Peggy A Rouleau

Population‐Based Study of Age and Sex Differences in Bone Volumetric Density, Size, Geometry, and Structure at Different Skeletal Sites

In a population‐based, cross‐sectional study, we assessed age‐ and sex‐specific changes in bone structure by QCT. Over life, the cross‐sectional area of the vertebrae and proximal femur increased by ∼15% in both sexes, whereas vBMD at these sites decreased by 39–55% and 34–46%, respectively, with greater decreases in women than in men.

A Population-Based Assessment of Rates of Bone Loss at Multiple Skeletal Sites : Evidence for Substantial Trabecular Bone Loss in Young Adult Women and Men

Using QCT, we made a longitudinal, population‐based assessment of rates of bone loss over life at the distal radius, distal tibia, and lumbar spine. Cortical bone loss began in perimenopause in women and later in life in men. In contrast, trabecular bone loss began in young adulthood in both sexes.

Structural Determinants of Vertebral Fracture Risk

Vertebral fractures are more strongly associated with specific bone density, structure, and strength parameters than with areal BMD, but all of these variables are correlated.

Age- and sex-specific differences in the factor of risk for vertebral fracture: a population-based study using QCT.

We used QCT scans obtained in 687 men and women, 21–97 years of age, to estimate the factor of risk for vertebral fracture, Φvert, defined as the ratio of spinal loading to vertebral strength. With age, vertebral strength declined and Φvert increased significantly more in women than men. Age‐ and sex‐specific differences in Φvert closely resembled previously reported vertebral fracture incidence.

Relationship of Volumetric BMD and Structural Parameters at Different Skeletal Sites to Sex Steroid Levels in Men

In a population‐based, cross‐sectional study, we related age‐associated changes in vBMD and in bone structural parameters to circulating bioavailable estradiol and testosterone levels in men. Associations between these bone mass/structural parameters and sex steroid levels were progressively stronger with age. Our previously postulated “threshold” for skeletal estrogen deficiency was most evident at cortical sites.

Population-based analysis of the relationship of whole bone strength indices and fall-related loads to age- and sex-specific patterns of hip and wrist fractures

In an age‐ and sex‐stratified population sample (n = 700), we estimated fall‐related loads and bone strength indices at the UDR and FN. These load/strength ratios more closely simulated patterns of wrist and hip fractures occurring in the same population than did measurement of vBMD.

Relation of vertebral deformities to bone density, structure, and strength.

Because they are not reliably discriminated by areal bone mineral density (aBMD) measurements, it is unclear whether minimal vertebral deformities represent early osteoporotic fractures. To address this, we compared 90 postmenopausal women with no deformity (controls) with 142 women with one or more semiquantitative grade 1 (mild) deformities and 51 women with any grade 2–3 (moderate/severe) deformities. aBMD was measured by dual‐energy X‐ray absorptiometry (DXA), lumbar spine volumetric bone mineral density (vBMD) and geometry by quantitative computed tomography (QCT), bone microstructure by high‐resolution peripheral QCT at the radius (HRpQCT), and vertebral compressive strength and load‐to‐strength ratio by finite‐element analysis (FEA) of lumbar spine QCT images. Compared with controls, women with grade 1 deformities had significantly worse values for many bone density, structure, and strength parameters, although deficits all were much worse for the women with grade 2–3 deformities. Likewise, these skeletal parameters were more strongly associated with moderate to severe than with mild deformities by age‐adjusted logistic regression. Nonetheless, grade 1 vertebral deformities were significantly associated with four of the five main variable categories assessed: bone density (lumbar spine vBMD), bone geometry (vertebral apparent cortical thickness), bone strength (overall vertebral compressive strength by FEA), and load‐to‐strength ratio (45‐degree forward bending ÷ vertebral compressive strength). Thus significantly impaired bone density, structure, and strength compared with controls indicate that many grade 1 deformities do represent early osteoporotic fractures, with corresponding implications for clinical decision making.

Does reduced skeletal loading account for age-related bone loss?

A leading theory suggests that decreasing activity and muscle mass is the main cause of age‐related bone loss. However, in a population‐based study of 375 women and 325 men (age, 21–97 years), we failed to find a close correspondence between these variables and changes in bone strength with aging.

Carotid Artery Tandem Lesions Frequency and Consequences for Endarterectomy

We determined the frequency of tandem carotid lesions within the carotid siphon, common carotid artery and proximal intracerebral arteries as well as incidental intracranial saccular aneurysms. We also determined the consequence of a tandem lesion on the surgeons decision-making process when a hemodynamically significant stenosis or aneurysm was detected during the preoperative evaluation.