Skeletal Muscle Energetics Explain the Sex Disparity in Mobility Impairment in the Study of Muscle, Mobility and Aging.

The age-related decline in muscle mitochondrial energetics contributes to the loss of mobility in older adults. Women experience a higher prevalence of mobility impairment compared to men, but it is unknown whether sex-specific differences in muscle energetics underlie this disparity. In the Study of Muscle, Mobility and Aging (SOMMA), muscle energetics were characterized using in vivo phosphorus-31 magnetic resonance spectroscopy and high-resolution respirometry of vastus lateralis biopsies in 773 participants (56.4% women, age 70-94 years). A Short Physical Performance Battery (SPPB) score ≤8 was used to define lower-extremity mobility impairment. Muscle mitochondrial energetics were lower in women compared to men (eg, Maximal Complex I&II OXPHOS: Women = 55.06 ± 15.95; Men = 65.80 ± 19.74; p < .001) and in individuals with mobility impairment compared to those without (eg, Maximal Complex I&II OXPHOS in women: SPPB ≥ 9 = 56.59 ± 16.22; SPPB ≤ 8 = 47.37 ± 11.85; p < .001). Muscle energetics were negatively associated with age only in men (eg, Maximal ETS capacity: R = -0.15, p = .02; age/sex interaction, p = .04), resulting in muscle energetics measures that were significantly lower in women than men in the 70-79 age group but not the 80+ age group. Similarly, the odds of mobility impairment were greater in women than men only in the 70-79 age group (70-79 age group, odds ratio [OR]age-adjusted = 1.78, 95% confidence interval [CI] = 1.03, 3.08, p = .038; 80+ age group, ORage-adjusted = 1.05, 95% CI = 0.52, 2.15, p = .89). Accounting for muscle energetics attenuated up to 75% of the greater odds of mobility impairment in women. Women had lower muscle mitochondrial energetics compared to men, which largely explain their greater odds of lower-extremity mobility impairment.

Skeletal muscle energetics explain the sex disparity in mobility impairment in the Study of Muscle, Mobility and Aging (SOMMA).

The age-related decline in muscle mitochondrial energetics contributes to the loss of mobility in older adults. Women experience a higher prevalence of mobility impairment compared to men, but it is unknown whether sex-specific differences in muscle energetics underlie this disparity. In the Study of Muscle, Mobility and Aging (SOMMA), muscle energetics were characterized using in vivo phosphorus-31 magnetic resonance spectroscopy and high-resolution respirometry of vastus lateralis biopsies in 773 participants (56.4% women, age 70-94 years). A Short Physical Performance Battery score ≤ 8 was used to define lower-extremity mobility impairment. Muscle mitochondrial energetics were lower in women compared to men (e.g. Maximal Complex I&II OXPHOS: Women=55.06 +/- 15.95; Men=65.80 +/- 19.74; p<0.001) and in individuals with mobility impairment compared to those without (e.g., Maximal Complex I&II OXPHOS in women: SPPB≥9=56.59 +/- 16.22; SPPB≤8=47.37 +/- 11.85; p<0.001). Muscle energetics were negatively associated with age only in men (e.g., Maximal ETS capacity: R=-0.15, p=0.02; age/sex interaction, p=0.04), resulting in muscle energetics measures that were significantly lower in women than men in the 70-79 age group but not the 80+ age group. Similarly, the odds of mobility impairment were greater in women than men only in the 70-79 age group (70-79 age group, OR age-adjusted =1.78, 95% CI=1.03, 3.08, p=0.038; 80+ age group, OR age-adjusted =1.05, 95% CI=0.52, 2.15, p=0.89). Accounting for muscle energetics attenuated up to 75% of the greater odds of mobility impairment in women. Women had lower muscle mitochondrial energetics compared to men, which largely explain their greater odds of lower-extremity mobility impairment.

Incidence and cost of vertebral fracture in urban China: a 5-year population-based cohort study.

BACKGROUND: Osteoporotic vertebral fractures cause pain and disability, which result in a heavy socioeconomic burden. However, the incidence and cost of vertebral fractures in China are unknown. We aimed to assess the incidence and cost of clinically recognized vertebral fractures among people aged 50 years and older in China from 2013 to 2017. MATERIALS AND METHODS: This population-based cohort study was conducted by using Urban Employee Basic Medical Insurance (UEBMI) and Urban Resident Basic Medical Insurance (URBMI) data in China from 2013 to 2017, which covered more than 95% of the Chinese population in urban areas. Vertebral fractures were identified by the primary diagnosis (i.e. International Classification of Diseases code or text of diagnosis) in UEBMI and URBMI. The incidence and medical cost of these clinically recognized vertebral fractures in urban China were calculated. RESULTS: A total of 271 981 vertebral fractures (186 428, 68.5% females and 85 553, 31.5% males) were identified, with a mean age of 70.26 years. The incidence of vertebral fractures among patients aged 50 years and over in China increased ~1.79-fold during the 5 years, from 85.21 per 100 000 person-years in 2013 to 152.13 per 100 000 person-years in 2017. Medical costs for vertebral fractures increased from US$92.74 million in 2013 to US$505.3 million in 2017. Annual costs per vertebral fracture case increased from US$3.54 thousand in 2013 to US$5.35 thousand in 2017. CONCLUSION: The dramatic increase in the incidence and cost of clinically recognized vertebral fractures among patients aged 50 and over in urban China implies that more attention should be given to the management of osteoporosis to prevent osteoporotic fractures.

Assessment of a Risk-Based Approach for Triaging Mammography Examinations During Periods of Reduced Capacity.

Importance: Breast cancer screening, surveillance, and diagnostic imaging services were profoundly limited during the initial phase of the coronavirus disease 2019 (COVID-19) pandemic. Objective: To develop a risk-based strategy for triaging mammograms during periods of decreased capacity. Design, Setting, and Participants: This population-based cohort study used data collected prospectively from mammography examinations performed in 2014 to 2019 at 92 radiology facilities in the Breast Cancer Surveillance Consortium. Participants included individuals undergoing mammography. Data were analyzed from August 10 to November 3, 2020. Exposures: Clinical indication for screening, breast symptoms, personal history of breast cancer, age, time since last mammogram/screening interval, family history of breast cancer, breast density, and history of high-risk breast lesion. Main Outcomes and Measures: Combinations of clinical indication, clinical history, and breast cancer risk factors that subdivided mammograms into risk groups according to their cancer detection rate were identified using classification and regression trees. Results: The cohort included 898 415 individuals contributing 1 878 924 mammograms (mean [SD] age at mammogram, 58.6 [11.2] years) interpreted by 448 radiologists, with 1 722 820 mammograms in individuals without a personal history of breast cancer and 156 104 mammograms in individuals with a history of breast cancer. Most individuals were aged 50 to 69 years at imaging (1 113 174 mammograms [59.2%]), and 204 305 (11.2%) were Black, 206 087 (11.3%) were Asian or Pacific Islander, 126 677 (7.0%) were Hispanic or Latina, and 40 021 (2.2%) were another race/ethnicity or mixed race/ethnicity. Cancer detection rates varied widely based on clinical indication, breast symptoms, personal history of breast cancer, and age. The 12% of mammograms with very high (89.6 [95% CI, 82.3-97.5] to 122.3 [95% CI, 108.1-138.0] cancers detected per 1000 mammograms) or high (36.1 [95% CI, 33.1-39.3] to 47.5 [95% CI, 42.4-53.3] cancers detected per 1000 mammograms) cancer detection rates accounted for 55% of all detected cancers and included mammograms to evaluate an abnormal mammogram or breast lump in individuals of all ages regardless of breast cancer history, to evaluate breast symptoms other than lump in individuals with a breast cancer history or without a history but aged 60 years or older, and for short-interval follow-up in individuals aged 60 years or older without a breast cancer history. The 44.2% of mammograms with very low cancer detection rates accounted for 13.1% of detected cancers and included annual screening mammograms in individuals aged 50 to 69 years (3.8 [95% CI, 3.5-4.1] cancers detected per 1000 mammograms) and all screening mammograms in individuals younger than 50 years regardless of screening interval (2.8 [95% CI, 2.6-3.1] cancers detected per 1000 mammograms). Conclusions and Relevance: In this population-based cohort study, clinical indication and individual risk factors were associated with cancer detection and may be useful for prioritizing mammography in times and settings of decreased capacity.

Proteomic assessment of serum biomarkers of longevity in older men.

The biological bases of longevity are not well understood, and there are limited biomarkers for the prediction of long life. We used a high-throughput, discovery-based proteomics approach to identify serum peptides and proteins that were associated with the attainment of longevity in a longitudinal study of community-dwelling men age ≥65 years. Baseline serum in 1196 men were analyzed using liquid chromatography-ion mobility-mass spectrometry, and lifespan was determined during ~12 years of follow-up. Men who achieved longevity (≥90% expected survival) were compared to those who died earlier. Rigorous statistical methods that controlled for false positivity were utilized to identify 25 proteins that were associated with longevity. All these proteins were in lower abundance in long-lived men and included a variety involved in inflammation or complement activation. Lower levels of longevity-associated proteins were also associated with better health status, but as time to death shortened, levels of these proteins increased. Pathway analyses implicated a number of compounds as important upstream regulators of the proteins and implicated shared networks that underlie the observed associations with longevity. Overall, these results suggest that complex pathways, prominently including inflammation, are linked to the likelihood of attaining longevity. This work may serve to identify novel biomarkers for longevity and to understand the biology underlying lifespan.

History of alendronate.

Alendronate was synthesized in 1970s in a search for inhibitors of calcification. Istituto Gentili investigators identified it as a potent inhibitor of bone resorption and obtained a patent covering its use in the treatment of osteoporosis and other disorders of excessive bone resorption in the 1980s. Merck licensed alendronate in 1988 and its pharmaceutical chemists reformulated it as a sodium salt with good solubility in a tablet that reduced its potential for esophageal irritation. Clinical trials proved that it reduced bone turnover, increased BMD and reduced the risk of vertebral fractures in postmenopausal osteoporotic women. Merck sponsored a large clinical trials that won FDA approval for treatment of osteoporosis in postmenopausal women and showed that it reduced the risk of spine and hip fractures. Its approval in the US in 1995 spurred sales of bone densitometers and BMD testing to screen for low bone mineral density and identify osteoporosis. Bone mass measurement was supported by medical society guidelines and reimbursement by Medicare and other insurers in the USA. A 70 mg weekly instead of 10 mg daily dose of alendronate produced the same effect on BMD and biochemical markers of bone remodelling with greater convenience and reduced potential for upper GI adverse events. Consequently, by 2006, about 30 million prescriptions for alendronate were written annually in the U.S. for about 15% of postmenopausal women in the U.S. Thereafter, publicity about rare but concerning atypical femoral fractures (AFF) and osteonecrosis of the jaw (ONJ) along with the expiry of Merck's patent (in 2008) and cessation of their promotion of alendronate, and a decline in use of densitometry led to a steady slide in its use even among patients for whom the benefits of alendronate far outweigh its potential risks. Nevertheless, in 25 years since its regulatory approval, alendronate has undoubtedly prevented millions of fractures world-wide.

The Ability of a Single BMD and Fracture History Assessment to Predict Fracture Over 25 Years in Postmenopausal Women: The Study of Osteoporotic Fractures.

The ability of bone mineral density (BMD) and other risk factors to predict fracture risk is well-established for as long as 5 to 10 years. However, their value to predict risk over a longer term has not been directly studied. We investigated whether a single assessment of femoral neck BMD and fracture history can predict fracture risk over 20 to 25 years. We used data from the Study of Osteoporotic Fractures (SOF) that assessed BMD and risk factors in 7959 women age ≥67 (mean = 73.4) in 1988-1990. Follow-up for fractures continued for 25 years for hip fracture, and for 20 years for any nonvertebral fracture. Using age-adjusted proportional hazards models, we analyzed the relationships between a single baseline assessment of femoral neck BMD, fracture history and age, and 20-25-year fracture incidence. The 25-year cumulative incidence of hip fracture was 17.9%; 20-year incidence of any nonvertebral fracture was 46.2%. The 25-year hip fracture incidence was highest in those ≥80 years old (22.6%) compared to 13.9% in women aged <70 years. A single femoral neck BMD measurement strongly predicted long-term hip fracture risk to 25 years: 29.6% risk in the lowest BMD quartile versus 7.6% with the highest relative hazard (RH) = 4.9 (95% CI, 4.1 to 6.0). Femoral neck BMD predicted hip fracture with little degradation over time from RH/SD = 2.6 (2.2 to 3.0) for 0 to 5 years to RH/SD = 1.8 (1.4 to 2.4) for 20 to 25 years. Lifetime hip fracture risk was similar (∼30%) regardless of age from 67 to >80 years. History of hip fracture predicted hip fractures only slightly better than history of nonvertebral fracture (RH = 1.6 [95% CI, 1.1 to 2.2] versus RH = 1.4 [95% CI, 1.2 to 1.5], respectively). Fracture history remained strongly predictive up to 25 years. We conclude that a single BMD and fracture history assessment can predict fracture risk over 20 to 25 years. Long-term risk of hip fracture remains extremely high in the oldest age groups, supporting risk assessment and consideration of treatment even in the oldest, highest-risk women.© 2017 American Society for Bone and Mineral Research.

Correction to: Comparison of fracture risk assessment tools in older men without prior hip or spine fracture: the MrOS study.

Owing to an oversight by the authors, the acknowledgments were incomplete.

Comparison of fracture risk assessment tools in older men without prior hip or spine fracture: the MrOS study.

Femoral neck bone mineral density (BMD), age plus femoral neck BMD T score, and three externally generated fracture risk tools had similar accuracy to identify older men who developed osteoporotic fractures. Risk tools with femoral neck BMD performed better than those without BMD. The externally developed risk tools were poorly calibrated. INTRODUCTION: We compared the performance of fracture risk assessment tools in older men, accounting for competing risks including mortality. METHODS: A comparative ROC curve analysis assessed the ability of the QFracture, FRAX® and Garvan fracture risk tools, and femoral neck bone mineral density (BMD) T score with or without age to identify incident fracture in community-dwelling men aged 65 years or older (N = 4994) without hip or clinical vertebral fracture or antifracture treatment at baseline. RESULTS: Among risk tools calculated with BMD, the discriminative ability to identify men with incident hip fracture was similar for FRAX (AUC 0.77, 95% CI 0.73, 0.81), the Garvan tool (AUC 0.78, 95% CI 0.74, 0.82), age plus femoral neck BMD T score (AUC 0.79, 95% CI 0.75, 0.83), and femoral neck BMD T score alone (AUC 0.76, 95% CI 0.72, 0.81). Among risk tools calculated without BMD, the discriminative ability to identify hip fracture was similar for QFracture (AUC 0.69, 95% CI 0.66, 0.73), FRAX (AUC 0.70, 95% CI 0.66, 0.73), and the Garvan tool (AUC 0.71, 95% CI 0.67, 0.74). Correlated ROC curve analyses revealed better diagnostic accuracy for risk scores calculated with BMD compared with QFracture (P < 0.0001). Calibration was good for the internally generated BMD T score predictor with or without age and poor for the externally developed risk tools. CONCLUSION: In untreated older men without fragility fractures at baseline, an age plus femoral neck BMD T score classifier identified men with incident hip fracture as accurately as more complicated fracture risk scores.

Mitochondrial DNA sequence variation is associated with free-living activity energy expenditure in the elderly.

The decline in activity energy expenditure underlies a range of age-associated pathological conditions, neuromuscular and neurological impairments, disability, and mortality. The majority (90%) of the energy needs of the human body are met by mitochondrial oxidative phosphorylation (OXPHOS). OXPHOS is dependent on the coordinated expression and interaction of genes encoded in the nuclear and mitochondrial genomes. We examined the role of mitochondrial genomic variation in free-living activity energy expenditure (AEE) and physical activity levels (PAL) by sequencing the entire (~16.5 kilobases) mtDNA from 138 Health, Aging, and Body Composition Study participants. Among the common mtDNA variants, the hypervariable region 2 m.185G>A variant was significantly associated with AEE (p=0.001) and PAL (p=0.0005) after adjustment for multiple comparisons. Several unique nonsynonymous variants were identified in the extremes of AEE with some occurring at highly conserved sites predicted to affect protein structure and function. Of interest is the p.T194M, CytB substitution in the lower extreme of AEE occurring at a residue in the Qi site of complex III. Among participants with low activity levels, the burden of singleton variants was 30% higher across the entire mtDNA and OXPHOS complex I when compared to those having moderate to high activity levels. A significant pooled variant association across the hypervariable 2 region was observed for AEE and PAL. These results suggest that mtDNA variation is associated with free-living AEE in older persons and may generate new hypotheses by which specific mtDNA complexes, genes, and variants may contribute to the maintenance of activity levels in late life.

Hip fracture and increased short-term but not long-term mortality in healthy older women.

BACKGROUND: Fractures have been associated with subsequent increases in mortality, but it is unknown how long that increase persists. METHODS: A total of 5580 women from a large community-based, multicenter US prospective cohort of 9704 (Study of Osteoporotic Fractures) were observed prospectively for almost 20 years. We age-matched 1116 hip fracture cases with 4 control participants (n = 4464). To examine the effect of health status, we examined a healthy older subset (n = 960) 80 years or older who attended the 10-year follow-up examination and reported good or excellent health. Incident hip fractures were adjudicated from radiology reports by study physicians. Death was confirmed by death certificates. RESULTS: Hip fracture cases had 2-fold increased mortality in the year after fracture compared with controls (16.9% vs 8.4%; multivariable adjusted odds ratio [OR], 2.4; 95% CI, 1.9-3.1]. When examined by age and health status, short-term mortality was increased in those aged 65 to 69 years (16.3% vs 3.7%; OR, 5.0; 95% CI, 2.6-9.5), 70 to 79 years (16.5% vs 8.9%; OR, 2.4; 95% CI, 1.8-3.3), and only in those 80 years or older with good or excellent health (15.1% vs 7.2%; multivariable adjusted OR, 2.8; 95% CI, 1.5-5.2). After the first year, survival of hip fracture cases and controls was similar except in those aged 65 to 69 years, who continued to have increased mortality. CONCLUSIONS: Short-term mortality is increased after hip fracture in women aged 65 to 79 years and in exceptionally healthy women 80 years or older. Women 70 years or older return to previous risk levels after a year. Interventions are needed to decrease mortality in the year after hip fracture, when mortality risk is highest.

Personalizing mammography by breast density and other risk factors for breast cancer: analysis of health benefits and cost-effectiveness.

BACKGROUND: Current guidelines recommend mammography every 1 or 2 years starting at age 40 or 50 years, regardless of individual risk for breast cancer. OBJECTIVE: To estimate the cost-effectiveness of mammography by age, breast density, history of breast biopsy, family history of breast cancer, and screening interval. DESIGN: Markov microsimulation model. DATA SOURCES: Surveillance, Epidemiology, and End Results program, Breast Cancer Surveillance Consortium, and the medical literature. TARGET POPULATION: U.S. women aged 40 to 49, 50 to 59, 60 to 69, and 70 to 79 years with initial mammography at age 40 years and breast density of Breast Imaging Reporting and Data System (BI-RADS) categories 1 to 4. TIME HORIZON: Lifetime. PERSPECTIVE: National health payer. INTERVENTION: Mammography annually, biennially, or every 3 to 4 years or no mammography. OUTCOME MEASURES: Costs per quality-adjusted life-year (QALY) gained and number of women screened over 10 years to prevent 1 death from breast cancer. RESULTS OF BASE-CASE ANALYSIS: Biennial mammography cost less than $100,000 per QALY gained for women aged 40 to 79 years with BI-RADS category 3 or 4 breast density or aged 50 to 69 years with category 2 density; women aged 60 to 79 years with category 1 density and either a family history of breast cancer or a previous breast biopsy; and all women aged 40 to 79 years with both a family history of breast cancer and a previous breast biopsy, regardless of breast density. Biennial mammography cost less than $50,000 per QALY gained for women aged 40 to 49 years with category 3 or 4 breast density and either a previous breast biopsy or a family history of breast cancer. Annual mammography was not cost-effective for any group, regardless of age or breast density. RESULTS OF SENSITIVITY ANALYSIS: Mammography is expensive if the disutility of false-positive mammography results and the costs of detecting nonprogressive and nonlethal invasive cancer are considered. LIMITATION: Results are not applicable to carriers of BRCA1 or BRCA2 mutations. CONCLUSION: Mammography screening should be personalized on the basis of a woman's age, breast density, history of breast biopsy, family history of breast cancer, and beliefs about the potential benefit and harms of screening. PRIMARY FUNDING SOURCE: Eli Lilly, Da Costa Family Foundation for Research in Breast Cancer Prevention of the California Pacific Medical Center, and Breast Cancer Surveillance Consortium.

Validation of an armband to measure daily energy expenditure in older adults.

BACKGROUND: Objective methods to measure daily energy expenditure in studies of aging are needed. We sought to determine the accuracy of total energy expenditure (TEE) and activity energy expenditure (AEE) estimates from the SenseWear Pro armband (SWA) using software versions 6.1 (SWA 6.1) and 5.1 (SWA 5.1) relative to criterion methods in free-living older adults. METHODS: Participants (n = 19, mean age 82.0 years) wore a SWA for a mean ± SD 12.5 ± 1.1 days, including while sleeping. During this same period, criterion values for TEE were assessed with doubly labeled water and for resting metabolic rate (RMR) with indirect calorimetry. AEE was calculated as 0.9 TEE - RMR. RESULTS: For TEE, there was no difference in mean ± SD values from doubly labeled water (2,040 ± 472 kcal/day) versus SWA 6.1 (2,012 ± 497 kcal/day, p = .593) or SWA 5.1 (2,066 ± 474 kcal/day, p = .606); individual values were highly correlated between methods (SWA 6.1 r = .893, p < .001; SWA 5.1 r = .901, p < .001) and demonstrated strong agreement (SWA 6.1 intraclass correlation coefficient = .896; SWA 5.1 intraclass correlation coefficient = .904). For AEE, mean values from SWA 6.1 (427 ± 304 kcal/day) were lower by 26.8% than criterion values (583 ± 242 kcal/day, p = .003), and mean values from SWA 5.1 (475 ± 299 kcal/day) were lower by 18.5% than criterion values (p = .021); however, individual values were highly correlated between methods (SWA 6.1 r = .760, p < .001; SWA 5.1 r = .786, p < .001) and demonstrated moderate agreement (SWA 6.1 intraclass correlation coefficient = .645; SWA 5.1 intraclass correlation coefficient = .720). Bland-Altman plots identified no systematic bias for TEE or AEE. CONCLUSIONS: Acceptable levels of agreement were observed between SWA and criterion measurements of TEE and AEE in older adults.

Mitochondrial DNA variation in human metabolic rate and energy expenditure.

The role of climate in driving selection of mtDNA as Homo sapiens migrated out of Africa into Eurasia remains controversial. We evaluated the role of mtDNA variation in resting metabolic rate (RMR) and total energy expenditure (TEE) among 294 older, community-dwelling African and European American adults from the Health, Aging and Body Composition Study. Common African haplogroups L0, L2 and L3 had significantly lower RMRs than European haplogroups H, JT and UK with haplogroup L1 RMR being intermediate to these groups. This study links mitochondrial haplogroups with ancestry-associated differences in metabolic rate and energy expenditure.

Circulating 25-hydroxyvitamin D levels and frailty status in older women.

CONTEXT: Vitamin D deficiency and frailty are common with aging, but the association between these conditions is uncertain. OBJECTIVE: To determine the association between 25-hydroxyvitamin D (25(OH)D) levels and prevalent and incident frailty status among older women. DESIGN: Cross-sectional and longitudinal analyses of a prospective cohort study. SETTING: Four U.S. centers. PARTICIPANTS: 6307 women aged≥69 years. MAIN OUTCOME MEASURES: Frailty status classified as robust, intermediate stage, or frail at baseline; and robust, intermediate stage, frail, or dead (all-cause mortality) at follow-up an average of 4.5 years later. RESULTS: At baseline, there was a U-shaped association between 25(OH)D level and odds of frailty with the lowest risk among women with levels 20.0-29.9 ng/ml (referent group). Compared with this group, the odds of frailty were higher among those with levels<15.0 ng/ml [multivariable odds ratio (MOR) 1.47, 95% confidence interval (CI), 1.19-1.82], those with levels 15.0-19.9 ng/ml (MOR 1.24, 95% CI 0.99-1.54), and those with levels≥30 ng/ml (MOR 1.32, 95% CI 1.06-1.63). Among 4551 nonfrail women at baseline, the odds of frailty/death (vs. robust/intermediate) at follow-up appeared higher among those with levels 15.0-19.9 ng/ml (MOR 1.21, 95% CI 0.99-1.49), but the CI overlapped 1.0. The odds of death (vs. robust/intermediate/frail at follow-up) was higher among those with levels<15.0 ng/ml (MOR 1.40, 95% CI 1.04-1.88) and those with levels 15.0-19.9 ng/ml (MOR 1.30, 95% CI 0.97-1.75), although the latter association did not quite reach significance. CONCLUSION: Lower (<20 ng/ml) and higher (≥30 ng/ml) levels of 25(OH)D among older women were moderately associated with a higher odds of frailty at baseline. Among nonfrail women at baseline, lower levels (<20 ng/ml) were modestly associated with an increased risk of incident frailty or death at follow-up.

Estimating long-term effects of treatment from placebo-controlled trials with an extension period, using virtual twins.

The best information about the benefits of long-term treatment is obtained from a long-term placebo-controlled trial. However, once efficacy has been demonstrated in relatively brief trials, it may not be possible to conduct long-term placebo-controlled trials, for ethical or practical reasons. This paper presents a method for estimating long-term effects of a treatment from a placebo-controlled trial in which some participants originally randomized to active-treatment volunteer to continue on treatment during an extension study, but follow-up of participants originally assigned to placebo ends with the trial, or they are crossed over to active treatment during the extension. We propose using data from the trial to project the outcomes for a 'virtual twin' for each active-treatment volunteer under the counterfactual placebo condition, and using bootstrap methods for inference. The proposed method is validated using simulation, and applied to data from the Fracture Intervention Trial and its extension, FLEX.

Do muscle mass, muscle density, strength, and physical function similarly influence risk of hospitalization in older adults?

OBJECTIVES: To examine the association between strength, function, lean mass, muscle density, and risk of hospitalization. DESIGN: Prospective cohort study. SETTING: Two U.S. clinical centers. PARTICIPANTS: Adults aged 70 to 80 (N=3,011) from the Health, Aging and Body Composition Study. MEASUREMENTS: Measurements were of grip strength, knee extension strength, lean mass, walking speed, and chair stand pace. Thigh computed tomography scans assessed muscle area and density (a proxy for muscle fat infiltration). Hospitalizations were confirmed by local review of medical records. Negative binomial regression models estimated incident rate ratios (IRRs) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately. Multivariate models adjusted for age, body mass index, health status, and coexisting medical conditions. RESULTS: During an average 4.7 years of follow-up, 1,678 (55.7%) participants experienced one or more hospitalizations. Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized (multivariate IRR=1.47, 95% confidence interval (CI)=1.24-1.73) than those in the highest quartile. Similarly, participants with the weakest grip strength were at greater risk of hospitalization (multivariate IRR=1.52, 95% CI=1.30-1.78, Q1 vs. Q4). Comparable results were seen for knee strength, walking pace, and chair stands pace. Lean mass and muscle area were not associated with risk of hospitalization. CONCLUSION: Weak strength, poor function, and low muscle density, but not muscle size or lean mass, were associated with greater risk of hospitalization. Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass.

Estimates of the proportion of older white women who would be recommended for pharmacologic treatment by the new U.S. National Osteoporosis Foundation Guidelines.

The new U.S. National Osteoporosis Foundation Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck (FN), or spine BMD T-scores or=3% or of major osteoporotic fracture >or=20%. The proportion of women who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to women participating in the Study of Osteoporotic Fractures (SOF). To determine how the SOF population differs from the general U.S. population of white women >or=65 yr of age, we compared women in SOF with women who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, women in SOF had higher FN BMD and were younger. Application of NOF guidelines to SOF data estimated that at least 72% of U.S. white women >or=65 yr of age and 93% of those >or=75 yr of age would be recommended for drug treatment. Application of the new NOF Guidelines would result in recommending a very large proportion of white women in the United States for pharmacologic treatment of osteoporosis.

Cost-effectiveness of bone densitometry followed by treatment of osteoporosis in older men.

CONTEXT: Osteoporotic fractures are common among elderly men. OBJECTIVE: To evaluate among older men the cost-effectiveness of bone densitometry followed by 5 years of oral bisphosphonate therapy to prevent fractures for those found to have osteoporosis (femoral neck T score < or =-2.5), compared with no intervention. DESIGN, SETTING, AND POPULATION: Computer Markov microsimulation model using a societal perspective and a lifetime horizon. Simulations were performed for hypothetical cohorts of white men aged 65, 70, 75, 80, or 85 years, with or without prior clinical fracture. Data sources for model parameters included the Rochester Epidemiology Project for fracture costs and population-based age-specific fracture rates; the Osteoporotic Fractures in Men (MrOS) study and published meta-analyses for the associations among prior fractures, bone density, and incident fractures; and published studies of fracture disutility. MAIN OUTCOME MEASURES: Costs per quality-adjusted life-year (QALY) gained for the densitometry and follow-up treatment strategy compared with no intervention, calculated from lifetime costs and accumulated QALYs for each strategy. RESULTS: Lifetime costs per QALY gained for the densitometry and follow-up treatment strategy were less than $50,000 for men aged 65 years or older with a prior clinical fracture and for men aged 80 years or older without a prior fracture. These results were most sensitive to oral bisphosphonate cost and fracture reduction efficacy, the strength of association between bone mineral density and fractures, fracture rates and disutility, and medication adherence. CONCLUSIONS: Bone densitometry followed by bisphosphonate therapy for those with osteoporosis may be cost-effective for men aged 65 years or older with a self-reported prior clinical fracture and for men aged 80 to 85 years with no prior fracture. This strategy may also be cost-effective for men as young as 70 years without a prior clinical fracture if oral bisphosphonate costs are less than $500 per year or if the societal willingness to pay per QALY gained is $100,000.