The effects of omega-3 polyunsaturated fatty acids on muscle and whole-body protein synthesis: a systematic review and meta-analysis

CONTEXT

Sarcopenia describes the age-related decline in skeletal muscle mass and strength that is driven, at least in part, by an imbalance between rates of muscle protein synthesis (MPS) and muscle protein breakdown. An expanding body of literature has examined the effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) ingestion on MPS rates in older adults, with mixed findings.

OBJECTIVE

The aim of this systematic review and meta-analysis was to investigate the effectiveness of n-3 PUFA ingestion in stimulating rates of MPS and whole-body protein synthesis in healthy adults and clinical populations.

DATA SOURCES

Searches were conducted of the PubMed, Web of Science, Cochrane Library, and Scopus databases from inception until December 2022 for articles on randomized controlled trials comparing the effect of n-3 PUFA ingestion vs a control or placebo on rates of MPS and whole-body protein synthesis. The search yielded 302 studies, of which 8 were eligible for inclusion.

DATA EXTRACTION

The random effects inverse-variance model was used and standardized mean differences (SMDs) with 95%CIs were calculated to assess the pooled effect. Risk of bias was assessed by the Cochrane Risk-of-Bias 2 tool.

DATA ANALYSIS

The main analysis indicated no effect of n-3 PUFA supplementation on MPS rates (k = 6; SMD: 0.03; 95%CI, -0.35 to 0.40; I2 = 30%; P = .89). Subgroup analysis based on age, n-3 PUFA dose, duration of supplementation, and method used to measure fractional synthetic rate also revealed no effect of n-3 PUFA ingestion on MPS. In contrast, the main analysis demonstrated an effect of n-3 PUFA ingestion on increasing whole-body protein synthesis rates (k = 3; SMD: 0.51; 95%CI, 0.12-0.90; I2 = 0%; P = .01).

CONCLUSIONS

n-3 PUFA ingestion augments the stimulation of whole-body protein synthesis rates in healthy adults and clinical populations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 42022366986.

Body composition, balance, functional capacity and falls in older women

BACKGROUND

The aim of this study was to examine the association of body composition, muscle strength, balance, and functional capacity on falls and fall injuries among community-dwelling older women.

METHODS

The study comprised of a 2-year randomized controlled trial involving 914 women with an average age of 76.5 (SD = 3.3) years at baseline. The women were assigned to exercise intervention (n = 457) and control groups (n = 457). Clinical measurements were conducted at baseline, 12 months and 24 months.

RESULTS

During the 2-year follow up, total of 546 women (59.7%) sustained a fall. The total number of falls was 1380 and out of these, 550 (40%) of falls were non-injurious and 745 (54%) were injurious. Higher femoral neck bone mineral density (BMD) was associated with a higher overall risk of falls [RR = 2.55 (95% CI = 1.70-3.84, p < 0.001)], but was a protective factor for severe fall injuries [RR = 0.03 (95% CI = 0.003-0.035, p < 0.01)]. Slower Timed Up and Go (TUG) was associated with an increased overall risk of falls [RR = 1.07 (95% CI = 1.05-1.10, p < 0.001)] and injuries requiring medical attention [RR = 1.10 (95% CI = 1.02-1.19, p = 0.02)]. Longer single leg standing time was a protective factor for falls [RR = 0.99 (95% CI = 0.99-1.00, p < 0.01)] and overall injurious falls [RR = 0.99 (95% CI = 0.99-1.00, p = 0.02)].

CONCLUSION

For postmenopausal women with higher femoral neck BMD appear to sustain more falls, but have a lower risk of severe fall injuries. Better TUG and single leg standing time predict lower risk of falls and fall injuries.

Sarcopenia is linked to higher levels of B-type natriuretic peptide and its N-terminal fragment in heart failure: a systematic review and meta-analysis

AIMS

Sarcopenia is linked to impaired physical function and exercise tolerance. The aim of this systematic review and meta-analysis was to examine the association of sarcopenia and low appendicular skeletal muscle (ASM) with biomarkers of cardiac function, B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP), in patients with heart failure (HF).

METHODS AND RESULTS

From inception until May 2023, a systematic literature search of observational studies was undertaken utilizing the PubMed, Web of Science, Scopus, and Cochrane Library databases. A meta-analysis employing a random-effects model was used to compute the pooled effects (CRD42023418465). Overall, 16 studies were included in this systematic review and meta-analysis. Our main analysis showed that sarcopenia in HF was linked to significantly higher levels of BNP (MD: 87.76, 95% CI 20.74-154.78, I2 = 61%, P = 0.01) and NT-proBNP (MD: 947.45, 95% CI 98.97-1795.93, I2 = 35%, P = 0.03). Similarly, low ASM was associated with significantly higher levels of BNP (MD: 118.95, 95% CI 46.91-191.00, I2 = 93%, P < 0.01) and NT-proBNP (MD: 672.01, 95% CI 383.72-960.30, I2 = 2%, P < 0.01). The quality of the included cohort studies was considered moderate, using the binary AXIS checklist and the Cochrane Tool to Assess the Risk of Bias in Cohort Studies.

CONCLUSIONS

In patients with HF, sarcopenia and reduced ASM are associated with considerably higher plasma levels of BNP and NT-proBNP. Future research is required to investigate whether sarcopenia may express dysregulated biomarkers of cardiac function.

Association between natriuretic peptides and C-reactive protein with frailty in heart failure: a systematic review and meta-analysis

BACKGROUND

Heart failure (HF) and frailty are accompanied by a bidirectional relationship, sharing common risk factors including elevated levels of natriuretic peptides and inflammation. The aim of this study was to compare biomarkers associated with poor clinical outcomes, that is, plasma brain natriuretic peptide (BNP), N-terminal-pro B-type natriuretic peptide (NT-proBNP), and C-reactive protein (CRP) in patients with HF and frailty vs. patients with HF without frailty.

METHODS

From inception until July 2023, PubMed, Scopus, Web of Science, and Cochrane Library a systematic literature search was conducted. To evaluate whether frailty is linked with greater levels of BNP, NT-proBNP, and CRP, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42023446607).

RESULTS

Fifty-three studies were included in this systematic review and meta-analysis. Patients with HF and frailty displayed significantly higher levels of BNP (k = 11; SMD: 0.53, 95%CI 0.30-0.76, I2 = 86%, P < 0.01), NT-proBNP (k = 23; SMD: 0.33, 95%CI 0.25-0.40, I2 = 72%, P < 0.01), and CRP (k = 8; SMD: 0.30, 95%CI 0.12-0.48, I2 = 62%, P < 0.01) vs. patients with HF without frailty. Using meta-regression, body mass index (BMI) and age were deemed potential moderators of these findings.

CONCLUSIONS

Frailty in HF is linked to increased concentrations of BNP, NT-proBNP, and CRP, which have been epidemiologically associated with adverse outcomes. The increased risk of NYHA III/IV classification further emphasizes the clinical impact of frailty in this population.

Diet quality is associated with adipose tissue and muscle mass: the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

Aging is associated with changes in body composition, and preventing loss of muscle mass and accumulation of excess adipose tissue in middle-aged adults may reduce age-related conditions at older ages. Dietary intake is one lifestyle factor shown to improve or maintain body composition. However, few studies have examined the Healthy Eating Index2015 (HEI2015), a measure of diet quality, and the association with body composition in adult men and women.

METHODS

Participant data (n = 3017) from the Coronary Artery Risk Development in Young Adults (CARDIA) study were used to examine the associations of the HEI2015 with body composition measures at Year 25 (Y25), including (1) 25 year-change in weight, body mass index (BMI), and waist circumference and (2) a computed tomography (CT) scan at Y25 measured muscle mass, muscle quality (better quality = less lipid within the muscle), and adipose tissue depots visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and adipose within skeletal muscle (intermuscular adipose tissue; IMAT). Dietary intake was assessed by a diet history three times over 20 years, at years 0, 7, and 20. HEI2015, averaged over three exams, was created and categorized into quintiles. Multiple regression analysis evaluated the associations of body composition stratified across quintiles of HEI2015 adjusted for demographic characteristics, energy intake, lifestyle factors, and baseline anthropometric measures as appropriate. Race-sex interaction was tested (Pinteraction  > 0.30).

RESULTS

Over 25 years of follow-up, averaged HEI2015 was significantly and inversely associated with weight gain (Quintile 1 (Q1) 37.3 lb vs. 32.9 in Q5; Ptrend  = 0.01), change in BMI (Q1 5.8 kg/m2 vs. 5.0 in Q5; Ptrend  = 0.005), and change in waist circumference (Q1 17.5 cm vs. 15.2 cm in Q5; Ptrend  < 0.001). By Y25, HEI2015 was inversely associated with VAT Q1 136.8 cm3 vs. 116.6 in Q5; Ptrend  < 0.001) and IMAT volumes (Q1 9.52 vs. 8.12 cm3 in Q5; Ptrend  < 0.001). Although total muscle volume declined (Ptrend  = 0.03), lean muscle mass volume was similar across quintiles (Ptrend  = 0.55). The IMAT/total muscle mass ratio declined across HEI2015 quintiles (Ptrend  < 0.001). Finally, higher HEI2015 was associated with better muscle quality at Y25 (higher value = less lipid within the muscle; Q1 41.1 vs. 42.2 HU in Q5; Ptrend  = 0.002). HEI2015 was nonlinearly, but inversely, associated with SAT (nonlinear P = 0.011).

CONCLUSIONS

Improving diet quality in young to middle-aged adults is a recommended strategy to promote better measures of body composition. Our study findings suggest that healthier food choices may influence body composition.

Is sarcopenia an associated factor of increased administration of specific medications in patients with heart failure? A systematic review and meta-analysis

Background

There is controversy in relation to commonly used drugs in heart failure (HF) and their impact on muscle function. The aim of this study was to evaluate the odds of receiving specific medications often used in clinical practice by patients with HF and sarcopenia vs. without sarcopenia.

Methods

A systematic literature search of cohort studies via databases (PubMed, Web of Science, Scopus, and Cochrane Library) was conducted from inception until March 2023. To determine if sarcopenia is linked to a higher number of specific HF-related medications, a meta-analysis using a random-effects model was used to calculate the pooled effects.

Results

Our main analyses showed no significant association of sarcopenia with administration of higher HF-related medication count vs. those without sarcopenia. Those with lower appendicular lean mass (ALM) had significantly lower odds of receiving angiotensin converting enzyme inhibitors (ACE-Is)/angiotensin receptor blockers (ARBs) (OR: 0.68, 95%CI 0.50-0.90, I2 = 12%, P < 0.01) vs. patients with higher ALM for which age could be an important confounder based on meta-regression. No statistically significant differences were found in relation to B-blockers OR: 0.84, 95%CI 0.63-1.12, I2 = 7%, P = 0.24) and loop diuretics (OR: 1.19, 95%CI 0.87-1.63, I2 = 0%, P = 0.27). Regarding handgrip strength, gait speed, and short physical performance battery, our narrative synthesis found mixed results.

Conclusion

This systematic review and meta-analysis did not find a relationship of specific medication count in sarcopenia vs. without sarcopenia in patients with HF, although increased odds of ACE-I/ARB was shown in those with higher ALM.

Systematic Review Registration

PROSPERO (CRD42023411137).

Randomised controlled trial combining vitamin E-functionalised chocolate with physical exercise to reduce the risk of protein-energy malnutrition in predementia aged people: study protocol for Choko-Age

OBJECTIVE

Protein-energy malnutrition and the subsequent muscle wasting (sarcopenia) are common ageing complications. It is knowing to be also associated with dementia. Our programme will test the cytoprotective functions of vitamin E combined with the cortisol-lowering effect of chocolate polyphenols (PP), in combination with muscle anabolic effect of adequate dietary protein intake and physical exercise to prevent the age-dependent decline of muscle mass and its key underpinning mechanisms including mitochondrial function, and nutrient metabolism in muscle in the elderly.

METHODS AND ANALYSIS

In 2020, a 6-month double-blind randomised controlled trial in 75 predementia older people was launched to prevent muscle mass loss, in respond to the 'Joint Programming Initiative A healthy diet for a healthy life'. In the run-in phase, participants will be stabilised on a protein-rich diet (0.9-1.0 g protein/kg ideal body weight/day) and physical exercise programme (high-intensity interval training specifically developed for these subjects). Subsequently, they will be randomised into three groups (1:1:1). The study arms will have a similar isocaloric diet and follow a similar physical exercise programme. Control group (n=25) will maintain the baseline diet; intervention groups will consume either 30 g/day of dark chocolate containing 500 mg total PP (corresponding to 60 mg epicatechin) and 100 mg vitamin E (as RRR-alpha-tocopherol) (n=25); or the high polyphenol chocolate without additional vitamin E (n=25). Muscle mass will be the primary endpoint. Other outcomes are neurocognitive status and previously identified biomolecular indices of frailty in predementia patients. Muscle biopsies will be collected to assess myocyte contraction and mitochondrial metabolism. Blood and plasma samples will be analysed for laboratory endpoints including nutrition metabolism and omics.

ETHICS AND DISSEMINATION

All the ethical and regulatory approvals have been obtained by the ethical committees of the Azienda Ospedaliera Universitaria Integrata of Verona with respect to scientific content and compliance with applicable research and human subjects' regulation. Given the broader interest of the society toward undernutrition in the elderly, we identify four main target audiences for our research activity: national and local health systems, both internal and external to the project; targeted population (the elderly); general public; and academia. These activities include scientific workshops, public health awareness campaigns, project dedicated website and publication is scientific peer-review journals.

TRIAL REGISTRATION NUMBER

NCT05343611.

Does omega-3 supplementation improve the inflammatory profile of patients with heart failure? a systematic review and meta-analysis

Omega-3 fatty acids are potential anti-inflammatory agents that may exert beneficial outcomes in diseases characterised by increased inflammatory profile. The purpose of this study was to comprehensively evaluate the existing research on the effectiveness of n-3 fatty acid supplementation in lowering levels of circulating inflammatory cytokines in patients with heart failure (HF). From the beginning until October 2022, randomised controlled trials (RCTs) were the subject of PubMed, Scopus, Web of Science, and Cochrane Library literature search. Omega-3 fatty acid supplementation vs. placebo were compared in eligible RCTs to see how they affected patients with HF in terms of inflammation, primarily of tumour necrosis factor-alpha (TNF-a), interleukin-6 (IL-6), and c-reactive protein (CRP). A meta-analysis employing the random effects inverse-variance model and standardised mean differences was performed to assess group differences. Ten studies were included in this systematic review and meta-analysis. Our main analysis (k = 5) revealed a beneficial response of n-3 fatty acid supplementation on serum TNF-a (SMD: - 1.13, 95% CI: - 1.75- - 0.50, I2 = 81%, P = 0.0004) and IL-6 levels (k = 4; SMD: - 1.27, 95% CI: - 1.88- - 0.66, I2 = 81%, P < 0.0001) compared to placebo; however, no changes were observed in relation to CRP (k = 6; SMD: - 0.14, 95% CI: - 0.35-0.07, I2 = 0%, P = 0.20). Omega-3 fatty acid supplementation may be a useful strategy for reducing inflammation in patients with HF, but given the paucity of current studies, future studies may increase the reliability of these findings.

Use of telemonitoring in patient self-management of chronic disease: a qualitative meta-synthesis

BACKGROUND

Telemonitoring for the remote patient self-management of chronic conditions can be a cost-effective method for delivering care in chronic disease; nonetheless, its implementation in clinical practice remains low. The aim of this meta-synthesis is to explore barriers and facilitators associated with the use of remote patient monitoring of chronic disease, drawing on qualitative research, and assessing participant interactions with this technology.

METHOD

A meta-synthesis of qualitative studies was performed. MEDLINE, SCOPUS and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from database date of inception to 5 February 2021. The Critical Appraisal Skills Programme (CASP) was used to critically appraise each study. Thematic synthesis was performed to identify user (patients, carers and healthcare professionals) perspectives and experiences of patient remote monitoring of chronic disease (Type 2 diabetes mellitus, chronic obstructive pulmonary disease, and cardiovascular disease).

RESULTS

Searches returned 10,401 studies and following independent screening by two reviewers, nine studies were included in this meta-synthesis. Data were synthesised and categorised into four key themes: (1) Improved care; (2) Communication; (3) Technology feasibility & acceptability; and (4) Intervention concerns. Most patients using patient remote devices felt motivated in managing their own lifestyles and felt reassured by the close monitoring and increased communication. Barriers identified involved generational differences and difficulties with the technology used.

CONCLUSION

Most studies showed a positive attitude to telemonitoring, with patients preferring the convenience of telemonitoring in comparison to attending regular clinics. Further research is required to assess the most effective technology for chronic disease management, how to maintain long-term patient adherence, and identify effective approaches to address generational variation in telemonitoring up-take.

Frailty Predicts Incident Atrial Fibrillation in Women but Not in Men: The Kuopio Ischaemic Heart Disease Risk Factor Study

INTRODUCTION

Frailty and atrial fibrillation (AF) are common aging problems and increasing globally. The association(s) between frailty and AF has been inconclusive. The purpose of this prospective population-based cohort was to investigate the associations between frailty and incident AF in older men and women.

METHODS

In total 839 participants, women (n = 458) and men (n = 381), aged 61-74 years from the Kuopio Ischaemic Heart Disease Risk Factor Study were included (March 1, 1998, to December 31, 2001). At the baseline, frailty prevalence was 49.3% (n = 414), and non-frailty 50.7% (n = 425) of the total population. Frailty was ascertained with the presence of 3-5 and prefrailty 1-2 of the following criteria: weight loss (highest 20% over 7 years), self-reported tiredness, weakness (measured by handgrip strength), slow walking speed (walking pace), and low physical activity (lowest 20%). AF events were obtained by record linkages from the national computerized hospitalization registry in Finland up to December 31, 2019. Multivariate Cox proportional hazard regression estimated the hazard ratio (HR) of incident events, adjusted for potential confounders.

RESULTS

During the mean follow-up of 14.2 years, 288 AF cases (169 women; 119 men) occurred. After adjustment for possible confounders, the HRs (95% confidence intervals [CIs]) for AF was 1.46 (1.48-1.85) in the frail population, compared to the non-frail group. The association was observed only among older frail women (multivariable-adjusted HR 1.78, 95% CI [1.28-2.48]) (p for interaction = 0.04). No statistically significant associations were observed between frailty and future AF incident among men (multivariable-adjusted HRs 1.12, 95% CI (0.77-1.63)).

CONCLUSIONS

In this population-based epidemiological cohort, the risk of developing AF was increased in women affected by frailty at baseline but not in men.

The Effect of Omega-3 Fatty Acids on Sarcopenia: Mechanism of Action and Potential Efficacy

Sarcopenia, a progressive disease characterized by a decline in muscle strength, quality, and mass, affects aging population worldwide, leading to increased morbidity and mortality. Besides resistance exercise, various nutritional strategies, including omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation, have been sought to prevent this condition. This narrative review summarizes the current evidence on the effect and mechanism of n-3 PUFA on musculoskeletal health. Despite conflicting evidence, n-3 PUFA is suggested to benefit muscle mass and volume, with more evident effects with higher supplementation dose (>2 g/day). n-3 PUFA supplementation likely improves handgrip and quadriceps strength in the elderly. Improved muscle functions, measured by walking speed and time-up-to-go test, are also observed, especially with longer duration of supplementation (>6 months), although the changes are small and unlikely to be clinically meaningful. Lastly, n-3 PUFA supplementation may positively affect muscle protein synthesis response to anabolic stimuli, alleviating age-related anabolic resistance. Proposed mechanisms by which n-3 PUFA supplementation improves muscle health include 1. anti-inflammatory properties, 2. augmented expression of mechanistic target of rapamycin complex 1 (mTORC1) pathway, 3. decreased intracellular protein breakdown, 4. improved mitochondrial biogenesis and function, 5. enhanced amino acid transport, and 6. modulation of neuromuscular junction activity. In conclusion, n-3 PUFAs likely improve musculoskeletal health related to sarcopenia, with suggestive effect on muscle mass, strength, physical performance, and muscle protein synthesis. However, the interpretation of the findings is limited by the small number of participants, heterogeneity of supplementation regimens, and different measuring protocols.

Frailty alone and interactively with obesity predicts heart failure: Kuopio Ischaemic Heart Disease Risk Factor Study

AIMS

We aim to evaluate the association of frailty and high body mass index with risk of incident heart failure.

METHODS AND RESULTS

From the Kuopio Ischaemic Heart Disease Risk Factor Study, 408 women and 369 men, aged 61-74 years were included in this study. Frailty was ascertained with the presence of 3-5 and prefrailty 1-2 of the following criteria: weight loss (highest 20% over 7 years), self-reported tiredness, weakness (measured by handgrip strength), slow walking speed (walking pace), and low physical activity (lowest 20%). At the baseline, participants were allocated to frail (n = 36), prefrail (n = 340), and robust (n = 441). HF incidents were obtained by record linkages from the national hospitalization registry in Finland up to 31 December 2019. Multivariate Cox proportional hazards regression estimated the hazard ratio (HR) of incident events, adjusted for potential confounders. Two hundred one HF events were recorded (111 in women and 90 in men) during the 14.2 years follow-up. After adjustment for the age and sex, the risk of HF events was higher among prefrail (HR 1.42, 95% CI 1.08 to 1.79, P = 0.02) and frail (HR 3.39, 95% CI 1.89 to 4.79, P ≤ 0.001) compared with the robust group. After adjusting for multiple confounders result remained significant for HF indecent in prefrail [1.46 (HR 1.46, 95% CI 1.09 to 1.95, P = 0.01] and frail (HR 3.33, 95% CI 1.86 to 5.70, P ≤ 0.001). In the sensitivity analysis, significant interaction between high BMI (≥25 kg/m² ) and frailty was observed (P for interaction = 0.02). The association of frailty [multivariate-adjusted HR: 2.88 (1.56 to 5.33), P ≤ 0.001)] and prefrailty [multivariate-adjusted HR: 1.40 (1.08 to 1.91), P = 0.03)] with risk of HF indecent was more pronounced in those with high BMI.

CONCLUSIONS

Frailty is highly common in older age, and our results indicated the high risk of HF incident in frail and prefrail groups. While frailty is clinically recognized by weight loss phenotype, our finding showed that frailly and high BMI can coexist and worsen the risk of HF incidence. Further research is warranted to substantiate these results in large studies and clinical settings.

Shorter sleep duration is associated with greater visceral fat mass in US adults: Findings from NHANES, 2011-2014

Habitual declines in sleep duration and increased rates of obesity are public health concerns worldwide. Accumulating evidence suggests a prominent link between reduced sleep duration and weight gain. Our cross-sectional study investigated the relationship between sleep duration and body fat distribution in US adults. We extracted data for 5151 participants (2575 men and 2576 women) aged 18-59 years from the US National Health and Nutrition Examination Survey 2011-2012 and 2013-2014. Weekday or workday night-time sleep duration was estimated using an in-home interview questionnaire. Dual-energy x-ray absorptiometry scans were used to determine regional body fat mass (arms, legs, trunk [android and gynoid], and abdominal [subcutaneous and visceral]). Multiple linear regression and restricted cubic spline analyses were performed after adjusting for several demographic, anthropometric, and nutritional covariates. There was a significant negative association between sleep duration and visceral fat mass overall (β: -12.139, P < 0.001) and by sex (men: β: -10.096, P < 0.001; women: β: -11.545, P = 0.038), after adjusting for age, ethnicity, body mass index, total body fat mass, daily energy and alcohol intake, sleep quality and sleep disorder status. Sleep duration and visceral fat appeared to plateau at ≥ 8 h of daily sleep. Sleep duration is negatively associated with visceral fat mass accumulation during adulthood with possibly no benefits beyond 8 h of sleep per day. Mechanistic and prospective studies are required to confirm the effect of sleep duration on visceral adiposity and determine its causes.

Handgrip strength is associated with learning and verbal fluency in older men without dementia: insights from the NHANES

Low handgrip strength, a hallmark measure of whole-body strength, has been linked with greater odds of cognitive decline and dementia; however, conflicting findings, which could be due to population characteristics and choice of tools, such for the assessment of handgrip strength and cognitive function domains, also exist. Therefore, we examined the relationship of handgrip strength with a comprehensive list of tests to assess domains of cognitive function using a representative sample of US older men and women without neurodegenerative disorders such as dementia. We analyzed cross-sectional data from the US National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014, with a study cohort of 777 older adults (380 men and 397 women) above 60 years of age. Handgrip strength was assessed using a handgrip dynamometer, while cognitive function was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), Intrusion Word Count Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Sex-stratified multiple linear regression analyses were performed upon covariate adjustment for age, ethnicity, socio-economic status, education, medical history, body mass index, physical activity, energy, protein, and alcohol intake. Maximal handgrip strength was positively associated with cognitive function scores, including CERAD WLLT (P = 0.009, R² = 0.146) and AFT (P = 0.022, R² = 0.024) in older men, but not in women (CERAD WLLT: P = 0.253, AFT: P = 0.370). No significant associations with CERAD WLLRT (men: P = 0.057, women: P = 0.976), WLLT-IC (men: P = 0.671, women: P = 0.869), WLLRT-IC (men: P = 0.111, women: P = 0.861), and DSST (men: P = 0.108, women: P = 0.091) were observed. Dose-response curves exhibited a prominent linear relationship between all significant associations after covariate adjustment, with no indication of a plateau in these relationships. In conclusion, higher handgrip strength was independently associated with better learning ability for novel verbal information and verbal fluency in US men over the age of 60 and without dementia. Longitudinal studies are required to confirm whether muscle strength independently predicts cognitive function changes in older adults in a sex-specific manner, and whether this connection is affirmed to the possibility of reverse causation due to declines in physical activity levels in the preclinical phase of dementia.

Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis

BACKGROUND AND AIMS

Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers.

METHODS

We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603).

RESULTS

Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I² = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I² = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I² = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I² = 0 %). These findings may be dependent on participant characteristics and treatment duration.

CONCLUSIONS

These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.

Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials

Probiotics have shown potential to counteract sarcopenia, although the extent to which they can influence domains of sarcopenia such as muscle mass and strength in humans is unclear. The aim of this systematic review and meta-analysis was to explore the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Scopus, Web of Science and Cochrane Library from inception until June 2022. Eligible RCTs compared the effect of probiotic supplementation versus placebo on muscle and total lean mass and global muscle strength (composite score of all muscle strength outcomes) in adults (>18 years). To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences. Twenty-four studies were included in the systematic review and meta-analysis exploring the effects of probiotics on muscle mass, total lean mass and global muscle strength. Our main analysis (k = 10) revealed that muscle mass was improved following probiotics compared with placebo (SMD: 0.42, 95% CI: 0.10-0.74, I²  = 57%, P = 0.009), although no changes were revealed in relation to total lean mass (k = 12; SMD: -0.03, 95% CI: -0.19 - 0.13, I²  = 0%, P = 0.69). Interestingly, a significant increase in global muscle strength was also observed among six RCTs (SMD: 0.69, 95% CI: 0.33-1.06, I²  = 64%, P = 0.0002). Probiotic supplementation enhances both muscle mass and global muscle strength; however, no beneficial effects were observed in total lean mass. Investigating the physiological mechanisms underpinning different ageing groups and elucidating appropriate probiotic strains for optimal gains in muscle mass and strength are warranted.

Markers of immune dysregulation in response to the ageing gut: insights from aged murine gut microbiota transplants

BACKGROUND

Perturbations in the composition and diversity of the gut microbiota are accompanied by a decline in immune homeostasis during ageing, characterized by chronic low-grade inflammation and enhanced innate immunity. Genetic insights into the interaction between age-related alterations in the gut microbiota and immune function remain largely unexplored.

METHODS

We investigated publicly available transcriptomic gut profiles of young germ-free mouse hosts transplanted with old donor gut microbiota to identify immune-associated differentially expressed genes (DEGs). Literature screening of the Gene Expression Omnibus and PubMed identified one murine (Mus musculus) gene expression dataset (GSE130026) that included small intestine tissues from young (5-6 weeks old) germ-free mice hosts that were compared following 8 weeks after transplantation with either old (~ 24-month old; n = 5) or young (5-6 weeks old; n = 4) mouse donor gut microbiota.

RESULTS

A total of 112 differentially expressed genes (DEGs) were identified and used to construct a gut network of encoded proteins, in which DEGs were functionally annotated as being involved in an immune process based on gene ontology. The association between the expression of immune-process DEGs and abundance of immune infiltrates from gene signatures in normal colorectal tissues was estimated from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) project. The analysis revealed a 25-gene signature of immune-associated DEGs and their expression profile was positively correlated with naïve T-cell, effector memory T-cell, central memory T-cell, resident memory T-cell, exhausted T-cell, resting Treg T-cell, effector Treg T-cell and Th1-like colorectal gene signatures. Conclusions These genes may have a potential role as candidate markers of immune dysregulation during gut microbiota ageing. Moreover, these DEGs may provide insights into the altered immune response to microbiota in the ageing gut, including reduced antigen presentation and alterations in cytokine and chemokine production.

Exercise and nutritional interventions on sarcopenia and frailty in heart failure: a narrative review of systematic reviews and meta-analyses

The purpose of this review is to describe the present evidence for exercise and nutritional interventions as potential contributors in the treatment of sarcopenia and frailty (i.e. muscle mass and physical function decline) and the risk of cardiorenal metabolic comorbidity in people with heart failure (HF). Evidence primarily from cross-sectional studies suggests that the prevalence of sarcopenia in people with HF is 37% for men and 33% for women, which contributes to cardiac cachexia, frailty, lower quality of life, and increased mortality rate. We explored the impact of resistance and aerobic exercise, and nutrition on measures of sarcopenia and frailty, and quality of life following the assessment of 35 systematic reviews and meta-analyses. The majority of clinical trials have focused on resistance, aerobic, and concurrent exercise to counteract the progressive loss of muscle mass and strength in people with HF, while promising effects have also been shown via utilization of vitamin D and iron supplementation by reducing tumour necrosis factor-alpha (TNF-a), c-reactive protein (CRP), and interleukin-6 (IL-6) levels. Experimental studies combining the concomitant effect of exercise and nutrition on measures of sarcopenia and frailty in people with HF are scarce. There is a pressing need for further research and well-designed clinical trials incorporating the anabolic and anti-catabolic effects of concurrent exercise and nutrition strategies in people with HF.

Dietary Fiber Intake is Associated with Cognitive Function in Older Adults: Data from the National Health and Nutrition Examination Survey

BACKGROUND

Aging is a global health challenge that is associated with a decline in cognitive function. In the United States, most older adults (≥50 years) do not meet the recommended daily fiber intake, although preliminary evidence suggests that dietary fiber consumption could elicit clinical benefits on cognitive function. We investigated the associations between dietary fiber intake and cognitive function in older adults.

METHODS

We analyzed data from the US National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014, with a study cohort of 1070 older adults (≥60 years). Cognitive function was assessed using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning Test (WLT), Word Recall Test (WRT) and their Intrusion Word Count Tests (WLT-IC and WRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Multiple linear regression and cubic spline analyses were employed to examine the association between dietary fiber intake and cognitive performance on a test-by-test basis, after covariates adjustment (ie, age, sex, race, socioeconomic status, educational level, medical history, body mass index, alcohol, and energy intake).

RESULTS

Participants had a mean age of 69.2 years and were primarily non-Hispanic white of middle-high socioeconomic status with a college degree at minimum. The mean dietary fiber intake was 17.3 g/d. The analysis showed that dietary fiber intake was positively associated with DSST (P = .031). No associations with CERAD WLT (P = .41), WRT (P = .68), WLT-IC (P = .07), and WRT-IC (P = .28), and AFT (P = .40) scores were observed. A plateau in DSST score was revealed at a dietary fiber intake of 34 g/d.

CONCLUSIONS

Higher dietary fiber intake is associated with improved specific components of cognitive function in older adults aged 60 years and older. Public health interventions that target a recommended dietary fiber intake may provide a promising strategy to combat cognitive decline in high-risk groups of older adults.

Lifetime serum concentration of 25-hydroxyvitamin D 25(OH) is associated with hand grip strengths: insight from a Mendelian randomisation

Clinical trials have suggested that increased 25-hydroxyvitamin D (25(OH)D) has positive effect on hand grip strength. This Mendelian randomisation (MR) was implemented using summary-level data from the largest genome-wide association studies on vitamin D (n = 73,699) and hand grip strength. Inverse variance weighted method (IVW) was used to estimate the causal estimates. Weighted median (WM)-based method, MR-Egger and leave-one-out were applied as sensitivity analysis. Results showed that genetically higher-serum 25(OH)D levels had a positive effect on both right hand grip (IVW = Beta: 0.038, P = 0.030) and left hand grip (IVW = Beta: 0.034, P = 0.036). There was a low likelihood (statistically insignificant) of heterogeneity and pleiotropy, and the observed associations were not driven by single single-nucleotide polymorphisms. Furthermore, MR pleiotropy residual sum and outlier did not highlight any outliers. In conclusion, our results highlighted the causal and beneficial effect of serum 25(OH) D on right- and left-hand grip strengths.

The Impact of Frailty and Comorbidities on Heart Failure Outcomes

Frailty is a multisystemic process leading to reduction of physiological reserve and a reduction in physical activity. Heart failure (HF) is recognised as a global cause of morbidity and mortality, increasing in prevalence over recent decades. Because of shared phenotypes and comorbidities, there is significant overlap and a bidirectional relationship, with frail patients being at increased risk of developing HF and vice versa. Despite this, frailty is not routinely assessed in patients with HF. Identification of these patients to direct multidisciplinary care is key, and the development of a frailty assessment tool validated in a large HF population is also an unmet need that would be of considerable benefit in directing multidisciplinary-team management. Non-pharmacological treatment should be included, as exercise and physical rehabilitation programmes offer dual benefit in frail HF patients, by treating both conditions simultaneously. The evidence for nutritional supplementation is mixed, but there is evidence that a personalised approach to nutritional support in frail HF patients can improve outcomes.

Lipid profile, lipid ratios, apolipoproteins, and risk of cardiometabolic multimorbidity in men: The Kuopio Ischaemic Heart Disease Risk Factor Study

The blood level of lipids, apolipoproteins, and lipid ratios are important predictors of some chronic diseases. However, their association with cardiometabolic multimorbidity (CMM) is less known. We evaluated a wide range of lipid profiles and lipid ratios, including low-density lipoprotein-cholesterol (LDL-C), very-low-density lipoprotein-cholesterol (VLDL-C), high-density lipoprotein-cholesterol (HDL-C), and apoA1 and B, as well triglyceride and total cholesterol with risk of incident CMM. In 1728 men aged 52.5 ± 5.2 years from the Kuopio Ischaemic Heart Disease were included in this study. We defined CMM as coexisting of two or more of stroke, type 2 diabetes mellitus (T2D), coronary heart disease (CHD). A Cox proportional hazard regression method was applied to evaluate the risk of CMM against the exposures. During the mean follow-up of 22.4 years, 335 men suffered from CMM conditions. Higher serum triglyceride and VLDL concentrations were associated with a higher risk of coexisting T2D-CHD (HRs 1.99 (95% CI, 1.12-3.53) and HRs 1.79 (95% CI, 1.04-3.11), respectively. Whereas higher HDL was associated with lower incident [HRs 0.49 (95% CI, 0.40-1.00)]. The HRs for coexisting T2D-CHD was 2.02 (95% CI, 1.01-3.07) for total cholesterol/HDL-C, 1.85 (95% CI, 1.04-3.29) for triglyceride/HDL-C, 1.69 (95% CI, 1.01-2.31) for Non-HDL-C/HDL-C, and 1.89 (95% CI, 1.03-2.46) for apoB/apoA1. In contrast, serum LDL-C/apoB ratios were inversely associated with the risk of coexisting T2D-CHD [HRs 0.50 (95% CI, 0.28-0.90)]. No associations were observed between our exposures and other CMM conditions. In conclusion, elevated triglyceride, VLDL-C, total cholesterol/HDL-C, TG/HDL-C, apoB/apoA1 as well as lower LDL-C/apoB were independently associated with the higher risk of T2D-CHD coexistence.

Genetically Determined Serum 25-Hydroxyvitamin D Is Associated with Total, Trunk, and Arm Fat-Free Mass: A Mendelian Randomization Study

PURPOSE

Low serum vitamin D status has been associated with reduced muscle mass in observational studies although the relationship is controversial and a causal association cannot be determined from such observations. Two-sample Mendelian randomization (MR) was applied to assess the association between serum vitamin D (25(OH)D) and total, trunk, arm and leg fat-free mass (FFM).

METHODS

MR was implemented using summary-level data from the largest genome-wide association studies (GWAS) on vitamin D (n=73,699) and total, trunk, arm and leg FFM. Inverse variance weighted method (IVW) was used to estimate the causal estimates. Weighted median (WM)-based method, and MR-Egger, leave-one-out were applied as sensitivity analysis.

RESULTS

Genetically higher serum 25(OH)D levels had a positive effect on total (IVW = Beta: 0.042, p = 0.038), trunk (IVW = Beta: 0.045, p = 0.023) and arm (right arm IVW = Beta: 0.044, p = 0.002; left arm IVW = Beta: 0.05, p = 0.005) FFM. However, the association with leg FFM was not significant (right leg IVW = Beta: 0.03, p = 0.238; left leg IVW = Beta: 0.039, p = 0.100). The likelihood of heterogeneity and pleiotropy was determined to be low (statistically non-significant), and the observed associations were not driven by single SNPs. Furthermore, MR pleiotropy residual sum and outlier test did not highlight any outliers.

CONCLUSIONS

Our results illustrate the potentially causal, positive effect of serum 25(OH)D concentration on total, trunk and upper body appendicular fat-free mass.

Dietary omega-3 polyunsaturated fatty acid and alpha-linolenic acid are associated with physical capacity measure but not muscle mass in older women 65-72 years

Purpose

The aim was to investigate the cross-sectional association of dietary omega-3 polyunsaturated fatty acids PUFA (alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)) intake with multiple physical functions, muscle mass and fat mass in older women.

Method

Study subjects were 554 women from the Osteoporosis Risk Factor and Prevention Fracture Prevention Study, with dietary intake assessed with 3-day food record. Body composition was measured by dual-energy X-ray absorptiometry. Physical function measures included walking speed 10 m, chair rises, one leg stance, knee extension, handgrip strength and squat. Short physical performance battery (SPPB) score was defined based on the European working group on sarcopenia criteria.

Results

The multivariable adjusted models showed statistically significant associations for dietary ALA with higher SPPB (β = 0.118, P = 0.024), knee extension force at baseline (β = 0.075, P = 0.037) and lower fat mass (β = − 0.081, P = 0.034), as well as longer one-leg stance (β = 0.119, P = 0.010), higher walking speed (β = 0.113, P = 0.047), and ability to squat to the ground (β = 0.110, P = 0.027) at baseline. Total dietary omega-3 PUFA was associated with better SPPB (β = 0.108, P = 0.039), one-leg stance (β = 0.102, P = 0.041) and ability to squat (β = 0.110, P = 0.028), and with walking speed (β = 0.110, P = 0.028). However, associations for dietary EPA and DHA with physical function and body composition were not significant.

Conclusion

Dietary omega-3 and ALA, but not EPA and DHA, were positively associated with muscle strength and function in older women. The intake of omega-3 and its subtypes was not associated with muscle mass. Longitudinal studies are needed to show whether omega-3 intake may be important for muscle function in older women.

Interactive remote patient monitoring devices for managing chronic health conditions: systematic review and meta-analysis (Preprint)

Background

Telemedicine is an expanding and feasible approach to improve medical care for patients with long-term conditions. However, there is a poor understanding of patients’ acceptability of this technology and their rate of uptake.

Objective

The aim of this study was to systematically review the current evidence on telemonitoring in the management of patients with long-term conditions and evaluate the patients’ uptake and acceptability of this technology.

Methods

MEDLINE, Scopus, and CENTRAL (the Cochrane Central Register of Controlled Trials) were searched from the date of inception to February 5, 2021, with no language restrictions. Studies were eligible for inclusion if they reported any of the following outcomes: intervention uptake and adherence; study retention; patient acceptability, satisfaction, and experience using the intervention; changes in physiological values; all-cause and cardiovascular-related hospitalization; all-cause and disease-specific mortality; patient-reported outcome measures; and quality of life. In total, 2 reviewers independently assessed the articles for eligibility.

Results

A total of 96 studies were included, and 58 (60%) were pooled for the meta-analyses. Meta-analyses showed a reduction in mortality (risk ratio=0.71, 95% CI 0.56-0.89; P=.003; I²=0%) and improvements in blood pressure (mean difference [MD]=−3.85 mm Hg, 95% CI −7.03 to −0.68; P=.02; I²=100%) and glycated hemoglobin (MD=−0.33, 95% CI −0.57 to −0.09; P=.008; I²=99%) but no significant improvements in quality of life (MD=1.45, 95% CI −0.10 to 3; P=.07; I²=80%) and an increased risk of hospitalization (risk ratio=1.02, 95% CI 0.85-1.23; P=.81; I²=79%) with telemonitoring compared with usual care. A total of 12% (12/96) of the studies reported adherence outcomes, and 9% (9/96) reported on satisfaction and acceptance outcomes; however, heterogeneity in the assessment methods meant that a meta-analysis could not be performed.

Conclusions

Telemonitoring is a valid alternative to usual care, reducing mortality and improving self-management of the disease, with patients reporting good satisfaction and adherence. Further studies are required to address some potential concerns regarding higher hospitalization rates and a lack of positive impact on patients’ quality of life.

Trial Registration

PROSPERO CRD42021236291; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=236291

Physical capacity, subjective health, and life satisfaction in older women: a 10-year follow-up study

Background

Physical capacity and subjective wellbeing are important for healthy aging. Our aim was to study how objective/subjective physical capacity and subjective health relate to life satisfaction, in a 10-year follow-up of aging women.

Methods

The participants (n = 1485, mean age 67.4 years) consisted of community-dwelling older women living in Kuopio, Finland. Grip strength and one-legged stance test time were used as objective, and self-rated mobility (SRM) as subjective physical capacity measures. Self-rated health (SRH) and SRM were assessed with one-item scales and life satisfaction with a 4-item scale. Correlation and linear regression were used to analyze these relationships and correlation network analysis to visualize them. Age and BMI were included in the analysis as adjusting factors.

Results

All the study variables were significantly correlated with baseline and follow-up life satisfaction, except BMI, which was only associated with life satisfaction at follow-up. On both occasions, SRH and SRM were the two strongest correlates of life satisfaction, but their mutual correlation was still higher. In linear regression analyses, SRH was positively associated with both baseline and follow-up life satisfaction, but physical capacity measures became non-significant after including SRH and SRM in the model. In the partial correlation network analyses, SRH and SRM were the most central nodes, connecting every other variable.

Conclusions

Self-reports on health, mobility, and life satisfaction are closely intertwined and provide easily accessible health information among aging women, but the impacts of objective physical capacity measures warrant further longitudinal studies in respect to subjective wellbeing among aging people.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02605-z.

Nutrition and Frailty: Opportunities for Prevention and Treatment

Frailty is a syndrome of growing importance given the global ageing population. While frailty is a multifactorial process, poor nutritional status is considered a key contributor to its pathophysiology. As nutrition is a modifiable risk factor for frailty, strategies to prevent and treat frailty should consider dietary change. Observational evidence linking nutrition with frailty appears most robust for dietary quality: for example, dietary patterns such as the Mediterranean diet appear to be protective. In addition, research on specific foods, such as a higher consumption of fruit and vegetables and lower consumption of ultra-processed foods are consistent, with healthier profiles linked to lower frailty risk. Few dietary intervention studies have been conducted to date, although a growing number of trials that combine supplementation with exercise training suggest a multi-domain approach may be more effective. This review is based on an interdisciplinary workshop, held in November 2020, and synthesises current understanding of dietary influences on frailty, focusing on opportunities for prevention and treatment. Longer term prospective studies and well-designed trials are needed to determine the causal effects of nutrition on frailty risk and progression and how dietary change can be used to prevent and/or treat frailty in the future.

High Postural Sway Is an Independent Risk Factor for Osteoporotic Fractures but Not for Mortality in Elderly Women

The aim of this prospective cohort study was to investigate the independent effect of postural sway on overall fracture and osteoporotic fracture risk after controlling for other established fracture risk factors. As a secondary outcome, mortality was also investigated. The study sample is a stratified random sample of 1568 women born between 1932 and 1941, residing in Kuopio province, eastern Finland. Fracture data were obtained through study questionnaires and verified through hospital records. Mortality data were verified through the National Registry. Using static posturography, postural sway was recorded for 1568 women at the fifth year of follow-up in 1994 through 1997. Mediolateral (ML), anteroposterior (AP), and total sway parameters were used for analysis. Mean follow-up time for any fractures, osteoporotic fractures, and mortality was 10.6, 11.4, and 17.5 years, respectively. After adjustment, subjects in the highest quartile of ML sway (HR, 2.0; 95% CI, 1.5 to 2.8) and total sway (HR, 1.6; 95% CI, 1.2 to 2.2) had a higher risk for any fracture. Osteoporotic fracture risk was also higher in the fourth quartile of ML sway (HR, 1.9; 95% CI, 1.1 to 3.0) and total sway (HR, 1.7; 95% CI, 1.0 to 2.8). The models were adjusted for fracture risk assessment tool risk factors and leg-extension strength. Further, women having both lowest bone density and highest postural sway were at 4.9 (95% CI, 2.6 to 9.5) times higher risk of overall fracture and 11.8 (95% CI, 2.7 to 51.3) times higher risk for osteoporotic fracture in comparison with subjects having highest bone density and lowest postural sway. The association between postural sway and mortality was not significant after adjustment. In conclusion, high postural sway is an independent risk factor for any fractures as well as for osteoporotic fractures. A combination of low bone density and high postural sway poses even higher fracture risk than either factor alone. Postural sway does not predict mortality independently. © 2019 American Society for Bone and Mineral Research.

Relationship of body anthropometric measures with skeletal muscle mass and strength in a reference cohort of young Finnish women

OBJECTIVES

1) To study if limb length explains variability in appendicular and total muscle mass better than height and 2) if muscle mass adjusted for limb length rather than height correlates better with grip and knee extension strength.

METHODS

400 healthy women aged 20-40 were recruited as a reference population. Body composition, limb length, grip strength and knee extension strength were measured. New relative muscle mass indexes were computed by adjusting upper limb muscle mass for upper limb length (ULRSMI) and lower limb muscle mass for lower limb length (LLRSMI).

RESULTS

Height correlated strongest with all muscle mass measures. Height had the highest R² values for predicting variability in appendicular skeletal muscle mass (0.33), upper limb skeletal muscle mass (0.20), lower limb skeletal muscle mass (0.34) and total skeletal muscle mass (0.36). Correlation of relative skeletal muscle mass index (RSMI) with grip and knee extension strength (r=0.47 and 0.43) was higher when compared with correlation of ULRSMI and LLRSMI with these measures.

CONCLUSION

Compared to limb length, height correlates better with regional and total muscle mass. Muscle mass adjusted for height correlates better with grip strength and knee strength when compared with muscle mass adjusted for limb length.

Association of Protein Intake with Bone Mineral Density and Bone Mineral Content among Elderly Women: The OSTPRE Fracture Prevention Study

It has been hypothesized that high protein intakes are associated with lower bone mineral content (BMC). Previous studies yield conflicting results and thus far no studies have undertaken the interaction of body mass index (BMI) and physical activity with protein intakes in relation to BMC and bone mineral density (BMD).

OBJECTIVE

To evaluate the associations of dietary total protein (TP), animal protein (AP) and plant protein (PP) intakes with BMC and BMD and their changes. We tested also the interactions of protein intake with, obesity (BMI ≤30 vs. >30 kg/m2) and physical activity level (passive vs. active). Design/ Setting: Prospective cohort study (Osteoporosis Risk-Factor and Fracture-Prevention Study). Participants/measures: At the baseline, 554 women aged 65-72 years filled out a 3-day food record and a questionnaire covering data on lifestyle, physical activity, diseases, and medications. Intervention group received calcium 1000 mg/d and cholecalciferol 800 IU for 3 years. Control group received neither supplementation nor placebo. Bone density was measured at baseline and year 3, using dual energy x-ray absorptiometry. Multivariable regression analyses were conducted to examine the associations between protein intake and BMD and BMC.

RESULTS

In cross-sectional analyses energy-adjusted TP (P≤0·029) and AP (P≤0·045) but not PP (g/d) were negatively associated with femoral neck (FN) BMD and BMC. Women with TP≥1·2 g/kg/body weight (BW) (Ptrend≤0·009) had lower FN, lumbar spine (LS) and total BMD and BMC. In follow-up analysis, TP (g/kg/BW) was inversely associated with LS BMD and LS BMC. The detrimental associations were stronger in women with BMI<30 kg/m2. In active women, TP (g/kg/BW) was positively associated with LS BMD and FN BMC changes.

CONCLUSIONS

This study suggests detrimental associations between protein intake and bone health. However, these negative associations maybe counteracted by BMI>30 kg/m2 and physical activity.