Abstract
Background
Sarcopenia varies by ethnicity, and has a major impact on health in older adults. However, little is known about sarcopenia characteristics in African ancestry populations outside ...the United States. We examined sarcopenia characteristics in 2,142 African Caribbean men aged 59.0 ± 10.4 years (range: 40–92 years) in Tobago, and their association with incident mobility limitations in those aged 55+ (n = 738).
Methods
Body mass index (BMI), grip strength, dual-x-ray absorptiometry (DXA) appendicular lean mass (ALM), and self-reported mobility limitations were measured at baseline, and 6 years later. Change in sarcopenia characteristics, including grip strength, grip strength/BMI, ALMBMI, and ALM/ht2, were determined. Foundations for the National Institutes of Health Sarcopenia Project (FNIH) and European Working Group for Sarcopenia in Older People 2 (EWGSOP2) cut-points were also examined. Odds ratios (OR) and 95% confidence intervals (CI) for mobility limitation were calculated using multivariable linear regression models adjusted for covariates.
Results
Overall, sarcopenia prevalence was quite low using the FNIH (0.3%) and EWGSOP2 (0.6%) operational cut-points, but was higher in those aged 75+ (2.1% FNIH and 3.7% EWGSOP2). Prevalence was also higher when based on “weakness”, versus “low ALM.” When sarcopenia markers were examined separately, baseline levels, but not changes, were associated with incident mobility limitations. Baseline grip strength/BMI was a particularly strong risk factor for incident mobility limitations (OR per SD: 0.50; 95% CI: 0.37–0.68).
Conclusions
Our findings suggest that grip strength normalized to body mass, measured at one time point, may be a particularly useful phenotype for identifying African Caribbean men at risk for future mobility limitations.
Abstract
Background
African Caribbeans have higher levels of myosteatosis than other populations; however, little is known about the impact of myosteatosis on physical function in African Caribbeans. ...Herein, we examined the association between regional myosteatosis of the calf, thigh, and abdomen versus physical function in 850 African-Ancestry men aged 64.2 ± 8.9 (range 50–95) living on the Caribbean Island of Tobago.
Methods
Myosteatosis was measured using computed tomography and included intermuscular adipose tissue (IMAT) and muscle density levels of the thigh, calf, psoas, and paraspinous muscles. Outcomes included grip strength, time to complete 5 chair-rises, and 4-meter gait speed. Associations were quantified using separate linear models for each myosteatosis depot and were adjusted for age, height, demographics, physical activity, and chronic diseases. Beta coefficients were presented per standard deviation of each myosteatosis depot.
Results
Higher thigh IMAT was the only IMAT depot significantly associated with weaker grip strength (β = −1.3 ± 0.43 kg, p = .003). However, lower muscle density of all 4 muscle groups was associated with weaker grip strength (all p < .05). Calf and thigh myosteatosis (IMAT and muscle density) were significantly associated with both worse chair rise time and gait speed (all p < .05), whereas psoas IMAT and paraspinous muscle density were associated with gait speed.
Conclusion
Myosteatosis of the calf and thigh―but not the abdomen―were strongly associated with grip strength and performance measures of physical function in African Caribbean men. However, posterior abdominal myosteatosis may have some utility when abdominal images are all that are available.
Abstract
Background
Mobility limitations are common, with higher prevalence in African Americans compared with whites, and are associated with disability, institutionalization, and death. Aging is ...associated with losses of lean mass and a shift to central adiposity, which are more pronounced in African Americans. We aimed to examine the association of body composition remodeling with incident mobility limitations in older men of African ancestry.
Methods
Seven-year changes in body composition were measured using peripheral quantitative computed tomography (pQCT) of the calf and whole-body dual x-ray absorptiometry (DXA) in 505 African ancestry men aged ≥60 years and free of self-reported mobility limitations at baseline. Self-reported incident mobility limitations were assessed at 7-year follow-up. Odds of developing mobility limitations associated with baseline and change in body composition were quantified using separate logistic regression models.
Results
Seventy-five men (14.9%) developed incident mobility limitations over 6.2 ± 0.6 years. Baseline body composition was not associated with incident mobility limitations. After adjustment for covariates, gaining total and intermuscular fat were associated with incident mobility limitations (odds ratio OR: 1.60; 95% confidence interval CI: 1.21–2.13; OR: 1.51; 95% CI: 1.18–1.94). Changes in DXA lean mass were not related to mobility limitations; however, maintaining pQCT calf muscle area was protective against mobility limitations (OR: 0.65; 95% CI: 0.48–0.87).
Conclusions
Increases in body fat, and particularly intermuscular fat, and decreases in calf skeletal muscle area were associated with a higher risk of developing mobility limitations. Our findings emphasize the importance of body composition remodeling in the development of mobility limitations among African ancestry men.
To identify and validate genes associated with bone mineral density (BMD), which is a prominent osteoporosis risk factor, we tested 379,319 SNPs in 1000 unrelated white U.S. subjects for associations ...with BMD. For replication, we genotyped the most significant SNPs in 593 white U.S. families (1972 subjects), a Chinese hip fracture (HF) sample (350 cases, 350 controls), a Chinese BMD sample (2955 subjects), and a Tobago cohort of African ancestry (908 males). Publicly available Framingham genome-wide association study (GWAS) data (2953 whites) were also used for
in silico replication. The GWAS detected two BMD candidate genes,
ADAMTS18 (ADAM metallopeptidase with thrombospondin type 1 motif, 18) and
TGFBR3 (transforming growth factor, beta receptor III). Replication studies verified the significant findings by GWAS. We also detected significant associations with hip fracture for
ADAMTS18 SNPs in the Chinese HF sample. Meta-analyses supported the significant associations of
ADAMTS18 and
TGFBR3 with BMD (p values: 2.56 × 10
−5 to 2.13 × 10
−8; total sample size: n = 5925 to 9828). Electrophoretic mobility shift assay suggested that the minor allele of one significant ADAMTS18 SNP might promote binding of the TEL2 factor, which may repress
ADAMTS18 expression. The data from NCBI GEO expression profiles also showed that
ADAMTS18 and
TGFBR3 genes were differentially expressed in subjects with normal skeletal fracture versus subjects with nonunion skeletal fracture. Overall, the evidence supports that
ADAMTS18 and
TGFBR3 might underlie BMD determination in the major human ethnic groups.
OBJECTIVE:African ancestry individuals are at high risk for hypertensive cardiovascular disease (CVD) and could benefit from early detection of arterial stiffening. We tested the association between ...the 2017 ACC/AHA hypertension categorizations, which include new blood pressure (BP) cutoffs and a definition for elevated BP, and arterial stiffness in 772 Afro-Caribbean men aged 50+ years (mean 64 years).
METHODS:Arterial stiffness was assessed by brachial–ankle pulse-wave velocity (PWV) using a waveform analyzer. Hypertension groups were based on the 2017 ACC/AHA guidelines and by pharmacologic control status. Multiple linear/logistic regression was used to determine the association of PWV with BP and hypertension.
RESULTS:Mean (SD) PWV was 1609 (298) cm/s and was independently correlated with age, SBP, pulse, diabetes, height, and alcohol intake (all P < 0.02). After adjusting for these, in men aged at least 65 years, those with stage 1 or uncontrolled stage 2 hypertension had significantly greater PWV than all other groups (all P < 0.05). Men with controlled hypertension had similar PWV to those with elevated BP (P = 0.7); however, this was significantly greater than men with normal BP (all P < 0.05). Patterns were similar, but with smaller effect sizes, in men aged less than 65 years (all P < 0.05 except controlled hypertension versus elevated or normal BP were not significant).
CONCLUSION:In these high-risk Afro-Caribbeansstage 1 hypertension is associated with increased PWV, which supports the new guidelines; and, pharmacologic control appears to partially protect men from increased PWV. Longitudinal studies are needed to determine optimal PWV and timing of antihypertensive treatment for preventing future CVD.
Background Animal and in vitro experiments implicate the Wnt pathway in cardiac development, fibrosis, vascular calcification, and atherosclerosis, but research in humans is lacking. We examined ...peripheral blood Wnt pathway gene expression and arterial stiffness in 369 healthy African ancestry men (mean age, 64 years). Methods and Results Gene expression was assessed using a custom Nanostring nCounter gene expression panel (N=43 genes) and normalized to housekeeping genes and background signal. Arterial stiffness was assessed via brachial-ankle pulse-wave velocity. Fourteen Wnt genes showed detectable expression and were tested individually as predictors of pulse-wave velocity using linear regression, adjusting for age, height, weight, blood pressure, medication use, resting heart rate, current smoking, alcohol intake, and sedentary lifestyle. Adenomatous polyposis coli regulator of Wnt signaling pathway (
), glycogen synthase kinase 3β (
), and transcription factor 4 (
) were significantly associated with arterial stiffness (
<0.05 for all). When entered into a single model,
and
expression remained independently associated with arterial stiffness (
=0.04 and 0.003, respectively), and each explained ≈3% of the variance in pulse-wave velocity. Conclusions The current study establishes a novel association between in vivo expression of the Wnt pathway genes,
and
, with arterial stiffness in African ancestry men, a population at high risk of hypertensive vascular disease.
This study tested the association of objectively measured physical activity with blood pressure and hypertension in African Caribbean men, an understudied population segment known to be at high-risk ...for cardiovascular disease (CVD) which has low levels of high-exertion physical activity. Men (N = 310) were from the Tobago Health Study and aged 50–89 years. Systolic (SBP) and diastolic (DBP) blood pressures were measured using an automated device, and hypertension was defined as SBP ≥ 140 mmHg, DBP ≥ 90 mmHg, or current use of antihypertensive medication. Physical activity was measured using the SenseWear Pro armband (SWA) and consisted of daily time engaged in sedentary behavior (SB), light physical activity (LPA), and moderate to vigorous activity (MVPA), as well as daily step count. Multiple regression analyses using the isotemporal substitution framework were used to test for associations between activity and blood pressures. Models were adjusted in stages for SWA wear time, age, antihypertensive medication use, alcohol consumption, smoking, diabetes, CVD, family history of hypertension, salt intake, and adiposity.
Replacement of SB with LPA was associated with lower SBP adjusted for wear time (β = -0.84, p < 0.05), but attenuated after adjustment for age. Replacement of SB with LPA was associated with lower DBP (β = -0.50) and lower odds of hypertension (OR = 0.88), adjusted for wear time and age (both p < 0.05). All model associations of replacement of SB with LPA were stronger when restricted to men not taking antihypertensive medications, regardless of their hypertension status.
These results support the strategy of increasing light physical activity for blood pressure management in high-risk Afro-Caribbean men.
INTRODUCTION
Alzheimer's disease (AD) is increasing in the Caribbean, especially for persons of African ancestry (PAA) and women. However, studies have mostly utilized surveys without AD biomarkers.
...METHODS
In the Tobago Health Study (n = 309; 109 women, mean age 70.3 ± 6.6), we assessed sex differences and risk factors for serum levels of phosphorylated tau‐181 (p‐tau181), amyloid‐beta (Aβ)42/40 ratio, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). Blood samples were from 2010 to 2013 for men and from 2019 to 2023 for women.
RESULTS
Women were more obese, hypertensive, and sedentary but reported less smoking and alcohol use than men (age‐adjusted p < 0.04). Compared to men, women had worse levels of AD biomarkers, with higher p‐tau181 and lower Aβ42/40, independent of covariates (p < 0.001). In sex‐stratified analyses, higher p‐tau181 was associated with older age in women and with hypertension in men. GFAP and NfL did not differ by sex.
DISCUSSION
Women had worse AD biomarkers than men, unexplained by age, cardiometabolic diseases, or lifestyle. Studying risk factors for AD in PAA is warranted, especially for women earlier in life.
BACKGROUND:Although obesity is strongly associated with diabetes, the greater prevalence of diabetes in persons of African ancestry than in those of other ancestries cannot be explained simply by ...differences in total or central adiposity. OBJECTIVE:We examined whether skeletal muscle composition is associated with diabetes in 1249 men of African ancestry aged >=40 y. DESIGN:Anthropometry and fasting serum glucose were measured, and lower-leg skeletal muscle composition was assessed with peripheral quantitative computerized tomography (pQCT). RESULTS:The prevalence of diabetes in this population was high (21%). We observed an age-associated adipose tissue remodeling in skeletal muscle and greater intermuscular (IMAT) and lesser subcutaneous (SAT) adipose tissue area with advancing age (P < 0.0001). Multivariate stepwise logistic regression identified more IMAT and less SAT to be significantly associated with a greater prevalence of diabetes. Even among normal-weight men body mass index (BMI; in kg/m²) < 25, diabetic men had significantly (P = 0.01) more IMAT than did those without diabetes. Greater IMAT was also associated with a greater prevalence of hyperglycemia in men with a family history of diabetes than in those without such history (P for interaction = 0.02). CONCLUSIONS:These findings underscore the independent associations of subcutaneous and intermuscular fat among men of African ancestry, an effect that may be modified by a family history of diabetes. Further studies are needed to identify the genetic and physiologic mechanisms that influence the distribution and remodeling of adipose tissue in skeletal muscle with aging.'
PDF
