Muscle mitochondrial bioenergetic capacities are associated with multimorbidity burden in older adults: the Study of Muscle, Mobility and Aging (SOMMA)

BACKGROUND

The geroscience hypothesis posits that aging biological processes contribute to many age-related deficits, including the accumulation of multiple chronic diseases. Though only one facet of mitochondrial function, declines in muscle mitochondrial bioenergetic capacities may contribute to this increased susceptibility to multimorbidity.

METHODS

The Study of Muscle, Mobility and Aging (SOMMA) assessed ex vivo muscle mitochondrial energetics in 764 older adults (mean age =76.4, 56.5% women, 85.9% non-Hispanic white) by high-resolution respirometry of permeabilized muscle fibers. We estimated the proportional odds ratio (POR [95%CI]) for the likelihood of greater multimorbidity (four levels: 0 conditions, N=332; 1 condition, N=299; 2 conditions, N=98; or 3+ conditions, N=35) from an index of 11 conditions, per SD decrement in muscle mitochondrial energetic parameters. Distribution of conditions allowed for testing the associations of maximal muscle energetics with some individual conditions.

RESULTS

Lower oxidative phosphorylation supported by fatty acids and/or complex-I and -II linked carbohydrates (e.g., Max OXPHOSCI+CII) was associated with a greater multimorbidity index score (POR=1.32[1.13,1.54]) and separately with diabetes mellitus (OR=1.62[1.26,2.09]), depressive symptoms (OR=1.45[1.04,2.00]) and possibly chronic kidney disease (OR=1.57[0.98,2.52]) but not significantly with other conditions (e.g., cardiac arrhythmia, chronic obstructive pulmonary disease).

CONCLUSIONS

Lower muscle mitochondrial bioenergetic capacities was associated with a worse composite multimorbidity index score. Our results suggest that decrements in muscle mitochondrial energetics may contribute to a greater global burden of disease and is more strongly related to some conditions than others.

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.

Childhood adverse life events and skeletal muscle mitochondrial function

Social stress experienced in childhood is associated with adverse health later in life. Mitochondrial function has been implicated as a mechanism for how stressful life events "get under the skin" to influence physical well-being. Using data from the Study of Muscle, Mobility, and Aging (n = 879, 59% women), linear models examined whether adverse childhood events (i.e., physical abuse) were associated with two measures of skeletal muscle mitochondrial energetics in older adults: (i) maximal adenosine triphosphate production (ATPmax) and (ii) maximal state 3 respiration (Max OXPHOS). Forty-five percent of the sample reported experiencing one or more adverse childhood events. After adjustment, each additional event was associated with -0.08 SD (95% confidence interval = -0.13, -0.02) lower ATPmax. No association was observed with Max OXPHOS. Adverse childhood events are associated with lower ATP production in later life. Findings indicate that mitochondrial function may be a mechanism for understanding how early social stress influences health in later life.

Perceived Neighborhood Characteristics and Later-Life Pain Outcomes: Evidence From the Health and Retirement Study

Objectives: This study examines whether perceived neighborhood characteristics relate to pain outcomes among middle-aged and older adults. Methods: Data were from the Health and Retirement Study (2006-2014; n = 18,814). Perceived neighborhood characteristics were physical disorder, social cohesion, safety, and social ties. We fitted adjusted generalized estimating equation models to evaluate prevalence, incidence, and recovery of moderate-to-severe limiting pain 2 years later. Results: The mean age of our sample was 65.3 years; 54.6% were female and 24.2% reported moderate-to-severe limiting pain at baseline. Positive neighborhood characteristics were associated with low prevalence (e.g., prevalence ratio [PR]: .71 for disorder) and reduced incidence (e.g., PR: .63 for disorder) of moderate-to-severe limiting pain. Positive neighborhood characteristics were associated with a high recovery rate from moderate-to-severe limiting pain (e.g., PR = 1.15 for safety), though the 95% CIs for disorder and cohesion crossed the null. Discussion: Neighborhood characteristics may be important determinants in predicting pain in later life.

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.

Childhood adverse life events and skeletal muscle mitochondrial function

Social stress experienced in childhood is associated with adverse health later in life. Mitochondrial function has been implicated as a mechanism for how stressful life events "get under the skin" to influence physical wellbeing. Using data from the Study of Muscle, Mobility and Aging (n=879, 59% women), linear models examined whether adverse childhood events (i.e., physical abuse) were associated with two measures of skeletal muscle mitochondrial energetics in older adults: (1) maximal adenosine triphosphate production (ATP max ) and (2) maximal state 3 respiration (Max OXPHOS). Forty-five percent of the sample reported experiencing 1+ adverse childhood event. After adjustment, each additional event was associated with -0.07 SD (95% CI= - 0.12, -0.01) lower ATP max . No association was observed with Max OXPHOS. Adverse childhood events are associated with lower ATP production in later life. Findings indicate that mitochondrial function may be a mechanism in understanding how early social stress influences health in later life.

Mitochondrial Energetics in Skeletal Muscle Are Associated With Leg Power and Cardiorespiratory Fitness in the Study of Muscle, Mobility and Aging

BACKGROUND

Mitochondrial energetics are an important property of aging muscle, as generation of energy is pivotal to the execution of muscle contraction. However, its association with functional outcomes, including leg power and cardiorespiratory fitness, is largely understudied.

METHODS

In the Study of Muscle, Mobility, and Aging, we collected vastus lateralis biopsies from older adults (n = 879, 70-94 years, 59.2% women). Maximal State 3 respiration (Max OXPHOS) was assessed in permeabilized fiber bundles by high-resolution respirometry. Capacity for maximal adenosine triphosphate production (ATPmax) was measured in vivo by 31P magnetic resonance spectroscopy. Leg extension power was measured with a Keiser press system, and VO2 peak was determined using a standardized cardiopulmonary exercise test. Gender-stratified multivariate linear regression models were adjusted for age, race, technician/site, adiposity, and physical activity with beta coefficients expressed per 1-SD increment in the independent variable.

RESULTS

Max OXPHOS was associated with leg power for both women (β = 0.12 Watts/kg, p < .001) and men (β = 0.11 Watts/kg, p < .050). ATPmax was associated with leg power for men (β = 0.09 Watts/kg, p < .05) but was not significant for women (β = 0.03 Watts/kg, p = .11). Max OXPHOS and ATPmax were associated with VO2 peak in women and men (Max OXPHOS, β women = 1.03 mL/kg/min, β men = 1.32 mL/kg/min; ATPmax β women = 0.87 mL/kg/min, β men = 1.50 mL/kg/min; all p < .001).

CONCLUSIONS

Higher muscle mitochondrial energetics measures were associated with both better cardiorespiratory fitness and greater leg power in older adults. Muscle mitochondrial energetics explained a greater degree of variance in VO2 peak compared to leg power.

Biological expressions of early life trauma in the immune system of older adults

BACKGROUND

Poor immune function is associated with increased risk for a number of age-related diseases, however, little is known about the impact of early life trauma on immune function in late-life.

METHODS

Using nationally representative data from the Health and Retirement Study (n = 5,823), we examined the association between experiencing parental/caregiver death or separation before age 16 and four indicators of immune function in late-life: C-reactive Protein (CRP), Interleukin-6 (IL-6), soluble Tumor Necrosis Factor (sTNFR), and Immunoglobulin G (IgG) response to cytomegalovirus (CMV). We also examined racial/ethnic differences.

FINDINGS

Individuals that identified as racial/ethnic minorities were more likely to experience parental/caregiver loss and parental separation in early life compared to Non-Hispanic Whites, and had poorer immune function in late-life. We found consistent associations between experiencing parental/caregiver loss and separation and poor immune function measured by CMV IgG levels and IL-6 across all racial/ethnic subgroups. For example, among Non-Hispanic Blacks, those that experienced parental/caregiver death before age 16 had a 26% increase in CMV IgG antibodies in late-life (β = 1.26; 95% CI: 1.17, 1.34) compared to a 3% increase in CMV antibodies among Non-Hispanic Whites (β = 1.03; 95% CI: 0.99, 1.07) controlling for age, gender, and parental education.

INTERPRETATION

Our results suggest a durable association between experiencing early life trauma and immune health in late-life, and that structural forces may shape the ways in which these relationships unfold over the life course.

Discordance in chromosomal and self-reported sex in the UK Biobank: Implications for transgender- and intersex-inclusive data collection

There is growing need to distinguish between sex and gender. While sex is assigned at birth, gender is socially constructed and may not correspond to one's assigned sex. However, in most research studies, sex or gender is assessed in isolation or the terms are used interchangeably, which has implications for research accuracy and inclusivity. We used data from the UK Biobank to quantify the prevalence of disagreement between chromosomal and self-reported sex and identify potential reasons for discordance. Among approximately 200 individuals with sex discordance, 71% of discordances were potentially explained by the presence of intersex traits or transgender identity. The findings indicate that when describing sex- and/or gender-specific differences in health, researchers may be limited in their ability to draw conclusions regarding specific sex and/or gender health information.

COVID-19 mortality and excess mortality among working-age residents in California, USA, by occupational sector: a longitudinal cohort analysis of mortality surveillance data

BACKGROUND

During the first year of the COVID-19 pandemic, workers in essential sectors had higher rates of SARS-CoV-2 infection and COVID-19 mortality than those in non-essential sectors. It is unknown whether disparities in pandemic-related mortality across occupational sectors have continued to occur during the periods of SARS-CoV-2 variants and vaccine availability.

METHODS

In this longitudinal cohort study, we obtained data from the California Department of Public Health on all deaths occurring in the state of California, USA, from Jan 1, 2016, to Dec 31, 2021. We restricted our analysis to residents of California who were aged 18-65 years at time of death and died of natural causes. We classified the occupational sector into nine essential sectors; non-essential; or unemployed or without an occupation provided on the death certificate. We calculated the number of COVID-19 deaths in total and per capita that occurred in each occupational sector. Separately, using autoregressive integrated moving average models, we estimated total, per-capita, and relative excess natural-cause mortality by week between March 1, 2020, and Nov 30, 2021, stratifying by occupational sector. We additionally stratified analyses of occupational risk into counties with high versus low vaccine uptake, categorising high-uptake regions as counties where at least 50% of the population were fully vaccinated according to US guidelines by Aug 1, 2021.

FINDINGS

From March 1, 2020, to Nov 30, 2021, 24 799 COVID-19 deaths were reported in residents of California aged 18-65 years and an estimated 28 751 (95% prediction interval 27 853-29 653) excess deaths. People working in essential sectors were associated with higher COVID-19 deaths and excess deaths than were those working in non-essential sectors, with the highest per-capita COVID-19 mortality in the agriculture (131·8 per 100 000 people), transportation or logistics (107·1 per 100 000), manufacturing (103·3 per 100 000), facilities (101·1 per 100 000), and emergency (87·8 per 100 000) sectors. Disparities were wider during periods of increased infections, including during the Nov 29, 2020, to Feb 27, 2021, surge in infections, which was driven by the delta variant (B.1.617.2) and occurred during vaccine uptake. During the June 27 to Nov 27, 2021 surge, emergency workers had higher COVID-19 mortality (113·7 per 100 000) than workers from any other sector. Workers in essential sectors had the highest COVID-19 mortality in counties with low vaccination uptake, a difference that was more pronounced during the period of the delta infection surge during Nov 29, 2020, to Feb 27, 2021.

INTERPRETATION

Workers in essential sectors have continued to bear the brunt of high COVID-19 and excess mortality throughout the pandemic, particularly in the agriculture, emergency, manufacturing, facilities, and transportation or logistics sectors. This high death toll has continued during periods of vaccine availability and the delta surge. In an ongoing pandemic without widespread vaccine coverage and with anticipated threats of new variants, the USA must actively adopt policies to more adequately protect workers in essential sectors.

FUNDING

US National Institute on Aging, Swiss National Science Foundation, and US National Institute on Drug Abuse.

Disparities in Health Care Spending and Utilization Among Black and White Medicaid Enrollees

Importance

Administrative records indicate that more than half of the 80 million Medicaid enrollees identify as belonging to a racial and ethnic minority group. Despite this, disparities within the Medicaid program remain understudied. For example, we know of no studies examining racial differences in Medicaid spending, a potential measure of how equitably state resources are allocated.

Objectives

To examine whether and to what extent there are differences in health care spending and utilization between Black and White enrollees in Medicaid.

Design Setting and Participants

This cross-sectional study used calendar year 2016 administrative data from 3 state Medicaid programs and included 1 966 689 Black and White Medicaid enrollees. Analyses were performed between January 28, 2021, and October 18, 2021.

Exposures

Self-reported race.

Main Outcomes and Measures

Rates and racial differences in health care spending and utilization (including Healthcare Effectiveness Data and Information Set [HEDIS] access measures).

Results

Of 1 966 689 Medicaid adults and children (mean [SD] age, 20.3 [17.1] years; 1 119 136 [56.9%] female), 867 183 (44.1%) self-identified as non-Hispanic Black and 1 099 506 (55.9%) self-identified as non-Hispanic White. Results were adjusted for age, sex, Medicaid eligibility category, zip code, health status, and usual source of care. On average, annual spending on Black adult (19 years or older) Medicaid enrollees was $317 (95% CI, $259-$375) lower than White enrollees, a 6% difference. Among children (18 years or younger), annual spending on Black enrollees was $256 (14%) lower (95% CI, $222-$290). Adult Black enrollees also had 19.3 (95% CI, 16.78-21.84), or 4%, fewer primary care encounters per 100 enrollees per year compared with White enrollees. Among children, the differences in primary care utilization were larger: Black enrollees had 90.1 (95% CI, 88.2-91.8) fewer primary care encounters per 100 enrollees per year compared with White enrollees, a 23% difference. Black enrollees had lower utilization of most other services, including high-value prescription drugs, but higher emergency department use and rates of HEDIS preventive screenings.

Conclusions and Relevance

In this cross-sectional study of US Medicaid enrollees in 3 states, Black enrollees generated lower spending and used fewer services, including primary care and recommended care for acute and chronic conditions, but had substantially higher emergency department use. While Black enrollees had higher rates of HEDIS preventive screenings, ensuring equitable access to all services in Medicaid must remain a national priority.

Associations Between Handgrip Strength and Dementia Risk, Cognition, and Neuroimaging Outcomes in the UK Biobank Cohort Study

IMPORTANCE

The associations between muscle strength and cognitive outcomes have sparked interest in interventions that increase muscle strength for prevention of dementia, but the associations between muscle strength and cognitive aging are unclear, particularly among middle-aged adults.

OBJECTIVE

To evaluate the association between handgrip strength (HGS) and dementia, reduced cognition, and poorer neuroimaging outcomes in a UK population of middle-aged adults.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study evaluated UK Biobank participants aged 39 to 73 years enrolled from 2006 to 2010 with measured HGS and prospectively followed up for dementia diagnosis. Data were analyzed from October 2021 to April 2022.

EXPOSURES

HGS assessed in both hands via dynamometer.

MAIN OUTCOMES AND MEASURES

Outcomes included cognitive test scores (fluid intelligence and prospective memory), brain magnetic resonance imaging measures (total brain volume, white matter hyperintensity, and hippocampal volume), and incident dementia (all-cause, vascular, and Alzheimer disease [AD] from primary care, hospital, or death records) over a median (IQR) of 11.7 (11.0-12.4) years of follow-up. Mixed-effects linear and logistic regressions and Cox proportional-hazard models were used to estimate associations, stratified by gender and adjusted for covariates. Estimates are presented per 5-kg decrement in HGS. To evaluate reverse causation, we assessed whether a polygenic risk score for AD is associated with HGS.

RESULTS

A subsample of 190 406 adult participants in the UK Biobank (mean [SD] age, 56.5 [8.1] years; 102 735 women [54%]) were evaluated. A 5-kg decrement in HGS was associated with lower fluid intelligence scores in men (β, -0.007; 95% CI, -0.010 to -0.003) and women (β, -0.04; 95% CI, -0.05 to -0.04. A 5-kg decrement in HGS was associated with worse odds of correctly responding to a prospective memory task for men (odds ratio, 0.91; 95% CI, 0.90 to 0.92) and women (odds ratio, 0.88; 95% CI, 0.87 to 0.90). A 5-kg decrement in HGS was associated with greater white matter hyperintensity volume in men (β, 92.22; 95% CI, 31.09 to 153.35) and women (β, 83.56; 95% CI, 13.54 to 153.58). A 5-kg decrement in HGS was associated with incident dementia for men (hazard ratio, 1.20; 95% CI, 1.12 to 1.28) and women (hazard ratio, 1.12; 95% CI, 1.00 to 1.26). The AD genetic risk score was not significantly associated with HGS.

CONCLUSIONS AND RELEVANCE

These findings suggest that HGS is associated with measures of neurocognitive brain health among men and women and they add to a growing body of research indicating that interventions designed to increase muscle strength, particularly among middle-aged adults, may hold promise for the maintenance of neurocognitive brain health.

Occupation and Educational Attainment Characteristics Associated With COVID-19 Mortality by Race and Ethnicity in California

IMPORTANCE

Racial and ethnic inequities in COVID-19 mortality may be driven by occupation and education, but limited evidence has assessed these mechanisms.

OBJECTIVE

To estimate whether occupational characteristics or educational attainment explained the associations between race and ethnicity and COVID-19 mortality.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study of Californians aged 18 to 65 years linked COVID-19 deaths to population estimates within strata defined by race and ethnicity, gender, age, nativity in the US, region of residence, education, and occupation. Analysis was conducted from September 2020 to February 2022.

EXPOSURES

Education and occupational characteristics associated with COVID-19 exposure (essential sector, telework option, wages).

MAIN OUTCOMES AND MEASURES

All confirmed COVID-19 deaths in California through February 12, 2021. The study estimated what COVID-19 mortality would have been if each racial and ethnic group had (1) the COVID-19 mortality risk associated with the education and occupation distribution of White people and (2) the COVID-19 mortality risk associated with the lowest-risk educational and occupational positions.

RESULTS

Of 25 235 092 participants (mean [SD] age, 40 [14] years; 12 730 395 [50%] men), 14 783 died of COVID-19, 8 125 565 (32%) had a Bachelor's degree or higher, 13 345 829 (53%) worked in essential sectors, 11 783 017 (47%) could not telework, and 12 812 095 (51%) had annual wages under $51 700. COVID-19 mortality ranged from 15 deaths per 100 000 for White women and Asian women to 139 deaths per 100 000 for Latinx men. Accounting for differences in age, nativity, and region of residence, if all races and ethnicities had the COVID-19 mortality associated with the occupational characteristics of White people (sector, telework, wages), COVID-19 mortality would be reduced by 10% (95% CI, 6% to 14%) for Latinx men, but increased by 5% (95% CI, -8% to 17%) for Black men. If all working-age Californians had the COVID-19 mortality associated with the lowest-risk educational and occupational position (Bachelor's degree, nonessential, telework, and highest wage quintile), there would have been 43% fewer COVID-19 deaths among working-age adults (8441 fewer deaths; 95% CI, 32%-54%), with the largest absolute risk reductions for Latinx men (3755 deaths averted; 95% CI, 3304-4255 deaths) and Latinx women (2329 deaths averted; 95% CI, 2038-2621 deaths).

CONCLUSIONS AND RELEVANCE

In this population-based cohort study of working-age California adults, occupational disadvantage was associated with excess COVID-19 mortality for Latinx men. For all racial and ethnic groups, excess risk associated with low-education, essential, on-site, and low-wage jobs accounted for a substantial fraction of COVID-19 mortality.

A descriptive analysis of 2020 California Occupational Safety and Health Administration covid-19-related complaints

COVID-19 mortality has disproportionately affected specific occupations and industries. The Occupational Safety and Health Administration (OSHA) protects the health and safety of workers by setting and enforcing standards for working conditions. Workers may file OSHA complaints about unsafe conditions. Complaints may indicate poor workplace safety during the pandemic. We evaluated COVID-19-related complaints filed with California (Cal)/OSHA between January 1, 2020 and December 14, 2020 across seven industries. To assess whether workers in occupations with high COVID-19-related mortality were also most likely to file Cal/OSHA complaints, we compared industry-specific per-capita COVID-19 confirmed deaths from the California Department of Public Health with COVID-19-related complaints. Although 7820 COVID-19-related complaints were deemed valid by Cal/OSHA, only 627 onsite inspections occurred, and 32 citations were issued. Agricultural workers had the highest per-capita COVID-19 death rates (402 per 100,000 workers) but were least represented among workplace complaints (44 per 100,000 workers). Health Care workers had the highest complaint rates (81 per 100,000 workers) but the second lowest COVID-19 death rate (81 per 100,000 workers). Industries with the highest inspection rates also had high COVID-19 mortality. Our findings suggest complaints are not proportional to COVID-19 risk. Instead, higher complaint rates may reflect worker groups with greater empowerment, resources, or capacity to advocate for better protections. This capacity to advocate for safe workplaces may account for relatively low mortality rates in potentially high-risk occupations. Future research should examine factors determining worker complaints and complaint systems to promote participation of those with the greatest need of protection.

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COVID-19 mortality disproportionately affected specific occupations and industries.

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Cal/OSHA workplace complaint system may indicate poor workplace safety during the pandemic.

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Overall, complaints varied markedly by industry and rarely resulted in inspection or citation.

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High COVID-19-related complaint rates did not align with the highest COVID-19 death rates.

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Complaints filed to Cal/OSHA may better reflect employee resources than COVID-19 risk.

A descriptive analysis of 2020 California Occupational Safety and Health Administration COVID-19-related complaints.. [PMID: 34909780 PMCID: PMC8669847 DOI: 10.1101/2021.12.06.21262384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

COVID-19 mortality disproportionately affected specific occupations and industries. The Occupational Safety and Health Administration (OSHA) protects the health and safety of workers by setting and enforcing standards for working conditions. Workers may file OSHA complaints about unsafe conditions. Complaints may indicate poor workplace safety during the pandemic. We evaluated COVID-19-related complaints filed with California (Cal)/OSHA between January 1, 2020 and December 14, 2020 across seven industries. To assess whether workers in occupations with high COVID-19-related mortality were also most likely to file Cal/OSHA complaints, we compared industry-specific per-capita COVID-19 confirmed deaths from the California Department of Public Health with COVID-19-related complaints. Although 7,820 COVID-19-related complaints were deemed valid by Cal/OSHA, only 627 onsite inspections occurred and 32 citations were issued. Agricultural workers had the highest per-capita COVID-19 death rates (402 per 100,000 workers) but were least represented among workplace complaints (44 per 100,000 workers). Health Care workers had the highest complaint rates (81 per 100,000 workers) but the second lowest COVID-19 death rate (81 per 100,000 workers). Industries with the highest inspection rates also had high COVID-19 mortality. Our findings suggest complaints are not proportional to COVID-19 risk. Instead, higher complaint rates may reflect worker groups with greater empowerment, resources, or capacity to advocate for better protections. This capacity to advocate for safe workplaces may account for relatively low mortality rates in potentially high-risk occupations. Future research should examine factors determining worker complaints and complaint systems to promote participation of those with the greatest need of protection.

The Association Between Cytomegalovirus and Disability by Race/Ethnicity and Sex: Results From the Health and Retirement Study

Recent studies have documented a decline in the overall prevalence of disability in the United States; however, racial/ethnic and sex disparities continue to persist. Cytomegalovirus (CMV) infection, a socially patterned exposure, may be a key mechanism in understanding these previously documented disparities. Using data from a nationally representative study, the 2016 Health and Retirement Study, we employed Poisson log-binomial models to estimate the prevalence of disability in a comparison of CMV-seropositive and -seronegative adults and investigated effect modification by race/ethnicity and sex. Among the 9,029 participants (55% women; mean age = 67.4 years), 63% were CMV-seropositive and 15% were disabled. CMV seropositivity was highest among non-Hispanic Black (88%) and Hispanic (92%) adults as compared with non-Hispanic White adults (57%). We found evidence for effect modification in the association between CMV and disability by sex but not race/ethnicity. While the 95% confidence intervals in the fully adjusted models included the null value, in comparison with seronegative women, our results suggest a greater prevalence of disability among CMV-seropositive women (prevalence ratio = 1.16, 95% confidence interval: 0.97, 1.38) but not among men (prevalence ratio = 0.85, 95% confidence interval: 0.69, 1.06). Results provide initial support for the hypothesis that CMV may be an important determinant of sex disparities in disability.

Geographically targeted COVID-19 vaccination is more equitable and averts more deaths than age-based thresholds alone

COVID-19 mortality increases markedly with age and is also substantially higher among Black, Indigenous, and People of Color (BIPOC) populations in the United States. These two facts can have conflicting implications because BIPOC populations are younger than white populations. In analyses of California and Minnesota—demographically divergent states—we show that COVID vaccination schedules based solely on age benefit the older white populations at the expense of younger BIPOC populations with higher risk of death from COVID-19. We find that strategies that prioritize high-risk geographic areas for vaccination at all ages better target mortality risk than age-based strategies alone, although they do not always perform as well as direct prioritization of high-risk racial/ethnic groups. Vaccination schemas directly implicate equitability of access, both domestically and globally.

Geographically-targeted COVID-19 vaccination is more equitable than age-based thresholds alone

COVID-19 mortality increases dramatically with age and is also substantially higher among Black, Indigenous, and People of Color (BIPOC) populations in the United States. These two facts introduce tradeoffs because BIPOC populations are younger than white populations. In analyses of California and Minnesota--demographically divergent states--we show that COVID vaccination schedules based solely on age benefit the older white populations at the expense of younger BIPOC populations with higher risk of death from COVID-19. We find that strategies that prioritize high-risk geographic areas for vaccination at all ages better target mortality risk than age-based strategies alone, although they do not always perform as well as direct prioritization of high-risk racial/ethnic groups.

Muscle Mass Assessed by the D3-Creatine Dilution Method and Incident Self-reported Disability and Mortality in a Prospective Observational Study of Community-Dwelling Older Men

BACKGROUND

Whether low muscle mass is a risk factor for disability and mortality is unclear. Associations between approximations of muscle mass (including lean mass from dual-energy x-ray absorptiometry [DXA]), and these outcomes are inconsistent.

METHODS

Muscle mass measured by deuterated creatine (D3Cr) dilution and appendicular lean mass (ALM, by DXA) were assessed at the Year 14 Visit (2014-2016) of the prospective Osteoporotic Fractures in Men study (N = 1,425, age 77-101 years). Disability in activities of daily living (ADLs), instrumental ADLs, and mobility tasks was self-reported at the Year 14 visit and 2.2 years later; deaths were centrally adjudicated over 3.3 years. Relative risks and 95% confidence intervals (CI) were estimated per standard deviation decrement with negative binomial, logistic regression, or proportional hazards models.

RESULTS

In age- and clinical center-adjusted models, the relative risks per decrement in D3Cr muscle mass/wgt was 1.9 (95% CI: 1.2, 3.1) for incident self-reported ADL disability; 1.5 (95% CI: 1.3, 1.9) for instrumental ADL disability; and 1.8 (95% CI: 1.5, 2.2) for mobility disability. In age-, clinical center-, and weight-adjusted models, the relative risks per decrement in D3Cr muscle mass was 1.8 (95% CI: 1.5, 2.2) for all-cause mortality. In contrast, lower DXA ALM was not associated with any outcome. Associations of D3Cr muscle mass with these outcomes were slightly attenuated after adjustment for confounding factors and the potentially mediating effects of strength and physical performance.

CONCLUSIONS

Low muscle mass as measured by D3Cr dilution is a novel risk factor for clinically meaningful outcomes in older men.

Projected All-Cause Deaths Attributable to COVID-19-Related Unemployment in the United States

Objectives. To project the range of excess deaths potentially associated with COVID-19-related unemployment in the United States and quantify inequities in these estimates by age, race/ethnicity, gender, and education.Methods. We used previously published meta-analyzed hazard ratios (HRs) for the unemployment-mortality association, unemployment data from the Bureau of Labor Statistics, and mortality data from the National Center for Health Statistics to estimate 1-year age-standardized deaths attributable to COVID-19-related unemployment for US workers aged 25 to 64 years. To accommodate uncertainty, we tested ranges of unemployment and HR scenarios.Results. Our best estimate is that there will be 30 231 excess deaths attributable to COVID-19-related unemployment between April 2020 and March 2021. Across scenarios, attributable deaths ranged from 8315 to 201 968. Attributable deaths were disproportionately high among Blacks, men, and those with low education.Conclusions. Deaths attributable to COVID-19-related unemployment will add to those directly associated with the virus and will disproportionately burden groups already experiencing incommensurate COVID-19 mortality.Public Health Implications. Supportive economic policies and interventions addressing long-standing harmful social structures are essential to mitigate the unequal health harms of COVID-19.

Sarcopenia Definition & Outcomes Consortium Defined Low Grip Strength in Two Cross-Sectional, Population-Based Cohorts

BACKGROUND/OBJECTIVES

The extent to which the prevalence of muscle weakness in the US population varies by different putative grip strength constructs developed by the Sarcopenia Definitions and Outcomes Consortium (SDOC) has not been described.

DESIGN

Cross-sectional analysis.

SETTING

Two nationally representative cohorts-2010 and 2012 waves of the Health and Retirement Survey and round 1 (2011) of the National Health and Aging Trends Survey.

PARTICIPANTS

Adults aged 65 years and older (n = 12,984) were included in these analyses.

MEASUREMENTS

We analyzed three constructs of muscle weakness developed by the SDOC, and found to be associated with mobility disability for men and women, respectively: absolute grip strength (<35.5 kg and 20 kg); grip strength standardized to body mass index (<1.05 kg/kg/m² and 0.79 kg/kg/m²); and grip strength standardized to weight (<0.45 kg/kg and 0.337 kg/kg). We estimated the prevalence of muscle weakness defined by each of these constructs in the overall older US population, and by age, sex, race, and ethnicity. We also estimated the sensitivity and specificity of each of the grip strength constructs to discriminate slowness (gait speed <0.8 m/s) in these samples.

RESULTS

The prevalence of muscle weakness ranged from 23% to 61% for men and from 30% to 66% for women, depending on the construct used. There was substantial variation in the prevalence of muscle weakness by race and ethnicity. The sensitivity and specificity of these measures for discriminating slowness varied widely, ranging from 0.30 to 0.92 (sensitivity) and from 0.17 to 0.88 (specificity).

CONCLUSIONS

The prevalence of muscle weakness, defined by the putative SDOC grip strength constructs, depends on the construct of weakness used. J Am Geriatr Soc 68:1438-1444, 2020.

Life course trauma and muscle weakness in older adults by gender and race/ethnicity: Results from the U.S. health and Retirement Study

Muscle weakness, as measured by handgrip strength, is a primary determinant of physical functioning and disability. There is a high burden of muscle weakness in the United States with close to 50 percent of older Americans meeting criteria for clinical muscle weakness. While previous racial/ethnic disparities have been documented among older adults, the extent to which lifecourse trauma shapes muscle strength trajectories is unknown. Using U.S. Health and Retirement Study (N = 20,472, Mean Age = 63.8 years) data on grip strength (2006-2014, up to 3 assessments) and retrospectively reported traumatic events, we fit gender-stratified growth curve models to investigate whether traumatic events experienced across the lifecourse or at distinct sensitive periods (childhood, early/emerging adulthood or mid-life) predicted later-life trajectories of grip strength. There was no association between cumulative trauma and trajectories of grip strength and the main effects for the life stage models were largely null. However, among White women, our results suggest that traumatic events experienced during childhood (β = -0.012; 95% CI = -0.024, 0.0004) compared to middle adulthood are associated with faster declines in grip strength in later life. Traumatic events reported during childhood was related to a slower decline in grip strength over time among Hispanic women compared to that for White women (β = 0.086, 95% CI = 0.044, 0.128). Among Black men, the association between traumatic events during early/emerging adulthood and age-related declines in grip strength was stronger for Black men than for White men (interaction β = -0.070; 95% CI = -0.138, 0.001). Traumatic events experienced during distinct life stages may influence later life declines in grip strength and exacerbate racial inequalities in later life. This study addresses an important gap by investigating the life course social determinants of later life muscle strength, which is a key driver of physical functioning and mobility.

Is perceived neighbourhood physical disorder associated with muscle strength in middle aged and older men and women? Findings from the US health and retirement study

BACKGROUND

Research documenting the relevance of neighbourhoods for the health of older adults has focused on global physical functioning outcomes, such as disability, rather than physiologic impairments that lead to disability. Muscle weakness is an age-related impairment and a central mechanism of disability. Evaluating neighbourhood effects on muscle weakness may offer insight into physiologic mechanisms of disability. We examined the association between perceived neighbourhood disorder and muscle strength in a nationally representative sample of US adults aged 51+.

METHODS

Among 11 277 participants (57% women; mean age: 66.6 years) in the Health and Retirement Study (2012-2014), we investigated whether self-reported neighbourhood physical disorder (1-7 scale, mean=2.61, SD=1.45); presence of vandalism/graffiti, litter, deserted houses, feeling safe walking alone) was associated with mean hand grip strength using linear regression models with sampling weights. We tested whether the association between neighbourhood disorder and grip strength differed by age and gender.

RESULTS

After adjusting for demographic characteristics, marital status, education and household wealth, residence in neighbourhoods with high perceived physical neighbourhood disorder was associated with lower muscle strength for men (β=-1.95 kg; 95% CI, 2.68 to -1.22) and to a lesser extent, for women (β=-0.64 kg, 95% CI, -1.11 to -0.19), (p for interaction <0.0001). For both men and women, associations between neighbourhood physical disorder and grip strength were more adverse among the middle aged (51-64 years) than for older (ages 65+) adults.

DISCUSSION

Perceived neighbourhood disorder was associated with lower muscle strength. Future studies should more rigorously evaluate causality and evaluate potential interventions.

Association of change in muscle mass assessed by D3 -creatine dilution with changes in grip strength and walking speed

BACKGROUND

Muscle mass declines with age. However, common assessments used to quantify muscle mass are indirect. The D₃ -creatine (D₃ Cr) dilution method is a direct assessment of muscle mass; however, longitudinal changes have not been examined in relation to changes in other measures of muscle mass, strength, and performance.

METHODS

A convenience sample of 40 men from the Osteoporotic Fractures in Men Study (mean age = 83.3 years, standard deviation = 3.9) underwent repeat assessment of D₃ Cr muscle mass, dual-energy X-ray absorptiometry (DXA) lean mass, grip strength, and walking speed at two time points approximately 1.6 years apart (2014-2016). One-sample t-tests and Pearson correlations were used to examine changes in DXA total body lean mass, DXA appendicular lean mass/height² , DXA appendicular lean mass/weight, D₃ Cr muscle mass, D₃ Cr muscle mass/weight, grip strength, walking speed, and weight.

RESULTS

D₃ -creatine muscle mass, D₃ Cr muscle mass/weight, grip strength, and walking speed all significantly declined (all P < 0.01). The change in DXA measures of lean mass was moderately correlated with changes in D₃ Cr muscle mass. There was no significant correlation between the change in DXA measures of lean mass and change in walking speed (all P > 0.05). The change in D₃ Cr muscle mass/weight was moderately correlated with change in walking speed (r = 0.33, P < .05). The change in grip strength was weakly correlated with the change in DXA measures of lean mass and D₃ Cr muscle mass (r = 0.19-0.32).

CONCLUSIONS

The results of our study provide new insights regarding the decline in muscle strength and D₃ Cr muscle mass. The D₃ Cr method may be a feasible tool to measure declines in muscle mass over time.

THE ASSOCIATION BETWEEN D3CR MUSCLE MASS AND MORTALITY IN COMMUNITY-DWELLING OLDER MEN

We have shown that men with low muscle mass assessed by D3Cr (deuterated creatine) dilution are more likely to have worse physical performance and incident fractures, injurious falls and disability. However, the relation between D3Cr muscle mass and mortality is unknown. With data from Year 14 Visit of the MrOS study (N=1400, mean age 84.2 yrs), proportional hazards models estimated the risk of mortality (hazard ratio and 95% CI) by quartiles of D3Cr muscle mass (standardized to body mass); we calculated p for trend across quartiles. Models were adjusted for age, race, clinical center, alcohol use, smoking status, comorbidities, activity, percent fat, exhaustion, and cognitive function. Cause of death was centrally adjudicated. Over 3.3±0.8 years of follow-up, 197 (14.1%) men died. Men in the lowest quartile of D3Cr muscle mass/wgt were 2.8-fold more likely to die than men in the highest quartile (HR: 2.8, 95% CI: 1.6, 4.9; p for trend<.001). The HRs for each cause-specific mortality outcome were of similar magnitude to the HR for overall mortality: cancer death (HR, Q1 vs Q4: 2.2, 95% CI: 0.7, 7.1; p trend =0.140); CVD death (HR, Q1 vs Q4: 3.7, 95% CI: 1.3, 10.5; p trend =0.008); or non-cancer non-CVD death (HR, Q1 vs Q4: 2.4, 95% CI: 1.0, 5.6; p trend=0.019). We conclude that low muscle mass assessed by D3Cr dilution is a strong risk factor for mortality in older men, providing additional evidence that low muscle mass is an important risk factor for adverse health outcomes.

Muscle Weakness and Physical Disability in Older Americans: Longitudinal Findings from the U.S. Health and Retirement Study

IMPORTANCE

Muscle weakness is an important indicator of disability, chronic disease and mortality. While we recently proposed sex/race specific grip strength cutpoints for clinical muscle weakness in a diverse, nationally representative sample of older Americans, the extent to which these cutpoints predict physical disability remains unknown.

OBJECTIVE

To examine whether sex/race specific muscle weakness cutpoints predict physical disability status in a nationally representative sample of Americans age 65+.

DESIGN

We used data from the 2006-2010 Health and Retirement Study. Fully-adjusted, weighted multinomial logistic regression models were used to quantify the odds of experiencing the onset, progression or persistence of disability in activities of daily living (ADL) among weak versus non-weak individuals over a 2-year period.

SETTING

General community, nationally representative sample of older Americans.

PARTICIPANTS

Population-based, community dwelling sample of older American adults aged 65-years+; 57 percent were women, 91% were White and the mean age was 75 years. Main Outcome(s) and Measure(s): The primary outcome of interest was disability dynamics, defined by changes in ADL status across at 2- year period. The primary exposure was clinical muscle weakness as defined by previously identified cutpoints. Hypotheses were formulated before analyses were conducted.

RESULTS

In this nationally representative sample (n= 8,725), 44% of individuals were classified as weak at baseline. At follow-up, 55% remained independent with no change in their ADL status, 11% had an onset of disability and 4% progressed in their disability status. The odds of experiencing an onset of ADL disability was 54% higher among weak individuals compared those who were not weak at baseline (OR= 1.54, 95% CI= 1.54, 1.5, p<.0001); the odds of experiencing a progression in physical disability status was 2.16 times higher among those who were weak at baseline compared to non-weak individuals (OR= 2.16, 95% CI= 2.15, 2.16, p<.0001).

CONCLUSIONS

This is the first study to use grip strength weakness cut-points to identify those who may be at greatest risk for experiencing physical disability in later life. Results underscore the importance of using population-specific cutpoints for clinical weakness in order to identify individuals at greatest risk for adverse health outcomes.

Cut Points for Clinical Muscle Weakness Among Older Americans

INTRODUCTION

Muscle weakness is an important indicator of disability, chronic disease, and early mortality. Grip strength is a simple, cost-effective measure of overall muscle strength. The Foundation of the National Institutes of Health recently proposed sex-specific grip strength cut points for clinical muscle weakness. However, these criteria were established using non-nationally representative data. This study used nationally representative data on Americans aged ≥65 years to identify race- and sex-specific cut points for clinical muscle weakness and quantify prevalence among older blacks and whites by sex.

METHODS

Classification and Regression Tree models were used to identify cut points based on individual-level grip strength associated with slow gait speed (<0.8 m/second) among 7,688 individuals (57% female; 8% black; mean age, 74.6 [SD=6.79] years) from the 2010/2012 Health and Retirement Study during January-April 2016. Identified cut points were then used to quantify the prevalence of weakness by race/sex subgroup.

RESULTS

Fifty-five percent of men (maximum grip strength <39 kg) and 47% of women (maximum grip strength <22 kg) were classified as weak. Higher cut points were identified for black men (maximum grip strength <40 kg) and women (maximum grip strength <31 kg), and the prevalence of weakness (57% and 88%, respectively) was higher compared with whites. Fifty-five percent of individuals had slow gait speed (<0.8 m/second).

CONCLUSIONS

Prevalence of weakness was substantially higher than previous reports, underscoring the importance of using population-level data to identify individuals at greatest risk for adverse health outcomes. This is the first study to establish cut points for muscle weakness in a nationally representative sample by race and sex.

Declines in Strength and Mortality Risk Among Older Mexican Americans: Joint Modeling of Survival and Longitudinal Data

BACKGROUND

Grip strength is a noninvasive method of risk stratification; however, the association between changes in strength and mortality is unknown. The purposes of this study were to examine the association between grip strength and mortality among older Mexican Americans and to determine the ability of changes in strength to predict mortality.

METHODS

Longitudinal data were included from 3,050 participants in the Hispanic Established Population for the Epidemiological Study of the Elderly. Strength was assessed using a hand-held dynamometer and normalized to body mass. Conditional inference tree analyses were used to identify sex- and age-specific weakness thresholds, and the Kaplan-Meier estimator was used to determine survival estimates across various strata. We also evaluated survival with traditional Cox proportional hazard regression for baseline strength, as well as with joint modeling of survival and longitudinal strength change trajectories.

RESULTS

Survival estimates were lower among women who were weak at baseline for only 65- to 74-year-olds (11.93 vs 16.69 years). Survival estimates were also lower among men who were weak at baseline for only ≥75-year-olds (5.80 vs 7.39 years). Lower strength at baseline (per 0.1 decrement) was significantly associated with mortality (hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01-1.19) for women only. There was a strong independent, longitudinal association between strength decline and early mortality, such that each 0.10 decrease in strength, within participants over time, resulted in a HR of 1.12 (95% CI: 1.00-1.25) for women and a HR of 1.15 (95% CI: 1.04-1.28) for men.

CONCLUSIONS

Longitudinal declines in strength are significantly associated with all-cause mortality in older Mexican Americans.