Search

ObjectiveThe objective of the study is was investigate the association between hearing impairment and anxiety.MethodWe conducted a cross-sectional analysis of 1,732 community-based adults aged 76 to 85 years who participated in the Health Aging and Body Composition (ABC) study. Logistic regression models were adjusted for demographic and cardiovascular risk factors. Hearing impairment was defined by the speech-frequency pure tone average. Anxiety was defined as reporting two symptoms of at least "a little" or one symptom "quite a bit" on the three-item Hopkins Symptom Checklist.ResultsCompared with individuals with no hearing impairment, the odds of prevalent anxiety were higher among individuals with mild hearing impairment (odds ratio [OR] = 1.32, 95% confidence interval [CI] = [1.01, 1.73]) and moderate or greater hearing impairment (OR = 1.59, 95% CI = [1.14, 2.22]). Hearing aid use was not significantly associated with lower odds of anxiety.DiscussionHearing impairment is independently associated with greater odds of anxiety symptoms in older adults.

ImportanceDepression has been identified as a risk factor for dementia. However, most studies have measured depressive symptoms at only one time point, and older adults may show different patterns of depressive symptoms over time.ObjectiveTo investigate the association between trajectories of depressive symptoms and risk of dementia in older adults.Design, setting, and participantsThis was a prospective cohort investigation of black and white community-dwelling older adults in the Health, Aging, and Body Composition study. Participants were enrolled between May 1997 and June 1998 and followed up through 2001-2002. The dates of this analysis were September 2014 to December 2015. The setting was community research centers in Memphis, Tennessee, and Pittsburgh, Pennsylvania. Trajectories of depressive symptoms were assessed from baseline to year 5. Symptoms were measured with the Center for Epidemiologic Studies Depression Scale Short Form, and trajectories were calculated using latent class growth curve analysis.Main outcomes and measuresIncident dementia through year 11, determined by dementia medication use, hospital records, or significant cognitive decline (≥1.5 SD race-specific decline on the Modified Mini-Mental State Examination). We examined the association between depressive symptom trajectories and dementia incidence using Cox proportional hazards regression models adjusted for demographics, health factors that differed between groups, and cognition during the depressive symptom assessment period (baseline to year 5).ResultsThe analytic cohort included 2488 black and white older adults with repeated depressive symptom assessments from baseline to year 5 who were free of dementia throughout that period. Their mean (SD) age at baseline was 74.0 (2.8) years, and 53.1% (n = 1322) were female. The following 3 depressive symptom trajectories were identified: consistently minimal symptoms (62.0% [n = 1542] of participants), moderate and increasing symptoms (32.2% [n = 801] of participants), and high and increasing symptoms (5.8% [n = 145] of participants). Compared with the consistently minimal trajectory, having a high and increasing depressive symptom trajectory was associated with significantly increased risk of dementia (fully adjusted hazard ratio, 1.94; 95% CI, 1.30-2.90), while the moderate and increasing trajectory was not associated with risk of dementia after full adjustment. Sensitivity analyses indicated that the high and increasing trajectory was associated with dementia incidence, while depressive symptoms at individual time points were not.Conclusions and relevanceOlder adults with a longitudinal pattern of high and increasing depressive symptoms are at high risk for dementia. Individuals' trajectory of depressive symptoms may inform dementia risk more accurately than one-time assessment of depressive symptoms.

ObjectivesTo better understand the potential impact of hearing impairment (HI) and hearing aid use on emotional vitality and mental health in older adults.MethodWe investigated the cross-sectional association of HI with emotional vitality in 1,903 adults aged 76-85 years in the Health ABC study adjusted for demographic and cardiovascular risk factors. Hearing was defined by the speech frequency pure tone average (no impairment < 25 dB, mild impairment 25-40 dB, and moderate or greater impairment > 40 dB). Emotional vitality was defined as having a high sense of personal mastery, happiness, low depressive symptomatology, and low anxiety.ResultsCompared with individuals with no HI, participants with moderate or greater HI had a 23% lower odds of emotional vitality (odds ratio [OR] = 0.77; 95% confidence interval [CI]: 0.59-0.99). Hearing aid use was not associated with better emotional vitality (OR = 0.98; 95% CI: 0.81-1.20).DiscussionHI is associated with lower odds of emotional vitality in older adults. Further studies are needed to examine the longitudinal impact of HI on mental health and well-being.

BackgroundDepression and disability are closely linked. Less is known regarding clinical and subclinical depressive symptoms over time and risk of disability and mortality.MethodsResponses to the Center for Epidemiologic Studies Short Depression scale (CES-D10) were assessed over a 4-year period in men (n = 1032) and women (n = 1070) aged 70-79 years initially free from disability. Depressive symptom trajectories were defined with group-based models. Disability (2 consecutive reports of severe difficulty walking one-quarter mile or climbing 10 steps) and mortality were determined for 9 subsequent years. Hazard ratios (HRs) were estimated using Cox proportional hazards adjusted for covariates.ResultsThree trajectories were identified: persistently nondepressed (54% of men, 54% of women, mean baseline CES-D10: 1.16 and 1.46), mildly depressed and increasing (40% of men, 38% of women, mean baseline CES-D10: 3.60 and 4.35), and depressed and increasing (6% of men, 8% of women, mean baseline CES-D10: 7.44 and 9.61). Disability and mortality rates per 1,000 person years were 41.4 and 60.3 in men and 45.8 and 41.9 in women. Relative to nondepressed, men in the mildly depressed (HR = 1.45, 95% confidence interval [CI] 1.11-1.89) and depressed trajectories (HR = 2.12, 95% CI 1.33-3.38) had increased disability; women in the depressed trajectory had increased disability (HR = 2.02, 95% CI 1.37-2.96). Men in the mildly depressed (HR = 1.24, 95% CI 1.01-1.52) and depressed trajectories (HR = 1.63, 95% CI 1.10-2.41) had elevated mortality risk; women exhibited no mortality risk.ConclusionsTrajectories of depressive symptoms without recovery may predict disability and mortality in apparently healthy older populations, thus underscoring the importance of monitoring depressive symptoms in geriatric care.

BackgroundCross-sectional studies suggest that low 25-hydroxyvitamin D (25[OH]D) may be a risk factor for depression; however, there are few prospective studies. We examined the association between 25(OH)D and depressive symptoms in community-dwelling persons aged 70-79 years in the Health, Aging, and Body Composition (Health ABC) Study (n = 2598).MethodsDepressive symptoms were assessed using the Center for Epidemiologic Studies-Depression Scale (CES-D) at baseline and 2-, 3- and 4-year follow-up. Serum 25(OH)D was measured at 1-year follow-up and categorized as

BackgroundLow literacy is common among the elderly and possibly more reflective of educational attainment than years of school completed. We examined the association between literacy and risk of likely dementia in older adults.MethodsParticipants were 2,458 black and white elders (aged 71-82) from the Health, Aging and Body Composition study, who completed the Rapid Estimate of Adult Literacy in Medicine and were followed for 8 years. Participants were free of dementia at baseline; incidence of likely dementia was defined by hospital records, prescription for dementia medication, or decline in Modified Mini-Mental State Examination score. We conducted Cox proportional hazard models to evaluate the association between literacy and incidence of likely dementia. Demographics, education, income, comorbidities, lifestyle variables, and apolipoprotein E (APOE) ε4 status were included in adjusted analyses.ResultsTwenty-three percent of participants had limited literacy (

BACKGROUND Leukocyte telomere length (LTL) is an emerging marker of biological age. Chronic inflammatory activity is commonly proposed as a promoter of biological aging in general, and of leukocyte telomere shortening in particular. In addition, senescent cells with critically short telomeres produce pro-inflammatory factors. However, in spite of the proposed causal links between inflammatory activity and LTL, there is little clinical evidence in support of their covariation and interaction. METHODOLOGY/PRINCIPAL FINDINGS To address this issue, we examined if individuals with high levels of the systemic inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) had increased odds for short LTL. Our sample included 1,962 high-functioning adults who participated in the Health, Aging and Body Composition Study (age range: 70–79 years). Logistic regression analyses indicated that individuals with high levels of either IL-6 or TNF-α had significantly higher odds for short LTL. Furthermore, individuals with high levels of both IL-6 and TNF-α had significantly higher odds for short LTL compared with those who had neither high (OR = 0.52, CI = 0.37–0.72), only IL-6 high (OR = 0.57, CI = 0.39–0.83) or only TNF-α high (OR = 0.67, CI = 0.46–0.99), adjusting for a wide variety of established risk factors and potential confounds. In contrast, CRP was not associated with LTL.BACKGROUND Leukocyte telomere length (LTL) is an emerging marker of biological age. Chronic inflammatory activity is commonly proposed as a promoter of biological aging in general, and of leukocyte telomere shortening in particular. In addition, senescent cells with critically short telomeres produce pro-inflammatory factors. However, in spite of the proposed causal links between inflammatory activity and LTL, there is little clinical evidence in support of their covariation and interaction. METHODOLOGY/PRINCIPAL FINDINGS To address this issue, we examined if individuals with high levels of the systemic inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) had increased odds for short LTL. Our sample included 1,962 high-functioning adults who participated in the Health, Aging and Body Composition Study (age range: 70–79 years). Logistic regression analyses indicated that individuals with high levels of either IL-6 or TNF-α had significantly higher odds for short LTL. Furthermore, individuals with high levels of both IL-6 and TNF-α had significantly higher odds for short LTL compared with those who had neither high (OR = 0.52, CI = 0.37–0.72), only IL-6 high (OR = 0.57, CI = 0.39–0.83) or only TNF-α high (OR = 0.67, CI = 0.46–0.99), adjusting for a wide variety of established risk factors and potential confounds. In contrast, CRP was not associated with LTL. CONCLUSIONS Results suggest that cumulative inflammatory load, as indexed by the combination of high levels of IL-6 and TNF-α, is associated with increased odds for short LTL. In contrast, high levels of CRP were not accompanied by short LTL in this cohort of older adults. These data provide the first large-scale demonstration of links between inflammatory markers and LTL in an older population.

ContextAlendronate sodium reduces fracture risk in postmenopausal women who have vertebral fractures, but its effects on fracture risk have not been studied for women without vertebral fractures.ObjectiveTo test the hypothesis that 4 years of alendronate would decrease the risk of clinical and vertebral fractures in women who have low bone mineral density (BMD) but no vertebral fractures.DesignRandomized, blinded, placebo-controlled trial.SettingEleven community-based clinical research centers.SubjectsWomen aged 54 to 81 years with a femoral neck BMD of 0.68 g/cm2 or less (Hologic Inc, Waltham, Mass) but no vertebral fracture; 4432 were randomized to alendronate or placebo and 4272 (96%) completed outcome measurements at the final visit (an average of 4.2 years later).InterventionAll participants reporting calcium intakes of 1000 mg/d or less received a supplement containing 500 mg of calcium and 250 IU of cholecalciferol. Subjects were randomly assigned to either placebo or 5 mg/d of alendronate sodium for 2 years followed by 10 mg/d for the remainder of the trial.Main outcome measuresClinical fractures confirmed by x-ray reports, new vertebral deformities detected by morphometric measurements on radiographs, and BMD measured by dual x-ray absorptiometry.ResultsAlendronate increased BMD at all sites studied (P2.5 SDs below the normal young adult mean; RH, 0.64; 95% CI, 0.50-0.82; treatment-control difference, 6.5%; number needed to treat [NNT], 15), but there was no significant reduction among those with higher BMD (RH, 1.08; 95% CI, 0.87-1.35). Alendronate decreased the risk of radiographic vertebral fractures by 44% overall (relative risk, 0.56; 95% CI, 0.39-0.80; treatment-control difference, 1.7%; NNT, 60). Alendronate did not increase the risk of gastrointestinal or other adverse effects.ConclusionsIn women with low BMD but without vertebral fractures, 4 years of alendronate safely increased BMD and decreased the risk of first vertebral deformity. Alendronate significantly reduced the risk of clinical fractures among women with osteoporosis but not among women with higher BMD.

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-[alpha]), 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-[alpha] 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-[alpha] and its soluble receptors were associated with 5-year decline in thigh muscle area and that higher levels of TNF-[alpha] were associated with decline in grip strength. Conclusions. TNF-[alpha] 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. Key Words: Muscle--Inflammatory markers--Aging--Weight. doi: 10.1093/gerona/glp097

Background. Reported fatigue has been identified as a component of frailty. The contribution of nighttime sleep quality (duration and complaints) to fatigue symptoms in community-dwelling older adults has not been evaluated. Methods. We studied 2264 men and women, aged 75-84 years (mean 77.5 years; standard deviation [SD] 2.9), participating in the Year 5 (2001-2002) clinic visit of the Health, Aging, and Body Composition (Health ABC) study. Fatigue was determined using a subscale of the Modified Piper Fatigue Scale (0-50; higher score indicating higher fatigue). Hours of sleep per night, trouble falling asleep, waking up during the night, and waking up too early in the morning were assessed using interviewer-administered questionnaires. Results. The average fatigue score was 17.7 (SD 8.4). In multivariate models, women had a 3.8% higher fatigue score than men did. Individuals who slept [less than or equal to] 6 hours/night had a 4.3% higher fatigue score than did those who slept 7 hours/ night. Individuals with complaints of awakening too early in the morning had a 5.5% higher fatigue score than did those without these complaints. These associations remained significant after multivariate adjustment for multiple medical conditions. Conclusion. The association between serf-reported short sleep duration ([less than or equal to] 6 hours), and waking up too early and fatigue symptoms suggests that better and more effective management of sleep behaviors may help reduce fatigue in older adults. Key Words: Sleep--Fatigue--Aging.

Background. Emerging evidence indicates an association between cognitive function and physical performance in late life. This study examines the relationship between cognitive function and subsequent gait speed decline among high-functioning older adults. Methods. Measures of global cognitive function (Modified Mini Mental State Examination [3MS]) and executive control function (ECF) (a clock drawing task [CLOX 1 ] and the 15-item Executive Interview [EXIT 15]) were obtained in the Health, Aging, and Body Composition Study in 1999-2000. Gait-speed (meters/second) was assessed over 20 meters at usual pace. Using a mixed model, we assessed the relationship between baseline cognitive function and gait-speed change over 3 years. Results. Two thousand, three hundred forty-nine older adults (mean age 75.6 [+ or -] 2.9 years) completed the assessments. After adjustment for baseline gait speed, a 1-standard-deviation (SD) lower performance on each cognitive test was associated with greater gait-speed decline over 3 years: 0.016 m/s for the 3MS (SD = 8.1), 0.009 m/s for CLOX 1 (SD = 2.4), and 0.012 m/s for EXIT 15 (SD = 4.1) (p < .0005 for all). After adjustment for comorbidities, the effect size was attenuated for 3MS and CLOX 1, and the association for EXIT 15 was no longer significant. Depression score was most strongly associated with the EXIT 15 effect reduction. Conclusion. Global and executive cognitive functions predict declines in gait speed. The association of ECF with gait speed decline is attenuated by comorbid conditions, particularly depression. Elucidation of the mechanisms underlying these associations may point to new pathways for the treatment of physical decline associated with diminished cognitive function.

Background. Psychosocial factors have been associated with metabolic abnormalities that increase the risk of cardiovascular disease and diabetes. This study investigated the cross-sectional relationship between psychosocial risk factors and the metabolic syndrome in a community-based sample of older persons. Methods. Participants were 2917 persons aged 70-79 years enrolled in the Health, Aging and Body Composition study. Depressive and anxiety symptoms, negative life events, and inadequate emotional support were assessed, and a summary psychosocial risk index was calculated. Metabolic syndrome was defined as three or more of the following criteria: abdominal obesity, high triglycerides, low high-density lipoprotein (HDL) cholesterol, high fasting glucose, and high blood pressure. Results. Negative life events and inadequate emotional support increased the odds of having metabolic syndrome after adjustment for demographic and lifestyle variables (odds ratio [OR] per life event = 1.13, 95% confidence interval [CI] = 1.05-1.22; OR = 1.35, 95% CI = 1.10-1.66, respectively). The relationship between depressive symptoms and metabolic syndrome was only found in white (OR per standard deviation [SD] = 1.11, 95% CI = 1.01-1.23), but not in black (OR per SD = 0.97, 95% CI = 0.86-1.11) persons. Anxiety symptoms were significantly associated with metabolic syndrome in men (OR per SD = 1.13, 95% CI = 1.00-1.28), but not in women (OR per SD = 0.98, 95% CI = 0.89-1.08). Moreover, a higher score on the psychosocial risk index was associated with an increased probability of having the metabolic syndrome (OR = 1.30, 95% CI = 1.12-1.52). Conclusions. In the elderly population, different psychosocial risk factors are associated with a higher prevalence of the metabolic syndrome. Whether reduction or better management of psychosocial risk factors can improve the metabolic profile remains to be demonstrated.

Background. This study examines the association between socioeconomic status (SES) and inflammatory markers in well-functioning older adults and seeks to determine whether any association remains after adjusting for biomedical and behavioral factors typically related to elevated serum levels of inflammatory markers. Methods. Data were obtained from 3044 men and women, aged 70-79 from Pittsburgh, Pennsylvania and Memphis, Tennessee participating in the Health, Aging and Body Composition study. Three indicators of SES were used: education, income, and ownership of financial assets. Serum levels of interleukin-6, C-reactive protein, and tumor necrosis factor-[alpha] were measured. Results. Low SES was associated with significantly elevated levels of interleukin-6, C-reactive protein, and tumor necrosis factor-[alpha] compared to high SES. Behavioral factors (including smoking, drinking, obesity) explained a substantial part of the inverse association between SES and inflammatory markers. Adjustment for prevalent diseases (including heart diseases, lung disease, and diabetes) associated with inflammation explained less of the association. Conclusions. This study suggests that interventions to improve health behaviors, even in old age and especially in low SES groups, may be useful in reducing risks associated with inflammation.

Methods. Total mortality rates were examined in the Health, Aging and Body Composition (Health ABC) Study in 2292 participants (aged 70-79 years, 51.6% women, and 38.8% black). Knee extension strength was measured with isokinetic dynamometry, grip strength with isometric dynamometry. Thigh muscle area was measured by computed tomography (CT) scan, and leg and arm lean soft tissue mass were determined by dual energy x-ray absorptiometry (DXA). Both strength and muscle size were assessed as in gender-specific Cox proportional hazards models, with age, race, comorbidities, smoking status, level of physical activity, fat area by CT or fat mass by DXA, height, and markers of inflammation, including interleukin-6, C-reactive protein, and tumor necrosis factor-[alpha] considered as potential confounders. Results. There were 286 deaths over an average of 4.9 (standard deviation = 0.9) years of follow-up. Both quadriceps and grip strength were strongly related to mortality. For quadriceps strength (per standard deviation of 38 Nm), the crude hazard ratio for men was 1.51 (95% confidence interval, 1.28-1.79) and 1.65 (95% confidence interval, 1.19-2.30) for women. Muscle size, determined by either CT area or DXA regional lean mass, was not strongly related to mortality. In the models of quadriceps strength and mortality, adjustment for muscle area or regional lean mass only slightly attenuated the associations. Further adjustment for other factors also had minimal effect on the association of quadriceps strength with mortality. Associations of grip strength with mortality were similar. Conclusion. Low muscle mass did not explain the strong association of strength with mortality, demonstrating that muscle strength as a marker of muscle quality is more important than quantity in estimating mortality risk. Grip strength provided risk estimates similar to those of quadriceps strength.

A study is conducted to determine whether the angiotensin-converting enzyme (ACE) genotype interacts with significant physical activity to affect the incidence of mobility limitation in well-functioning older adults. The findings indicate that older individuals who exercised with ACE are less likely to develop mobility limitation than those who did not exercise.

Background. Obesity increases the risk for functional decline in later years, but the functional consequences of weight change in older adults are currently unclear. The aim of this study was to determine whether weight, weight change, and weight change intention are associated with risk for mobility limitation in elderly persons. Methods. This study included 2932 well-functioning black and white men and women aged 70 to 79 years, participating in the Health. Aging and Body Composition (Health ABC) Study, who were followed for 30 months. At baseline, reported weight change of 5 or more pounds during the previous year and weight change intention were assessed. Mobility limitation was defined as reported difficulty or inability to walk one-quarter mile or to climb 10 steps during two conservative semi-annual assessments during a period of 30 months. Results. Approximately 30% of participants developed mobility limitation. Higher body mass index (BMI) was associated with increased risk for mobility limitation. Unintentional weight loss in the previous year was associated with increased risk for mobility limitation in the extremely obese, which was defined as BMI [greater than or equal to] 35 (hazard ratios |HR| = 3-79; 95% confidence interval |CI|, 1.84-7.79), and the normal BMI, which was defined as BMI < 25 (HR, 2.55: 95% CI, 1.803.60). In persons with BM125 to 29.9, intentional weight loss (HR, 1.59; 95% CI, 1.12-2.25) and weight fluctuation with any intention (HR, 1.59: 95% CI, 1.10-2.28) increased the risk for mobility limitation. Unintentional weight gain or fluctuation did not confer additional risk for mobility Iimitation compared with weight stability, regardless of the level of body weight. Conclusion. In this cohort of well-functioning elderly persons, functional consequences of past weight change depended on the type of weight change, intentionality, and current measured body weight.

Background. The association between low socioeconomic status and poor physical functioning has been well described; biomedical factors may play an important role in explaining these differences. This study examines the association between socioeconomic status and incident mobility limitation in well-functioning older adults, and seeks to determine whether this link could be explained by biomedical factors. Methods. Data were obtained from 3066 men and women, aged 70-79 years from Pittsburgh, Pennsylvania and Memphis, Tennessee participating in the Health; Aging and Body Composition (Health ABC) study. Three indicators of socioeconomic status were used: education, income, and ownership of financial assets. Mobility limitation was defined as reporting difficulty walking 1/4 mile or climbing 10 steps during two consecutive semiannual assessments over 4.5 years. Biomedical factors included a wide range of diseases (e.g., heart and cerebrovascular disease) and biological risk factors (e.g. hypertension, poor pulmonary function, and high serum levels of inflammatory markers). Results. Adjusted hazard ratios of incident mobility limitation were significantly higher in those persons with low education, low income, and few assets. Hazard ratios ranged from 1.66 to 2.80 in the lowest socioeconomic groups. Additional adjustment for biomedical factors reduced the hazard ratios by an average of 41% for education, 17% for income, and 29% for assets. Conclusion. Biomedical factors can account for some of the association between socioeconomic status and incident mobility limitation. However, to reduce physical disabilities and, in particular, the socioeconomic differences therein, it may not be sufficient to solely intervene upon biological risk factors and risks of diseases.

Background. Lower muscle mass has been correlated with poor physical function; however, no studies have examined this relationship prospectively. This study aims to investigate whether low muscle mass, low muscle strength, and greater fat infiltration into the muscle predict incident mobility limitation. Methods. Our study cohort included 3075 well functioning black and white men and women aged 70-79 years participating in the Health, Aging, and Body Composition study. Participants were followed for 2.5 years. Muscle cross-sectional area and muscle tissue attenuation (a measure of fat infiltration) were measured by computed tomography at the mid-thigh, and knee extensor strength by using a KinCom dynamometer. Incident mobility limitation was defined as two consecutive self-reports of any difficulty walking one-quarter mile or climbing 10 steps. Results: Mobility limitations were developed by 22.3% of the men and by 31.8% of the women. Cox's proportional hazards models, adjusting for demographic, lifestyle, and health factors, showed a hazard ratio of 1.90 [95% confidence interval (CI), 1.27-2.84] in men and 1.68 (95% CI, 1.23-2.31) in women for the lowest compared to the highest quartile of muscle area (p < .01 for trend). Results for muscle strength were 2.02 (95% CI, 1.39-2.94) and 1.91 (95% CI, 1.41-2.58), p < .001 trend, and for muscle attenuation were 1.91 (95% CI, 1.31-2.83) and 1.68 (95% CI, 1.20-2.35), p < .01 for trend. When included in one model, only muscle attenuation and muscle strength independently predicted mobility limitation (p < .05). Among men and women, associations were similar for blacks and whites. Conclusion. Lower muscle mass (smaller cross-sectional thigh muscle area), greater fat infiltration into the muscle, and lower knee extensor muscle strength are associated with increased risk of mobility loss in older men and women. The association between low muscle mass and functional decline seems to be a function of underlying muscle strength.