Estimated appendicular skeletal muscle mass using calf circumference and mortality: Results from the aging and longevity study in the Sirente geographic area (ilSIRENTE study)

Muscle mass mediates the association between dietary diversity and mortality among the older adults: A prospective cohort study

AIMS

The association between dietary diversity and increased mortality risk is well-documented. However, it remains unclear whether and to what extent dietary diversity affects mortality through appendicular skeletal muscle mass (ASM). Therefore, we assessed whether ASM mediated the association between dietary diversity and mortality.

METHODS

We used data from the Chinese longitudinal healthy longevity survey (CLHLS) (2011-2018). The baseline Dietary Diversity Score (DDS) was derived from 9 food items, and the Anti-inflammatory Dietary Diversity Score (AIDDS) was used to assess the diversity of anti-inflammatory foods in the diet. Cox regression models were employed to estimate the association of DDS and AIDDS with mortality. Interaction analysis was performed to analyze the association between DDS, AIDDS, and ASM in different groups. Subsequently, mediation analysis was performed to examine whether ASM partly accounted for the association.

RESULTS

A total of 5422 participants (average age 85.99 years) were included in the analysis. Among them, 3241 participants died during the follow-up period. We observed that participants with higher DDS (HR = 0.907, 95 % CI: 0.842-0.977) and AIDDS scores (HR = 0.947, 95 % CI: 0.917-0.977) had lower mortality rates. Subgroup analyses showed no interaction between DDS, AIDDS, and ASM (p for interaction>0.05). ASM mediated the 14.0 % association between DDS and mortality, and the 10.7 % association between AIDDS and mortality.

CONCLUSIONS

Dietary diversity and anti-inflammatory dietary diversity could reduce mortality risk and promote longevity in older adults. The association between these factors was partially mediated by an increase in muscle mass among older adults.

Mapping Normative Muscle Health Metrics Across the Aging Continuum: A Multinational Study Pooling Data From Eight Cohorts in Japan, Malaysia and Taiwan

BACKGROUND

The vigour of our musculature wanes as the years advance, and prognosticating the concomitant trajectories throughout the course of life assumes paramount importance for judicious and timely interventions. In the present study, we aimed to establish age- and sex-specific reference centiles for multiple muscle health metrics and reveal the distributions of these metrics throughout the aging process in the Asian population.

METHODS

By using cross-sectional pooled data of community dwellers aged 20 years or older in eight cohorts from Taiwan, Japan and Malaysia, normative values for muscle health metrics (calf circumference (cm), relative appendicular skeletal muscle (RASM) (kilogram per square metre), body mass index (BMI)-adjusted appendicular skeletal muscle mass (kilogram/(kilogram per square metre)), handgrip strength (kilogram), five-time chair stand (seconds) and gait speed (metre per second)) in men and women, categorized by age groups, are calculated. The mean values, along with the 5th, 25th, 50th, 75th and 95th percentiles of these muscle health metrics, are also delineated for both sexes.

RESULTS

Among 34 265 (16 164 men, 18 101 women) participants from eight cohorts, calf circumference declined in age groups from 60 years onward. RASM values declined from the 50s in men but were stable in women until the 80s. ASM/BMI values showed declines in older age groups for both sexes. Handgrip strength declined similarly from 40 years of age in both sexes. Five-time chair stand performance declined from the 30s. Gait speed peaked at 1.6 m/s in men in their 50s and then declined, while it declined in women in their 60s. The inflection points for decline differed by metric and sex. The 20th percentile cutoffs for individuals aged 65-69 years were as follows: calf circumference, 33.0 cm (men) and 31.5 cm (women); RASM, 7.0 kg/m2 (men) and 5.5 kg/m2 (women); ASM/BMI, 0.78 kg/(kg/m2) (men) and 0.56 kg/(kg/m2) (women); handgrip strength, 30.4 kg (men) and 18.1 kg (women); five-time chair stand, 9.4 s (men) and 10.0 s (women); and gait speed, 0.9 m/s (both). Those in the fifth percentile of all muscle health metrics faced earlier declines than their 95th percentile counterparts did, highlighting the critical roles in identifying these high-risk groups.

CONCLUSION

The pooled analysis of eight Asian cohorts clearly outlined the age-related changes in various muscle health metrics, with the inflection point of accelerated decline showing age- and sex-specific characteristics. Defining trajectories of muscle health metrics across life stages facilitates timely interventions to mitigate age-related risks and promote healthy longevity.

Waist-to-calf circumference ratio as a potential indicator of diabetes risk: results from the Longevity Check-Up (Lookup) 8

Diabetes is a prevalent metabolic condition with substantial health and economic impacts. Therefore, effective and accessible indicators are essential for early detection and prevention. This study investigates the link between the waist-to-calf circumference ratio (WCR) and diabetes risk in a large cohort from the Longevity Check-Up (Lookup) 8+ Study. The present investigation is a retrospective cross-sectional study. Diabetes was defined either as self-reported diagnosis, or fasting plasma glucose equal to or greater than 126 mg/dL, or random plasma glucose equal to or greater than 200 mg/dL. The WCR was calculated by dividing waist circumference by calf circumference. A total population of 8900 participants (mean age 57.1 ± 14.8 years, 55% women) was included in the study. The prevalence of diabetes was 9.4%. Mean WCR displayed a significant trend (p for trend < 0.001), and the analysis of covariance (ANCOVA) revealed significant differences among the normal, pre-diabetes, diabetes groups. Unadjusted logistic regression showed a positive association between higher WCR and diabetes, which remained significant in the adjusted models. Receiver operating characteristic curve analysis indicated that WCR had a higher area under the curve compared to waist circumference alone, with cut-off values of 2.35 for men and 2.12 for women providing high sensitivity (91% for men, 92% for women) and specificity (74% for men, 75% for women). Our study introduces WCR as a novel, simple, and cost-effective anthropometric measure for identifying individuals at risk of diabetes, suitable for clinical use, especially in resource-limited settings.

Glyphosate exposure, muscular health and functional limitations in middle-aged and older adults

BACKGROUND

Glyphosate is the most widely used herbicide worldwide, both in domestic and industrial settings. Experimental research in animal models has demonstrated changes in muscle physiology and reduced contractile strength associated with glyphosate exposure, while epidemiological studies have shown associations between glyphosate exposure and adverse health outcomes in critical biological systems affecting muscle function.

METHODS

This study used data from a nationally representative survey of the non-institutionalized U.S. general population (NHANES, n = 2132). Urine glyphosate concentrations were determined by ion chromatography with tandem mass spectrometry. Hand grip strength (HGS) was measured using a Takei Dynamometer, and relative strength estimated as the ratio between HGS in the dominant hand and the appendicular lean mass (ALM) to body mass index (ALMBMI) ratio. Low HGS and low relative HGS were defined as 1 sex-, age- and race-specific SD below the mean. Physical function limitations were identified as significant difficulty or incapacity in various activities.

RESULTS

In fully-adjusted models, the Mean Differences (MD) and 95% confidence intervals [95%CI] per doubling increase in glyphosate concentrations were -0.55 [-1.09, -0.01] kg for HGS in the dominant hand, and -0.90 [-1.58. -0.21] kg for HGS/ALMBMI. The Odds Ratios (OR) [95% CI] for low HGS, low relative HGS and functional limitations by glyphosate concentrations were 1.27 [1.03, 1.57] for low HGS; 1.43 [1.05; 1.94] for low relative HGS; 1.33 [1.08, 1.63] for stooping, crouching or kneeling difficulty; 1.17 [0.91, 1.50] for lifting or carrying items weighting up to 10 pounds difficulty; 1.21 [1.01, 1.40] for standing up from armless chair difficulty; and 1.47 [1.05, 2.29] for ascending ten steps without pause difficulty.

CONCLUSIONS

Glyphosate exposure may be a risk factor for decreased grip strength and increased physical functional limitations. More studies investigating the influence of this and other environmental pollutants on functional aging are needed.

How to support general practitioners to better detect sarcopenia among older adults: a nested case-control analysis

PURPOSE

This study explores correlations of sarcopenia and its proxies, such as history of falls, asthenia, and ambulation issues, with frailty levels among older adults in primary care.

METHODS

In a cohort of 546,590 patients aged 60 years or older, "definite" sarcopenia cases were operationally defined through the use of non-specific diagnostic codes coupled with inspection of free-texts. Proxies of sarcopenia, such as falls history, asthenia, and ambulation issues were considered as well. Frailty was calculated using an Index intended to primary care.

RESULTS

Overall, 171 definite sarcopenia cases were found, rising to 51,520 cases when including proxies (9.4% prevalence). There was a significant association between severe frailty and increased odds of sarcopenia, consistently observed across different event definitions.

CONCLUSIONS

Sarcopenia was strongly associated with severe frailty in primary care. The history of falls, asthenia, and ambulation issues were reliable proxies to raise the suspect of sarcopenia. Improved strategies for sarcopenia detection, focusing on specific indicators within severely frail individuals, are warranted.