Weight-adjusted lean body mass and calf circumference are protective against obesity-associated insulin resistance and metabolic abnormalities

Weight gain leads to greater adverse metabolic responses in South Asian compared with white European men: the GlasVEGAS study

South Asians (SAs) develop type 2 diabetes at lower body mass index values than white Europeans (WEs). This basic human experimental study aimed to compare the metabolic consequences of weight gain in SA and WE men without overweight or obesity. Fourteen SAs and 21 WEs had assessments of body composition, metabolic responses to mixed-meal ingestion, cardiorespiratory fitness and physical activity, and a subcutaneous abdominal adipose tissue biopsy, before and after 4-6 weeks of overfeeding to induce 5-7% weight gain. Here we show that body mass index and whole-body adipose tissue volume increases similarly between ethnic groups, but SAs gain less lean tissue. SAs experience a substantially greater decrease in insulin sensitivity compared with WEs (38% versus 7% decrease, P = 0.009), have fewer small (37.1% versus 60.0%, P = 0.003) and more large (26.2% versus 9.1%, P = 0.005) adipocytes at baseline and have a smaller decrease in very small adipocytes with weight gain (-0.1% versus -1.9%, P < 0.0001). Ethnic differences in adipocyte morphology are associated with SA's greater adverse metabolic changes with weight gain. ClinicalTrials.gov registration: NCT02399423 .

Association between animal protein intake, oral frailty and calf circumference in middle-aged and older adults: a cross-sectional analysis from the Shika study

OBJECTIVE

To investigate the relationship between oral frailty (OF), nutrient intake and calf circumference (CC) in middle-aged and older adults.

DESIGN

Cross-sectional study.

SETTING

Residents of four model districts of Shika town, Ishikawa Prefecture, Japan, using data from November 2017 to February 2018.

PARTICIPANTS

One hundred and ninety-four residents aged ≥50 years in four model districts of Shika town. The OF total score ≥3 was defined as OF. Participants were divided into OF and non-OF groups and divided into the low-CC/kg and the high-CC/kg groups.

OUTCOME MEASURES

The primary outcome is to use a two-way analysis of covariance to analyse the interaction between the two CC/kg groups and the two OF groups on nutrition intake. The secondary outcome is to use multiple regression analysis to investigate the nutrients significantly related to CC/kg when stratified by OF, with age, sex, body mass index, drinking status, smoking status and regular exercise as input covariates.

RESULTS

A two-way analysis of covariance revealed a significant interaction between the two CC/kg groups and the two OF groups on animal protein intake (p=0.039). Multiple comparisons using the Bonferroni analysis revealed a significantly lower animal protein intake in the OF group than in the non-OF group with a low CC/kg (p=0.033) but not in the group with a high CC/kg. The multiple regression analysis stratified by OF revealed a positive correlation between animal protein intake and CC/kg (p=0.002).

CONCLUSIONS

The present results revealed a significantly lower animal protein intake in the OF group than in the non-OF group in the low-CC/kg group, but no such difference was observed in the high-CC/kg group. Further longitudinal studies are needed to elucidate this relationship.

Association between lean body mass and hypertension: A cross-sectional study of 50 159 NHANES participants

Increasing attention has been paid to the association between lean body mass (LBM) and hypertension in recent years, but the previous findings have often been contradictory. Therefore, the authors investigated the association between LBM and hypertension through a cross-sectional study in the United States. To investigate the relationship between LBM and hypertension, the authors conducted weighted multivariable logistic regression models. The authors used the restricted cubic spline regression model to determine if there was a nonlinear correlation. In order to locate the inflection point, the authors built a two-part linear regression model using a recursive method. In the full adjustment model, LBM was positively associated with hypertension, with ORs (95% CI) of 1.19 (1.02, 1.38). In the further linear trend test, the ORs (95% CI) for Q2, Q3, and Q4 were 0.76 (0.60, 0.95), 0.62 (0.47, 0.80), and 0.66 (0.48, 0.91), respectively, compared to Q1, which suggested that the association between LBM and hypertension might be non-linear. The authors performed the restricted cubic spline curve to confirm this non-linear relationship and found the inflection point of 43.21 kg with an opposite relationship in which LBM and hypertension exhibited a negative correction of 0.66 (0.50, 0.86) before the inflection point and a positive correlation of 1.20 (1.03, 1.39) after the inflection point. Our study highlighted a non-linear association between LBM and hypertension in the general US population.

Association between creatinine to body weight ratio and all-cause mortality: a cohort study of NHANES

Research on the relationship between the weight-adjusted skeletal muscle mass index and all-cause mortality is rare, and even rarer is the relationship between the creatinine/body weight (Cre/BW) ratio and all-cause mortality. Therefore, this study aimed to investigate the relationship between the Cre/BW ratio and mortality in individuals with normal renal function. This prospective study used data from the National Health and Nutrition Examination Survey (NHANES) database. A Cox hazard model was used to analyze the relationship between the Cre/BW ratio and mortality risk. In total, 45,459 participants were included, of which 49.97% were women, with an average age of 45.68 ± 18.08 years. The incidence of all-cause mortality was 10.9% among these participants during the median (interquartile range) follow-up of 9.6 (5.2, 14.2) years. After adjusting for all covariates, a U-shaped relationship was found between the Cre/BW ratio and all-cause mortality (P for nonlinearity <0.001), with the lowest risk observed at Cre/BW ratios (×100) between 0.821 and 0.987. In the threshold effect analysis, the Cre/BW ratio (×100) had a threshold value of 0.96. When the Cre/BW ratio (×100) was <0.96, all-cause mortality was negatively associated with the Cre/BW ratio (×100) (0.63 (0.41, 0.97)). In contrast, when the Cre/BW ratio (×100) was ≥0.96, the higher Cre/BW ratio was associated with a greater hazard ratio of all-cause mortality (1.67 (1.41, 1.97)). In conclusion, we report a U-shaped relationship between the Cre/BW ratio and all-cause mortality. Controlling the Cre/BW ratio within a certain range may reduce the risk of all-cause mortality.

Anticipated correlation between lean body mass to visceral fat mass ratio and insulin resistance: NHANES 2011-2018

Objective

The relationship between body composition and insulin resistance (IR) is controversial. This study aimed to thoroughly examine the correlation between adipose tissue, lean body mass, and IR as evaluated by the Homeostatic Model Assessment (HOMA-IR).

Methods

In this cross-sectional study, we utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2018. Our study included 4981 subjects, and we employed multiple linear regression, smoothed curve fitting, threshold, and saturation effect analysis to investigate the relationship between lean body mass, visceral fat mass, and IR. Also, we used the lean body mass to visceral fat ratio (Log LM/VFM) as a proxy variable to analyze its association with IR alone.

Results

The study discovered a negative link between lean body mass and IR, but the visceral fat mass was positively correlated after correcting for covariates. A negative correlation was observed when the alternative variable Log LM/VFM was analyzed separately for its association with IR. This association was present regardless of whether the exposure variables were analyzed as continuous or categorical. The data analysis revealed a nonlinear relationship between Log LM/VFM and IR, as evidenced by the generalized additive model. In addition, a threshold effect with a critical value of 1.80 and a saturation effect with a critical point of 2.5 were also observed. Further subgroup analysis for sex, age, BMI, active levels, hypertension, and diabetes showed considerable robustness between the relationship of Log LM/VFM and IR.

Conclusion

Maintaining a proper ratio of lean body mass and visceral fat is beneficial for decreasing IR.

Fitness, Food, and Biomarkers: Characterizing Body Composition in 19,634 Early Adolescents

Adolescent obesity persists as a major concern, especially in Central and Eastern Europe, yet evidence gaps exist regarding the pivotal early adolescent years. Our objective was to provide a comprehensive picture using a holistic approach of measured anthropometry in early adolescence, including body composition, cardiorespiratory fitness (CRF), and reported lifestyle characteristics. We aimed to elucidate potential sex/gender differences throughout and associations to biomarkers of disease risk for obese adolescents. Methods: Trained nurses measured 19,634 early adolescents (12−14-year-olds), we collected parental reports, and, for obese adolescents, fasting blood samples in four major Polish cities using a cross-sectional developmental design. Results: 24.7% boys and 18.6% girls were overweight/obese, and 2886 had BMI ≥ 90th percentile. With increasing age, there was greater risk of obesity among boys (p for trend = 0.001) and a decreasing risk of thinness for girls (p for trend = 0.01). Contrary to debate, we found BMI (continuous) was a useful indicator of measured fat mass (FM). There were 38.6% with CRF in the range of poor/very poor and was accounted for primarily by FM in boys, rather than BMI, and systolic blood pressure in girls. Boys, in comparison to girls, engaged more in sports (t = 127.26, p < 0.0001) and consumed more fast food (t = 188.57, p < 0.0001) and sugar-sweetened beverages (167.46, p < 0.0001). Uric acid, a potential marker for prediabetes, was strongly related to BMI in the obese subsample for both boys and girls. Obese girls showed signs of undernutrition. Conclusion: these findings show that overweight/obesity is by far a larger public health problem than thinness in early adolescence and is characterized differentially by sex/gender. Moreover, poor CRF in this age, which may contribute to life course obesity and disease, highlights the need for integrated and personalized intervention strategies taking sex/gender into account.

Creatinine-to-body weight ratio is a predictor of incident diabetes: a population-based retrospective cohort study

PURPOSE

Creatinine to body weight (Cre/BW) ratio is considered the independent risk factor for incident type 2 diabetes mellitus (T2DM), but research on this relationship is limited. The relationship between the Cre/BW ratio and T2DM among Chinse individuals is still ambiguous. This study aimed to evaluate the correlation between the Cre/BW ratio and the risk of T2DM in the Chinese population.

METHODS

This is a retrospective cohort study from a prospectively collected database. We included a total of 200,658 adults free of T2DM at baseline. The risk of incident T2DM according to Cre/BW ratio was estimated using multivariable Cox proportional hazards models, and a two-piece wise linear regression model was developed to find out the threshold effect.

RESULTS

With a median follow-up of 3.13 ± 0.94 years, a total of 4001 (1.99%) participants developed T2DM. Overall, there was an L-shaped relation of Cre/BW ratio with the risk of incident T2DM (P for non-linearity < 0.001). When the Cre/BW ratio (× 100) was less than 0.86, the risk of T2DM decreased significantly as the Cre/BW ratio increased [0.01 (0.00, 0.10), P < 0.001]. When the Cre/BW ratio (× 100) was between 0.86 and 1.36, the reduction in the risk of developing T2DM was not as significant as before [0.22 (0.12, 0.38), P < 0.001]. In contrast, when the Cre/BW ratio (× 100) was greater than 1.36, the reduction in T2DM incidence became significantly flatter than before [0.73 (0.29,1.8), P = 0.49].

CONCLUSION

There was an L-shaped relation of Cre/BW ratio with incidence of T2DM in general Chinese adults. A negative curvilinear association between Cre/BW ratio and incident T2DM was present, with a saturation effect predicted at 0.86 and 1.36 of Cre/BW ratio (× 100).

Relative low muscle mass and muscle strength is associated with the prevalence of metabolic syndrome in patients with type 2 diabetes

This cross-sectional study investigated the association of metabolic syndrome (MetS) with sarcopenia defined by absolute low muscle mass (aLMM) and absolute low muscle strength (aLMS), or sarcopenia defined by relative low muscle mass (rLMM) and relative low muscle strength (rLMS). The cut-off values for men and women were as follows: aLMM, appendicular muscle mass in kg/height‍² was <7.0 kg/m‍² and <5.7 kg/m‍²; rLMM, appendicular muscle mass/body weight ×100 was <28.64% and <24.12%; aLMS, handgrip strength was <28 kg and <18 kg; and rLMS, handgrip strength/body weight ×100 was 51.26% and 35.38%. Among 207 men and 164 women, 41.5% men and 57.3% women had MetS, 14.0% men and 6.1% women had sarcopenia as defined by aLMM and aLMS, and 14.0% men and 22.0% women had sarcopenia defined by rLMM and rLMS. Compared with non-sarcopenia, adjusted OR of sarcopenia defined by aLMM and aLMS for the prevalence of MetS was 0.79 (95% CI 0.38–1.67), whereas that of sarcopenia defined by rLMM and rLMS for the prevalence of MetS was 20.6 (95% CI 7.81–54.3). Sarcopenia defined by rLMM and rLMS was associated with the risk of prevalence of MetS, whereas sarcopenia defined by aLMM and aLMS was not.

Relative Lean Body Mass and Waist Circumference for the Identification of Metabolic Syndrome in the Korean General Population

Lean body mass (LBM) comprises organs and muscle, which are the primary determinants of energy expenditure and regulation of glucose and lipid metabolism. Excessive abdominal fat is associated with metabolic abnormality. Little is known about the relationship between metabolic abnormality and LBM and waist circumference (WC), especially in the Asian general population. The aim of this study was to clarify this relationship. We performed a cross-sectional study with 499,648 subjects who received health check-ups at 16 health promotion centers in 13 Korean cities between January 2018 and October 2019. The subjects were categorized into four groups: (a) High (H)-RLBM (relative lean body mass)/Normal (N)-WC, (b) High-RLBM/Abnormal (A)-WC, (c) Low (L)-RLBM/Normal-WC, and (d) Low-RLBM/Abnormal-WC. RLBM was calculated using fat mass data that were estimated via bioelectrical impedance analysis. L-RLBM/A-WC was significantly associated with metabolically unhealthy status (OR: 4.40, 95% CI: 4.326–4.475) compared to H-RLBM/N-WC. L-RLBM/N-WC (OR: 2.170, 95% CI: 2.122–2.218) and H-RLBM/A-WC (OR: 2.713, 95% CI: 2.659–2.769) were also significantly related to metabolic unhealthy status. The cut-offs of RLBM for predicting metabolic syndrome (MetS) were 74.9 in males and 66.4 in females (p < 0.001). L-RLBM and A-WC are associated with metabolic abnormality in the Korean general population. RLBM is an anthropometric index that can be used to predict MetS in primary health care.

Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and narrative synthesis

BACKGROUND

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI), a measure of weight for height, has been extensively reviewed in children, showing consistent associations between disadvantaged SEP and higher BMI in high-income countries (HICs) and lower BMI in middle-income countries (MICs). Fat mass (FM), a more accurate measure of adiposity, and fat-free mass (FFM) are not captured by BMI, but have been shown to track from childhood to adulthood, and be important for cardiovascular health and functional outcomes in later life. It is not clear whether body composition is associated with SEP. We systematically reviewed the association between SEP and body composition in childhood.

METHODS

A systematic review was carried out following PRISMA guidelines. The protocol was pre-registered with PROSPERO (CRD42019119937). Original studies in the English language, which examined the association between SEP and body composition in childhood, were included. An electronic search of three databases was conducted. Two independent reviewers carried out screening, data extraction and quality assessment. Due to heterogeneity in results, a narrative synthesis was conducted. Heterogeneity in findings according to SEP, sex, body composition measure and country income level was investigated.

RESULTS

50 papers were included, the majority from HICs. No papers were from low-income countries. Disadvantage in childhood was associated with greater FM and lower FFM in HICs, but with lower FM and lower FFM in MICs. When measures of FFM indexed to height were used there was no evidence of associations with SEP. In HICs, more studies reported associations between disadvantaged SEP and higher FM among girls comparative to boys.

CONCLUSIONS

Inequalities in FM are evident in HICs and, in the opposite direction, in MICs and follow similar trends to inequalities for BMI. Inequalities in height are likely important in understanding inequalities in FFM.

Area-level and family-level socioeconomic position and body composition trajectories: longitudinal analysis of the UK Millennium Cohort Study

BACKGROUND

Inequalities in the trajectories of body composition in childhood and adolescence have been infrequently studied. Despite the importance of environmental factors in obesity development, little research has looked at area-level socioeconomic position, independent of family socioeconomic position. We aimed to assess how inequalities in body composition develop with age.

METHODS

The Millennium Cohort Study is a longitudinal study of 19 243 families who had a child born between 2000 and 2002 in the UK. Multilevel growth curve models were applied to examine change in fat mass index (FMI), fat free mass index (FFMI; using the Benn index), and fat mass to fat free mass ratio (FM:FFM), measured using Bioelectrical Impedance Analysis, from ages 7 years to 17 years by the Index of Multiple Deprivation (IMD) and household income at baseline.

FINDINGS

Inequalities in FMI and FM:FFM ratio are evident at age 7 years and widen with age. At age 17 years, adolescents in the most disadvantaged IMD group had FMI 0·57 kg/mB (B=Benn parameter; 95% CI 0·43 to 0·70) higher and FM:FFM ratio 0·037 (95% CI 0·026 to 0·047) higher compared with the most advantaged group. Disadvantaged socioeconomic position is associated with higher FFMI but is reversed in adolescence after adjustment for FMI. Inequalities were greater in girls at age 7 years (mean FMI 0·22 kg/mB; 95% CI 0·13 to 0·32) compared with boys of the same age (0·05 kg/mB; -0·04 to 0·15, p=0·3), but widen fastest in boys, especially for FMI, in which there was over an 11 times increase in the inequality from age 7 years of 0·05kg/mB (95% CI -0·04 to 0·15) to 0·62 kg/mB at 17 years (0·42 to 0·82). Inequalities for the IMD were similar to income, and persisted at age 17 years independent of family socioeconomic position.

INTERPRETATION

Childhood and adolescence is an important period to address inequalities in body composition, as they emerge and widen. Policies should consider FFM as well as FM, and inequalities in the environment.

FUNDING

Medical Research Council, Economic and Social Research Council.

Anthropometric Measures and Incident Diabetic Nephropathy in Participants With Type 2 Diabetes Mellitus

BACKGROUND

The prevalence of diabetes is on the rise globally coupled with its associated complications, such as diabetic nephropathy (DN). Obesity has been identified as a risk factor for the development of DN but it is still unclear which obesity index is the best predictor of incident DN.

METHODS

Data from the participants with type 2 diabetes mellitus (T2DM) in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study were used to examine the sex-specific association between waist circumference (WC), waist-to-height ratio (WHtR), and body mass index (BMI) with incident DN risk.

RESULTS

Among the 8,887 participants with T2DM (5,489 men and 3,398 women), 5,296 participants (3,345 men and 1,951 women) developed the DN composite outcome during a follow-up period of 24302 person-years. Among men, null associations were observed between all anthropometric measures with incident DN in the multivariate analysis although the 3^rd quartile of WHtR showed marginally significant results (P = 0.052). However, among women, both central and general obesity measures were associated with increased risks of incident DN. Compared with participants in the WC <88 cm category, the fully adjusted HR and 95% CI for those in the ≥88 cm of WC was 1.35 (95% CI 1.15-1.57). Compared with the lowest quartile, the fully adjusted HRs and 95% CIs for the 2^nd to the 4^th quartile of WHtR were 1.09 (95% CI 0.96-1.25), 1.12 (95% CI 0.98-1.28), and 1.14 (95% CI 1.00-1.30) respectively; also, compared with the normal BMI category, the fully adjusted HRs and 95% CIs for class I - class III obese were 1.36 (95% CI 1.10 - 1.67), 1.43 (95% CI 1.16 - 1.78) and 1.32 (95% CI 1.05 - 1.66) respectively.

CONCLUSIONS

Among participants with T2DM, higher levels of both central and general obesity indexes were associated with DN risk among women but not in men. Women with T2DM should maintain a healthy weight targeted at reducing both central and general obesity to enhance nephroprotection. Trial registration: ClinicalTrials.gov., no. NCT00000620.

Life course socioeconomic position and body composition in adulthood: a systematic review and narrative synthesis

INTRODUCTION

Multiple systematic reviews have investigated the relation between socioeconomic position (SEP) and body mass index (BMI) throughout the life course. However, BMI does not capture quantity and distribution of fat and muscle, which are better indicators of obesity than BMI, and have been independently linked to adverse health outcomes. Less is known about the relation between SEP and body composition, and the literature has not been reviewed. We therefore systematically reviewed the literature on the association between life course SEP and body composition in adulthood.

METHODS

A protocol was registered on PROSPERO (CRD42019119937), and the review followed PRISMA guidelines. An electronic search of three databases (MEDLINE, Embase Classic + Embase and SPORTDiscus) was conducted. Original studies in the English language were included that examine the association between any recognised measure of SEP at any age and body composition (fat mass, fat-free mass, ratio and distribution) in adulthood, measured using a direct technique, i.e., not an anthropometric measure. A narrative synthesis was conducted.

RESULTS

A total of 47 papers were included in the final review, none were from low-income countries (LICs). Greater advantage in childhood and adulthood was associated with lower fat levels in high-income countries (HICs). Associations in the opposite direction were found exclusively in middle-income countries (MICs). No studies in MICs reported associations for childhood SEP. For measures of lean mass, the majority of papers reported no association, or greater advantage in adulthood associated with higher lean mass, with little variation between HICs and MICs. Associations in HICs are more often observed in women than men.

CONCLUSION

The results indicate that fat measures follow similar patterns to those seen for BMI, and that women in HICs are more likely to experience inequalities in both fat and lean measures. Further research in LICs and MICs is needed.

Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with a Low Prevalence of Sarcopenia in Patients with Type 2 Diabetes: A Cross-Sectional Study

Insulin resistance is a risk of sarcopenia, and the presence of sarcopenia is high in patients with type 2 diabetes (T2DM). It has been reported that habitual miso soup consumption was associated with lower insulin resistance. However, the association between habitual miso consumption and the presence of sarcopenia in patients with T2DM, especially sex difference, was unclear. In this cross-sectional study, 192 men and 159 women with T2DM were included. Habitual miso consumption was defined as consuming miso soup regularly. Having both low skeletal muscle mass index (<28.64% for men, <24.12% for women) and low adjusted hand grip strength (<51.26% for men, <35.38% for women) was defined as sarcopenia. The proportions of sarcopenia were 8.7% in men and 22.6% in women. The proportions of habitual miso consumption were 88.0% in men and 83.6% in women. Among women, the presence of sarcopenia was lower in the group with habitual miso consumption (18.8% versus 42.3%, p = 0.018); however, there was no association between habitual miso consumption and the presence of sarcopenia in men. Habitual miso consumption was negatively associated with the presence of sarcopenia in women (adjusted odds ratio (OR), 0.20 (95% confidence interval (CI): 0.06-0.62), p = 0.005) but not in men. This study indicated that habitual miso consumption was associated with the presence of sarcopenia in women but not in men.

Association of lean body mass to menopausal symptoms: The Study of Women's Health Across the Nation

Background

The purpose of this study was to examine the association of lean body mass (LBM) to the development of vasomotor symptoms (VMS) as women transition through menopause.

Methods

This study is a secondary use of data available for public use from follow up visits six through 10 for participants in the Study of Women’s Health Across the Nation. The study examined 2533 women, between the ages 42–52 years, each year over a10-year period. Data was modeled for associations of lean body mass and VMS. Changes in LBM since prior visit and since baseline were also modeled along with differences in means using binary logistic regression, adjusting for covariates.

Results

LBM was significantly associated to concurrent VMS (p = .036), percent change in LBM since prior visit (p = .003), percent change since baseline (p < .001), and overall means associations (p = .023). LBM was not significant for VMS at individual visit measures. In mixed regression modeling, time was significant (p < .0001) at all visits. The estimated probability of developing VMS decreases significantly as LBM increases.

Conclusions

Lean body mass is negatively associated with incident VMS. Our data suggests that maintaining higher levels of LBM during the menopausal transition may be protective against the development of VMS. Every woman will experience menopause in her life and the ability to potentially prevent the onset of specific symptoms through basic interventions, such as resistance training to increase lean body mass, may positively impact this large population.

Creatinine/(cystatin C × body weight) ratio is associated with skeletal muscle mass index

We have previously reported that the creatinine (Cre) to cystatin C (CysC) ratio is associated with height-adjusted skeletal muscle mass index (SMI). However, weight-adjusted SMI is reported to be a more useful marker of insulin sensitivity than height-adjusted SMI. Thus, we hypothesized that the creatinine to (cystatin C × body weight [BW]) relationship (Cre/[CysC × BW]) might be associated with weight-adjusted SMI. In this cross-sectional study of 169 males and 132 females, a body composition analyzer was used and the weight-adjusted SMI was calculated as (absolute muscle mass [kg]/BW [kg]) × 100. The cut-off of low muscle mass was defined as weight-adjusted SMI <37.0% for males and <28.0% for females. The Cre/(CysC × BW) was correlated with weight-adjusted SMI in both males (r = 0.484, p < 0.001) and females (r = 0.538, p < 0.001). In addition, Cre/(CysC × BW) was associated with weight-adjusted SMI in both males (standardized β = 0.493, p < 0.001) and females (standardized β = 0.570, p < 0.001) after adjusting for covariates. According to the receiver operator characteristic (ROC) curve analysis, the optimal cut-off point of Cre/(CysC × BW) for low muscle mass was 0.0145 (area under the ROC curve [AUC] 0.756 [95% confidence interval {95% CI} 0.644-0.842], sensitivity = 0.96, specificity = 0.47, p < 0.001) in males and 0.0090 (AUC 0.976 [95% CI 0.894-0.995], sensitivity = 1.00, specificity = 0.93, p < 0.001) in females. There is a correlation between Cre/(CysC × BW) and weight-adjusted SMI. The Cre/(CysC × BW) could be a practical screening marker for low muscle mass.

Creatinine to Body Weight Ratio Is Associated with Incident Diabetes: Population-Based Cohort Study

We investigated the association between creatinine to body weight (Cre/BW) ratio and incident diabetes. In this cohort study, 9659 men and 7417 women were follow up mean (SD) 5.6 (3.5) years and 5.4 (3.4) years, respectively. For men, tertile 1 (T1; n = 3176), Cre/BW < 0.01275; tertile 2 (T2; n = 3258), 0.01275 ≤ Cre/BW < 0.0148; and tertile 3 (T3; n = 3225), Cre/BW ≥ 0.0148; and for women, T1 (n = 2437), Cre/BMI < 0.0118; T2 (n = 2516), 0.0118 ≤ Cre/BMI < 0.014; and T3 (n = 2477), Cre/BMI ≥ 0.014. Among them, 362 men and 102 women developed diabetes. The hazard ratios (HRs) of incident diabetes in the T2 group was 0.56 (95% CI 0.44–0.71, p < 0.001) in men and 0.61 (0.38–0.99, p = 0.045) in women and in the T3 group was 0.42 (0.32–0.54, p < 0.001) in men and 0.55 (0.34–0.89, p = 0.014) in women after adjusting for covariates, compared with the T1 group. Moreover, Δ0.001 incremental of Cre/BW is negatively associated with incident diabetes (adjusted HR 0.84, 95% CI 0.80–0.88, p < 0.001 for men and 0.88, 0.81–0.96, p = 0.003 for women). In conclusion, Cre/BW ratio is inversely related to incident diabetes. Checking Cre/BW ratios may predict future diabetes risks.

Creatinine-to-bodyweight ratio is a predictor of incident non-alcoholic fatty liver disease: A population-based longitudinal study

AIM

Serum creatinine (Cre) is used as a surrogate marker of muscle mass. We investigated the impact of the Cre-to-bodyweight (BW) ratio (Cre/BW) on incident non-alcoholic fatty liver disease (NAFLD).

METHODS

Fatty liver disease was diagnosed by abdominal ultrasonography. In this historical cohort study of 13 728 participants (6397 men and 7331 women), we divided the participants into two groups by sex and into quartiles according to Cre (mg/dL)/BW (kg; Q1-4). We carried out Cox proportional hazard models, adjusting for age, alanine aminotransferase, fasting plasma glucose, systolic blood pressure, alcohol consumption, smoking status, and exercise.

RESULTS

During the 5.1-year follow up for men and 6.0-year follow up for women, 2497 participants (1696 men, 801 women) developed NAFLD. The 4000-days cumulative incidence rates of FLD for men and women were 29.6% and 16.6% in Q1, 28.2% and 10.6% in Q2, 25.5% and 8.8% in Q3, and 22.7% and 7.7% in Q4, respectively. The hazard ratios of incident NAFLD in Q1 (Cre/BW [×100]: men <1.28; women <1.17) were 1.89 (95% confidence interval 1.64-2.17, P < 0.001) in men and 2.96 (2.42-3.62, P < 0.001) in women, compared with Q4 (Cre/BW [×100]: men ≥1.61; women ≥1.51).

CONCLUSIONS

A low Cre/BW is associated with an increased risk of NAFLD. Screening Cre/BW can be used to identify individuals who are at high risk of NAFLD.

A Low Creatinine to Body Weight Ratio Predicts the Incident Nonalcoholic Fatty Liver Disease in Nonelderly Chinese without Obesity and Dyslipidemia: A Retrospective Study

AIM

A lower ratio of creatinine to body weight (Cr/BW) is considered the independent risk factor for incident nonalcoholic fatty liver disease (NAFLD). However, the relationship between the Cr/BW ratio and NAFLD among individuals without obesity and dyslipidemia and how this relationship is impacted by age are still ambiguous. Therefore, we explored the effect of the Cr/BW ratio on the incident NAFLD among Chinese without obesity and dyslipidemia of different age groups.

METHODS

A total of 9756 participants without NAFLD at baseline were included and grouped by the median value (1.32) of the Cr/BW ratio. Then, a further analysis was stratified by age (60 years old). The primary outcome was new-onset NAFLD.

RESULTS

After a median follow-up of 2.76 years, 844 (8.7%) participants developed NAFLD. The elderly had a higher person-years incidence rate and cumulative incidence rate than the nonelderly. A high Cr/BW ratio showed a lower cumulative incidence compared to a low Cr/BW ratio for the whole population (P = 0.039) and the nonelderly group (P = 0.008). After being adjusted for multivariate variables, the lower Cr/BW ratio was the independent risk factor for incident NAFLD in the nonelderly (HR 0.718, 95% CI 0.548-0.942), instead of the elderly.

CONCLUSIONS

The Cr/BW ratio has a negative relationship with incident NAFLD among nonobese Chinese without dyslipidemia before the age of 60.

Socioeconomic position and body composition across the life course: a systematic review protocol

INTRODUCTION

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI) has been extensively reviewed, but there is less research on the association between SEP and body composition. Fat distribution and muscle quality have been linked to adverse health outcomes such as cardiovascular disease, diabetes and poor physical capability. There is some evidence of secular changes in body composition with increasing fat-mass and reducing muscle quantity and strength, but it is unclear whether there have been secular changes in social inequalities in body composition. The aim is to perform a systematic review of the existing literature on the association between SEP and body composition and to explore any secular changes.

METHODS

The systematic review will be carried out according to PRISMA guidelines. An electronic search of MEDLINE and Embase Classic + Embase will be conducted using OvidSP as the database interface, as well as SPORTDiscus using EBSCO. Two independently working reviewers will initially screen abstracts to exclude papers that are clearly ineligible, followed by a full-text screening to exclude papers not meeting all inclusion criteria. Any disagreements will be resolved through discussion. Data extraction and quality assessment of eligible papers will be carried out by 2 reviewers using a standardised form. The reference lists of identified papers will be searched for additional papers. Original studies in the English language, which examine the association between SEP at any age and body composition at the same or later age will be included if they use any recognised measures of SEP (e.g. income, occupation, over-crowding) and a recognised measure of body composition (total, proportional or location of fat mass and fat-free mass, using any appropriate methods, excluding anthropometry). Due to expected heterogeneity, a narrative synthesis is expected, with a descriptive summary to be provided in tables. If there is consistency in reporting of associations, a random-effects meta-analysis will be used to provide an overall summary estimate.

DISCUSSION

The results of the review will summarise the existing evidence on social inequalities in body composition. Findings will identify gaps in knowledge and where further research is required.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019119937.

Disentangling the genetics of lean mass

Background

Lean body mass (LM) plays an important role in mobility and metabolic function. We previously identified five loci associated with LM adjusted for fat mass in kilograms. Such an adjustment may reduce the power to identify genetic signals having an association with both lean mass and fat mass.

Objectives

To determine the impact of different fat mass adjustments on genetic architecture of LM and identify additional LM loci.

Methods

We performed genome-wide association analyses for whole-body LM (20 cohorts of European ancestry with n = 38,292) measured using dual-energy X-ray absorptiometry) or bioelectrical impedance analysis, adjusted for sex, age, age2, and height with or without fat mass adjustments (Model 1 no fat adjustment; Model 2 adjustment for fat mass as a percentage of body mass; Model 3 adjustment for fat mass in kilograms).

Results

Seven single-nucleotide polymorphisms (SNPs) in separate loci, including one novel LM locus (TNRC6B), were successfully replicated in an additional 47,227 individuals from 29 cohorts. Based on the strengths of the associations in Model 1 vs Model 3, we divided the LM loci into those with an effect on both lean mass and fat mass in the same direction and refer to those as "sumo wrestler" loci (FTO and MC4R). In contrast, loci with an impact specifically on LM were termed "body builder" loci (VCAN and ADAMTSL3). Using existing available genome-wide association study databases, LM increasing alleles of SNPs in sumo wrestler loci were associated with an adverse metabolic profile, whereas LM increasing alleles of SNPs in "body builder" loci were associated with metabolic protection.

Conclusions

In conclusion, we identified one novel LM locus (TNRC6B). Our results suggest that a genetically determined increase in lean mass might exert either harmful or protective effects on metabolic traits, depending on its relation to fat mass.

Calf Circumference as a Novel Tool for Risk of Disability of the Elderly Population

Disability became increasingly common with age, and crude rates of disability were rising around the globe. The aim of this study was to investigate the association between calf circumference (CC) and disability in the U.S. elderly population. From the 1999-2006 National Health and Nutrition Examination Survey, a total of 4,245 participants with an age range of 60-84 years were included. Disability was defined as the total number of difficulties within the following 5 major domains of disability, such as activities of daily living (ADL), instrumental ADL, general physical activities, lower extremity mobility, and leisure and social activities. The association between CC and disability was investigated through the regression model adjusted for multiple covariates. According to the fully adjusted model regarding disability, the β coefficients for each quartile of increasing CC were -0.041 for quartile 2 (P = 0.096), -0.060 for quartile 3 (P = 0.027), and -0.073 for quartile 4 (P = 0.026) respectively, compared with lowest quartile. There was a negative association between CC and disability among the elderly population. Calf circumference may be a novel risk assessment for disability of elderly people.