS). Subjects were 1149 Italian postmenopausal women (age: 54.9 +/- 5.0 years (mean +/- standard deviation); range: 45-74 years) resident in the Naples area. Clinical risk factors for osteoporosis resulting in exclusion from the study were family history of osteoporosis, dietary, smoking and alcohol habits, personal history of fractures and/or metabolic diseases. The following QUS parameters were calculated: amplitude-dependent speed of sound (AD-SoS), T-score and Z-score. We found significant inverse correlations between AD-SoS and age (r = - 0.23), time since menopause (r = - 0.25) and body mass index (BMI) (r = - 0.16). The same was observed for T-score. In contrast, Z-score showed a significant positive correlation with age and time since menopause, and a negative correlation with BMI. A T-score suggestive of high risk for osteoporosis (less than -3.2) was found in 1.6% of subjects, while a T-score suggestive of moderate risk for osteoporosis (between -3.2 and -2) was found in 19.3% of patients. In this group of women without clinical risk factors for osteoporosis we found a very low prevalence of QUS results suggesting a high risk for osteoporosis. However, a condition of 'moderate' risk for osteoporosis was present in a remarkable percentage of these women.

An in vitro study of the ultrasonic axial transmission technique at the radius: 1-MHz velocity measurements are sensitive to both mineralization and intracortical porosity

The ultrasonic axial transmission technique allows for investigating skeletal sites such as the cortical layer of long bones (radius, tibia, phalanges). Using synchrotron radiation microCT, we investigated, in vitro, the relationships between 1-MHz axial transmission SOS measurements at the radius and site-matched measurements of C.Th, POR, MIN, and vBMD.

INTRODUCTION

The ultrasonic axial transmission technique allows for investigating skeletal sites such as the cortical layer of long bones (radius, tibia, phalanges).

MATERIALS AND METHODS

Using synchrotron radiation microCT, we investigated, in vitro, the relationships between 1-MHz axial transmission speed of sound (SOS) measurements at the radius and site-matched measurements of cortical thickness (C.Th), intracortical porosity (POR), tissue mineralization (MIN), and volumetric BMD (vBMD). SOS measurements were based on bidirectional axial transmission and were performed with a 1-MHz proprietary probe on 39 excised human radii.

RESULTS

The highest correlations between SOS values and bone parameters (R(2)(SOS/POR) = 0.28, p < 10(-3); R(2)(SOS/MIN) = 0.38, p < 10(-4); R(2)(SOS/vBMD) = 0.57, p < 10(-3)) were found for bone parameters assessed in a 1-mm-thick periosteal region of the cortex rather than throughout the whole cortex. The observed moderate correlation between SOS and C.Th values (R(2)(SOS/C.Th) = 0.20, p < 10(-2)) disappeared when controlled for other variables. The two best multilinear predictive models, including either BMD alone or the pair of dependent variables MIN and POR (all assessed in the periosteal cortex), were equally accurate in predicting SOS values (R(2)(SOS/(POR,MIN)) = 0.59, p < 10(-5); R(2)(SOS/vBMD) = 0.57, p < 10(-5)).

CONCLUSION

For the first time, the respective adjusted contributions of POR (-24 m/s%(-1)) and tissue mineralization (+3.5 m/s/mg/cm(-3)) to SOS values were assessed. These results suggest potential sensitivity of axial transmission SOS values to changes in cortical bone status under different pathological conditions or treatments affecting POR and/or tissue mineralization.

Hormone replacement therapy and risk for foot, distal forearm, proximal humerus, and pelvis fractures

This case-control epidemiologic study examines the relationship between hormone replacement therapy (HRT) and risk for fractures of four sites among women 45 years of age and older. From October 1996 to May 2001, incident patients with distal forearm ( n=744), foot ( n=618), proximal humerus ( n=331), and pelvis ( n=109) fractures were recruited from five Kaiser Permanente Medical Centers in northern California. Controls ( n=1617) were selected at random from the same five medical centers over the same time period within strata defined by 5-year age group, gender, and white versus nonwhite or unknown recorded race/ethnicity. Trained interviewers collected information using a standardized questionnaire. Compared with postmenopausal women who never used HRT, postmenopausal women currently using HRT for at least 3 months had a decreased risk of fracture at the distal forearm (adjusted OR=0.55, 95% CI: 0.43, 0.72), proximal humerus (adjusted OR=0.51, 95% CI: 0.36, 0.74), and pelvis (adjusted OR=0.51, 95% CI: 0.27, 0.95), but not the foot (adjusted OR=1.05, 95% CI: 0.81, 1.35). Past use of HRT for more than 7 years also appeared to be associated with a reduced risk of fracture at the distal forearm and proximal humerus. The longer a woman went without HRT after her last menstrual period, the greater her risk of fracture in the distal forearm, proximal humerus, and pelvis. The findings of this study support long-term, current use of HRT for the prevention of osteoporotic fractures, but other risks and benefits also need to be considered.