Strength In Older Adults Research Articles

HUMAN AGING INTERVENTIONS

Abstract Biological aging is the greatest risk factor for multiple non-communicable diseases affecting multiple organ systems. Evidence from animal studies suggest that the rate of biological aging is modifiable and that slowing the rate of biological aging may decrease the incidence of age-related morbidity and mortality. Based on these findings, several approaches are currently being studied to slow the rate of biological aging in humans. This symposium features internationally renowned aging research scientists whose work focuses on clinical interventions to modify biological aging in humans. We will hear from Rajagopal Sekhar from the Baylor College of Medicine who will present his research on “Improving oxidative stress, mitochondrial dysfunction, inflammaging, aging hallmarks and muscle strength in older adults: the novel role of GlyNAC and the 'Power of 3'”; Jamie Justice from the Wake Forest School of Medicine will present her work on “Response to dietary restriction interventions in older adults: biomarkers of cellular senescence and biological aging”; Reem Waziry from the Columbia University Mailman School of Public Health will present her work “Does Caloric Restriction Slow the Process of Biological Aging in Non-Obese Healthy Adults? Evidence from the CALERIE™ Trial”; and Daniel Parker from the Duke University School of Medicine will present his work “Does APOE genotype moderate the impact of diet modification and exercise training on age-related outcomes?”. Attendees will learn about recent advances in interventions targeting human aging.

Chronic Loneliness, Gender, and Trajectories of Change in Hand Grip Strength in OlderAdults.

This study examined whether exposure to chronic loneliness is associated with a persistent decline in hand grip strength among community-dwelling older adults in Korea, and this association varies by gender. This study analyzed data from 2,570 adults aged 65 or older collected over the course of 7 waves (12years) of the Korean Longitudinal Study of Ageing from 2006 to 2018 (1,403 women and 1,167 men). Exposure to chronic loneliness was assessed by the experience of loneliness over a period of years, and hand grip strength was measured by an objective diagnostic tool. Gender-stratified fixed effects models were estimated to determine whether the association between chronic loneliness and hand grip strength differs by gender while accounting for time-invariant individual heterogeneity. Chronic loneliness was associated with a persistent decline in hand grip strength in older adults over an extended period of time. Gender-specific analyses revealed that only men continued to experience a decline in hand grip strength up to the fifth and subsequent waves of exposure (b=-1.889). By contrast, for older women, a significant decrease in hand grip strength was observed only in the second wave of exposure (b=-0.690). These gendered trajectories were statistically significant. Chronic loneliness impairs the physical health of older adults in the long run. These physical health consequences of chronic loneliness were more pronounced among older men than older women. The study's findings inform the development of interventions that mitigate the adverse health consequences of chronic loneliness.

Reproducibility of isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with Alzheimer’s disease

BackgroundTo interpret changes of muscle strength in older adults with Alzheimer’s disease (AD), determining the reliability of outcome measures is necessary. Therefore, the purpose of the present study was to investigate the relative and absolute intra-rater reliability of concentric isokinetic measures of the knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.MethodsA methodological study was conducted. The participants were submitted to two isokinetic evaluations with an interval of three to seven days. The evaluations consisted of knee extension and flexion at 60°/s (five repetitions) and 180°/s (15 repetitions) and plantar flexion and dorsiflexion of the ankle at 30°/s (five repetitions). The measures of interest were peak torque, average peak torque and total work. The intraclass correlation coefficient two-way mixed model of a single-measure (ICC3,1), standard error of measurement (SEM) and minimal detectable change at the 95% confidence interval (MDC95) were calculated. The ICC3,1 was interpreted based on Munro’s classification. Standard error of measurement and MDC95 were analyzed in absolute and relative values (percentage of error [SEM%] and change [MDC95%]).ResultsA total of 62 older adults were included and allocated to the three groups: mild-AD (n = 22, 79.9 years, 15 female and seven male), moderate-AD (n = 20, 81.6 years, 15 female and five male) and without-AD (n = 20, 74.3 years, 10 female and seven male). The ICCs3,1 of the measures of knee were high/very high in the three groups (0.71–0.98). The ICCs3,1 of the measures of ankle were high/very high in the mild-AD group (0.78–0.92), moderate/high/very high in the moderate-AD group (0.63–0.93) and high/very high in the group without-AD (0.84–0.97). The measurements of knee extensors at 60°/s, knee extensors (peak torque and total work), with the exception of peak torque in the mild-AD group, and flexors (average peak torque) at 180°/s, and ankle dorsiflexors at 30°/s had the lowest of SEM% and MDC95% in the three groups.ConclusionConcentric isokinetic measures are reliable for the assessment of knee and ankle muscle strength in community-dwelling older adults without and with AD in the mild and moderate stages.

Serum α-Carotene, but Not Other Antioxidants, Is Positively Associated with Muscle Strength in Older Adults: NHANES 2001-2002.

Aging is associated with an increased reactive oxygen species that can decrease muscle strength. Thus, antioxidant substances could be positively associated with muscle strength in older adults. To investigate the association between serum antioxidants and muscle strength in older adults. A cross-sectional study evaluating 1172 individuals (627 men and 545 women), aged 50 to 85 years from NHANES 2001-2002, was performed. Carotenoids (α-carotene, trans-β-carotene, cis-β-carotene, β-cryptoxanthin, lutein/zeaxanthin combination, trans-lycopene), vitamin E, and retinol were analyzed via the high-performance liquid chromatography method. Muscle strength was evaluated by the isokinetic knee extension test. Linear regression was performed to evaluate the association between tertiles of serum antioxidant levels and strength, adjusted for confounders (energy and protein intake, body mass index, sex, age, C-reactive protein, uric acid, race/ethnicity, marital status, annual household income, educational level, physical activity, smoking, hypertension, arthritis, and diabetes). Alpha-carotene levels (p-trend = 0.027) were positively associated with muscle strength. However, serum vitamin E, trans-β-carotene, cis-β-carotene, β-cryptoxanthin, carotenoids, and retinol levels were not associated with strength. Serum α-carotene, but not other antioxidants, was positively associated with muscle strength in older adults.

“What If I Die and No One Notices?” A Qualitative Study Exploring How Living Alone and in Poverty Impacts the Health and Well-Being of Older People in Hong Kong

Despite the growing number of older people who live alone and in poverty, the intersection of these two social risk factors and the impacts on older adults' health and well-being have not been widely examined. This qualitative study explores the challenges and strengths of 47 older people who live alone and in poverty in Hong Kong. Thematic analysis was used to identify eight themes related to challenges: (i) social isolation and loneliness, (ii) self-esteem and self-efficacy, (iii) declining mobility, health and activity levels, (iv) high medical expenses, (v) age discrimination and long wait times for medical health services, (vi) age discrimination, retirement, and wanting part-time employment, (vii) not enough gender-specific social participation activities, and (viii) housing insecurity. Four themes related to strengths were identified: (i) An "I have enough" mindset, (ii) strong formal social support, (iii) contributing to the community and others, and (v) "Most of us like to be alone." Successfully addressing poverty in old age and tackling the challenges associated with living alone will require focusing on and activating not only external and systemic resources but also the intrinsic capacities and strengths of older adults themselves. Five discussion points are raised addressing the implications for future gerontological research and practice.

Month-of-Birth Effect on Muscle Mass and Strength in Community-Dwelling Older Women: The French EPIDOS Cohort.

Background. Vitamin D is involved in muscle health and function. This relationship may start from the earliest stages of life during pregnancy when fetal vitamin D relies on maternal vitamin D stores and sun exposure. Our objective was to determine whether there was an effect of the month of birth (MoB) on muscle mass and strength in older adults. Methods. Data from 7598 community-dwelling women aged ≥ 70 years from the French multicentric EPIDOS cohort were used in this analysis. The quadricipital strength was defined as the mean value of 3 consecutive tests of the maximal isometric voluntary contraction strength of the dominant lower limb. The muscle mass was defined as the total appendicular skeletal muscle mass measured using dual energy X-ray absorptiometry scanner. The MoB was used as a periodic function in regressions models adjusted for potential confounders including age, year of birth, latitude of recruitment center, season of testing, body mass index, number of comorbidities, IADL score, regular physical activity, sun exposure at midday, dietary protein intake, dietary vitamin D intake, use vitamin D supplements, history and current use of corticosteroids. Results. A total of 7133 older women had a measure of muscle strength (mean age, 80.5 ± 3.8 years; mean strength, 162.3 ± 52.1 N). Data on total ASM were available from 1321 women recruited in Toulouse, France (mean, 14.86 ± 2.04 kg). Both the sine and cosine functions of MoB were associated with the mean quadricipital strength (respectively β = -2.1, p = 0.045 and β = -0.5, p = 0.025). The sine function of MoB was associated with total ASM (β = -0.2, p = 0.013), but not the cosine function (β = 0.1, p = 0.092). Both the highest value of average quadricipital strength (mean, 163.4 ± 20.2 N) and the highest value of total ASM (15.24 ± 1.27 kg) were found among participants born in August. Conclusions. Summer-early fall months of birth were associated with higher muscle mass and strength in community-dwelling older women.

Handgrip strength in older adults with chronic diseases from 27 European countries and Israel.

Understanding the association of deconditioned strength with the most prevalent chronic diseases in older adults and inferring possible interventional strategies is of utmost importance. We aimed to investigate the association between handgrip strength and chronic diseases in a large representative European population of adults over the age of 50 years. Individuals aged 50 or older residing in 27 European countries and Israel participated in this cross-sectional study. Data on prior or current chronic disease and handgrip strength were retrieved from the 7th wave of Survey of Health, Ageing and Retirement in Europe (SHARE). We tested associations using binary logistic regression adjusted for potential confounders. Based on data from 73,463 participants, the examined diseases showed a negative association with handgrip strength in the fully adjusted model. Participants from the highest tertile of handgrip strength had particularly lower odds for Parkinson ((Adjusted odds ratio (AOR) = 0.42 [95% Confidence Interval = 0.32-0.56])), stroke (AOR = 0.51 [95% Confidence Interval = 0.44-0.59], and emotional disorders ((Adjusted odds ratio (AOR) = 0.51 [95% Confidence Interval = 0.45-0.58])) compared with participants with the lowest level of handgrip strength in the fully adjusted model. There is a negative association between handgrip strength and a wide range of chronic diseases. Evaluating handgrip strength in this population may provide a valuable clinical measure and a simple preventive strategy in relation to these diseases. The present findings support the use of resistance training for the prevention of specific chronic conditions, particularly Parkinson, stroke and emotional disorders.

Protein intake and physical function in older adults: A systematic review and meta-analysis.

The present study explored cross-sectional and longitudinal associations between protein intake and physical function in older adults. We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association between protein intake and measures of physical function in older adults. Cross-sectional, case-control, and longitudinal cohort studies that investigated the association between protein intake and physical function as a primary or secondary outcome in people aged 60+years were included. Studies published in languages other than English, Italian, Portuguese, or Spanish were excluded. Studies were retrieved from MEDLINE, SCOPUS, EMBASE, CINAHL, AgeLine, and Food Science Source databases through January 31, 2022. A pooled effect size was calculated based on standard mean differences (SMD), MD, log odds ratio (OR) and Z-score.. Twenty-two cross-sectional studies examined a total of 11,332 community-dwellers, hospitalized older adults, and elite senior athletes with a mean age of approximately 75 years. The pooled analysis indicated that a protein intake higher than the recommended dietary allowance (RDA) was significantly associated with higher Short Physical Performance Battery (SPPB) scores (SMD: 0.63, 95% CI: 0.27, 0.99, P-value: 0.0006), faster walking speed, greater lower-limb (SMD: 0.22, 95% CI: 0.04, 0.40, P-value: 0.02) and isometric handgrip strength (Z-score: 0.087, 95% CI: 0.046-0.128, P-value: 0.0001), and better balance (SMD: 0.33, 95% CI: 0.05, 0.62, P-value: 0.02). Nine longitudinal studies investigated 12,424 community-dwelling and native older adults with a mean age of approximately 85 years. A protein intake higher than the current RDA was not associated with lower decline in either isometric handgrip strength (logOR: 0.99, 95% CI: 0.97-1.02, P-value= 0.67) or walking speed (logOR: 0.92, 95% CI: 0.77-1.10, P-value= 0.35). A protein intake higher than the RDA is cross-sectionally associated with better physical performance and greater muscle strength in older adults. However, a high consumption of proteins does not seem to prevent physical function decline over time.

Effectiveness of Elastic Band Exercises on the Functional Fitness of Older Adults in Long-Term Care Facilities.

Population aging has caused a rise in the institutionalization, disability, and mortality rates of older adults worldwide. Older adults are able to engage in muscle training. Elastic band exercises can safely and effectively improve the upper and lower muscle strength and balance of older adults. This study was developed to examine the effects of a 3-month elastic band exercise program on the activities of daily living (ADLs), hand muscle strength, balance, and lower limb muscle strength of older adults living in institutional settings. This was a randomized controlled trial. Sixty-one participants were randomly sampled from two long-term care facilities (LTCFs) in northern Taiwan (31 participants in the experimental group and 30 participants in the control group). Both groups underwent pretesting concurrently. The experimental group participated in 3 months of elastic band exercises, whereas the control group participated in the routine exercise program in their LTCFs. All of the participants were tested 1 and 3 months after the intervention. The average ADL, hand muscle strength, balance, and lower limb muscle strength scores of participants in the experimental group had improved significantly more than those of the control group at posttest (all p s < .05). Elastic band exercises positively affect ADLs, hand muscle strength, balance, and lower limb muscle strength in older adults living in LTCFs. Moreover, the high benefit-to-cost ratio of these exercises helps lower the threshold of health promotion. We recommend including elastic band exercises in routine activities and designing different elastic band exercises for older adults at different proficiency levels. Furthermore, an elastic band exercise network should be established to improve the policy and implementation aspects of elastic band activities, raise awareness among community-dwelling and institutionalized older adults, and promote elastic band exercises to LTCFs nationwide.

Longitudinal association of handgrip strength with all-cause and cardiovascular mortality in older adults using a causal framework.

To date, there is no study addressing the time-varying confounding bias in the association of handgrip strength (HGS) with all-cause or cardiovascular mortality. Therefore, we conducted marginal structural models (MSM) to provide causal estimations on the associations of HGS with all-cause and cardiovascular mortality in a representative sample of adults aged 50years or older. Data from 29 countries including 121,116 participants (276,994 observations; mean age 63.7years; 56.3% women) free from prior heart attack or stroke were retrieved from consecutive waves of the Survey of Health, Ageing and Retirement in Europe (SHARE). During a median of 7.7years follow-up (interquartile range 3.8-11.8) and 1,009,862 person-years, 6407 participants (5.3%) died due to all causes, and 2263 (1.9%) died due to cardiovascular diseases. Using repeated measures of handheld dynamometry, we determined absolute and relative to body mass index HGS of each participant. We applied adjusted MSM to estimate hazard ratios (HRs) associated with changes over time in HGS addressing the time-varying confounding bias. An increase of 5kg in HGS was associated with a reduced risk of all-cause [HR 0.86, 95% confidence interval (CI), 0.86-0.90], overall cardiovascular (HR 0.86, 95% CI 0.82-0.86), heart attack (HR 0.90, 95% CI 0.86-0.95), and stroke (HR 0.86, 95% CI 0.82-0.90) mortality. The associations of relative HGS were of stronger magnitude in all cases. Our findings provide critical evidence on the importance of increasing general muscle strength in older adults to reduce mortality risk, particularly concerning cardiovascular causes.

Association between Plasma Omega-3 and Handgrip Strength According to Glycohemoglobin Levels in Older Adults: Results from NHANES 2011-2012.

Background: Low muscle strength is a predictor of mortality in older adults. Although the evidence concerning hyperglycemia is limited, evidence shows that omega-3 (ω-3) intake may be positively associated with muscle strength. However, the association between plasma ω-3 and muscle strength in older adults according to glycohemoglobin (HbA1c) levels has not yet been investigated. Objective: To evaluate whether plasma ω-3 levels are associated with handgrip strength in individuals over 50 years according to HbA1c levels. Methods: This cross-sectional study included 950 older adults (50–85 years) from NHANES 2011–2012. Linear regression analysis was performed to evaluate the association between plasma ω-3 and handgrip strength in individuals with elevated (≥5.7%) or normal HbA1c levels after adjustments for confounders. Results: Total plasma ω-3, docosahexaenoic acid, eicosapentaenoic acid and alpha-linolenic acid were not associated with handgrip strength in older adults regardless of HbA1c levels. Conclusion: Plasma ω-3 levels are not associated with handgrip strength in individuals over 50 years old independent of HbA1c levels.

Effect of Multicomponent Home-Based Training on Gait and Muscle Strength in Older Adults After Hip Fracture Surgery: A Single Site Randomized Trial

ObjectiveTo investigate the effect of 16-week home-based physical therapy interventions on gait and muscle strength. DesignA single-blinded randomized controlled trial. SettingGeneral community. ParticipantsThirty-four older adults (N=34) post hip fracture were randomly assigned to either experimental group (a specific multi-component intervention group [PUSH], n=17, 10 women, age=78.6±7.3 years, 112.1±39.8 days post-fracture) or active control (a non-specific multi-component intervention group [PULSE], n=17, 11 women, age=77.8±7.8 years, 118.2±37.5 days post-fracture). InterventionPUSH and PULSE groups received 32-40 sessions of specific or non-specific multi-component home-based physical therapy, respectively. Training in the PUSH group focused on lower extremity strength, endurance, balance, and function for community ambulation, while the PULSE group received active movement and transcutaneous electrical nerve stimulation on extremities. Main Outcome MeasuresGait characteristics, and ankle and knee muscle strength were measured at baseline and 16 weeks. Cognitive testing of Trail Making Test (Part A: TMT-A; Part-B: TMT-B) was measured at baseline. ResultsAt 16 weeks, both groups demonstrated significant increases in usual (P<.05) and fast (P<.05) walking speed, while there was no significant difference in increases between the groups. There was only 1 significant change in lower limb muscle strength over time (non-fractured side) between the groups, such that PUSH did better (mean: 4.33%, 95% confidence interval:1.43%-7.23%). The increase in usual and fast walking speed correlated with the baseline Trail-making Test-B score (r=-0.371, P=.037) and improved muscle strength in the fractured limb (r=0.446, P=.001), respectively. ConclusionGait speed improved in both home-based multicomponent physical therapy programs in older adults after hip fracture surgery. Muscle strength of the non-fractured limb improved in the group receiving specific physical therapy training. Specific interventions targeting modifiable factors such as muscle strength and cognitive performance may assist gait recovery after hip fracture surgery.

Validity And Reliability Of Hand-held Dynamometer In Assessing Isometric Leg Strength In Older Adults

The hand-held dynamometer (HHD) is portable in measuring an isometric muscle strength at multiple angles and limbs. The accuracy and consistency of the HHD in measuring muscle strength in older adults remains less explored. PURPOSE:We investigated the sex-specific and overall concurrent validity and interclass reliability of the HHD (microFET 2) in assessing isometric leg muscle strength in older men and women. We also constructed the prediction model for isometric leg strength using HHD, gait-speed, sit-to-stand, handgrip strength, and sex. METHODS: Forty-eight older adults (12 males and 36 females), aged 60-85 years, were recruited for this study. All participants had anthropometric, dual-energy x-ray absorptiometry, gait speed, sit-to-stand, handgrip, and hand-held dynamometer measurements. All participants also had both isometric and isokinetic leg strengths assessed by a Biodex isokinetic dynamometer. Pearson partial correlations were used to investigate the concurrent validity of HHD compared with an isokinetic dynamometer after adjustment for age and race and additional adjustment for sex. Cronbach alpha coefficients (α) were used to estimate the interclass reliability of HHD. Multiple regression with stepwise selection procedures were used to develop the prediction models for isometric leg strength with HHD, gait-speed, sit-to-stand, handgrip strength, and sex. RESULTS: Age-, sex-, and race-adjusted partial Pearson correlation coefficients were 0.62 for isokinetic leg strength (p < 0.001) and 0.90 for isometric leg strength (p < 0.001) with the HHD. Age- and race-adjusted partial Pearson correlations between isometric leg strength and HHD were 0.93 for men and 0.81 for women, and between isokinetic leg strength and HHD were 0.45 for men and 0.59 for women. Stepwise regression procedures documented the prediction model for isometric leg strength with HHD, gait-speed, and sex (R2 = 0.93, SEE = 5.01). Cronbach α coefficients showed high interclass reliabilities in estimating the leg muscle strength using the HHD in men (α = 0.99) and women (α = 0.97). CONCLUSIONS: The HHD (microFET 2) had high concurrent validity and interclass reliability in assessing the isometric leg muscle strength in older adults.

Does Resistance Training Plus Low-intensity Physical Activity Affect Body Composition Or Strength In Older Adults?

Does Resistance Training Plus Low-intensity Physical Activity Affect Body Composition Or Strength In Older Adults?

Effect of concurrent and multi-component training on balance, fear of falling, and muscle strength in older adults: a review

Effect of concurrent and multi-component training on balance, fear of falling, and muscle strength in older adults: a review

The role of motivation factors in exergame interventions for fall prevention in older adults: A systematic review and meta-analysis

Balance disorders and falls are common in the elderly population. Regular balance exercises are an evidence-based physical intervention to prevent falls in older adults, while patient motivation and adherence are important factors for intervention outcome. Exergames are a relatively new, alternative intervention for physical rehabilitation as they improve balance and strength in older adults. The aims of this systematic review and meta-analysis were to assess the (1) effect of motivation factors as per the Capability, Opportunity and Motivation model of Behavior change (COM-B) on the effectiveness of exergame interventions in healthy older adults, (2) effectiveness of exergames to improve balance in older healthy adults and, (3) impact of exergames on cognitive outcomes. Results show that motivation and capability components influence the general outcome of the exergame training. Motivational factors should thus be considered when setting-up an exergame intervention. Furthermore, exergame intervention appears to be a promising training method in comparison to traditional exercise training. However, exergame training in itself might not be sufficient to improve fall risk and cognitive performance.

Dietary Essential Amino Acid Intake Is Associated with High Muscle Strength in Korean Older Adults.

The relationship between daily dietary intake of an individual or all essential amino acids (EAAs) and muscle strength in older adults is still inadequately characterized. This population-based cross-sectional study included 5971 participants aged ≥65 years from the 2014–2019 Korea National Health and Nutrition Examination Survey. Dietary information was derived from the 24 h recall data. Total essential amino acid score (EAAS) was calculated with an intake that satisfied the recommended nutrient intake (RNI) in each essential amino acid (EAA). The mean handgrip strength was estimated from triplicate measurements obtained using the dominant hand, and high muscle strength was defined as handgrip strength ≥28 kg for men and ≥18 kg for women. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. After multivariable adjustment, we found that a high total EAAS was associated with high muscle strength in Korean older adults (OR: 1.38, 95% CI: 1.07–1.79). High muscle strength was significantly enhanced with increased total EAA intake from animal sources (OR: 1.27, 95% CI: 1.02–1.58), but there was no significant association with total EAA intake from non-animal sources. EAA intake and high muscle strength are associated based on a positive dose-response relationship in which high muscle strength is further increased when the overall EAA intake meets the RNI. Thus, Korean older adults should ensure an adequate intake of all EAAs from various food sources (especially animal sources) to meet the RNI as a prerequisite for achieving high muscle strength.

Diet-induced inflammation is associated with sarcopenia and muscle strength in older adults who visit a frailty clinic.

Diet-induced inflammation may be associated with sarcopenia; however, few reports have examined this relationship. To examine the association between the dietary inflammatory index (DII) and sarcopenia in older adults who visited a frailty clinic in Japan. This cross-sectional study used outpatient data from the Frailty Registry Study. The DII is an index of diet-induced inflammation, and a dietary assessment was performed using a brief self-administered diet history questionnaire to calculate the DII score. We classified DII scores by quartiles (Q1-Q4), and sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia 2019 consensus. Logistic regression analyses for sarcopenia were performed. Age, sex, comorbidities, and physical activity were entered as confounding factors (Model 1) and Models 2, 3, and 4 with BMI, protein intake, and energy intake added to Model 1. We included 304 patients in the analysis (mean age, 77.6 ± 6.3years; female, 67.4%). The prevalence of sarcopenia was 14.5%. Logistic regression analyses showed that DII scores were significantly associated with sarcopenia in Model 1 and 2 (Model 1, reference: Q1, Q4: OR 3.10, P = 0.020; Model 2, Q4: OR 3.40, P = 0,022) but not in Model 3 and 4. Diet-induced inflammation is associated with a higher likelihood of sarcopenia; however, this association disappeared after confounding for protein and energy intake. The results demonstrated that dietary protein and energy parameters were the main drivers for muscle health in medical patients.

Association between dietary inflammatory index score and muscle mass and strength in older adults: a study from National Health and Nutrition Examination Survey (NHANES) 1999–2002

PurposeChronic low-grade systemic inflammation affects muscle protein metabolism. The dietary inflammatory index (DII®) is a tool designed to assess the inflammatory potential of the diet. The available data on the association between DII and sarcopenia are limited. We aimed to investigate the association of the DII with components of sarcopenia in individuals over 50 years of age.MethodsThis cross-sectional study used the National Health and Nutrition Examination Survey (NHANES) 1999–2002 dataset. Body composition was measured, and isokinetic strength of the knee extensors (peak force) was evaluated. Low muscle mass and strength were defined using sex-specific thresholds. Energy-adjusted DII (E-DII™) scores were calculated using 24-h dietary recall data. Regression models were fit to evaluate the association between E-DII scores and low muscle mass and low muscle strength, alone and combined.ResultsMean age of study participants was 62.1 ± 9.5 years, and 138 participants (7.4%) belonged to the combination group of low muscle mass and low muscle strength. In multivariable-adjusted regression models, higher E-DII score was associated with lower appendicular skeletal muscle index (ASMI) (β = − 0.03, P < 0.001, P trend <0.001), and lower peak force (β = −2.15, P = 0.04, P trend = 0.01) and higher likelihood for these components combined (OR = 1.12, 95% CI 1.01–1.25, P = 0.03).ConclusionHigher E-DII score is associated with lower muscle mass and muscle strength, and increased likelihood for the combination of low muscle mass and low muscle strength in older adults. This has important implications for healthy aging.

Protein intake, physical activity and grip strength in European and North American community-dwelling older adults: a pooled analysis of individual participant data from four longitudinal ageing cohorts.

Higher dietary protein, alone or in combination with physical activity (PA), may slow the loss of age-related muscle strength in older adults. We investigated the longitudinal relationship between protein intake and grip strength, and the interaction between protein intake and PA, using four longitudinal ageing cohorts. Individual participant data from 5584 older adults (52% women; median: 75, IQR: 71.6, 79.0 years) with up to 8.5 years (mean: 4.9, SD: 2.3 years) of follow-up from the Health ABC, NuAge, LASA and Newcastle 85+ cohorts were pooled. Baseline protein intake was assessed with food frequency questionnaires and 24h recalls and categorized into <0.8, 0.8-<1.0, 1.0-<1.2 and ≥1.2 g/kg adjusted body weight (aBW)/d. The prospective association between protein intake, its interaction with PA, and grip strength (sex- and cohort-specific) was determined using joint models (hierarchical linear mixed effects and a link function for Cox proportional hazards models). Grip strength declined on average by 0.018 SD (95%CI: -0.026, -0.006) every year. No associations were found between protein intake, measured at baseline, and grip strength, measured prospectively, or rate of decline of grip strength in models adjusted for sociodemographic, anthropometric, lifestyle and health variables (e.g., protein intake ≥1.2 vs <0.8 g/kg aBW/d: β= -0.003, 95%CI: -0.014,0.005 SD per year). There also was no evidence of an interaction between protein intake and PA. We failed to find evidence in this study to support the hypothesis that higher protein intake, alone or in combination with higher PA, slowed the rate of grip strength decline in older adults.