Bone Mineral Density and Risk of Heart Failure in Older Adults: The Cardiovascular Health Study.

BACKGROUND: Despite increasing evidence of a common link between bone and heart health, the relationship between bone mineral density (BMD) and heart failure (HF) risk remains insufficiently studied. METHODS AND RESULTS: We investigated whether BMD measured by dual-energy x-ray absorptiometry was associated with incident HF in an older cohort. Cox models were stratified by sex and interactions of BMD with race assessed. BMD was examined at the total hip and femoral neck separately, both continuously and by World Health Organization categories. Of 1250 participants, 442 (55% women) developed HF during the median follow-up of 10.5 years. In both black and nonblack women, neither total hip nor femoral neck BMD was significantly associated with HF; there was no significant interaction by race. In black and nonblack men, total hip, but not femoral neck, BMD was significantly associated with HF, with evidence of an interaction by race. In nonblack men, lower total hip BMD was associated with higher HF risk (hazard ratio, 1.13 [95% CI, 1.01-1.26] per 0.1 g/cm2 decrement), whereas in black men, lower total hip BMD was associated with lower HF risk (hazard ratio, 0.74 [95% CI, 0.59-0.94]). There were no black men with total hip osteoporosis. Among nonblack men, total hip osteoporosis was associated with higher HF risk (hazard ratio, 2.83 [95% CI, 1.39-5.74]) compared with normal BMD. CONCLUSIONS: Among older adults, lower total hip BMD was associated with higher HF risk in nonblack men but lower risk in black men, with no evidence of an association in women. Further research is needed to replicate these findings and to study potential underlying pathways.

Relation of the Myocardial Contraction Fraction, as Calculated from M-Mode Echocardiography, With Incident Heart Failure, Atherosclerotic Cardiovascular Disease and Mortality (Results from the Cardiovascular Health Study).

We evaluated the association between 2-dimensional (2D) echocardiography (echo)-determined myocardial contraction fraction (MCF) and adverse cardiovascular outcomes including incident heart failure (HF), atherosclerotic cardiovascular disease (ASCVD), and mortality. The MCF, the ratio of left ventricular (LV) stroke volume (SV) to myocardial volume (MV), is a volumetric measure of myocardial shortening that can distinguish pathologic from physiological hypertrophy. Using 2D echo-guided M-mode data from the Cardiovascular Health Study, we calculated MCF in subjects with LV ejection fraction (EF) ≥55% and used Cox models to evaluate its association with incident HF, ASCVD, and all-cause mortality after adjusting for clinical and echo parameters. We assessed whether log2(SV) and log2(MV) were consistent with the expected 1:-1 ratio used in the definition of MCF. Among 2,147 participants (age 72 ± 5 years), average MCF was 59 ± 13%. After controlling for clinical and echo variables, each 10% absolute increment in MCF was associated with lower risk of HF (hazard ratio [HR] 0.88; 95% confidence interval [CI] 0.82, 0.94), ASCVD (HR 0.90; 95% CI 0.85, 0.95), and death (HR 0.93; 95% CI 0.89, 0.97). Moreover, the MCF was still significantly associated with ASCVD and mortality, but not HF, after adjustment for percent-predicted LV mass. Significant departure from the 1:-1 ratio was not observed for ASCVD or death, but did occur for HF, driven by a stronger association for MV than SV. In conclusion, among older adults without CVD or low LV ejection fraction, 2D echo-guided M-mode-derived MCF was independently associated with lower risk of adverse cardiovascular outcomes, but this ratiometric index may not capture the full relation that is apparent when its components are modeled separately in the case of HF.

Respiratory chain protein turnover rates in mice are highly heterogeneous but strikingly conserved across tissues, ages, and treatments.

The mitochondrial respiratory chain (RC) produces most of the cellular ATP and requires strict quality-control mechanisms. To examine RC subunit proteostasis in vivo, we measured RC protein half-lives (HLs) in mice by liquid chromatography-tandem mass spectrometry with metabolic [(2)H3]-leucine heavy isotope labeling under divergent conditions. We studied 7 tissues/fractions of young and old mice on control diet or one of 2 diet regimens (caloric restriction or rapamycin) that altered protein turnover (42 conditions in total). We observed a 6.5-fold difference in mean HL across tissues and an 11.5-fold difference across all conditions. Normalization to the mean HL of each condition showed that relative HLs were conserved across conditions (Spearman's ρ = 0.57; P < 10(-4)), but were highly heterogeneous between subunits, with a 7.3-fold mean range overall, and a 2.2- to 4.6-fold range within each complex. To identify factors regulating this conserved distribution, we performed statistical analyses to study the correlation of HLs to the properties of the subunits. HLs significantly correlated with localization within the mitochondria, evolutionary origin, location of protein-encoding, and ubiquitination levels. These findings challenge the notion that all subunits in a complex turnover at comparable rates and suggest that there are common rules governing the differential proteolysis of RC protein subunits under divergent cellular conditions.