Role of sarcopenia in the frailty transitions in older adults: a population-based cohort study

BACKGROUND

Frailty and sarcopenia are age-associated syndromes that have been associated with the risk of several adverse events, mainly functional decline and death, that usually coexist. However, the potential role of one of them (sarcopenia) in modulating some of those adverse events associated to the other one (frailty) has not been explored. The aim of this work is to assess the role of sarcopenia within the frailty transitions and mortality in older people.

METHODS

Data from the Toledo Study of Healthy Aging (TSHA) were used. TSHA is a cohort of community-dwelling older adults ≥65. Frailty was assessed according with the Frailty Phenotype (FP) and the Frailty Trait Scale-5 (FTS5) at baseline and at follow-up. Basal sarcopenia status was measured with the standardized Foundation for the National Institutes of Health criteria. Fisher's exact test and logistic regression model were used to determine if sarcopenia modified the transition of frailty states (median follow-up of 2.99 years) and Cox proportional hazard model was used for assessing mortality.

RESULTS

There were 1538 participants (74.73 ± 5.73; 45.51% men) included. Transitions from robustness to prefrailty and frailty according to FP were more frequent in sarcopenic than in non-sarcopenic participants (32.37% vs. 15.18%, P ≤ 0.001; 5.76% vs. 1.12%; P ≤ 0.001, respectively) and from prefrailty-to-frailty (12.68% vs. 4.27%; P = 0.0026). Improvement from prefrail-to-robust and remaining robust was more frequent in non-sarcopenic participants (52.56% vs. 33.80%, P ≤ 0.001; 80.18% vs 61.15%, P ≤ 0.001, respectively). When classified by FTS5, this was also the case for the transition from non-frail-to-frail (25.91% vs. 4.47%, P ≤ 0.001) and for remaining stable as non-frail (91.25% vs. 70.98%, P ≤ 0.001). Sarcopenia was associated with an increased risk of progression from robustness-to-prefrailty [odds ratio (OR) 2.34 (95% confidence interval, CI) (1.51, 3.63); P ≤ 0.001], from prefrailty-to-frailty [OR(95% CI) 2.50 (1.08, 5.79); P = 0.033] (FP), and from non-frail-to-frail [OR(95% CI) 4.73 (2.94, 7.62); P-value ≤ 0.001]. Sarcopenia does not seem to modify the risk of death associated with a poor frailty status (hazard ratios (HR, 95%) P > 0.05).

CONCLUSIONS

Transitions within frailty status, but not the risk of death associated to frailty, are modulated by the presence of sarcopenia.

Associations between frailty trajectories and frailty status and adverse outcomes in community-dwelling older adults

BACKGROUND

The association between frailty and adverse outcomes has been clearly defined. Frailty is associated with age, but different frailty evolution patterns might determine the incidence of adverse outcomes at older ages. So far, few observational studies have examined how distinct frailty trajectories could be associated with differences in the risk of adverse events and assessing whether frailty trajectories could define risk of death, hospitalization, worsening, and incident disability better than one-off assessment. Our hypothesis is that prospective increases in frailty levels are associated with higher risk of adverse events compared with subjects that prospectively decreased frailty levels.

METHODS

Participants' data were taken from the Toledo Study of Healthy Ageing. Frailty was evaluated using the Frailty Trait Scale 5 (FTS5), being 0 the lower (the most robust) and 50 the highest (the frailest) score. FTS5 scores at baseline and follow-up (median 5.04 years) were used to construct frailty trajectories according to group-based trajectory modelling (GBTM). Multivariate Cox proportional hazard and logistic regression models were used to explore associations between frailty status and trajectory membership and the adverse outcomes. Deaths were ascertained through the Spanish National Death Index. Disability was evaluated through the Katz Index. Hospitalization was defined as first admission to Toledo Hospital.

RESULTS

Nine hundred and seventy-five older adults (mean age 73.14 ± 4.69; 43.38% men) were included. GBTM identified five FTS5 trajectories: worsening from non-frailty (WNF), improving to non-frailty (INF), developing frailty (DF), remaining frail (RF), and increasing frailty (IF). Subjects belonging to trajectories of increasing frailty scores or showing consistently higher frailty levels presented with an increased risk of mortality {DF [hazard ratio (HR), 95% confidence interval (CI)] = 2.01 [1.21-3.32]; RF = 1.92 [1.18-3.12]; IF = 2.67 [1.48-4.81]}, incident [DF (HR, 95% CI) = 2.06 (1.11-3.82); RF = 2.29 (1.30-4.03); IF = 3.55 (1.37-9.24)], and worsening disability [DF (HR, 95% CI) = 2.11 (1.19-3.76); RF = 2.14 (1.26-3.64); IF = 2.21 (1.06-4.62)], compared with subjects prospectively showing decreases in frailty levels or maintaining low FTS5 scores. A secondary result was a significant dose-response relationship between baseline FTS5 score and adverse events.

CONCLUSIONS

Belonging to trajectories of prospectively increasing/consistently high frailty scores over time are associated with an increased risk of adverse outcomes compared with maintaining low or reducing frailty scores. Our results support the dynamic nature of frailty and the potential benefit of interventions aimed at reducing its levels on relevant and burdensome adverse outcomes.

Obesity, fat distribution, and risk of frailty in two population-based cohorts of older adults in Spain

OBJECTIVE

To evaluate for the first time the longitudinal relationship between abdominal obesity and the onset of frailty.

METHODS

Study based on results from two population-based cohorts, the Seniors-ENRICA, with 1801 individuals aged ≥60, and the Toledo Study for Healthy Ageing (TSHA), with 1289 participants ≥65 years. Incident frailty was assessed with the Fried criteria.

RESULTS

During 3.5 years of follow-up, 125 individuals with incident frailty in Seniors-ENRICA and 162 in TSHA were identified. After adjustment for the main confounders, the pooled odds ratio (pooled OR) for general obesity and risk of frailty was 1.73 (95% confidence interval [CI]: 1.18-2.28). Abdominal obesity was also associated with frailty (pooled OR: 1.67; 95% CI: 1.09-2.25). Compared with individuals with BMI <25 kg/m(2) and no abdominal obesity, the risk of frailty was highest among individuals with concurrent general and abdominal obesity (pooled OR: 2.55; 95% CI: 1.23-3.86). General obesity was associated with increased risk of exhaustion (pooled OR: 1.66; 95% CI: 1.11-2.21), low physical activity (pooled OR: 1.57; 95% CI: 1.08-2.05), and weakness (pooled OR: 1.63; 95% CI: 1.12-2.05). For abdominal obesity, results were in the same direction, although they showed statistical significance only for weakness (OR: 1.46; 95% CI: 1.11-1.80).

CONCLUSIONS

General and abdominal obesity are associated with incident frailty in the elderly.

Age and gender, two key factors in the associations between physical activity and strength during the ageing process

OBJECTIVES

The aims of this study were to identify if the associations of physical activity (PA) and muscle strength may vary throughout the ageing process; to study the differences among genders in the relationships between PA and strength in elderly people and to test whether these differences are explained by the hormonal, nutritional and inflammatory status.

STUDY DESIGN

A total of 1741 people ≥65 years of age participated in this cross-sectional study.

MAIN OUTCOME MEASURES

Upper- and lower-limbs maximal voluntary isometric strength was obtained using standardized techniques and equipment. PA was recorded by a validated questionnaire. The associations of PA with strength were assessed using generalized linear regression models with a Gamma-distributed dependent variable.

RESULTS

A significant gender by PA interaction was found for all strength-related variables (all P<0.01). Moreover, when sexual hormones, albumin or C-Reactive protein were taken into account in the model, the results did not significantly change. In women, PA was positively associated with upper and lower-body strength; however in men, PA was only associated with grip and knee strength (both P<0.01). Higher strength values were associated with higher levels of PA, especially in women. However, this tendency had a different pattern across the age range, showing a stronger association in the 'young' elderly compared with the 'old' elderly.

CONCLUSION

Higher levels of PA are related to greater muscle strength, especially in women and those who were younger.

Association between endothelial dysfunction and frailty: the Toledo Study for Healthy Aging

Cardiovascular disease (CVD), both clinical and subclinical, has been proposed as one of the mechanisms underlying frailty. However, there is no evidence addressing the relationship between the earliest stage of CVD (endothelial dysfunction) and frailty. The goal of the study was to analyze the association between endothelial dysfunction, evaluated by asymmetric dimethylarginine (ADMA) levels, and frailty. We used data from the Toledo Study for Healthy Aging, a prospective Spanish cohort study. Biological samples were obtained and ADMA levels were determined using an enzyme immunoassay method. Logistic regression was used to estimate the odds ratio (OR) and 95 % confidence intervals of frailty associated with ADMA. Adjustments were made for age, gender, cardiovascular risk factors, and presence of atherosclerotic disease (assessed by ankle–brachial index; ABI). One thousand two hundred eighty-seven community-dwelling elderly were included. One hundred seven (8.3 %) were identified as frail, 542 (42.1 %) as pre-frail, and 638 (49.6 %) as non-frail. ADMAvalues were higher in frail subjects than in non-frail ones. In addition, an interaction between the presence of atherosclerotic disease and ADMA on the odds of frailty (p=0.045) was detected. After adjustments for age, classical cardiovascular risk factors, and ABI, the risk of frailty was associated with increasing levels of ADMA in subjects without atherosclerotic disease [OR for 1 standard deviation increase in ADMA=1.14 (1.01–1.28), p=0.032] but not in those with atherosclerotic disease. In our study, endothelial dysfunction, assessed by ADMA levels, is associated with frailty. These findings provide additional support for a relevant role of vascular system since its earliest stage in frailty.

Sex differences in the association between serum levels of testosterone and frailty in an elderly population: the Toledo Study for Healthy Aging

BACKGROUND

Age-associated decline in testosterone levels represent one of the potential mechanisms involved in the development of frailty. Although this association has been widely reported in older men, very few data are available in women. We studied the association between testosterone and frailty in women and assessed sex differences in this relationship.

METHODS

We used cross-sectional data from the Toledo Study for Healthy Aging, a population-based cohort study of Spanish elderly. Frailty was defined according to Fried's approach. Multivariate odds-ratios (OR) and 95% confidence intervals (CI) associated with total (TT) and free testosterone (FT) levels were estimated using polytomous logistic regression.

RESULTS

In women, there was a U-shaped relationship between FT levels and frailty (p for FT(2) = 0.03). In addition, very low levels of FT were observed in women with ≥ 4 frailty criteria (age-adjusted geometric means = 0.13 versus 0.37 in subjects with <4 components, p = 0.010). The association of FT with frailty appeared confined to obese women (p-value for interaction = 0.05).In men, the risk of frailty levels linearly decreased with testosterone (adjusted OR for frailty = 2.9 (95%CI, 1.6-5.1) and 1.6 (95%CI, 1.0-2.5), for 1 SD decrease in TT and FT, respectively). TT and FT showed association with most of frailty criteria. No interaction was found with BMI.

CONCLUSION

There is a relationship between circulating levels of FT and frailty in older women. This relation seems to be modulated by BMI. The relevance and the nature of the association of FT levels and frailty are sex-specific, suggesting that different biological mechanisms may be involved.