The impact of anorexia nervosa and BMI polygenic risk on childhood growth: A 20-year longitudinal population-based study.

Growth deviating from the norm during childhood has been associated with anorexia nervosa (AN) and obesity later in life. In this study, we examined whether polygenic scores (PGSs) for AN and BMI are associated with growth trajectories spanning the first two decades of life. AN PGSs and BMI PGSs were calculated for participants of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 8,654). Using generalized (mixed) linear models, we associated PGSs with trajectories of weight, height, body mass index (BMI), fat mass index (FMI), lean mass index (LMI), and bone mineral density (BMD). Female participants with AN PGSs one standard deviation (SD) higher had, on average, 0.004% slower growth in BMI between the ages 6.5 and 24 years and a 0.4% slower gain in BMD between the ages 10 and 24 years. Higher BMI PGSs were associated with faster growth for BMI, FMI, LMI, BMD, and weight trajectories in both sexes throughout childhood. Female participants with both a high AN PGS and a low BMI PGS showed slower growth compared to those with both a low AN PGS and a low BMI PGS. We conclude that AN PGSs and BMI PGSs have detectable sex-specific effects on growth trajectories. Female participants with a high AN PGS and low BMI PGS likely constitute a high-risk group for AN, as their growth was slower compared to their peers with high PGSs on both traits. Further research is needed to better understand how the AN PGS and the BMI PGS co-influence growth during childhood and whether a high BMI PGS can mitigate the effects of a high AN PGS.

Correlates of Body Composition in Children with Stunting: A Cross-sectional Study in Uganda.

BACKGROUND: Development of body composition (BC) may be disrupted in children with stunting. Such disruption may affect the later risk of excess adiposity and metabolic health, yet few studies have investigated correlates of BC in children with stunting. OBJECTIVES: We aimed to investigate nutritional status, infection and inflammation, breastfeeding behaviors, and other factors as correlates of BC in children with stunting. METHODS: Among Ugandan children with a height-for-age z-score <-2, BC was estimated using bioelectrical impedance analysis and compared with United Kingdom references. We used multiple linear regression analysis to identify correlates of fat mass (FM), fat-free mass (FFM), FM-index (FMI), and FFM index (FFMI) and height, adjusting for gender and age. RESULTS: In 750 children aged 1-5 y, FMI was 0.46 (95% confidence interval [CI]: 0.38, 0.54] and FFMI 0.18 [95% CI: 0.11, 0.26) z-scores lower than United Kingdom references. Elevated serum α1-acid glycoprotein was associated with 1.14 [0.76, 1.52] cm lower height, 0.50 [0.35, 0.65] kg/m2 less FFMI, and 0.48 [0.31, 0.66] kg/m2 greater FMI. Similar, weaker, associations for elevated serum C-reactive protein were detected. A positive malaria rapid test was associated with 0.64 [0.25, 1.02] cm shorter height, but 0.36 [0.18, 0.54] kg/m2 greater FMI. Anemia (according to hemoglobin) was associated with 0.20 [0.07, 0.33] kg less FFM in proportion to shorter height. Longer breastfeeding duration was associated with 0.03 [0.02, 0.04] kg greater FFM per month, in proportion to greater height. CONCLUSIONS: These children exhibited deficits in FM and FFM, proportionally to their stunted height, compared with United Kingdom references. Systemic inflammation correlated inversely with linear growth and FFM but positively with fatness, making it a possible target for intervention where fat-free tissue accretion is desirable. Longer breastfeeding may offer protection to lean linear growth, but findings for micronutrients were less clear. Longitudinal studies are warranted to support these findings. The study was registered at www.isrctn.com (Ref. ISRCTN13093195).

Appendicular lean mass index and motor function in ambulatory patients with Duchenne muscular dystrophy.

INTRODUCTION/AIMS: Appendicular lean mass index (ALMI) has been linked to motor function in patients with Duchenne muscular dystrophy (DMD). However, quantification of the relationship between ALMI and disease-specific clinical outcome assessment trajectories is needed. The purpose of this study was to determine associations between dual-energy x-ray absorptiometry (DXA) derived estimates of ALMI and motor function in ambulatory patients with DMD. METHODS: A retrospective analysis of longitudinal clinical visit data from 137 glucocorticoid-treated patients with DMD collected via structured motor assessment protocol evaluated associations between ALMI and motor function indexed by the North Star Ambulatory Assessment (NSAA) and 10 Meter Walk/run Test (10MWT). Body composition was assessed using DXA. ALMI was calculated by dividing arm and leg lean mass by height in m2; fat mass index (FMI) was calculated by dividing whole body fat mass by height in m2. Linear mixed-effects models were used to estimate associations between ALMI and motor function, controlling for age and FMI. RESULTS: The full prediction model (age, age,2 ALMI, and FMI) explained 57% of the variance in NSAA scores and 63% of the variance in 10MWT speed. A 1 kg/m2 higher ALMI value predicted a 5.4-point higher NSAA score (p < .001) and 0.45 m/s faster 10MWT speed (p < .001). A 1 kg/m2 higher FMI value predicted a 1.5-point lower NSAA score (p < .001) and 0.14 meters/second slower 10MWT speed (p < .001). DISCUSSION: DXA-derived estimates of ALMI and FMI are associated with motor function in DMD and may explain variation in DMD disease progression.

Dietary patterns and adiposity over time - analysis of the ELSA-Brasil.

PURPOSE: Combining different statistical methods to identify dietary patterns (DP) may provide new insights on how diet is associated with adiposity. This study investigated the association of DP derived from three data-driven methods and adiposity indicators over time. METHODS: This study used data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). DP were identified at baseline applying three statistical methods: Factor Analysis (FA), Treelet Transform (TT), and Reduced Rank Regression (RRR). The association between DP and adiposity indicators (weight, body mass index, waist circumference, body fat percentage and fat mass index) over the period of 8.2 years of follow-up was assessed by linear mixed-models. RESULTS: Convenience DP, marked by unhealthy food groups, was associated with higher adiposity over the follow-up period, regardless of the method applied. The DP identified by TT and marked by high consumption of rice and beans was associated with lower adiposity, whereas the similar DP identified by FA, but additionally characterised by consumption of poultry and red meat was associated with higher adiposity. Prudent DP, marked by plant-based food groups and fish, identified by FA was associated with lower adiposity across the median follow-up time. CONCLUSION: Applying different methods to identify DP showed that a convenience DP was associated with higher adiposity independent of the method applied. We also identified the nuances within adherence to a Brazilian traditional dietary pattern characterised by the consumption of rice and beans, that only when combined with reduced consumption of animal protein and unhealthy foods was associated with lower adiposity over time.

Comparison of body mass index and fat mass index to classify body composition in adolescents-The EVA4YOU study.

The objectives of this study were to develop age- and sex-specific reference percentiles for fat mass index (FMI) and fat-free mass index (FFMI) in adolescents aged 14 to 19 years and to determine differences in overweight/obesity classification by FMI and body mass index (BMI). The EVA4YOU study is a single-center cross-sectional study conducted in western Austria. Cardiovascular risks including anthropometric measurements and bioelectrical impedance analysis were assessed in adolescents (mean age 17 years). FMI and FFMI were calculated as the ratio of fat mass (FM) and fat-free mass (FFM) to the square of height and compared to study population-specific BMI percentiles. One thousand four hundred twenty-two adolescents were included in the analysis. Girls had a significantly higher mean FM and FMI and a significantly lower mean FFM, FFMI (p < 0.001, each), and mean BMI (p = 0.020) than boys. Body composition classification by FMI and BMI percentiles shows a concordance for the < 75th and > 97th percentile, but a significant difference in percentile rank classifications between these two cut-off values (all p < 0.05). Based on FMI, 15.5% (221/1422) of the whole population and 29.4% (92/313) of those between the 75th and 97th percentiles are classified one category higher or lower than those assigned by BMI. CONCLUSION:  Classification of normal or pathologic body composition based on BMI and FMI shows good accordance in the clearly normal or pathologic range. In an intermediate range, FMI reclassifies categories based on BMI in more than a quarter of adolescents. Cut-off values to differentiate normal from pathologic FMI values on a biological basis are needed. TRIAL REGISTRATION: The study is registered at www. CLINICALTRIALS: gov  (Identifier: NCT04598685; Date of registration: October 22, 2020). WHAT IS KNOWN: • Chronic non-communicable diseases (NCDs) are the leading cause of morbidity and mortality globally, with major risk factors including unhealthy diets, harmful behaviors, and obesity. Obesity in children and adolescents is a key risk factor for later NCDs, which is commonly measured by Body Mass Index (BMI). • BMI can be misleading as it doesn't distinguish between fat mass (FM) and fat-free mass (FFM), leading to potential misclassification of obesity in children. Previous studies have already suggested the use of the Fat Mass Index (FMI) and Fat-Free Mass Index (FFMI) as a more accurate measures of body composition. WHAT IS NEW: • This study adds the first age- and sex-specific reference values for FMI and FFMI in Austrian adolescents using bioelectrical impedance analysis (BIA) as a safe and secure measurement method of a large representative cohort. • We found percentile misclassification between BMI and FMI when categorizing for obesity, especially in intermediate categories of body composition. Furthermore, when comparing the new reference values for FMI and FFMI to existing ones from the US, UK, and Germany we could show a good alignment within the European cohorts and major differences with American values, indicating and confirming the difference of FMI and FFMI for different populations of different ethnical background, living on different continents.

Does the association between adiposity measures and pre-frailty among older adults vary by social position? Findings from the Tromsø study 2015/2016.

INTRODUCTION: Pre-frailty provides an ideal opportunity to prevent physical frailty and promote healthy ageing. Excess adiposity has been associated with an increased risk of pre-frailty, but limited studies have explored whether the association between adiposity measures and pre-frailty varies by social position. METHODS: We used data from the seventh survey of the Tromsø Study (Tromsø7) conducted in 2015-2016. Our primary sample consisted of 2,945 women and 2,794 men aged ≥ 65 years. Pre-frailty was defined as the presence of one or two of the five frailty components: low grip strength, slow walking speed, exhaustion, unintentional weight loss and low physical activity. Adiposity was defined by body mass index (BMI), waist circumference (WC), fat mass index (FMI) and visceral adipose tissue (VAT) mass. Education and subjective social position were used as measures of social position. Poisson regression with robust variance was used to assess the association between adiposity measures and pre-frailty, and the interaction term between adiposity measures and social position measures were utilised to explore whether the association varied by social position. RESULTS: In our sample, 28.7% of women and 25.5% of men were pre-frail. We found sub-multiplicative interaction of BMI-defined obesity with education in women and subjective social position in men with respect to development of pre-frailty. No other adiposity measures showed significant variation by education or subjective social position. Regardless of the levels of education or subjective social position, participants with excess adiposity (high BMI, high WC, high FMI and high VAT mass) had a higher risk of pre-frailty compared to those with low adiposity. CONCLUSION: We consistently observed that women and men with excess adiposity had a greater risk of pre-frailty than those with low adiposity, with only slight variation by social position. These results emphasize the importance of preventing excess adiposity to promote healthy ageing and prevent frailty among all older adults across social strata.

Association of body composition with ambulatory blood pressure among Chinese youths.

BACKGROUND: For youths, abnormalities in ambulatory blood pressure (ABP) patterns are known to be associated with increased cardiovascular disease risk and potential target organ damage. Body composition, including indicators such as lean mass index (LMI), fat mass index (FMI), and visceral fat level (VFL), plays a significant role in blood pressure (BP) regulation. However, little is known about the association between these body composition indicators and ABP. Therefore, the present study examined the association between these body composition indicators and BP among Chinese youths. METHODS: A total of 477 college students aged 17 to 28 years old (mean ± Standard deviation = 18.96 ± 1.21) from a university in Changsha, Hunan Province, China, were included in this study. Body composition indicators were measured with a bioelectrical impedance body composition analyzer, and 24-hour ambulatory blood pressure monitoring (ABPM) was conducted. Multivariable logistic regression was performed to assess the relationship between body composition indicators and abnormal ABP. RESULTS: The prevalence of abnormal BP, including 24-hour BP, daytime BP, nighttime BP, and clinic BP, were 4.8%, 4.2%, 8.6%, and 10.9%, respectively. After adjusting for potential covariates, LMI [abnormal 24-hour BP (OR = 1.85, 95%CI:1.31, 2.62), abnormal daytime BP (OR = 1.76, 95%CI:1.21, 2.58), abnormal nighttime BP (OR = 1.64, 95%CI:1.25, 2.14), abnormal clinic BP (OR = 1.84, 95%CI:1.38, 2.45)], FMI [abnormal 24-hour BP (OR = 1.20, 95%CI:1.02, 1.41), abnormal daytime BP (OR = 1.30, 95%CI:1.07, 1.57), abnormal nighttime BP (OR = 1.24, 95%CI:1.10, 1.39), abnormal clinic BP (OR = 1.42, 95%CI:1.22, 1.65)], and VFL [abnormal 24-hour BP (OR = 1.22, 95%CI:1.06, 1.39), abnormal daytime BP (OR = 1.29, 95%CI:1.10, 1.51), abnormal nighttime BP (OR = 1.24, 95%CI:1.12, 1.39), abnormal clinic BP (OR = 1.38, 95%CI:1.21, 1.57)] are positively linked to abnormal BP. Additionally, there were significant sex differences in the association between body composition and abnormal BP. CONCLUSIONS: Our findings suggested maintaining an individual's appropriate muscle mass and fat mass and focusing on the different relations of males' and females' body composition is crucial for the achievement of appropriate BP profiles.

Body composition parameters and sarcopenia in adults with Down syndrome: a case-control study.

BACKGROUND: Individuals with Down syndrome (DS) experience premature aging. Whether accelerated aging involves changes in body composition parameters and is associated with early development of sarcopenia is unclear. AIMS: To compare parameters of body composition and the prevalence of sarcopenia between adults with DS and the general population. METHODS: Body composition was assessed by whole-body dual-energy X-ray absorptiometry (DXA). Fat mass (FMI) and skeletal mass indices (SMI) were calculated as the ratio between total body fat mass and appendicular lean mass and the square of height, respectively. Fat mass distribution was assessed by the android/gynoid fat ratio (A/G). Sarcopenia was defined according to the criteria and cut-points recommended by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). Data on age- and sex-matched non-DS controls were retrieved from the 2001-2002 National Health and Nutrition Examination Survey (NHANES) population. RESULTS: Sixty-four DS adults (mean age 37.2 ± 12.0 years, 20.3% women) were enrolled and compared with age- and sex-matched NHANES participants (n = 256), in a 1:4 ratio. FMI (7.96 ± 3.18 kg/m2 vs. 8.92 ± 4.83 kg/m2, p = 0.135), SMI (7.38 ± 1.01 kg/m2 vs. 7.46 ± 2.77 kg/m2, p = 0.825) and A/G (0.98 ± 0.17 vs. 1.01 ± 0.22, p = 0.115) were not significantly different between DS and control participants. When the sample was stratified by sex, women with DS had a higher FMI compared with their NHANES controls (10.16 ± 4.35 kg/m2 vs. 8.11 ± 4.29 kg/m2, p < 0.001), while men with DS had lower A/G ratio (1.04 ± 0.16 vs. 1.11 ± 0.22, p = 0.002). Sarcopenia was more frequent in individuals with DS than in controls (35.6% vs. 19.9%, p = 0.007). This association was stronger in men 40 years and older. CONCLUSIONS: Adults with DS have a higher prevalence of sarcopenia compared with the general population. This finding suggests that DS is associated with early muscle aging and calls for the design of interventions targeting the skeletal muscle to prevent or treat sarcopenia.

Changes in body composition and low blood urea nitrogen level related to an increase in the prevalence of fatty liver over 20 years: A cross-sectional study.

AIM: Qualitative body composition (BC) change, characterized by the combination of visceral fat gain and muscle loss, is drawing attention as a risk factor for fatty liver (FL). The present study aimed to describe trends in BC change and its association with FL in the Japanese population. METHODS: Data from medical checkups carried out on 56 639 Japanese participants every 5 years from 1997 to 2017 were analyzed. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated using body mass index and body fat percentage. Subjects were divided into two groups according to deviations from the correlation line of FMI and FFMI as the reference: FMI-predominant BC and FFM-dominant BC. Fatty liver was determined using abdominal ultrasonography. RESULTS: The prevalence of FL significantly increased from 27.3% to 42.7% in men and from 18.0% to 25.5% in women. The prevalence of FMI predominance significantly increased from 33.6% to 43.9% in men and from 29.1% to 47.0% in women. Fat mass index predominance was independently associated with FL in men and women (odds ratio: 1.96 and 1.94, respectively). Serum blood urea nitrogen level was inversely associated with FL in men and women (0.958 and 0.961, respectively) and significantly decreased from 15.8 to 14.9 mg/dl in men and from 15.1 to 14.0 mg/dl in women. CONCLUSIONS: Increasing FMI-predominant BC and decreasing serum blood urea nitrogen level could account for the increase in the prevalence of FL over 20 years. We believe that these factors stem from current lifestyle habits in Japan.

Assessment of muscle and fat mass in type 2 diabetes patients by dual-energy X-ray absorptiometry.

OBJECTIVES: The aim of this study was to assess the quantitative composition of muscle and adipose tissue in type 2 diabetes mellitus (T2DM) patients on the basis of dual-energy X-ray absorptiometry for the diagnosis of obesity and sarcopenia. METHODS: Dual-energy X-ray absorptiometry was administered to 50 patients with T2DM. Evaluation of the composition of muscle and adipose tissue was performed. RESULTS: The median of Appendicular Lean Mass Index (ALMI) in the general group was 8.04 [7.32; 8.97]. In general, there was a decrease in the appendicular muscle mass with increasing age. According to the results of T-score ALMI and Z-score ALMI, we did not identify patients with sarcopenia. However, the calculation of the T- and Z-criteria, adjusted for fat mass, led to a significant decrease of these parameters and in 98.0% it was possible to identify patients who meet the criteria of sarcopenia. CONCLUSION: We did not detect patients with sarcopenia on the basis of ALMI, T-ALMI. After revision of these criteria for fat mass, almost all patients started to meet the criteria of sarcopenia (98.0%).

Fat-Free Mass Index Controlled for Age and Sex and Malnutrition Are Predictors of Survival in Interstitial Lung Disease.

BACKGROUND: Literature focusing on nutritional variables and survival in interstitial lung disease (ILD) is limited by its focus on weight and BMI and has not considered body composition. OBJECTIVES: The primary objective of this study was to examine whether body composition measures, specifically fat-free mass index z-score (z-FFMI) and body fat mass index z-score (z-BFMI), were predictors of survival in fibrotic ILD patients. The second objective was to examine if nutrition status was a predictor of survival. METHOD: Seventy-eight outpatients diagnosed with fibrotic ILD were recruited in this cross-sectional study. Body composition data using dual frequency bioelectrical impedance analysis (BodyStat 1500MD; UK) and nutrition status using the subjective global assessment (SGA) were determined. To control for age and sex, z-FFMI and z-BFMI were calculated using population means. Participant charts were reviewed for diagnosis, age, disease severity, and exercise capacity. RESULTS: Age (HR 1.08, 95% CI [1.03-1.13], p < 0.01), BMI (HR 0.90, 95% CI [0.84-0.97], p < 0.01]), z-FFMI (HR 0.70, 95% CI [0.56-0.87], p = 0.02), z-BFMI (HR 0.74, 95% CI [0.57-0.96], p < 0.01), 6-min walk distance (6MWD) (HR 0.99, 95% CI [0.99-1.00], p < 0.01), percent predicted diffusing capacity for carbon monoxide (%DLco) (HR 0.93, 95% CI [0.89-0.97], p < 0.01), and severe malnutrition (SGA-C) (HR 6.98, 95% CI [2.00-24.27], p < 0.01) were significant predictors of survival. When controlled for exercise capacity and disease severity, z-FFMI and severe malnutrition were significant predictors of survival independent of %DLco. CONCLUSION: z-FFMI and severe malnutrition were significant predictors of survival in fibrotic ILD patients independent of disease severity.

Moderate-to-vigorous intensity physical activity trajectories during adolescence and young adulthood predict adiposity in young adulthood: The Iowa Bone Development Study.

This study examined the associations of moderate-to-vigorous intensity physical activity (MVPA) trajectories in adolescence through young adulthood with adiposity in young adults. Participants from The Iowa Bone Development Study cohort were longitudinally assessed (N = 297; 57% female). Accelerometry-measured MVPA (min/day) at ages 15 through 23 years, and fat mass and visceral adipose tissue mass indices (kg/m2, g/m2) derived from dual-energy X-ray absorptiometry scans at age 23 years were analyzed. Latent trajectory analyses classified MVPA into two patterns. Multivariable linear regression analyses showed that being in the high MVPA trajectory group was associated with lower fat mass index z-scores. Individuals who were consistently active with high MVPA (vs. moderately active with decreasing MVPA) during adolescence up until early young adulthood had less accumulation of total body adiposity in young adulthood. This study suggests that adopting a consistently active lifestyle throughout adolescence can result in healthier body composition in young adulthood.

Association between the combined fat mass and fat-free mass index and hypertension: The Tohoku Medical Megabank Community-based Cohort Study.

BACKGROUND: A  higher body fat percentage is associated with hypertension, even in non-obese individuals. The difference in body composition may be related to hypertension. The fat mass index (FMI) and fat-free mass index (FFMI) are proposed indicators of body composition. This study aimed to examine the relationship of a combination of FMI and FFMI with hypertension. METHODS: We conducted a cross-sectional study of 5,058 men and 11,842 women aged ≥ 20 years in the Miyagi Prefecture, northeastern Japan. The FMI and FFMI were calculated as the fat mass and fat-free mass divided by the height squared, respectively. The indices were classified into quartiles and combined into 16 groups. Hypertension was defined as casual blood pressure ≥ 140/90 mmHg and/or self-reported treatment for hypertension. Multivariable logistic regression models, adjusted for potential confounders, were used to assess the relationship of a combination of FMI and FFMI with hypertension. RESULTS: Higher FMI was associated with hypertension in most of the FFMI subgroups. Similarly, a higher FFMI was associated with hypertension in most of FMI subgroups. For men, the association between FFMI and hypertension in the lowest FMI group was not significant. CONCLUSIONS: Reducing the FMI and FFMI may be important in preventing hypertension. For men, the relationship between the FFMI and hypertension in the lowest FMI group might be weak.

Effects of the application of a prolonged combined intervention on body composition in adolescents with obesity.

BACKGROUND: The aim of this study is to describe the effects of a prolonged dietary-behavioral-physical activity intervention (24 months) on body composition in a group of adolescents with obesity. METHODS: Longitudinal study in 196 individuals with obesity (86 boys and 110 girls) aged 10.1-14.9 years that completed a prolonged combined intervention (24 months). Values for weight, height, skinfold thickness, waist circumference, BMI, body fat, fat mass index (FMI) and fat-free mass index (FFMI) were registered or calculated. A good response to treatment was reported when a BMI z-score reduction of greater than or equal to 0.5 units of the initial value occurred after 24 month of follow up. RESULTS: A good response after 24 months of follow-up reached 58.2% (n = 114). In boys with obesity and BMI status improvement, weight z-score, BMI z-score, body fat, and FMI significantly decreased (p < 0.05). In girls with obesity and BMI status improvement, weight z-score, BMI z-score, waist circumference, waist z-score, body fat and FMI significantly decreased (p < 0.05). In both sexes the height and FFMI increased significantly (p < 0.05). The multiple logistic regression analysis showed that girls and younger age were associated with BMI status improvement; concurrently, the place of residence (urban or rural) and degree of obesity were not associated with BMI status improvement. CONCLUSION: The application of long-term combined strategies in the treatment of childhood obesity seems to be effective. As BMI decreases, a reduction in fat mass is also detected, with evident sexual dimorphism, in the absence of changes in fat-free mass and, consequently, in longitudinal growing.

Reference Centiles for the Evaluation of Nutritional Status in Children using Body Fat Percentage, Fat Mass and Lean Body Mass Index.

BACKGROUND: Body fat percentage (BF%), fat mass index (FMI), and lean body mass index (LBMI) are often used to evaluate the nutritional status of children. Until now, no pediatric FMI reference centiles are applicable for GE Healthcare Lunar DXA systems. The aim of the study was to generate age-specific BF%, FMI, and LBMI references centiles for GE Healthcare Lunar DXA systems. METHODOLOGY: Published values from the National Health and Nutrition Examination Survey 1999-2004 (age 8-20 years) were used to generate the reference centiles for the non-Hispanic black, non-Hispanic white, and Mexican American NHANES population. The LMS and LMSP methods were used to generate the reference centiles. RESULTS: Data of 2433 non-Hispanic black children (972 females), 2026 non-Hispanic white children (873 females), and 2547 Mexican American children (1010 females) were eligible. CONCLUSIONS: We presented age-specific reference centiles for BF%, FMI, and LBMI for children and adolescents which were ethnicity specific (non-Hispanic black, non-Hispanic white, and Mexican American) and directly applicable to Prodigy and iDXA GE Healthcare Lunar systems with software version 14.0. We proposed the use of BF%, FMI, and LBMI together to evaluate nutritional status in children.

The relationship between anthropometric measures and cardiometabolic health in shift work: findings from the Atlantic PATH Cohort Study.

PURPOSE: To evaluate the relationship between anthropometric measures and cardiometabolic health in shift workers compared to non-shift workers. METHODS: A population health study was conducted with 4155 shift workers and 8258 non-shift workers from the Atlantic Partnership for Tomorrow's Health (PATH) cohort. Linear and logistic regression models were used to assess the differences in anthropometric measures (body adiposity) and self-reported cardiometabolic disease outcomes (obesity, diabetes, and cardiovascular disease) between shift workers and non-shift workers. RESULTS: There was a significant increased risk of cardiovascular disease, obesity, and diabetes among shift workers compared to matched controls despite higher levels of physical activity and lower levels of sedentary behaviour. Shift workers were 17% more likely to be obese (95% CI 7-27) and 27% more likely to have diabetes (95% CI 8-51). The strength of this association was demonstrated by also controlling for body mass index and fat mass index. CONCLUSIONS: Shift work is associated with obesity, cardiovascular disease, and diabetes despite higher levels of physical activity and lower levels of sedentary behaviour. The association between shift work and cardiometabolic health was independent of body mass index for cardiovascular disease and diabetes, and independent of fat mass index for diabetes.

Associations of accelerometer-measured sedentary time, sedentary bouts, and physical activity with adiposity and fitness in children.

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO2max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO2max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO2max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO2max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.

Relationship between BMI and adiposity among different ethnic groups in 2-year-old New Zealand children.

Age- and sex-based BMI cut-offs are used to define overweight and obesity, but the relationship between BMI and body composition has not been very well studied in children or compared between children of different ethnic groups. Body size and composition in childhood are also influenced by size at birth. Our aim was to compare body size and composition at 2 years in children with different ethnicity and size at birth. We prospectively followed a multi-ethnic cohort of 300 children born with risk factors for neonatal hypoglycaemia (infants of diabetics, large or small at birth or late preterm) to 2 years corrected age. Complete data on weight, height and head circumference and body composition using bioelectrical impedance 24±1 months corrected age were available in 209 children. At birth, compared with European children, Chinese, Indian and other ethnicity children were lighter, and Indian children had smaller head circumferences, but birth lengths were similar in all ethnic groups. At 2 years, Pacific children were heavier and had higher BMI z scores, and Indian children had smaller head circumferences and lower BMI z scores than those from other ethnic groups. However, fat mass and fat-free mass indices were similar in all groups. At median BMI, fat mass:fat-free mass ratio was 23 % lower in Pacific than in Indian children (0·22 v. 0·27, P=0·03). BMI is not a good indicator of adiposity in this multi-ethnic cohort of 2-year-old New Zealand children.

Stunting, wasting and breast-feeding as correlates of body composition in Cambodian children at 6 and 15 months of age.

The study aimed at assessing stunting, wasting and breast-feeding as correlates of body composition in Cambodian children. As part of a nutrition trial (ISRCTN19918531), fat mass (FM) and fat-free mass (FFM) were measured using 2H dilution at 6 and 15 months of age. Of 419 infants enrolled, 98 % were breastfed, 15 % stunted and 4 % wasted at 6 months. At 15 months, 78 % were breastfed, 24 % stunted and 11 % wasted. Those not breastfed had lower FMI at 6 months but not at 15 months. Stunted children had lower FM at 6 months and lower FFM at 6 and 15 months compared with children with length-for-age z ≥0. Stunting was not associated with height-adjusted indexes fat mass index (FMI) or fat-free mass index (FFMI). Wasted children had lower FM, FFM, FMI and FFMI at 6 and 15 months compared with children with weight-for-length z (WLZ) ≥0. Generally, FFM and FFMI deficits increased with age, whereas FM and FMI deficits decreased, reflecting interactions between age and WLZ. For example, the FFM deficits were -0·99 (95 % CI -1·26, -0·72) kg at 6 months and -1·44 (95 % CI -1·69; -1·19) kg at 15 months (interaction, P<0·05), while the FMI deficits were -2·12 (95 % CI -2·53, -1·72) kg/m2 at 6 months and -1·32 (95 % CI -1·77, -0·87) kg/m2 at 15 months (interaction, P<0·05). This indicates that undernourished children preserve body fat at the detriment of fat-free tissue, which may have long-term consequences for health and working capacity.

Associations of dietary energy density with body composition and cardiometabolic risk in children with overweight and obesity: role of energy density calculations, under-reporting energy intake and physical activity.

This study examined (1) the association of dietary energy density from solid (EDS) and solid plus liquids (EDSL) with adiposity and cardiometabolic risk factors (CRF) in children with overweight and obesity, (2) the effect of under-reporting on the mentioned associations and (3) whether the association between ED and body composition and CRF is influenced by levels of physical activity. In a cross-sectional design, 208 overweight and obese children (8-12-year-old; 111 boys) completed two non-consecutive 24 h recalls. ED was calculated using two different approaches: EDS and EDSL. Under-reporters were determined with the Goldberg method. Body composition, anthropometry and fasting blood sample measurements were performed. Moderate to vigorous physical activity (MVPA) was registered with accelerometers (7-d-register). Linear regressions were performed to evaluate the association of ED with the previously mentioned variables. Neither EDS nor EDSL were associated with body composition or CRF. However, when under-reporters were excluded, EDS was positively associated with BMI (P=0·019), body fat percentage (P=0·005), abdominal fat (P=0·008) and fat mass index (P=0·018), while EDSL was positively associated with body fat percentage (P=0·008) and fat mass index (P=0·026). When stratifying the group according to physical activity recommendations, the aforementioned associations were only maintained for non-compliers. Cluster analysis showed that the low-ED and high-MVPA group presented the healthiest profile for all adiposity and CRF. These findings could partly explain inconsistencies in literature, as we found that different ED calculations entail distinct results. Physical activity levels and excluding under-reporters greatly influence the associations between ED and adiposity in children with overweight and obesity.