Serum IL-6 level and the development of disability in older persons.

BACKGROUND: The serum concentration of interleukin 6 (IL-6), a cytokine that plays a central role in inflammation, increases with age. Because inflammation is a component of many age-associated chronic diseases, which often cause disability, high circulating levels of IL-6 may contribute to functional decline in old age. We tested the hypothesis that high levels of IL-6 predict future disability in older persons who are not disabled. METHODS: Participants at the sixth annual follow-up of the Iowa site of the Established Populations for Epidemiologic Studies of the Elderly aged 71 years or older were considered eligible for this study if they had no disability in regard to mobility or in selected activities of daily living (ADL), and they were re-interviewed 4 years later. Incident cases of mobility-disability and of ADL-disability were identified based on responses at the follow-up interview. Measures of IL-6 were obtained from specimens collected at baseline from the 283 participants who developed any disability and from 350 participants selected randomly (46.9%) from those who continued to be non-disabled. FINDINGS: Participants in the highest IL-6 tertile were 1.76 (95% CI, 1.17-2.64) times more likely to develop at least mobility-disability and 1.62 (95% CI, 1.02-2.60) times more likely to develop mobility plus ADL-disability compared with to the lowest IL-6 tertile. The strength of this association was almost unchanged after adjusting for multiple confounders. The increased risk of mobility-disability over the full spectrum of IL-6 concentration was nonlinear, with the risk rising rapidly beyond plasma levels of 2.5 pg/mL. INTERPRETATION: Higher circulating levels of IL-6 predict disability onset in older persons. This may be attributable to a direct effect of IL-6 on muscle atrophy and/or to the pathophysiologic role played by IL-6 in specific diseases.     

Heterogeneity in rate of decline in grip, hip, and knee strength and the risk of all-cause mortality: the Women's Health and Aging Study II

OBJECTIVES: To assess the relationship between rate of change in muscle strength and all‐cause mortality. DESIGN: Prospective observational study of the causes and course of physical disability. SETTING: Twelve contiguous ZIP code areas in Baltimore, Maryland. PARTICIPANTS: Three hundred seven community‐dwelling women aged 70 to 79 at study baseline. MEASUREMENTS: The outcome was all‐cause mortality (1994–2009); predictors included up to seven repeated measurements of handgrip, knee extension, and hip flexion strength, with a median follow‐up time of 10 years. Demographic factors, body mass index, smoking status, number of chronic diseases, depressive symptoms, physical activity, interleukin‐6, and albumin were assessed at baseline and included as confounders. The associations between declining muscle strength and mortality were assessed using a joint longitudinal and survival model. RESULTS: Grip and hip strength declined an average of 1.10 and 1.31 kg/year between age 70 and 75 and 0.50 and 0.39 kg/year thereafter, respectively; knee strength declined at a constant rate of 0.57 kg/year. Faster rates of decline in grip and hip strength, but not knee strength, independently predicted mortality after accounting for baseline levels and potential confounders (hazard ratio (HR)=1.33, 95% confidence interval (95% CI)=1.06–1.67, HR=1.14, 95% CI=0.91–1.41, and 2.62, 95% CI=1.43–4.78 for every 0.5 standard deviation increase in rate of decline in grip, knee, and hip strength, respectively). CONCLUSION: Monitoring the rate of decline in grip and hip flexion strength in addition to absolute levels may greatly improve the identification of women most at risk of dying.     

The protective effect of emotional vitality on adverse health outcomes in disabled older women

OBJECTIVE: Although the adverse physical health consequences of negative emotions have been studied extensively, much less is known about the potential impact of positive emotions. This study examines whether emotional vitality protects against progression of disability and mortality in disabled older women. DESIGN: A community-based study, The Women's Health and Aging Study. PARTICIPANTS: A total of 1002 moderately to severely disabled women aged 65 years and older living in the community. MEASUREMENTS: Emotional vitality was defined as having a high sense of personal mastery, being happy, and having low depressive symptomatology and anxiety. The onset of new disability was determined by semiannual assessments of disability in performing activities of daily living (ADLs), walking across a room, walking 1/4 mile, and lifting/carrying 10 pounds. Mortality status was determined by proxy interviews and linkage with death certificates. Survival analyses with time to onset of specific disabilities (among those not disabled at baseline) and time to mortality were performed and adjusted for age, baseline level of difficulty, physical performance, and chronic conditions. RESULTS: Three hundred fifty-one of the 1002 older disabled women studied were emotionally vital. Among women without the specific disability at baseline, emotional vitality was associated with a significantly decreased risk for incident disability performing ADLs (RR = 0.81, 95% CI = 0.66-0.99), for incident disability walking one-quarter mile (RR = 0.73, 95% CI = 0.59-0.92), and for incident disability lifting/carrying 10 pounds (RR = 0.77, 95% CI = 0.63-0.95). Emotional vitality was also associated with a lower risk of dying (RR = 0.56, 95% CI = 0.39-0.80). These results were not simply caused by the absence of depression since protective health effects remained when emotionally vital women were compared with 334 women who were not emotionally vital and not depressed. CONCLUSIONS: Emotional vitality in older disabled women reduces the risk for subsequent new disability and mortality. Our findings suggest that positive emotions can protect older persons against adverse health outcomes.     

Coimpairments as predictors of severe walking disability in older women

OBJECTIVE: Severe disabilities are common among older people who have impairments in a range of physiologic systems. It is not known, however, whether the presence of multiple impairments, or coimpairments, is associated with increased risk of developing new disability. The aim of this study was to determine the combined effects of two impairments, decreased knee-extension strength and poor standing balance, on the risk of developing severe walking disability among older, moderately-to-severely disabled women who did not have severe walking disability at baseline. DESIGN: The Women's Health and Aging Study is a 3-year prospective study with 6 semi-annual follow-up data-collection rounds following the baseline. SETTING: At baseline, knee-extension strength and standing balance tests took place in the participants' homes. PARTICIPANTS: 758 women who were not severely walking disabled at baseline. MEASUREMENTS: Severe walking disability was defined as customary walking speed of < 0.4 meters/second and inability to walk one quarter of a mile, or being unable to walk. RESULTS: Over the course of the study, 173 women became severely disabled in walking. The cumulative incidence of severe walking disability from the first to the sixth follow-up was: 7.8%, 12.0%, 15.1% 19.5% 21.2%, and 22.8%. In Cox proportional hazards models, both strength and balance were significant predictors of new walking disability. In the best balance category, the rates of developing severe walking disability expressed per 100 person years were 3.1, 6.1, and 5.3 in the highest- to lowest-strength tertiles. In the middle balance category, the rates were 9.6, 13.2, and 14.7, and in the poorest balance category 21.6, 12.7, and 37.1, correspondingly. The relative risk (RR) of onset of severe walking disability adjusted for age, height, weight, and race was more than five times greater in the group with poorest balance and strength (RR 5.12, 95% confidence limit [95% CI] 2.68-9.80) compared with the group with best balance and strength (the reference group). Among those who had poorest balance and best strength, the RR of severe walking disability was 3.08 (95% CI 1.33-7.14). Among those with best balance and poorest strength, the RR was 0.97 (95% CI 0.49-1.93), as compared with the reference group. CONCLUSION: The presence of coimpairments is a powerful predictor of new, severe walking disability, an underlying cause of dependence in older people. Substantial reduction in the risk of walking disability could be achieved even if interventions were successful in correcting only one of the impairments because a deficit in only one physiologic system may be compensated for by good capacity in another system.     

High-density lipoprotein cholesterol and objective measures of lower extremity performance in older nondisabled persons: the InChianti study

OBJECTIVES: To evaluate the independent association between high-density lipoprotein cholesterol (HDL-C) levels and objective measures of lower extremity performance.
DESIGN: Cross-sectional cohort study.
SETTING: Community-based.
PARTICIPANTS: Eight hundred thirty-six nondisabled women and men aged 65 and older enrolled in the Invecchiare in Chianti study.
MESASUREMENTS: Lower extremity performance was assessed using 4-m walking speed at fast pace, 400-m walking speed, and knee extension torque. Fasting HDL-C levels were determined using commercial enzymatic tests.
RESULTS: The mean age of participants was 73.7 (65–92), and 55.6% were women. After adjusting for potential confounders (sociodemographic factors, smoking, physical activity, body composition, and clinical conditions including cardiovascular and cerebrovascular disease, inflammatory markers, and serum testosterone) HDL-C levels were significantly associated with knee extension torque in men and women and with 4-m and 400-m walking speed in men. Men in the highest tertile of the HDL-C distribution (>55 mg/dL) had, on average, a three times greater probability of belonging to the best tertile of all indexes of lower extremity performance, including 4-m fast walking speed (odds ratio (OR)=2.57, 95%=confidence interval (CI)=1.07–6.17), 400-m walking speed (OR=3.74, 95% CI=1.20–11.7), and knee extension torque (OR=3.63, 95%=CI 1.41–9.33). Path analysis suggested a direct relationship between HDL-C and knee extension torque.
CONCLUSION: In older nondisabled persons, HDL-C levels are highly correlated with knee extension torque and walking speed. Further research should focus on the biological mechanism of this association.     

Low serum vitamin d does not predict new disability or loss of muscle strength in older women

OBJECTIVES: To determine whether serum levels of 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) predict accelerated decline in muscular strength or onset of new disability in mobility and upper extremity functioning over a 3-year follow-up. DESIGN: A community-based prospective cohort study. PARTICIPANTS: Six hundred twenty-eight moderately to severely disabled women aged 65 and older living in the community. MEASUREMENTS: Subjects were divided into three groups of baseline 25(OH)D serum levels (deficiency: <25 nmol/L; low normal: 25-52 nmol/L; high normal: > or =53 nmol/L) and into tertiles of PTH levels. Objective performance measures (hip flexor, knee extensor, and grip strengths; walking speed; and time for repeated chair stands) and disability in activities involving mobility and upper extremity function were assessed at baseline and every 6 months for 3 years. Decline in performance measures and onset of new disability were compared between 25(OH)D and PTH groups using random effects models and proportional hazards models, respectively, while adjusting for age, race, education, body mass index, baseline performance, and chronic conditions. RESULTS: The annual rate of decline over 3 years in muscular strength, walking speed, and time to perform repeated chair stands was similar across 25(OH)D groups. We observed a nonsignificantly faster decline in proximal muscle strength and walking speed with increasing PTH levels. There was no association for either measure between serum levels and the risk of incident disability in activities relating to mobility and upper extremity function. CONCLUSION: This study does not support the hypothesis that vitamin D deficiency is associated with loss in muscular strength and decline in mobility and upper extremity functioning over time in older women who were moderately to severely disabled at baseline.     

Handgrip strength and cause-specific and total mortality in older disabled women: exploring the mechanism

OBJECTIVES: To examine the association between muscle strength and total and cause-specific mortality and the plausible contributing factors to this association, such as presence of diseases commonly underlying mortality, inflammation, nutritional deficiency, physical inactivity, smoking, and depression. DESIGN: Prospective population-based cohort study with mortality surveillance over 5 years. SETTING: Elderly women residing in the eastern half of Baltimore, Maryland, and part of Baltimore County. PARTICIPANTS: Nine hundred nineteen moderately to severely disabled women aged 65 to 101 who participated in handgrip strength testing at baseline as part of the Women's Health and Aging Study. MEASUREMENTS: Cardiovascular disease (CVD), cancer, respiratory disease, other measures (not CVD, respiratory, or cancer), total mortality, handgrip strength, and interleukin-6. RESULTS: Over the 5-year follow-up, 336 deaths occurred: 149 due to CVD, 59 due to cancer, 38 due to respiratory disease, and 90 due to other diseases. The unadjusted relative risk (RR) of CVD mortality was 3.21 (95% confidence interval (CI) = 2.00-5.14) in the lowest and 1.88 (95% CI = 1.11-3.21) in the middle compared with the highest tertile of handgrip strength. The unadjusted RR of respiratory mortality was 2.38 (95% CI = 1.09-5.20) and other mortality 2.59 (95% CI = 1.59-4.20) in the lowest versus the highest grip-strength tertile. Cancer mortality was not associated with grip strength. After adjusting for age, race, body height, and weight, the RR of CVD mortality decreased to 2.17 (95% CI = 1.26-3.73) in the lowest and 1.56 (95% CI = 0.89-2.71) in the middle, with the highest grip-strength tertile as the reference. Further adjustments for multiple diseases, physical inactivity, smoking, interleukin-6, C-reactive protein, serum albumin, unintentional weight loss, and depressive symptoms did not materially change the risk estimates. Similar results were observed for all-cause mortality. CONCLUSION: In older disabled women, handgrip strength was a powerful predictor of cause-specific and total mortality. Presence of chronic diseases commonly underlying death or the mechanisms behind decline in muscle strength in chronic disease, such as inflammation, poor nutritional status, disuse, and depression, all of which are independent predictors of mortality, did not explain the association. Handgrip strength, an indicator of overall muscle strength, may predict mortality through mechanisms other than those leading from disease to muscle impairment. Grip strength tests may help identify patients at increased risk of deterioration of health.     

Carotenoids as protection against disability in older persons

The purpose was to examine the relationship of total plasma carotenoids, an indicator of fruit and vegetable intake, with walking speed and severe walking disability in older adults. Nine hundred twenty-eight men and women aged 65 to 102 years from the Invecchiare in Chianti (Aging in the Chianti Area [InCHIANTI]) study, a population-based cohort in Tuscany, Italy, were studied. Plasma carotenoids were measured at enrollment (1998-2000), and walking speed over 4 meters and 400 meters distance were assessed at enrollment and 6 years later (2004-2006). At enrollment, 85 of 928 (9.2%) participants had severe walking disability (defined as being unable to walk or having a walking speed at the 4-meter walking test < 0.4 m/sec). After adjusting for potential confounders, participants with high total plasma carotenoids were significantly less likely to have prevalent severe walking disability (odds ration [OR] 0.59, 95% confidence interval [CI] 0.38-0.90, p = 0.01) and had higher walking speed over 4 meters (beta = 0.024, standard error [SE] = 0.011, p = 0.03) and over 400 meters (beta = 0.019, SE = 0.010, p = 0.04). Of 621 participants without severe walking disability at enrollment who were seen 6 years later, 68 (11.0%) developed severe walking disability. After adjusting for potential confounders, higher total plasma carotenoids were associated with a significantly lower risk of developing severe walking disability (OR 0.51, 95% CI 0.30-0.86, p = 0.01) and were associated with a less steep decline in 4-meter walking speed over a 6-year follow-up (n = 579; beta = 0.026, SE = 0.012, p = 0.03) and with lower incidence rates of being unable to successfully complete the 400-meter walking test at the 6-year follow-up visit (beta = -0.054, SE = 0.03, p = 0.04). High plasma carotenoids concentrations may be protective against the decline in walking speed and the development of severe walking disability in older adults.     

Low plasma carotenoids and skeletal muscle strength decline over 6 years

BACKGROUND: Higher intake of fruits and vegetables appears to protect against inflammation, poor physical performance, and disability, but its relationship with muscle strength is unclear. We examined the association between total plasma carotenoids, an indicator of fruit and vegetable intake, and changes in muscle strength over a 6-year follow-up in the participants aged 65 years and older in the InCHIANTI study, a population-based study in Tuscany, Italy. METHODS: Plasma carotenoids were measured at enrollment (1998-2000). Hip, knee, and grip strength were measured at enrollment and 6 years later (2004-2006) in 628 of the 948 participants evaluated at baseline. Poor muscle strength was defined as the lowest sex-specific quartile of hip, knee, and grip strength at enrollment. The main outcome was poor muscle strength at the 6-year follow-up visit among those participants originally in the upper three quartiles of strength at enrollment. RESULTS: Overall, 24.9% (110/441), 25.0% (111/444), and 24.9% (118/474) participants developed poor hip, knee, and grip strength, respectively. After adjusting for potential confounders, participants in the lowest versus the highest quartile of total plasma carotenoids at enrollment were at higher risk of developing poor hip (odds ratio [OR] = 3.01, 95% CI, 1.43-6.31, p =.004), knee (OR = 2.89, 95% CI, 1.38-6.02, p =.005), and grip (OR = 1.88, 95% CI, 0.93-3.56, p =.07) muscle strength at the 6-year follow-up visit. CONCLUSION: These findings suggest that older community-dwelling adults with lower plasma carotenoids levels, a marker of poor fruit and vegetable intake, are at a higher risk of decline in skeletal muscle strength over time.     

Women who maintain optimal cognitive function into old age

OBJECTIVES: To determine whether older women who maintain optimal cognitive function into old age differ from those who experience minor cognitive decline typically associated with normal aging. DESIGN: Prospective cohort study. SETTING: The Study of Osteoporotic Fractures. PARTICIPANTS: Nine thousand seven hundred four older women. MEASUREMENTS: A modified Mini-Mental State Examination (mMMSE) was performed at baseline and Years 6, 8, 10, and 15. Random-effects regression was used to classify subjects as cognitive maintainers (slope>/=0), minor decliners (slope < 0 but > lowest tertile), or major decliners (slope 相似文献   

Knee extension strength cutpoints for maintaining mobility

OBJECTIVES: To identify levels of knee extensor strength that are associated with high and low risk of incident severe mobility limitation (SML) in initially well-functioning older adults. DESIGN: Prospective cohort study. SETTING: University clinic center. PARTICIPANTS: One thousand three hundred fifty-five men and 1,429 women (aged 73.6+/-2.85) who reported no mobility limitation. MEASUREMENTS: Unilateral knee extensor isokinetic strength of participants was obtained. Participants were followed over a median of 5.90 years for the onset of SML, defined as two consecutive reports of a lot of difficulty or inability to walk one-quarter of a mile or climb 10 steps. Deciles of knee extension strength relative to body weight were evaluated to identify cutpoints most predictive of incident SML. Cutpoints were then compared with prevalence of having slow gait speed (<1.22 m/s) and mortality. RESULTS: Two sex-specific knee extension strength cutpoints were found. High and low risk of SML corresponded to less than 1.13 newton-meters (Nm)/kg (1st decile) and more than 1.71 Nm/kg (6th decile) in men and less than 1.01 Nm/kg (3rd decile) and more than 1.34 Nm/kg (7th decile) in women, respectively. Moderate risk was defined as being between the low- and high-risk cutpoints. Individuals with knee extension strength in the high- and moderate-risk categories were more likely to have a gait speed less than 1.22 m/s (hazard ratio (HR)=7.00, 95% confidence interval (CI)=5.47-8.96 and HR=2.14 7.00, 95% CI=1.73-2.64, respectively) and had a higher risk of death (HR=1.77, 95% CI=1.41-2.23 and HR=1.51, 95% CI=1.24-1.84, respectively) than individuals in the low-risk category. Adjustment for demographic factors, health behaviors, and medical conditions did not alter these associations. CONCLUSION: Knee extensor strength cutpoints provide objective markers to identify initially well-functioning older adults at high and low risk of future mobility limitation.     

The relationship between interleukin-6 levels and physical performance in mobility-limited older adults with chronic low-grade inflammation: The ENRGISE Pilot study

Previous studies have found an inverse relation between serum concentrations of interleukin (IL)-6 and physical performance in seniors, however this was limited to higher functioning older adults with low to moderate levels of inflammation.We explored the consistency of this association in a cohort of mobility limited older adults with chronic low-grade inflammation. This study included 289 participants (≥ 70 years old) with IL-6 level between 2.5 and 30 pg/mL and a walking speed < 1.0 m/sec from the ENRGISE Pilot study. Physical performance was assessed using the short physical performance battery (SPPB), usual gait speed over 400 m, grip strength, and knee extensor and flexor strength measured by isokinetic dynamometry at 60 and 180°/sec.There was a significant inverse correlation between log IL-6 and knee extensor strength at 60°/sec (r= -0.20, p = 0.002), at 180°/sec (r = -0.14, p = 0.037), and knee flexor strength at 60°/sec (r = -0.15, p = 0.021). After adjustment for potential confounders, the values of knee extensor strength at 60°/sec showed a trend toward a progressive reduction across IL-6 tertiles as IL-6 levels increased (p = 0.024). No significant association was found between IL-6 and other objectively measured physical performance.The findings were generally of smaller magnitude and less consistent than previously reported, which suggests that the associations are attenuated in those with both elevated inflammation and mobility limitations. These results have implications for planning and interpreting future intervention studies in older adults with low-grade inflammation and mobility limitations.     

Vitamin D intake is inversely associated with rheumatoid arthritis: results from the Iowa Women's Health Study

OBJECTIVE: Vitamin D is a potent regulator of calcium homeostasis and may have immunomodulatory effects. The influence of vitamin D on human autoimmune disease has not been well defined. The purpose of this study was to evaluate the association of dietary and supplemental vitamin D intake with rheumatoid arthritis (RA) incidence. METHODS: We analyzed data from a prospective cohort study of 29,368 women of ages 55-69 years without a history of RA at study baseline in 1986. Diet was ascertained using a self-administered, 127-item validated food frequency questionnaire that included supplemental vitamin D use. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazards regression, adjusting for potential confounders. RESULTS: Through 11 years of followup, 152 cases of RA were validated against medical records. Greater intake (highest versus lowest tertile) of vitamin D was inversely associated with risk of RA (RR 0.67, 95% CI 0.44-1.00, P for trend = 0.05). Inverse associations were apparent for both dietary (RR 0.72, 95% CI 0.46-1.14, P for trend = 0.16) and supplemental (RR 0.66, 95% CI 0.43-1.00, P for trend = 0.03) vitamin D. No individual food item high in vitamin D content and/or calcium was strongly associated with RA risk, but a composite measure of milk products was suggestive of an inverse association with risk of RA (RR 0.66, 95% CI 0.42-1.01, P for trend = 0.06). CONCLUSION: Greater intake of vitamin D may be associated with a lower risk of RA in older women, although this finding is hypothesis generating.     

Predictors of Interleukin-6 Elevation in Older Adults

OBJECTIVES: To investigate the characteristics of older adults who develop high interleukin-6 (IL-6) levels at 3-year follow-up.
DESIGN: Population-based study of adults living in Tuscany, Italy.
SETTING: Community.
PARTICIPANTS: Adults aged 65 and older and were selected for this study. Of 1,155 baseline participants aged 65 and older, 741 had IL-6 measurements at baseline and 3-year follow-up.
MEASUREMENTS: The uppermost quartile of IL-6 was used as the threshold for defining high IL-6 (≥4.18 pg/mL). Serum IL-6 levels were assessed using enzyme immunoassay.
RESULTS: Of the 581 participants with IL-6 levels less than 4.18 pg/mL at baseline, 106 (18.2%) had developed high IL-6 at follow-up. Although women had lower IL-6 levels at baseline than men, the risk of developing high IL-6 did not differ according to sex. High adiposity, defined as a body mass index of 30.0 kg/m² or higher (odds ratio (OR)=2.63, 95% confidence interval (CI)=1.40–4.96), and large waist circumference, defined as 102 cm or greater for men and 88 cm or greater for women (OR=2.05, 95% CI=1.24–3.40), were significant predictors of developing high IL-6 at follow-up. Other significant predictors were presence of three or more chronic diseases (OR=3.66, 95% CI=1.54–8.70), higher baseline IL-6 (OR=1.82, 95% CI=1.39–2.38) and higher white blood cell count (OR=1.24, 95% CI=1.06–1.45). Faster walking speed associated with decreased risk of progressing to elevated IL-6 (OR=0.83, 95% CI=0.74–0.92).
CONCLUSION: Older age, greater adiposity, slower walking speed, higher disease burden, and higher white blood cell count were associated with greater risk of IL-6 elevation over a 3-year period. Future research should target older adults with these characteristics to prevent progression to a proinflammatory state.     

Physical activity and fracture risk in a free-living elderly cohort

A prospective study to determine if regular leisure-time physical activity (including recreational walking) is associated with fracture risk was conducted in a large cohort (N = 3110) of free-living elderly men and women in the retirement community of Dunedin, Florida. Sixty-three percent of the cohort was female, all were white, and the average age was 73.0 years +/- 5.3 (SD). Participants in regular physical activity at baseline had a reduced risk of fracture; the risk ratio (RR) of fracture for men and women, respectively, was RR = 0.41, 95% CI = 0.17 to 1.01 and RR = 0.76, 95% CI = 0.50 to 1.15. Walking at least one mile 3 times/week appeared to offer a protective effect for both sexes. After controlling for potentially confounding variables including body mass and selected health conditions, the RR for regular physical activity on fracture incidence in men and women remained essentially unchanged. We conclude that regular physical activity such as walking may protect against fracture in older persons.     

The influence of anxiety on the progression of disability

OBJECTIVES: To determine the influence of anxiety on the progression of disability and examine possible mediators of the relationship. DESIGN: Community-based observational study. SETTING: Women's Health and Aging Study I, a prospective observational study with assessments every 6 months for 3 years. PARTICIPANTS: One thousand two functionally limited women aged 65 and older. MEASUREMENTS: Anxiety symptoms were assessed using four questions from the Hopkins Symptom Checklist (nervous or shaky, avoidance of certain things, tense or keyed up, fearful). Participants who reported experiencing two or more of these symptoms at baseline were considered anxious. Anxiety as a predictor of the onset of four types of disability was examined using Cox proportional hazards models. Three models were tested: an unadjusted model, a model adjusted for confounding variables (age, race, vision, number of diseases, physical performance, depressive symptoms), and a mediational model (benzodiazepine and psychotropic medication use, physical activity, emotional support). RESULTS: Nineteen percent of women reported two or more symptoms of anxiety at baseline. Unadjusted models indicate that anxiety was associated with a greater risk of worsening disability: activity of daily living (ADL) disability (relative risk (RR)=1.40, 95% confidence interval (CI)=1.10-1.79), mobility disability (RR=1.41, 95% CI=1.06-1.86), lifting disability (RR=1.54, 95% CI=1.20-1.97), and light housework disability (RR=1.77, 95% CI=1.32-2.37). After adjusting for confounding variables, anxiety continued to predict the development of two types of disability: ADL disability (RR=1.41, 95% CI=1.08-1.84) and light housework disability (RR=1.56, 95% CI=1.14-2.14). Finally, benzodiazepine and psychotropic medication use, physical activity, and emotional support were not significant mediators of the effect of anxiety on the development of a disability. CONCLUSION: Anxiety is a significant risk factor for the progression of disability in older women. Studies are needed to determine whether treatment of anxiety delays or prevents disability.     

Coimpairments: strength and balance as predictors of severe walking disability

BACKGROUND: Little information is available on the joint effects of multiple impairments (coimpairments) on the risk of disability. Our aim was to study the joint effects of strength and balance impairments on severe walking disability. METHODS: The data are from the baseline of the Women's Health and Aging Study (WHAS), a study of moderately to severely disabled women. A total of 1,002 women aged 65 and older participated in the tests, which took place in their homes. Severe walking disability was defined as self-reported inability to walk one-quarter mile and customary walking speed in a 4-meter test of < or =0.4 m/s. Balance was measured as an ability to hold progressively more difficult stands (feet side-by-side, semitandem and tandem stands). Maximal knee extension strength was measured using a hand-held dynamometer. RESULTS: There were 129 women who were severely walking disabled but able to walk at least minimally. In logistic regression analysis, balance and knee extension strength were independent predictors of severe walking disability. To study the combined effects, nine groups were formed on the basis of strength tertiles by balance categories in the entire population. In the best balance category, the crude prevalences of severe walking disability were 1.2%, 4.9%, and 14.3% in the highest to lowest strength tertiles. In the middle balance category, the rates were 2.9%, 10.0%, and 45.4.1%, and in the poorest balance category 4.9%, 22.1%, and 42.6%, correspondingly. The age, body weight, and height-adjusted odds ratios (OR) showed that the risk of severe walking disability in the subgroup with best balance and strength was less than 5% of the risk in the subgroup with poorest balance and strength (OR .034, 95% confidence interval [CI] .007-.166). Correspondingly, in the subgroups with poorest strength and best balance (OR .097, 95% CI .025-.38) or poorest balance and best strength (OR .102, 95% CI .012-.866) the risk was about 10%. The age-specific estimates of prevalence of severe walking disability in women were: 2.0% for ages 65-74 years, 3.4% for ages 75-84 years, and 9.1% for ages 85 years and older. CONCLUSIONS: The burden of coimpairments seems to be greater than the sum of single impairments involved. An effective way to reduce severe disabilities could be prevention of coimpairments.     

Low serum carotenoids and development of severe walking disability among older women living in the community: the women's health and aging study I

OBJECTIVE: to determine whether low serum carotenoid levels, an indicator of low intake of fruits and vegetables, are associated with the progression of disability in older women. DESIGN: longitudinal analysis in a population-based cohort. SETTING: moderately-severely disabled women, >or=65 years, living in the community in Baltimore, Maryland (the Women's Health and Aging Study I). PARTICIPANTS: 554 women without severe walking disability (inability to walk or walking speed <0.4 m/s) at baseline. MAIN OUTCOME MEASURE: incidence of severe walking disability assessed every 6 months over 3 years. RESULTS: 155 women (27.9%) developed severe walking disability during follow-up. Rates of development of severe walking disability per 100 person-years among women in the lowest and in the three upper quartiles of total carotenoids were, respectively, 13.8 versus 10.9 (P=0.0017). Adjusting for confounders, women in the lowest quartile of total carotenoids were more likely to develop severe walking disability (hazards ratio 1.57, 95% confidence interval 1.24-2.00, P=0.0002) compared with women in the three upper quartiles. CONCLUSION: low serum carotenoid levels, an indicator of low intake of fruits and vegetables, are independent predictors of the progression towards severe walking disability among older women living in the community.     

Baseline Lower Extremity Strength and Subsequent Decline in Functional Performance at 6‐Year Follow‐Up in Persons with Lower Extremity Peripheral Arterial Disease

OBJECTIVES: To evaluate associations between baseline lower extremity strength and decline in functional performance over 6 years of follow‐up in men and women with lower extremity peripheral arterial disease (PAD). DESIGN: Prospective observational study. SETTING: Three Chicago‐area hospitals. PARTICIPANTS: Three hundred seventy‐four men and women with PAD. MEASUREMENTS: Baseline isometric hip extension, hip flexion, knee flexion, and knee extension strength were measured using a musculoskeletal fitness evaluation chair. Usual and fastest‐paced 4‐m walking speed, 6‐minute walk, and Short Physical Performance Battery (SPPB) were assessed at baseline and annually thereafter. Analyses were adjusted for age, sex, race, ankle–brachial index (ABI), comorbidities, and other confounders. RESULTS: In women with PAD, weaker baseline hip and knee flexion strength were associated with faster average annual decline in usual‐pace 4‐m walking speed (P trend <.001 and .02, respectively) and SPPB (P trend=.02 and .01, respectively). In women, weaker hip extension strength was associated with faster decline in usual‐pace 4‐m walking speed and SPPB (P trend=.01 and <.01, respectively). There were no significant associations between baseline strength and decline in 6‐minute walk in women. There were no significant associations between any baseline strength measure and functional decline in men. CONCLUSION: Weaker baseline leg strength is associated with faster functional decline in nonendurance measures of functional performance in women with PAD but not in men with PAD.     

Association of IGF-I levels with muscle strength and mobility in older women

The functional consequences of the age-associated decline in IGF-I are unknown. We hypothesized that low IGF-I levels in older women would be associated with poor muscle strength and mobility. We assessed this question in a population representative of the full spectrum of health in the community, obtaining serum IGF-I levels from women aged 70-79 yr, enrolled in the Women's Health and Aging Study I or II. Cross-sectional analyses were performed using 617 women with IGF-I levels drawn within 90 d of measurement of outcomes. After adjustment for age, there was an association between IGF-I and knee extensor strength (P = 0.004), but not anthropometry or other strength measures. We found a positive relationship between IGF-I levels and walking speed for IGF-I levels below 50 microg/liter (P < 0.001), but no relationship above this threshold. A decline in IGF-I level was associated with self-reported difficulty in mobility tasks. All findings were attenuated after multivariate adjustment. In summary, in a study population including frail and healthy older women, low IGF-I levels were associated with poor knee extensor muscle strength, slow walking speed, and self-reported difficulty with mobility tasks. These findings suggest a role for IGF-I in disability as well as a potential target population for interventions to raise IGF-I levels.