Large-scale circulating proteome association study (CPAS) meta-analysis identifies circulating proteins and pathways predicting incident hip fractures.

Hip fractures are associated with significant disability, high cost, and mortality. However, the exact biological mechanisms underlying susceptibility to hip fractures remain incompletely understood. In an exploratory search of the underlying biology as reflected through the circulating proteome, we performed a comprehensive Circulating Proteome Association Study (CPAS) meta-analysis for incident hip fractures. Analyses included 6430 subjects from two prospective cohort studies (Cardiovascular Health Study and Trøndelag Health Study) with circulating proteomics data (aptamer-based 5 K SomaScan version 4.0 assay; 4979 aptamers). Associations between circulating protein levels and incident hip fractures were estimated for each cohort using age and sex-adjusted Cox regression models. Participants experienced 643 incident hip fractures. Compared with the individual studies, inverse-variance weighted meta-analyses yielded more statistically significant associations, identifying 23 aptamers associated with incident hip fractures (conservative Bonferroni correction 0.05/4979, P < 1.0 × 10-5). The aptamers most strongly associated with hip fracture risk corresponded to two proteins of the growth hormone/insulin growth factor system (GHR and IGFBP2), as well as GDF15 and EGFR. High levels of several inflammation-related proteins (CD14, CXCL12, MMP12, ITIH3) were also associated with increased hip fracture risk. Ingenuity pathway analysis identified reduced LXR/RXR activation and increased acute phase response signaling to be overrepresented among those proteins associated with increased hip fracture risk. These analyses identified several circulating proteins and pathways consistently associated with incident hip fractures. These findings underscore the usefulness of the meta-analytic approach for comprehensive CPAS in a similar manner as has previously been observed for large-scale human genetic studies. Future studies should investigate the underlying biology of these potential novel drug targets.

Hip fractures are associated with significant disability, high cost, and mortality. However, the exact biological mechanisms underlying susceptibility to hip fractures remain incompletely understood. To increase the understanding of the underlying mechanisms, we performed a meta-analysis of the associations between 4860 circulating proteins and risk of fractures using two large cohorts, including 6430 participants with 643 incident hip fractures. We identified 23 proteins/aptamers associated with incident hip fractures. Two proteins of the growth hormone/insulin growth factor system (GHR and IGFBP2), as well as GDF15 and EGFR were most strongly associated with hip fracture risk. High levels of several inflammation-related proteins were also associated with increased hip fracture risk. Pathway analysis identified reduced LXR/RXR activation and increased acute phase response signaling to be overrepresented among those proteins associated with increased hip fracture risk. Future mechanistic studies should investigate the underlying biology of these novel protein biomarkers which may be potential drug targets.

The Association of Tryptophan and Its Metabolites With Incident Hip Fractures, Mortality, and Prevalent Frailty in Older Adults: The Cardiovascular Health Study.

Amino acids are the building blocks of proteins, and sufficient protein intake is important for skeletal health. We utilized stored serum from the Cardiovascular Health Study in 1992-1993 to examine the relationship between levels of the essential amino acid tryptophan (trp) and its oxidized and nonoxidized metabolites to risk for incident hip fractures and mortality over 12 years of follow-up. We included 131 persons who sustained a hip fracture during this time period and 131 without a hip fracture over these same 12 years of follow-up; 58% female and 95% White. Weighted multivariable Cox hazards models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of incident hip fracture associated with a one standard deviation (SD) higher trp or its metabolites exposure. Relative risk regression was used to evaluate the cross-sectional association of trp and its metabolites with frailty. Higher serum levels of trp were significantly associated with lower risk of incident hip fractures (HR = 0.75 per SD of trp (95% CI 0.57-0.99) but were not significantly associated with mortality or frailty status by Freid's frailty index. There were no statistically significant associations between any of the oxidized or nonoxidized products of trp with incident hip fractures (p ≥ 0.64), mortality (p ≥ 0.20), or cross-sectional frailty status (p ≥ 0.13) after multiple testing adjustment. Randomized clinical trials examining whether increasing trp intake is beneficial for osteoporosis are needed. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Energy-Adjusted Dietary Inflammatory Index and Diabetes Risk in Postmenopausal Hispanic Women.

BACKGROUND: Type 2 diabetes is a major public health concern in the United States and worldwide. The dietary inflammatory index (DII) and the energy-adjusted DII (E-DII) are tools that assess dietary inflammation. Previous evidence suggests that obesity can modify the association between inflammation and disease. OBJECTIVE: The aim of this study was to evaluate the association between the DII/E-DII and incident diabetes in self-identified Hispanic women from the Women's Health Initiative (WHI). The secondary aim was to evaluate whether obesity modifies the association between the DII/E-DII scores and incident diabetes. DESIGN: Participants were from the WHI Observational Study and the Clinical Trial Components (except women from the treatment arm in the Dietary Modification Trial) conducted among postmenopausal women in the United States. DII/E-DII scores were calculated from a self-administered food frequency questionnaire at baseline that included 122 food items, of which 12 are representative of Hispanic eating patterns. PARTICIPANTS/SETTINGS: Participants included 3,849 postmenopausal women who self-identified as Hispanic that were recruited for the WHI from 1993 to 1998 at 40 US clinical centers. MAIN OUTCOME MEASURES: The outcome was incident diabetes. STATISTICAL ANALYSIS PERFORMED: Cox regression models were used to assess the association between DII/E-DII and incident diabetes. Models were adjusted for age at baseline, lifestyle-related risk factors, known type 2 diabetes mellitus (T2DM) risk factors, and neighborhood socioeconomic status. Interaction was tested between the DII/E-DII scores and obesity. RESULTS: The incidence of diabetes was 13.1% after a median follow-up of 13 years. Higher E-DII scores were associated with a higher risk of incident diabetes (hazard ratio [HR], 1.09; 95% confidence interval [CI], 1.04-1.14). There was no interaction between E-DII scores and obesity (P = 0.73). CONCLUSIONS: Pro-inflammatory diets, as measured by higher E-DII scores, were associated with a higher risk of incident diabetes. Future research is needed for understanding how the inflammatory potential of diets can be decreased.

Association of Immune Cell Subsets with Incident Hip Fracture: The Cardiovascular Health Study.

In this study, we aimed to evaluate the association of innate and adaptive immune cell subsets in peripheral blood mononuclear cells (PBMCs) with hip fracture. To conduct this study, we used data from the Cardiovascular Health Study (CHS), a U.S. multicenter observational cohort of community-dwelling men and women aged ≥ 65 years. Twenty-five immune cell phenotypes were measured by flow cytometry from cryopreserved PBMCs of CHS participants collected in 1998-1999. The natural killer (NK), γδ T, T helper 17 (Th17), and differentiated/senescent CD4+CD28- T cell subsets were pre-specified as primary subsets of interest. Hip fracture incidence was assessed prospectively by review of hospitalization records. Multivariable Cox hazard models evaluated associations of immune cell phenotypes with incident hip fracture in sex-stratified and combined analyses. Among 1928 persons, 259 hip fractures occurred over a median 9.7 years of follow-up. In women, NK cells were inversely associated with hip fracture [hazard ratio (HR) 0.77, 95% confidence interval (CI) 0.60-0.99 per one standard deviation higher value] and Th17 cells were positively associated with hip fracture [HR 1.18, 95% CI 1.01-1.39]. In men, γδ T cells were inversely associated with hip fracture [HR 0.60, 95% CI 0.37-0.98]. None of the measured immune cell phenotypes were significantly associated with hip fracture incidence in combined analyses. In this large prospective cohort of older adults, potentially important sex differences in the associations of immune cell phenotypes and hip fracture were identified. However, immune cell phenotypes had no association with hip fracture in analyses combining men and women.

Plasma Levels of Branched Chain Amino Acids, Incident Hip Fractures, and Bone Mineral Density of the Hip and Spine.

OBJECTIVE: Branched chain amino acids (BCAA) are building blocks for protein, an essential component of bone. However, the association of plasma levels of BCAA with fractures in populations outside of Hong Kong or with hip fractures in particular is not known. The purpose of these analyses was to determine the relationship of BCAA including valine, leucine, and isoleucine and total BCAA (SD of the sum of Z-scores for each BCAA) with incident hip fractures and bone mineral density (BMD) of the hip and lumbar spine in older African American and Caucasian men and women in the Cardiovascular Health Study. DESIGN: Longitudinal analyses of association of plasma levels of BCAA with incident hip fractures and cross-sectional BMD of the hip and lumbar spine from the Cardiovascular Health Study. SETTING: Community. PARTICIPANTS: A total of 1850 men (38% of cohort) and women; mean age 73 years. MAIN OUTCOME MEASURES: Incident hip fractures and cross-sectional BMD of the total hip, femoral neck, and lumbar spine. RESULTS: In fully adjusted models, over 12 years of follow-up, we observed no significant association between incident hip fracture and plasma values of valine, leucine, isoleucine, or total BCAA per 1 SD higher of each BCAA. Plasma values of leucine but not valine, isoleucine, or total BCAA, were positively and significantly associated with BMD of the total hip (P = .03) and femoral neck (P = .02), but not the lumbar spine (P = .07). CONCLUSIONS: Plasma levels of the BCAA leucine may be associated with higher BMD in older men and women. However, given the lack of significant association with hip fracture risk, further information is needed to determine whether BCAAs would be novel targets for osteoporosis therapies.

Race and Ethnicity and Fracture Prediction Among Younger Postmenopausal Women in the Women's Health Initiative Study.

Importance: The best approach to identify younger postmenopausal women for osteoporosis screening is uncertain. The Fracture Risk Assessment Tool (FRAX), which includes self-identified racial and ethnic information, and the Osteoporosis Self-assessment Tool (OST), which does not, are risk assessment tools recommended by US Preventive Services Task Force guidelines to identify candidates for bone mineral density (BMD) testing in this age group. Objective: To compare the ability of FRAX vs OST to discriminate between younger postmenopausal women who do and do not experience incident fracture during a 10-year follow-up in the 4 racial and ethnic groups specified by FRAX. Design, Setting, and Participants: This cohort study of Women's Health Initiative participants included 67 169 women (baseline age range, 50-64 years) with 10 years of follow-up for major osteoporotic fracture (MOF; including hip, clinical spine, forearm, and shoulder fracture) at 40 US clinical centers. Data were collected from October 1993 to December 2008 and analyzed between May 11, 2022, and February 23, 2023. Main Outcomes and Measures: Incident MOF and BMD (in a subset of 4607 women) were assessed. The area under the receiver operating characteristic curve (AUC) for FRAX (without BMD information) and OST was calculated within each racial and ethnic category. Results: Among the 67 169 participants, mean (SD) age at baseline was 57.8 (4.1) years. A total of 1486 (2.2%) self-identified as Asian, 5927 (8.8%) as Black, 2545 (3.8%) as Hispanic, and 57 211 (85.2%) as White. During follow-up, 5594 women experienced MOF. For discrimination of MOF, AUC values for FRAX were 0.65 (95% CI, 0.58-0.71) for Asian, 0.55 (95% CI, 0.52-0.59) for Black, 0.61 (95% CI, 0.56-0.65) for Hispanic, and 0.59 (95% CI, 0.58-0.59) for White women. The AUC values for OST were 0.62 (95% CI, 0.56-0.69) for Asian, 0.53 (95% CI, 0.50-0.57) for Black, 0.58 (95% CI, 0.54-0.62) for Hispanic, and 0.55 (95% CI, 0.54-0.56) for White women. For discrimination of femoral neck osteoporosis, AUC values were excellent for OST (range, 0.79 [95% CI, 0.65-0.93] to 0.85 [95% CI, 0.74-0.96]), higher for OST than FRAX (range, 0.72 [95% CI, 0.68-0.75] to 0.74 [95% CI, 0.60-0.88]), and similar in each of the 4 racial and ethnic groups. Conclusions and Relevance: These findings suggest that within each racial and ethnic category, the US FRAX and OST have suboptimal performance in discrimination of MOF in younger postmenopausal women. In contrast, for identifying osteoporosis, OST was excellent. The US version of FRAX should not be routinely used to make screening decisions in younger postmenopausal women. Future investigations should improve existing tools or create new approaches to osteoporosis risk assessment for this age group.

Mortality Following Hip Fracture in Older Adults With and Without Coronary Heart Disease.

BACKGROUND: Comorbidities like coronary heart disease are common among older people who sustain an osteoporotic hip fracture. However, their impact on short- and long-term mortality post-hip fracture is not well quantified. METHODS: We examined 4092 and 1173 older adults without and with prevalent coronary heart disease, respectively. Post-hip fracture mortality rates were computed with Poisson models and hazard ratios with Cox regression. For perspective, we compared mortality rates among participants with prevalent coronary heart disease who had either a hip fracture or incident heart failure (but no hip fracture). RESULTS: Among participants without prevalent coronary heart disease, the mortality rate post-hip fracture was 21.83 per 100 participant years, including 49.27 per 100 participant years in the first 6 months following hip fracture. Among participants with prevalent coronary heart disease, the corresponding mortality rates were 32.52 and 79.44 per 100 participant years, respectively. Participants with prevalent coronary heart disease and incident heart failure (but no hip fracture) had corresponding post-incident heart failure mortality rates per 100 participant years of 25.62 overall and 46.4 in the first 6 months. In all 3 groups, the hazard ratio for mortality was similarly elevated: 5- to 7-fold at 6 months and 1.7- to 2.5-fold beyond 5 years. CONCLUSION: As a case study in the absolute effects of a comorbidity on post-hip fracture mortality, hip fracture in a person with coronary heart disease carries an exceedingly high mortality rate, even higher than that following incident heart failure in individuals with coronary heart disease.

Age-Related Factors Associated With The Risk of Hip Fracture.

OBJECTIVE: Advancing age is a powerful risk factor for hip fractures. The biological mechanisms through which aging impacts the risk of hip fractures have not been well studied. METHODS: Biological factors associated with "advancing age" that help to explain how aging is associated with the risk of hip fractures are reviewed. The findings are based on analyses of the Cardiovascular Health Study, an ongoing observational study of adults aged ≥65 years with 25 years of follow-up. RESULTS: The following 5 age-related factors were found to be significantly associated with the risk of hip fractures: (1) microvascular disease of the kidneys (albuminuria and/or elevated urine-albumin-to-creatinine ratio) and brain (abnormal white matter disease on brain magnetic resonance imaging); (2) increased serum levels of carboxymethyl-lysine, an advanced glycation end product that reflects glycation and oxidative stress; (3) reduced parasympathetic tone, as derived from 24-hour Holter monitoring; (4) carotid artery atherosclerosis in the absence of clinical cardiovascular disease; and (5) increased transfatty acid levels in the blood. Each of these factors was associated with a 10% to 25% increased risk of fractures. These associations were independent of traditional risk factors for hip fractures. CONCLUSION: Several factors associated with older age help to explain how "aging" may be associated with the risk of hip fractures. These same factors may also explain the high risk of mortality following hip fractures.

The associations of markers of endothelial dysfunction with hip fracture risk.

Endothelial dysfunction underlies the development of atherosclerotic vascular disease, which in turn is associated with osteoporotic fractures. Here, we examined the association of two markers of endothelial dysfunction with incident hip fracture risk in older adults but found no statistically significant associations between them. PURPOSE/INTRODUCTION: Endothelial dysfunction underlies the development of atherosclerotic vascular disease. Vascular disease, in turn, is associated with the risk of osteoporotic fractures, such as hip fractures. Here, we examine whether two measures of endothelial dysfunction are related to hip fracture risk. METHODS: Participants for this study were 2792 individuals (mean age 78.6 years) who had flow-mediated dilation (FMD) measured after ischemia in the forearm and 2255 adults (mean age 73.3 years) with measured soluble intercellular adhesion molecule (siCAM) levels, a constitutive endothelial cell membrane protein associated with the initiation of atherosclerosis. Mean follow-up was 9.7 and 11.7 years, respectively. There were 375 and 265 incident hip fractures, respectively, in each group. RESULTS: In Cox proportional hazards models, there was no significant association between FMD response and incident hip fracture (HR per 1% higher FMD was 0.98 [0.93, 1.04]; p = 0.44). In exploratory analyses, when data were examined dichotomously, participants in the lowest 80% of FMD (≤ 4.5%) had an adjusted 1.29 (0.98, 1.68; p = 0.067) higher hazard of hip fracture compared to participants in the upper 20% of FMD change. There were no significant associations between siCAM and incident hip fracture whether examined as a continuous or dichotomized variable. CONCLUSIONS: Among older adults, two measures of endothelial dysfunction were not significantly associated with hip fracture risk. There was a trend for higher fracture risk with lower FMD.

Dietary inflammatory index and cardiovascular disease risk in Hispanic women from the Women's Health Initiative.

BACKGROUND: To evaluate the association between the dietary inflammatory index (DII®) and incident cardiovascular disease (CVD) in Hispanic women from the Women's Health Initiative (WHI), and to determine if body mass index (BMI) interacted with the DII scores. METHODS: Secondary analysis of baseline dietary data and long-term CVD outcomes among 3,469 postmenopausal women who self-identified as Hispanic enrolled in WHI. DII scores were calculated from self-administered food frequency questionnaires. The CVD outcomes included coronary heart disease (CHD) and stroke. Stratified Cox regression models were used to assess the relationship between DII scores and CVD in women with and without obesity. Models were adjusted for age, lifestyle risk factors, known risk factors, and neighborhood socioeconomic status. RESULTS: The incidence of CHD was 3.4 and 2.8% for stroke after a median follow-up of 12.9 years. None of the DIIs were associated with CVD risk in this sample of Hispanic women. BMI interacted with the DII (p < 0.20) and stratified models showed that the associations between the DII and CVD were only significant in women with overweight (p < 0.05). In this group, higher DII scores were associated with a higher risk of CHD (HR 1.27; 95% CI: 1.08, 1.51) and a higher risk of stroke (HR 1.32; 95% CI: 1.07, 1.64). CONCLUSION: Among postmenopausal Hispanic women with overweight, greater adherence to pro-inflammatory diets was associated with higher risk of CVD. Additional research is needed to understand how to promote long-term heart-healthy dietary habits to reduce inflammation and prevent CVD in at-risk Hispanic women.

The association of hormone therapy with blood pressure control in postmenopausal women with hypertension: a secondary analysis of the Women's Health Initiative clinical trials.

OBJECTIVE: The objective of this study was to assess the effect of menopausal hormone therapy (HT) on blood pressure control in postmenopausal women with hypertension. METHODS: The Women's Health Initiative HT clinical trials were double-blinded, randomized, placebo-controlled studies of women aged 50 to 79 years testing the effects of HT (conjugated equine estrogens [CEE, 0.625 mg/d] or CEE + medroxyprogesterone acetate [MPA; 2.5 mg/d]) on risks for coronary heart disease and invasive breast cancer, the primary outcomes for efficacy and safety, respectively. This secondary analysis of the Women's Health Initiative HT trials examined a subsample of 9,332 women with hypertension (reported ever taking pills to treat hypertension or were taking antihypertensive medication) at baseline. Blood pressure was measured at baseline and up to 10 annual follow-up visits during the planned study phase. Antihypertensive medications were inventoried at baseline and years 1, 3, 6, and 9 during the study, and self-reported during extended follow-up: 2009-2010 and 2012-2013, which occurred median of 13 and 16 years after randomization, respectively. The intervention effect was estimated through year 6. Cumulative follow-up included all visits. RESULTS: Compared with placebo, CEE-alone had significantly ( P = 0.02) higher systolic blood pressure (SBP) by mean (95% confidene interval [CI]) = 0.9 (0.2-1.5) mm Hg during the intervention phase. For cumulative follow-up, the CEE arm was associated with increased SBP by mean (95% CI) = 0.8 (0.1-1.4) mm Hg ( P = 0.02). Furthermore, CEE + MPA relative to placebo was associated with increased SBP by mean (95% CI) = 1.8 (1.2-2.5) mm Hg during the intervention phase ( P < 0.001). For cumulative follow-up, the CEE + MPA arm was associated with increased SBP by mean (95% CI) = 1.6 (1.0-2.3) mm Hg ( P < 0.001). The mean number of antihypertensive medications taken at each follow-up visit did not differ between randomization groups during the intervention or long-term extended follow-up of 16 years. CONCLUSION: There was a small but statistically significant increase in SBP in both CEE-alone and CEE + MPA arms compared with placebo during both the intervention and cumulative follow-up phases among postmenopausal women with hypertension at baseline. However, this increase in SBP was not associated with an increased antihypertensive medication use over time among women randomized to HT compared with placebo.

The severity of individual menopausal symptoms, cardiovascular disease, and all-cause mortality in the Women's Health Initiative Observational Cohort.

OBJECTIVE: The aim of this study was to examine the association between common menopausal symptoms (MS) and long-term cardiovascular disease (CVD) and all-cause mortality. METHODS: In an observational cohort of 80,278 postmenopausal women with no known CVD at baseline from the Women's Health Initiative, we assessed individual MS severity (mild vs none; moderate/severe vs none) for night sweats, hot flashes, waking up several times at night, joint pain or stiffness, headaches or migraines, vaginal or genital dryness, heart racing or skipping beats, breast tenderness, dizziness, tremors (shakes), feeling tired, forgetfulness, mood swings, restless or fidgety, and difficulty concentrating. Outcomes included total CVD events (primary) and all-cause mortality (secondary). Associations between specific MS, their severity, and outcomes were assessed during a median of 8.2 years of follow-up. All results were multivariable adjusted, and individual associations were Bonferroni corrected to adjust for multiple comparisons. A machine learning approach (least absolute shrinkage and selection operator) was used to select the most parsimonious set of MS most predictive of CVD and all-cause mortality. RESULTS: The severity of night sweats, waking up several times at night, joint pain or stiffness, heart racing or skipping beats, dizziness, feeling tired, forgetfulness, mood swings, restless or fidgety, and difficulty concentrating were each significantly associated with total CVD. The largest hazard ratio (HR) for total CVD was found for moderate or severe heart racing or skipping beats (HR, 1.55; 95% confidence interval [CI], 1.29-1.86). The individual severities of heart racing or skipping beats, dizziness, tremors (shakes), feeling tired, forgetfulness, mood swings, restless or fidgety, and difficulty concentrating were associated with increased all-cause mortality. Moderate or severe dizziness had the largest HR (1.58; 95% CI, 1.24-2.01). Multiple symptom modeling via least absolute shrinkage and selection operator selected dizziness, heart racing, feeling tired, and joint pain as most predictive of CVD, whereas dizziness, tremors, and feeling tired were most predictive of all-cause mortality. CONCLUSION: Among postmenopausal women with no known CVD at baseline, the severity of specific individual MS was significantly associated with incident CVD and mortality. Consideration of severe MS may enhance sex-specific CVD risk predication in future cohorts, but caution should be applied as severe MS could also indicate other health conditions.

Genetic admixture and cardiovascular disease risk in postmenopausal Hispanic women.

BACKGROUND: Hispanics are a heterogeneous population with differences in the prevalence of cardiovascular disease (CVD) and its related risk factors among ethnic sub-groups. This study evaluated the association of genetic admixture and CVD in self-identified Hispanic women from the Women's Health Initiative (WHI). METHODS: Data came from the WHI Observational Study and the Clinical Trial Components conducted among postmenopausal women. The CVD outcomes included coronary heart disease (CHD) and stroke. The proportions of European (EUR), sub-Saharan African (AFR), and Amerindian (AMI) admixture were estimated using 92 ancestry-informative markers. Cox regression models were used to assess the relationship between genetic admixture and CVD adjusting for age, lifestyle risk factors, known risk factors, and neighborhood socioeconomic status. RESULTS: Among 5195 participants EUR ancestry was associated with a lower CHD risk after adjusting for age (HR 0.41, p = 0.02), and in the fully adjusted model (HR 0.40, p = 0.03). AFR ancestry was associated with a higher CHD risk after adjusting for age (HR 2.91, p = 0.03), but it only showed a trend in in the fully adjusted model (HR 2.46, p = 0.10). AMI ancestry was not statistically significantly associated with CHD and none of the genetic admixture proportions were statistically significantly associated with stroke (p > 0.05). CONCLUSION: EUR ancestry was associated with a lower risk of CHD in Hispanic women. This highlights the need to account for genetic admixture in future CVD studies to consider different heritage groups to understand the role that genetic, neighborhood socioeconomic status, and environmental factors contribute to CVD health disparities in Hispanic women.

The Association of Lipids and Lipoproteins with Hip Fracture Risk: The Cardiovascular Health Study.

BACKGROUND: It is uncertain if lipids or lipoproteins are associated with osteoporotic fractures. In this study, incident hip fracture risk according to conventional lipid levels and lipoprotein levels and sizes was examined. METHODS: We followed 5832 participants aged ≥65 years from the Cardiovascular Health Study for hip fracture for a mean of 13.5 (SD 5.7) years. Standard enzymatic methods were used to determine lipid levels (ie, high-density lipoprotein-cholesterol [HDL-c], low-density lipoprotein-cholesterol [LDL-c], and triglycerides). Nuclear magnetic resonance spectroscopy was used to measure lipoprotein fractions (ie, very-low-density lipoprotein-particle [VLDL-P], low-density lipoprotein-particle [LDL-P], high-density lipoprotein-particle [HDL-P]) in a subset of 1849 participants. RESULTS: We documented 755 incident hip fractures among women (1.19 fractures per 100 participant years [95% confidence interval, 1.04, 1.35]) and 197 among men (0.67 fractures per 100 participant years [95% CI, 0.41, 1.10]) over an average follow-up. HDL-c and LDL-c levels had statistically significant nonlinear U-shaped relationships with hip fracture risk (HDL-c, P = .009; LDL-c, P = .02). Triglyceride levels were not significantly associated with hip fracture risk. In fully adjusted conjoint models, higher VLDL-P concentration (hazard ratio [HR] per 1 standard deviation [SD] increment 1.47 [1.13, 1.91] and size [HR per 1 SD increment 1.24 [1.05, 1.46]) and higher high-density lipoprotein particle size (HR per 1 SD increment 1.81 [1.25, 2.62]) were all associated with higher hip fracture risk. CONCLUSIONS: Lipids and lipoproteins are associated with hip fracture risk in older adults. The associations are complex. Mechanistic studies are needed to understand these findings.

Trimethylamine N-oxide and hip fracture and bone mineral density in older adults: The cardiovascular health study.

CONTEXT: Gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) may adversely affect bone by inducing oxidative stress. Whether this translates into increased fracture risk in older adults is uncertain. OBJECTIVE: Determine the associations of plasma TMAO with hip fracture and bone mineral density (BMD) in older adults. DESIGN AND SETTING: Cox hazard models and linear regression stratified by sex examined the associations of TMAO with hip fracture and BMD in the longitudinal cohort of the Cardiovascular Health Study. PARTICIPANTS: 5019 U.S. adults aged ≥65 years. EXPOSURE: Plasma TMAO. MAIN OUTCOME MEASURES: Incident hip fractures; total hip BMD dual x-ray absorptiometry in a subset (n = 1400). RESULTS: Six hundred sixty-six incident hip fractures occurred during up to 26 years of follow-up (67,574 person-years). After multivariable adjustment, TMAO was not significantly associated with hip fracture (women: hazard ratio (HR) [95% confidence interval (CI)] of 1.00[0.92,1.09] per TMAO doubling; men: 1.12[0.95,1.33]). TMAO was also not associated with total hip BMD (women: BMD difference [95% CI] of 0.42 g/cm2*100 [-0.34,1.17] per TMAO doubling; men: 0.19[-1.04,1.42]). In exploratory analyses, we found an interaction between body mass index (BMI) and the association of TMAO with hip fracture (P < 0.01). Higher TMAO was significantly associated with risk of hip fracture in adults with overweight or obesity (BMI ≥ 25) (HR [95% CI]:1.17[1.05,1.31]), but not normal or underweight. CONCLUSIONS: Among older US men and women, TMAO was not significantly associated with risk of hip fracture or BMD overall. Exploratory analyses suggested a significant association between higher TMAO and hip fracture when BMI was elevated, which merits further study.

Cardiovascular autonomic nervous system function and hip fracture risk: the Cardiovascular Health Study.

Among 1299 older adults with 24-h Holter monitoring data at baseline, followed for approximately 15 years, 190 incident hip fractures occurred. Increased heart rate variability was independently associated with reduced risk of hip fracture among female participants. PURPOSE: Autonomic nervous system function modulates bone remodeling in rodent osteoporosis models. We tested whether cardiovascular autonomic function is associated with hip fracture risk in humans. METHODS: Participants were 1299 subjects from the Cardiovascular Health Study (mean age 72.8 years). Eight heart rate variability (HRV) measures (time and frequency domains, detrended fluctuation analysis variables, and heart rate turbulence) were derived from 24-h Holter monitor scans in sinus rhythm. Median follow-up for incident hip fracture was 14.7 years [IQR 9.1, 20.2]. Cox proportional hazards models were used to calculate hazard ratios (95% confidence intervals, CI). RESULTS: There were 144 hip fractures among 714 women (1.31 [1.06, 1.61] per 100-person years) and 46 among 585 men (0.62 [0.43, 0.90] per 100 person-years). From among HRV variables examined, a one standard deviation (SD) higher variation between normal heart beats over 24 h (the SD of NN intervals [SDNN]) was associated with a multivariable-adjusted lower hip fracture risk (HR [Formula: see text] 0.80; 95% CI 0.65-0.99; p = 0.04) in women. The adjusted association between very low frequency power, and hip fracture was borderline statistically significant in women (HR [Formula: see text] 0.82; 95% CI, 0.66-1.00; p = 0.06). When the 8 HRV variables were considered conjointly and adjusted for each other's association with hip fracture risk, a 1 SD higher SDNN value was significantly associated with reduced hip fracture risk in women (HR 0.74; 95% CI, 0.50-0.99; p = 0.05). No HRV variables were associated with hip fracture in men. CONCLUSIONS: In older women, increased heart rate variation is associated with hip fracture risk.

After the initial fracture in postmenopausal women, where do subsequent fractures occur?

BACKGROUND: The locations of subsequent fractures after initial fracture in postmenopausal women are poorly characterized. METHODS: We conducted a prospective analysis of subsequent fractures after initial fracture in Women's Health Initiative (1993-2018) participants who provided follow-up (mean 15.4 years, SD 6.2 years) data (n = 157,282 participants; baseline age 50-79; 47,458 participants with incident fracture). Cox proportional hazards models were adjusted for age, race/ethnicity, body mass index, and other covariates. FINDINGS: The risk of each type of subsequent fracture was increased after each type of initial fracture. Incident lower arm/wrist fracture was associated with significantly elevated risks of subsequent fractures at the upper arm/shoulder, upper leg, knee, lower leg/ankle, hip/pelvis, and spine (adjusted hazard ratios [aHRs] ranging 2·63-5·68). The risk of hip fracture was increased after initial lower arm or wrist fracture (aHR 4·80, 95% CI 4·29-5·36), initial upper arm or shoulder fracture (aHR 5·06, 95% CI 4·39-5·82), initial upper leg fracture (aHR 5·11, 95% CI 3·91-6·67), initial knee fracture (aHR 5·03, 95% CI 4·20-6·03), initial lower leg/ankle fracture (aHR 4·10, 95% CI 3·58-4·68), and initial spine fracture (aHR 6·69, 95% CI 5·95-7·53). Associations were significant in all age groups, even women aged 50-59 years. Risks of subsequent fracture were more pronounced among non-Hispanic Black, Hispanic/Latina, and Asian/Pacific Islander than among non-Hispanic White women. INTERPRETATION: Increased risk of subsequent fracture is observed for all fracture types across all ages. Women who experience any of these fractures should be targeted for interventions to prevent subsequent fractures. FUNDING: National Institutes of Health HHSN268201600018C,HHSN268201600001C, HHSN268201600002C, HHSN268201600003C, and HHSN268201600004C.

Risk of Subsequent Fractures in Postmenopausal Women After Nontraumatic vs Traumatic Fractures.

Importance: The burden of fractures among postmenopausal women is high. Although nontraumatic fractures are strong risk factors for future fracture, current clinical guidelines do not address traumatic fractures. Objective: To determine how future fracture risk varies according to whether an initial fracture is traumatic or nontraumatic. Design, Setting, and Participants: We conducted a prospective observational study using data from the Women's Health Initiative Study (WHI) (enrollment, September 1994-December 1998; data analysis, September 2020 to March 2021), which enrolled postmenopausal women aged 50 to 79 years at baseline at 40 US clinical centers. The WHI Clinical Trials and WHI Bone Density Substudy, conducted at 3 of the clinical centers, asked participants to report the mechanism of incident fractures. Of 75 335 participants, information regarding incident fracture and covariates was available for 66 874 participants (88.8%), who comprised the analytic sample of this study. Mean (SD) follow-up was 8.1 (1.6) years. Interventions: None. Main Outcomes and Measures: Incident clinical fractures were self-reported at least annually and confirmed using medical records. Participants reported the mechanism of incident fracture as traumatic or nontraumatic. Results: Among the 66 874 participants in the analytic sample (mean [SD] age, 63.1 [7.0] years and 65.3 [7.2] years among women without and with clinical fracture, respectively), 7142 participants (10.7%) experienced incident fracture during the study follow-up period. The adjusted hazard ratio (aHR) of subsequent fracture after initial fracture was 1.49 (95% CI, 1.38-1.61). Among women whose initial fracture was traumatic, the association between initial fracture and subsequent fracture was significantly increased (aHR, 1.25; 95% CI, 1.06-1.48). Among women whose initial fracture was nontraumatic, the association between initial fracture and subsequent fracture was also increased (aHR, 1.52; 95% CI, 1.37-1.68). Confidence intervals for associations between initial fracture and subsequent fracture were overlapping for traumatic and nontraumatic initial fracture strata. Conclusions and Relevance: In this cohort study, among postmenopausal women older than 50 years, fracture was associated with a greater risk of subsequent fracture regardless of whether the fracture was traumatic or nontraumatic. These findings suggest that clinical osteoporosis assessment should include high-trauma as well as low-trauma fractures.

Testosterone, dihydrotestosterone, bone density, and hip fracture risk among older men: The Cardiovascular Health Study.

BACKGROUND: Little is known about the relationships of dihydrotestosterone (DHT), a more potent androgen than testosterone (T), with bone mineral density (BMD) and fracture risk. Our objectives were to evaluate the relationships of T, DHT and sex hormone binding globulin (SHBG) with BMD, fracture risk, and lean body mass (LBM). METHODS: We evaluated 1128 older men free of cardiovascular disease in a prospective cohort study using data from the Cardiovascular Health Study. T and DHT were measured by liquid chromatography-tandem mass spectrometry and SHBG by fluoroimmunoassay. Our outcomes included incident hip fracture (n = 106) over a median of 10.2 years and BMD and LBM by dual-energy x-ray absorptiometry (n = 439). RESULTS: In Cox regression models mutually adjusted for T, SHBG, and covariates, each standard deviation increment in DHT (0.23 ng/ml) was associated with a 26% lower risk of hip fracture (adjusted hazard ratio [aHR] 0.74, 95% confidence interval (CI) 0.55-1.00, p = 0.049). Similarly, SHBG was associated with fracture in mutually adjusted models (aHR HR 1.26, 95% CI, 1.01-1.58, p = 0.045). In contrast, T (aHR, 1.16, 95% CI, 0.86-1.56, p = 0.324) was not significantly associated with fracture in mutually adjusted models. T, DHT and SHBG were not associated with BMD. T and DHT were both positively associated with LBM in individual models. CONCLUSIONS: In older men, DHT was inversely associated with hip fracture risk and SHBG was positively associated with hip fracture risk, while T was not. Future studies should elucidate the mechanisms by which DHT affects bone health.

Association of skeletal muscle mass, kidney disease and mortality in older men and women: the cardiovascular health study.

Low muscle mass (sarcopenia) is a prevalent and major concern in the aging population as well as in patients with chronic kidney disease (CKD). We hypothesized that sarcopenia is an independent predictor of incident and progressive CKD and increased mortality in older men and women (≥65 years) from the Cardiovascular Health Study. Sarcopenia was defined by bioimpedance-estimated skeletal muscle mass index (SMI) as a continuous variable and categorically (normal, class I, and class II). Cox regression hazard ratios (HRs) estimated the risk of incident and prevalent CKD and mortality in individuals with and without CKD. Low SMI was associated with increased prevalence of CKD in men (p<0.001), but lower prevalence of CKD in women (p=0.03). Low muscle mass was not associated with incident CKD or rapid CKD progression (>3 ml/minute/1.73m2/year decline in eGFR) in men, but was associated with lower risk of incident CKD in women ([adjusted RR=0.69, 95% (0.51,0.94)]. Low muscle mass (class II) was independently associated with higher mortality only in men [(adjusted HR=1.26, 95% (1.05,1.50)]. Neither definition of sarcopenia was associated with mortality in men or women with CKD. Further studies are needed to understand the mechanisms by which sarcopenia contributes to higher mortality in aging men.