This study has shown that less than one-third of the exacerbations were reported. The number of symptoms at onset was the most important predictor of reporting an exacerbation, and both reported and unreported exacerbations had an impact on health status.

We estimated peak bone mass (PBM) in 615 women and 527 men aged 16 to 40 years using longitudinal data from the Canadian Multicentre Osteoporosis Study (CaMos). Individual rates of change were averaged to find the mean rate of change for each baseline age. The age range for PBM was defined as the period during which bone mineral density (BMD) was stable. PBM was estimated via years in women and 19 to 21 years in men (1.093 AE 0.169 g/cm 2 ). Analysis of Canadian geographic variation revealed that the levels of PBM and of mean BMD in those over age 65 sometimes were discordant, suggesting that PBM and subsequent rates of bone loss may be subject to different genetic and/or environmental influences. Based on our longitudinally estimated PBM values, the estimated Canadian prevalences of osteoporosis (T-score < -2.5) were 12.0% (L 1 -L 4 ) and 9.1% (total hip) in women aged 50 years and older and 2.9% (L 1 -L 4 ) and 0.9% (total hip) in men aged 50 years and older. These were higher than prevalences using cross-sectional PBM data. In summary, we found that the age at which PBM is achieved varies by sex and skeletal site, and different reference values for PBM lead to different estimates of the prevalence of osteoporosis. Furthermore, lack of concordance of PBM and BMD over age 65 suggests different determinants of PBM and subsequent bone loss. ß

We compared two methods for osteoporotic vertebral fracture (VF) assessment on lateral spine radiographs, the Genant semiquantitative (GSQ) technique and a modified algorithm-based qualitative (mABQ) approach. We evaluated 4465 women and 1771 men aged ≥50 years from the Canadian Multicentre Osteoporosis Study with available X-ray images at baseline. Observer agreement was lowest for grade 1 VFs determined by GSQ. Among physician readers, agreement was greater for VFs diagnosed by mABQ (ranging from 0.62 [95% confidence interval (CI) 0.00-1.00] to 0.88 [0.76-1.00]) than by GSQ (ranging from 0.38 [0.17-0.60] to 0.69 [0.54-0.85]). GSQ VF prevalence (16.4% [95% CI 15.4-17.4]) and incidence (10.2/1000 person-years [9.2; 11.2]) were higher than with the mABQ method (prevalence 6.7% [6.1-7.4] and incidence 6.3/1000 person-years [5.5-7.1]). Women had more prevalent and incident VFs relative to men as defined by mABQ but not as defined by GSQ. Prevalent GSQ VFs were predominantly found in the mid-thoracic spine, whereas prevalent mABQ and incident VFs by both methods co-localized to the junction of the thoracic and lumbar spine. Prevalent mABQ VFs compared with GSQ VFs were more highly associated with reduced adjusted L to L bone mineral density (BMD) (-0.065 g/cm [-0.087 to -0.042]), femoral neck BMD (-0.051 g/cm [-0.065 to -0.036]), and total hip BMD (-0.059 g/cm [-0.076 to -0.041]). Prevalent mABQ VFs compared with prevalent GSQ were also more highly associated with incident VF by GSQ (odds ratio [OR] = 3.3 [2.2-5.0]), incident VF by mABQ (9.0 [5.3-15.3]), and incident non-vertebral major osteoporotic fractures (1.9 [1.2-3.0]). Grade 1 mABQ VFs, but not grade 1 GSQ VFs, were associated with incident non-vertebral major osteoporotic fractures (OR = 3.0 [1.4-6.5]). We conclude that defining VF by mABQ is preferred to the use of GSQ for clinical assessments. © 2017 American Society for Bone and Mineral Research.

Summary-A new Canadian WHO fracture risk assessment (FRAX ® ) tool to predict 10-year fracture probability was compared with observed 10-year fracture outcomes in a large Canadian population-based study (CaMos). The Canadian FRAX tool showed good calibration and discrimination for both hip and major osteoporotic fractures.

Intermediate stage and frail older community-dwelling women had higher subsequent total healthcare costs and utilization after accounting for multimorbidity and functional limitations. Frailty phenotype assessment may improve identification of older adults likely to require costly, extensive care.