Dose-Response Relationships Between Body Composition Indices and All-Cause Mortality in Older Japanese Adults

Association of fat-to-muscle mass ratio with physical activity and dietary protein, carbohydrate, sodium, and fiber intake in a cross-sectional study

Higher fat-to-muscle mass ratio (FMR) is reported to be a risk factor for various diseases, including type 2 diabetes and cardiovascular diseases, and mortality. Although this association suggests that reducing FMR may help to prevent certain diseases and mortality, the relationship between FMR and lifestyle factors is unclear. Therefore, we performed a cross-sectional study with the aim to elucidate this relationship. This cross-sectional study included 1518 healthy Japanese adults aged 30 to 64 years. We measured FMR in the whole body, arms, legs, and trunk and assessed various lifestyle factors. Then, we performed forced entry multiple regression analyses for FMR with the following variables: sex, age, physical activity, dietary intake, sleep quality, cigarette smoking, stress levels, and body mass index. As a result, whole-body and regional FMRs were correlated with female sex (β = 0.71); age (β = 0.06); physical activity (β = - 0.07); dietary intake of protein (β = - 0.12), carbohydrate (β = 0.04), sodium (β = 0.13), and fiber (β = - 0.16); and body mass index (β = 0.70). The results suggest that in the Japanese middle-aged population, low FMR is associated with certain lifestyle factors, i.e. higher physical activity and a diet with higher protein and fiber and lower carbohydrate and sodium, independent of age, sex, and body mass index.

Functional and Combined Training Promote Body Recomposition and Lower Limb Strength in Postmenopausal Women: A Randomized Clinical Trial and a Time Course Analysis

Encouraging healthy aging in postmenopausal women involves advocating for lifestyle modifications, including regular physical exercise like combined training (CT) and functional training (FT). Regarding this population, age-related alterations in body composition, such as decreased muscle mass and heightened adipose tissue, impact health. The aim of this study was to analyze the effects of FT and CT on body recomposition in postmenopausal women. About the methods, we randomly allocated 96 post-menopausal women to the FT, CT, or control group (CG). We measured body composition by bioimpedance and lower limb muscle strength by sit-to-stand test in five repetitions, respectively. The training protocol lasted 16 weeks, and we measured body composition and lower limb muscle strength every 4 weeks, totaling five assessments. Regarding results, we notice that both training groups increased lean mass from the 8th week of training. In addition, a reduction was observed in total fat percentage and an increase in appendicular lean mass from the 12th week of intervention. No differences were found for body mass. Furthermore, only the experimental groups increase muscle strength, starting from the 4th week of training. The conclusion was that FT and CT promote similar adaptations in body recomposition without affecting body mass in postmenopausal women.

Appendicular Muscle Mass Index was Stronger than Body Mass Index in Association with Atherosclerosis in the Community-Dwelling Elderly

AIMS

Low muscle mass is associated with advanced atherosclerosis. However, only very few studies on the elderly have investigated a dose-response relationship between muscle mass and atherosclerosis. Furthermore, whether the relationship between muscle mass and atherosclerosis is stronger than that between body mass index (BMI) and atherosclerosis among the elderly population remains to be determined.

METHODS

A community-based sample of apparently healthy elderlies (≥ 65 years) was cross-sectionally examined for the association between appendicular skeletal muscle mass (ASM) and brachial-ankle pulse wave velocity (baPWV), a measure of atherosclerosis. We categorized the participants according to sex-specific quintiles of the ASM index (ASM/height2) or BMI. Using multivariable linear regression, we compared the slope of one standard deviation higher ASM index for baPWV with the corresponding slope of BMI, separately (single-index model) and jointly (simltaneously-adjusted model).

RESULTS

The ASM index and BMI of a total of 995 participants (60.0% women, mean age 73 years) were significantly inversely associated with baPWV in a dose-response manner across the quintiles in both sexes. The slope for the ASM index tended to be greater than that for BMI in the single-index and simultaneously-adjusted models in both sexes after adjusting for confounders.

CONCLUSIONS

Among a community-dwelling elderly population, the association between ASM and baPWV was stronger than, and independent of that between BMI and baPWV. These findings suggest that ASM provides more important information on atherosclerosis in the elderly than BMI does.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

Association Between Serum GDF15 Concentration and Total Mortality in Community-Dwelling Japanese Older Populations: The Involvement of Renal Dysfunction

BACKGROUND

Serum growth differentiation factor 15 (GDF15) is associated with age-related adverse outcomes. However, renal function has not been thoroughly evaluated in studies addressing the association between GDF15 and mortality. We aimed to clarify whether GDF15 is associated with total mortality after carefully controlling renal function markers.

METHODS

We divided 1 801 community-dwelling Japanese older adults into quartiles according to their serum GDF15 concentrations. The correlation of GDF15 with renal function and inflammation markers was assessed by calculating Spearman correlation coefficients. Cumulative survival rates of the quartiles were estimated. In a Cox regression analysis adjusted for confounders, the association between GDF15 and mortality was evaluated. The discriminative capacity of GDF15 for the prediction of mortality was assessed with receiver-operating characteristic analysis.

RESULTS

GDF15 was correlated with cystatin C (r = 0.394), β2-microglobulin (r = 0.382), C-reactive protein (r = 0.124), and interleukin-6 (r = 0.166). The highest GDF15 quartile showed poor survival compared to the others. Older adults with higher GDF15 were associated with an increased mortality risk, independent of demographics and clinically relevant variables (hazard ratio [95% confidence interval]: 1.98 [1.09-3.59]). This significant association disappeared when additionally adjusted for cystatin C (1.65 [0.89-3.05]) or β2-microglobulin (1.69 [0.91-3.12]). The ability to predict mortality was approximately comparable between GDF15 (area under the curve: 0.667), cystatin C (0.691), and β2-microglobulin (0.715).

CONCLUSIONS

Serum GDF15 is associated with total mortality in older Japanese after adjustment for major confounders. The increased mortality risk in older adults with higher GDF15 may be partly attributed to decreased renal function.

Association of muscle wasting with mortality risk among adults: A systematic review and meta-analysis of prospective studies

The relationship between muscle wasting and mortality risk in the general population remains unclear. Our study was conducted to examine and quantify the associations between muscle wasting and all-cause and cause-specific mortality risks. PubMed, Web of Science and Cochrane Library were searched until 22 March 2023 for main data sources and references of retrieved relevant articles. Prospective studies investigating the associations of muscle wasting with risks of all-cause and cause-specific mortality in the general population were eligible. A random-effect model was used to calculate the pooled relative risk (RR) and 95% confidence intervals (CIs) for the lowest versus normal categories of muscle mass. Subgroup analyses and meta-regression were performed to investigate the potential sources of heterogeneities among studies. Dose-response analyses were conducted to evaluate the relationship between muscle mass and mortality risk. Forty-nine prospective studies were included in the meta-analysis. A total of 61 055 deaths were ascertained among 878 349 participants during the 2.5- to 32-year follow-up. Muscle wasting was associated with higher mortality risks of all causes (RR = 1.36, 95% CI, 1.28 to 1.44, I²  = 94.9%, 49 studies), cardiovascular disease (CVD) (RR = 1.29, 95% CI, 1.05 to 1.58, I²  = 88.1%, 8 studies), cancer (RR = 1.14, 95% CI, 1.02 to 1.27, I²  = 38.7%, 3 studies) and respiratory disease (RR = 1.36, 95% CI, 1.11 to 1.67, I²  = 62.8%, 3 studies). Subgroup analyses revealed that muscle wasting, regardless of muscle strength, was significantly associated with a higher all-cause mortality risk. Meta-regression showed that risks of muscle wasting-related all-cause mortality (P = 0.06) and CVD mortality (P = 0.09) were lower in studies with longer follow-ups. An approximately inverse linear dose-response relationship was observed between mid-arm muscle circumference and all-cause mortality risk (P < 0.01 for non-linearity). Muscle wasting was associated with higher mortality risks of all causes, CVD, cancer and respiratory disease in the general population. Early detection and treatment for muscle wasting might be crucial for reducing mortality risk and promoting healthy longevity.

The Obesity Paradox and Mortality in Older Adults: A Systematic Review

“Obesity paradox” describes the counterintuitive finding that aged overweight and obese people with a particular disease may have better outcomes than their normal weight or underweight counterparts. This systematic review was performed to summarize the publications related to the obesity paradox in older adults, to gain an in-depth understanding of this phenomenon. PubMed©, Embase©, and Scopus© were used to perform literature search for all publications up to 20 March 2022. Studies were included if they reported data from older adults on the relation between BMI and mortality. The following article types were excluded from the study: reviews, editorials, correspondence, and case reports and case series. Publication year, study setting, medical condition, study design, sample size, age, and outcome(s) were extracted. This review has been registered with PROSPERO (no. CRD42021289015). Overall, 2226 studies were identified, of which 58 were included in this systematic review. In all, 20 of the 58 studies included in this review did not find any evidence of an obesity paradox. Of these 20 studies, 16 involved patients with no specific medical condition, 1 involved patients with chronic diseases, and 2 involved patients with type 2 diabetes mellitus. Seven out of the nine studies that looked at short-term mortality found evidence of the obesity paradox. Of the 28 studies that examined longer-term mortality, 15 found evidence of the obesity paradox. In the studies that were conducted in people with a particular medical condition (n = 24), the obesity paradox appeared in 18 cases. Our work supports the existence of an obesity paradox, especially when comorbidities or acute medical problems are present. These findings should help guide strategies for nutritional counselling in older populations.

Skeletal muscle mass and all-cause mortality: Findings from the CRONICAS cohort study

OBJECTIVE

We aimed (1) to evaluate the agreement between two methods (equation and bio-impedance analysis [BIA]) to estimate skeletal muscle mass (SMM), and (2) to assess if SMM was associated with all-cause mortality risk in individuals across different geographical sites in Peru.

METHODS

We used data from the CRONICAS Cohort Study (2010-2018), a population-based longitudinal study in Peru to assess cardiopulmonary risk factors from different geographical settings. SMM was computed as a function of weight, height, sex and age (Lee equation) and by BIA. All-cause mortality was retrieved from national vital records. Cox proportional-hazard models were developed and results presented as hazard ratios (HRs) with 95% confidence intervals (95% CIs).

RESULTS

At baseline, 3216 subjects, 51.5% women, mean age 55.7 years, were analysed. The mean SMM was 23.1 kg (standard deviation [SD]: 6.0) by Lee equation, and 22.7 (SD: 5.6) by BIA. Correlation between SMM estimations was strong (Pearson's ρ coefficient = 0.89, p < 0.001); whereas Bland-Altman analysis showed a small mean difference. Mean follow-up was 7.0 (SD: 1.0) years, and there were 172 deaths. In the multivariable model, each additional kg in SMM was associated with a 19% reduction in mortality risk (HR = 0.81; 95% CI: 0.75-0.88) using the Lee equation, but such estimate was not significant when using BIA (HR = 0.98; 95% CI: 0.94-1.03). Compared to the lowest tertile, subjects at the highest SMM tertile had a 56% reduction in risk of mortality using the Lee equation, but there was no such association when using BIA estimations.

CONCLUSION

There is a strong correlation and agreement between SMM estimates obtained by the Lee equation and BIA. However, an association between SMM and all-cause mortality exists only when the Lee equation is used. Our findings call for appropriate use of approaches to estimate SMM, and there should be a focus on muscle mass in promoting healthier ageing.

Fat-Free Mass Index as a Surrogate Marker of Appendicular Skeletal Muscle Mass Index for Low Muscle Mass Screening in Sarcopenia

OBJECTIVES

We aimed to examine the relationship between the fat-free mass index (FFMI; FFM/height²) and appendicular skeletal muscle mass index (ASMI; ASM/height²), measured using both bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), and investigate the effects of age and obesity. We also evaluated the suitability of BIA-measured FFMI as a simple surrogate marker of the ASMI and calculated the optimal FFMI cutoff value for low muscle mass screening to diagnose sarcopenia.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

This study included 1313 adults (women, 33.6%) aged 40-87 years (mean age, 55 ± 10 years) from the WASEDA'S Health Study.

METHODS

Body composition was measured using multifrequency BIA and DXA. Low muscle mass was defined according to the criteria of the Asian Working Group for Sarcopenia 2019.

RESULTS

BIA-measured FFMI showed strong positive correlations with both BIA- (r = 0.96) and DXA-measured (r = 0.95) ASMIs. Similarly, in the subgroup analysis according to age and obesity, the FFMI was correlated with the ASMI. The areas under the receiver operating characteristic curve for screening low muscle mass defined by DXA-measured ASMI using BIA-measured FFMI values were 0.95 (95% CI 0.93-0.97) for men and 0.91 (95% CI 0.87-0.94) for women. The optimal BIA-measured FFMI cutoff values for screening low muscle mass defined by DXA-measured ASMI were 17.5 kg/m² (sensitivity 89%, specificity 88%) for men and 14.6 kg/m² (sensitivity 80%, specificity 86%) for women.

CONCLUSIONS AND IMPLICATIONS

The FFMI showed a strong positive correlation with BIA- and DXA-measured ASMIs, regardless of age and obesity. The FFMI could be a useful simple surrogate marker of the ASMI for low muscle mass screening in sarcopenia in community settings. The suggested FFMI cutoff values for predicting low muscle mass are <18 kg/m² in men and <15 kg/m² in women.

Skeletal muscle mass index is independently associated with all-cause mortality in men: The Nagahama study

BACKGROUND

We aimed to determine if skeletal muscle mass is a predictor of all-cause mortality and if muscle mass plays a role in the association between body mass index (BMI) and all-cause mortality in community residents.

METHODS

The study population consists of 3582 elderly (age ≥65 years) adults. The skeletal muscle mass index (SMI) was measured between 2013 and 2016. Men with SMI <7.0 kg/m² and women with SMI <5.7 kg/m² were considered to have low SMI. All-cause mortality was determined by reviewing residential registry records (follow-up duration: 2564 ± 373 days).

RESULTS

The mortality rate of the low SMI group was significantly higher than that of the normal SMI group in men (191.3 vs. 93.0 per 10 000 person-years, P < 0.001), but not in women (P = 0.191). In Cox proportional hazard analysis adjusted for possible covariates, the group differences remained significant (hazard ratio = 1.82, P = 0.011). The results were similar when individuals who died within 1 year of follow-up were excluded from the analysis (P = 0.015). Cubic splines revealed that SMI <6.9 kg/m² is a risk factor of all-cause mortality in men. BMI was found to be significantly associated with all-cause mortality in men (P = 0.010), but not in women (P = 0.288); however, the association disappeared after adjustment for SMI (P = 0.163).

CONCLUSION

SMI <6.9 kg/m² is a risk factor of all-cause mortality in men but not in women. SMI underlies the relationship between BMI and all-cause mortality. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2022; ••: ••-••.

Effects of age and gender on body composition indices as predictors of mortality in middle-aged and old people

To determine whether body composition indices interact with age and gender as a predictor of all-cause mortality, 1200 participants at least 40 years of age were recruited in 2009 and 2010. A multi-frequency bioelectrical impedance analysis device was used to measure each participant's body composition indices, including the fat mass index (FMI), fat free mass index (FFMI), skeletal muscle mass index (SMMI), and visceral fat area index (VFAI). A baseline questionnaire was used to collect demographic information about lifestyle habits, socioeconomic status, and medical conditions. All claimed records of death from 2009 to 2018 in the National Health Insurance Research Databank were identified. The all-cause mortality rate was 8.67% after a mean follow-up period of 5.86 ± 2.39 person-years. The Cox proportional hazard model analysis showed significantly negative associations between FFMI or SMMI with all-cause mortality in the total group and those aged ≥ 65 y/o. The FFMI and SMMI were negative predictors of mortality in both genders. The FMI and VFAI were positive predictors of mortality exclusively in females. In conclusion, the SMMI is a better predictor of mortality than the BMI, FMI, and FFMI, especially in older adults. A higher fat mass or visceral fat distribution may predict higher mortality in females.

Dose-response relationships of sarcopenia parameters with incident disability and mortality in older Japanese adults

BACKGROUND

Sarcopenia-related parameters may have differential impacts on health-related outcomes in older adults. We examined dose-response relationships of body composition, muscle strength, and physical performance with incident disability and mortality.

METHODS

This prospective study included 1765 Japanese residents (862 men; 903 women) aged ≥65 years who participated in health check-ups. Outcomes were incident disability and all-cause mortality. Fat mass index (FMI) and skeletal muscle mass index (SMI), determined using segmental multi-frequency bioelectrical impedance analysis, handgrip strength (HGS), and usual gait speed (UGS) were measured. We determined multivariate-adjusted hazard ratios (HRs) for disability and mortality relative to sex-specific reference values (FMI: medians; SMI: 7.0 kg/m² for men and 5.7 kg/m² for women; HGS: 28 kg for men and 18 kg for women; or UGS: 1.0 m/s for both sexes). Association shapes were examined using restricted cubic splines or fractional polynomial functions.

RESULTS

The median follow-up was 5.3 years; 107 (12.7%) men and 123 (14.2%) women developed disability, and 101 (11.7%) men and 56 (6.2%) women died. FMI did not impact any outcome in men and disability in women, while an FMI ≤ 7.3 kg/m² (median) was significantly associated with higher mortality risk in women, compared with median FMI. SMI did not impact disability in either sex and mortality in women, but showed a significant inverse dose-response relationship with mortality risk in men [HRs (95% confidence intervals) of minimum and maximum values compared with the reference value: 2.18 (1.07-4.46) and 0.43 (0.20-0.93), respectively], independent of HGS and UGS. HGS and UGS showed a significant inverse dose-response relationship with disability in both sexes [HGS: 1.71 (1.00-2.91) and 0.31 (0.09-0.99), respectively, in men, 2.42 (1.18-4.96) and 0.41 (0.20-0.85), respectively, in women; UGS: 2.14 (1.23-3.74) and 0.23 (0.08-0.67), respectively, in men, 3.26 (2.07-5.14) and 0.11 (0.05-0.26), respectively, in women] and mortality in women [HGS: 6.84 (2.84-16.47) and 0.06 (0.02-0.21), respectively; UGS: 2.67 (1.14-6.27) and 0.30 (0.11-0.85), respectively], independent of body composition, but did not impact mortality in men.

CONCLUSIONS

Disability risk was more dependent on muscle strength and physical performance in both sexes. Mortality risk in men was more dependent on muscle mass, and mortality risk in women was influenced by lower fat mass along with muscle strength and physical performance. Although improving muscle strength and physical performance should be the first target for health promotion, it is also necessary to pay attention to body composition to extend life expectancy in older adults.

Association of Lean Body Mass and Fat Mass With 1-Year Mortality Among Patients With Heart Failure

Background

Prior studies have found an unexplained inverse or U-shaped relationship between body mass index (BMI) and mortality in heart failure (HF) patients. However, little is known about the independent effects of each body component, i.e., lean body mass (LBM) and fat mass (FM), on mortality.

Methods

We used data from the China Patient-centered Evaluative Assessment of Cardiac Events-Prospective Heart Failure Study. LBM and FM were calculated using equations developed from the National Health and Nutrition Examination Survey. LBM and FM index, calculated by dividing LBM or FM in kilograms by the square of height in meters, were used for analysis. We used restricted cubic spline and Cox model to examine the association of LBM and FM index with 1-year all-cause mortality.

Results

Among 4,305 patients, median (interquartile range) age was 67 (57–76) years, 37.7% were women. During the 1-year follow-up, 691 (16.1%) patients died. After adjustments, LBM index was inversely associated with mortality in a linear way (P-overall association &lt; 0.01; P-non-linearity = 0.52), but no association between FM index and mortality was observed (P-overall association = 0.19). Compared with patients in the 1st quartile of the LBM index, those in the 2nd, 3rd, and 4th quartiles had lower risk of death, with hazard ratio of 0.80 (95% CI 0.66–0.97), 0.65 (95% CI 0.52–0.83), and 0.61 (95% CI 0.45–0.82), respectively. In contrast, this association was not observed between FM index quartiles and mortality.

Conclusion

Higher LBM, not FM, was associated with lower 1-year mortality among HF patients.

Higher Body Mass Index in Hospitalized Older Patients Is Related to Higher Muscle Quality

OBJECTIVES

This study aimed to examine the relationship between muscle mass, intramuscular adipose tissue, and body mass index (BMI) in older inpatients.

DESIGN

Cross-sectional study.

SETTING

Hospital-based study.

PARTICIPANTS

This study included 413 inpatients aged ≥ 65 years (186 men and 227 women).

MEASUREMENTS

Muscle mass and intramuscular adipose tissue of the quadriceps were assessed by measuring the muscle thickness and echo intensity on ultrasound images. To examine the relationship between quadriceps thickness and echo intensity and BMI in total participants and each sex, the Kendall rank correlation coefficient was used. Multiple regression analysis was performed to examine whether BMI was independently and significantly related to the quadriceps thickness and echo intensity, even after adjusting for other variables for total participants and each sex. The independent variables in multiple regression analyses were BMI, age, disease, days from onset disease.

RESULTS

The results of the correlation analyses showed that BMI was significantly related to the quadriceps thickness (total participants, τ = 0.431; men, τ = 0.491; women, τ = 0.388) and echo intensity (total participants, τ = -0.239; men, τ = -0.318; women, τ = -0.188). In the multiple regression analysis, BMI was independently and significantly associated with the quadriceps thickness (total participants, β = 0.535; men, β = 0.548; women, β = 0.519) and echo intensity (total participants, β = -0.287; men, β = -0.398; women, β = -0.210).

CONCLUSION

This study indicated that older inpatients with a higher BMI have greater muscle mass and less intramuscular adipose tissue of the quadriceps. These results suggested that a higher BMI in older inpatients is related to higher quadriceps muscle quality.

Low muscle mass in older adults and mortality: A systematic review and meta-analysis

Sarcopenia comprises a loss of muscle function and muscle mass. So far, the association between the later and mortality in older adults is inconsistent. A meta-analysis was performed to assess whether muscle mass measured by appendicular skeletal muscle mass index (ASMI) is associated with higher mortality in older adults. Articles of interest were searched for in two databases (PudMed® and Embase®). Cohort and case-control studies reporting ASMI and mortality and enrolling community-dwelling adults aged 65 years or more were included. Nine articles were eligible and included for analysis (n = 10,028). All but one study were considered of high quality by Newcastle-Ottawa Scale assessment. We calculated the standardized mean difference (SMD) for ASMI between dead and living individuals during follow-up across studies. A reduced pooled ASMI in individuals who died as compared to those who survived (ASMI SMD = -0.18, CI95% -0.23 to -0.12, REM) was found. A meta-regression was performed including ASMI SMD, grip strength SMD, body mass index (BMI), sex, study quality, method used to assess ASMI, site of study and age. BMI and ethnicity were found to significantly impact the difference in ASMI between dead and living individuals. These results reinforce the prognostic importance of assessing muscle mass in older adults.