Background. Aging is characterized by declines in physical capacity and bone mineral density (BMD), both of which contribute to increased risk for fracture. However, it is unclear if these factors ...coexist or are independent in elderly people, and if a relationship does exist, whether it varies by sex and/or race. Methods. Data are from 847 white women, 723 black women, 927 white men, and 544 black men aged 70–79 years participating in the Health Aging and Body Composition (ABC) Study, a cohort of well-functioning community-dwelling elders. BMD (g/cm2) of the hip (femoral neck and trochanter) was determined by dual X-ray absorptiometry. Physical capacity measures included knee extensor strength, repeated chair-stands, gait speed (6 m), walking endurance (400 m), and standing balance. Results. In analyses of BMD as a continuous measure, BMD and physical performance were most consistently related at the trochanter in black women, even after adjusting for body size and several covariates including physical activity. For each performance measure, black women in the bottom quartile(s) had lower BMD than those in the top quartile(s). For the femoral neck, there was a significant association with performance tasks, except for the 400-m walk. In comparison, only chair-rise performance was related to BMD at the femoral neck, and knee extensor strength, chair-rise performance, and balance with the trochanter in white women. For white and black men, trends existed only for lower BMD in those with poorer knee extensor strength. Conclusions. In this cohort of well-functioning young-old seniors, physical capacity is only modestly related to BMD at the hip. The association was strongest in black women, who as a group exhibited the poorest functional capacity in the cohort. Our data show that, although both poorer physical performance and low BMD are risk factors for fracture, they remain largely independent in the well-functioning young-old, except in black women. This independence suggests that interventions to reduce fracture incidence should be targeted at improving both physical performance and bone density.
Background There is growing evidence that higher levels of inflammatory markers are associated with physical decline in older persons, possibly through the catabolic effects of inflammatory markers ...on muscle. The aim of this study was to investigate the association between serum levels of inflammatory markers and loss of muscle mass and strength in older persons. Methods Using data on 2,177 men and women in the Health, Aging, and Body Composition Study, we examined 5-year change in thigh muscle area estimated by computed tomography and grip and knee extensor strength in relation to serum levels of interleukin-6 (IL-6), C-reactive protein, tumor necrosis factor-alpha (TNF-α), and soluble receptors (measured in a subsample) at baseline. Results Higher levels of inflammatory markers were generally associated with greater 5-year decline in thigh muscle area. Most associations, with the exception of soluble receptors, were attenuated by adjustment for 5-year change in weight. Higher TNF-α and interleukin-6 soluble receptor levels remained associated with greater decline in grip strength in men. Analyses in a subgroup of weight-stable persons showed that higher levels of TNF-α and its soluble receptors were associated with 5-year decline in thigh muscle area and that higher levels of TNF-α were associated with decline in grip strength. Conclusions TNF-α and its soluble receptors showed the most consistent associations with decline in muscle mass and strength. The results suggest a weight-associated pathway for inflammation in sarcopenia.
Most genome-wide association studies are confined to middle-aged populations. It is unclear whether associations between single nucleotide polymorphisms (SNPs) and obesity persist in old age. We ...aimed to relate 10 body mass index (BMI)-associated SNPs to weight, BMI, % fat, visceral and subcutaneous adipose tissue in Health ABC and AGES-Reykjavik comprising 4,846 individuals of European Ancestry, and 1,139 African Americans over age 65. SNPs were scaled using effect estimates from candidate SNPs. In Health ABC, a SNP near GNPDA2 was modestly associated with weight and SAT area (p = .008, p = .001). Risk score (sum of scaled SNPs) was associated with weight, BMI, and SAT area (p < .0001 for all), but neither GNPDA2 nor risk score was associated with weight, BMI, visceral adippose tissue, subcutaneous adipose tissue, or % fat in AGES-Reykjavik. In African Americans, a SNP near SEC16B was weakly associated with weight (p = .04). In this sample of older adults, no BMI-associated SNPs were associated with weight or adiposity.
Individual-specific percent European ancestry was assessed in 1,277 African Americans. We found significant correlations between proportion of European ancestry and several musculoskeletal traits, ...indicating that admixture mapping may be a useful strategy for locating genes affecting these traits.
Genotype data for admixed populations can be used to detect chromosomal regions influencing disease risk if allele frequencies at disease-related loci differ between parental populations. We assessed evidence for differentially distributed alleles affecting bone and body composition traits in African Americans.
Bone mineral density (BMD) and body composition data were collected for 1,277 African and 1,790 European Americans (aged 70-79). Maximum likelihood methods were used to estimate individual-specific percent European ancestry for African Americans genotyped at 37 ancestry-informative genetic markers. Partial correlations between body composition traits and percent European ancestry were calculated while simultaneously adjusting for the effects of covariates.
Percent European ancestry (median = 18.7%) in African Americans was correlated with femoral neck BMD in women (r = -0.18, p < 10(-5)) and trabecular spine BMD in both sexes (r = -0.18, p < 10(-5)) independently of body size, fat, lean mass, and other covariates. Significant associations of European ancestry with appendicular lean mass (r = -0.19, p < 10(-10)), total lean mass (r = -0.12, p < 10(-4)), and total body fat (r = 0.09, p < 0.002) were also observed for both sexes.
These results indicate that some population differences in body composition may be due to population-specific allele frequencies, suggesting the utility of admixture mapping for identifying susceptibility genes for osteoporosis, sarcopenia, and obesity.
Although the beneficial effects of estrogen use on cardiovascular and cognitive function in postmenopausal women have been recently discredited, controversy remains regarding its usefulness for ...maintaining skeletal muscle mass or strength. Therefore, the purpose of this study was to determine whether estrogen use is associated with enhanced muscle composition and, if so, whether this translates into improved strength and physical function.
Cross-sectional analysis of 840 well-functioning community-dwelling white women (current estrogen replacement therapy (ERT) users = 259, nonusers = 581) aged 70-79 yr participating in the Health, Aging and Body Composition Study. Muscle composition of the midthigh by computed tomography included cross-sectional area (CSA) of the quadriceps, hamstrings, intermuscular fat and subcutaneous fat, and muscle attenuation in Hounsfield units (HU) as a measure of muscle density. Isometric hand grip and isokinetic knee extensor strength were assessed by dynamometry. Physical function was assessed using a summary scale that included usual 6-m walk and narrow walk speed, repeated chair stands, and standing balance.
In analyses of covariance adjusted for relevant confounders, quadriceps muscle CSA and HU were greater in current ERT than non-ERT women (P < 0.05). Grip strength was also greater (P < 0.05) in women taking ERT while knee extensor strength approached significance (P < 0.10). However, differences in muscle composition and strength were modest at < or =3.3%. There was no difference by ERT status for the hamstring muscles, fat CSA, or for physical function.
The associations between ERT and muscle composition and strength were minor and did not translate into improved physical function. Initiation of ERT for preservation of muscle composition and function may not be indicated.
To examine potential for bias in reported total energy intake on a Food Frequency Questionnaire (FFQ) among older adults.
Longitudinal cohort study.
2,706 Community-dwelling Black and White older ...adults, aged 70-79 years, enrolled in the Health, Aging, and Body Composition study. Multivariate logistic regression analyses were conducted with potential errors on reported total energy intake on the Food Frequency Questionnaire (FFQ) as the outcome variable and with cognitive ability, measured by the Modified Mini Mental State Exam (3MS) as the primary independent variable. The regression model controlled for site, race, gender, age, body size, and physical activity. Separate models were fit using 3MS as a continuous variable and for multiple 3MS cutpoints. All models revealed similar findings.
Cognitive ability was inversely associated with potential errors in reporting total energy intake, whereby a five-point increase in 3MS scores was associated with a 14% decreased likelihood of reporting errors (Odds Ratio=0.86, 95% Confidence Interval: 0.77, 0.95). Additionally, compared to White women, White men were 2 times more likely, and Black women and Black men were 3 times more likely, to have errors in reporting total energy intake.
This study provides evidence that for older adults, lower cognition scores are associated with increased potential errors in reporting total energy intake.
Dietary reporting from older adults may be inaccurate due to cognitive deficits. A brief assessment of cognitive function may assist clinicians in dietary evaluations and recommendation and may benefit studies using FFQ data where the measure of cognitive function could be utilized to stratify data analyses and conduct sensitivity analyses.
Studies suggest that physically active people have reduced risk of incident cognitive impairment in late life. However, these studies are limited by reliance on self-reports of physical activity, ...which only moderately correlate with objective measures and often exclude activity not readily quantifiable by frequency and duration. The objective of this study was to investigate the relationship between activity energy expenditure (AEE), an objective measure of total activity, and incidence of cognitive impairment.
We calculated AEE as 90% of total energy expenditure (assessed during 2 weeks using doubly labeled water) minus resting metabolic rate (measured using indirect calorimetry) in 197 men and women (mean age, 74.8 years) who were free of mobility and cognitive impairments at study baseline (1998-1999). Cognitive function was assessed at baseline and 2 or 5 years later using the Modified Mini-Mental State Examination. Cognitive impairment was defined as a decline of at least 1.0 SD (9 points) between baseline and follow-up evaluations.
After adjustment for baseline Modified Mini-Mental State Examination scores, demographics, fat-free mass, sleep duration, self-reported health, and diabetes mellitus, older adults in the highest sex-specific tertile of AEE had lower odds of incident cognitive impairment than those in the lowest tertile (odds ratio, 0.09; 95% confidence interval, 0.01-0.79). There was also a significant dose response between AEE and incidence of cognitive impairment (P = .05 for trend over tertiles).
These findings indicate that greater AEE may be protective against cognitive impairment in a dose-response manner. The significance of overall activity in contrast to vigorous or light activity should be determined.
Low 25-hydroxyvitamin D (25(OH)D) concentrations are common among older adults and are associated with poorer physical performance and strength, but results from longitudinal studies have been ...inconsistent. The 25(OH)D threshold for physical performance and strength was determined, and both cross-sectional and longitudinal associations between 25(OH)D and physical performance and strength were examined, in men and women aged 71-80 years from the Health, Aging, and Body Composition Study (n = 2,641). Baseline serum 25(OH)D was measured in 1998-1999, and physical performance and strength were measured at baseline and at 2- and 4-year follow-up. Piecewise regression models were used to determine 25(OH)D thresholds. Linear regression and mixed models were used to examine cross-sectional and longitudinal associations. The 25(OH)D thresholds were 70-80 nmol/L for physical performance and 55-70 nmol/L for strength. Participants with 25(OH)D <50 nmol/L had poorer physical performance at baseline and at 2- and 4-year follow-up than participants with 25(OH)D ≥75 nmol/L (P < 0.01). Although physical performance and strength declined over 4 years of follow-up (P < 0.0001), in general, the rate of decline was not associated with baseline 25(OH)D. Older adults with low 25(OH)D concentrations had poorer physical performance over 4 years of follow-up, but low 25(OH)D concentrations were not associated with a faster rate of decline in physical performance or strength.
The inflammation of aging hypothesis purports that aging is the accumulation of damage, which results, in part, from chronic activation of inflammation process. We tested this hypothesis in ...relationship to fractures in 2985 men and women enrolled in the Health ABC study. Results showed that subjects with the greatest number of inflammatory markers have the highest risk of fracture.
Introduction: Cytokines play major roles in regulating bone remodeling in the bone microenvironment, but their relationship to fractures is uncertain.
Materials and Methods: The study population includes 2985 well‐functioning white and black women and men (42%, black; 51%, women) 70–79 yr of age enrolled in the Health Aging and Body Composition Study. Inflammatory markers were measured in frozen serum using standardized assays. We measured interleukin (IL‐6), TNFα, C‐reactive protein (CRP), and soluble receptors (IL‐2 sR, IL‐6 sR, TNF sR1and TNF sR2).Cytokine‐soluble receptors were measured in a subset (n = 1430). Total hip BMD was measured by DXA. During 5.8 ± 1.6 yr of 95% complete follow‐up, incident fractures were confirmed in 268 subjects. The risk of fracture was compared among subjects with the highest inflammatory markers (quartile 4) versus lower levels (quartiles 1, 2, and 3) using proportional hazard models.
Results and Conclusions: Subjects who fractured were more likely to be white and female. Baseline markers of inflammation were higher among subjects who subsequently experienced an incident fracture. In multivariate models, the relative risk of fracture (95% CIs) for subjects with the highest inflammatory markers (quartile 4) compared with those with lower inflammatory markers (quartiles 1, 2, and 3) was 1.34 (0.99, 1.82) for CRP; 1.28 (0.95–1.74) for IL‐6; 1.28 (0.97–1.70) for TNFα; 1.52 (1.04–2.21) for IL‐2 sR; 1.33 (0.90–1.96) for IL‐6 sR; 1.73 (1.18–2.55) for TNF sR1 and 1.48 (1.01–2.20) for TNF sR2. In subjects with three or more (out of seven) high inflammatory markers, the relative risk of fracture was 2.65 (1.44–4.89) in comparison with subjects with no elevated markers. (p trend = 0.001). We conclude that elevated inflammatory markers are prognostic for fractures, extending the inflammation hypothesis of aging to osteoporotic fractures.
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