Infants born at high altitudes, such as in the Puno region, typically exhibit higher birthweights than those born at low altitudes; however, the influence of ethnicity on childhood anthropometric patterns in high-altitude settings remains poorly understood. This study aimed to characterise the nutritional status, body composition and indices, and somatotype of Quechua and Aymara children aged 6–10 years. A cross-sectional, descriptive, and comparative design was employed, with a simple random sampling of children from six provinces representative of the Puno region, including 1,289 children of both sexes. Twenty-nine anthropometric measurements were taken, and fat, muscle, and bone components were assessed using bioelectrical impedance analysis. Standardised equations were applied to determine body indices. Among the findings, most children presented normal nutritional status according to BMI-for-age and height-for-age Z-scores. However, high rates of overweight and obesity were observed in Aymara (39%) and Quechua (28.4%) children, with differences in fat content between ethnic groups at the 5th, 10th, 50th, and 75th percentiles. Both groups were characterised by brachytypy and brachybrachial proportions; Quechua children were mesoskelic and Aymara brachyskelic, with macrocormic proportions, rectangular trunks, and broad backs. The predominant somatotype was mesomorphic, with a stronger endomorphic tendency among Aymara. It is concluded that both groups exhibit normal nutritional status; however, Aymara children show a greater tendency towards fat accumulation and notable morphological differences. Differences were also observed in limb proportions, particularly a relatively shorter lower limb.

Proper nutrition enhances athletes’ performance and recovery during sports activities. This review aims to investigate the effects of nutrition education interventions on dietary intake, nutrition knowledge, and body composition of female athletes. From a comprehensive search, we identified 20 single-arm and 8 double arm studies that met the inclusion criteria. The interventions in these studies ranged from personalized consultations to group workshops. The mode of delivery was mainly face-to-face. Most of these interventions consisted of group sessions with variable duration and frequency. From the studies finally included, nutrition education intervention significantly increased the nutrition knowledge of female athletes in 76% and improved their dietary intake in 67%. However, only 44% of the studies that measured changes in body composition reported significant changes. Moreover, only a minority of studies (14%) maintained follow-up assessments to measure the lasting impact of the interventions. Sixty percent of interventions were delivered by professional nutritionists or dietitians, ensuring high-quality education. There is a need for standardized methodologies and more robust study designs to better assess the effectiveness of nutrition education interventions. Knowing athletes’ preferences when planning education may improve engagement and intervention efficacy. Also, longer-term follow-up of athletes would allow for a more accurate evaluation of the consolidation of acquired knowledge. Including coaches in nutrition education interventions would probably amplify the impact on athletes’ dietary behaviours. Nutrition education can positively influence the knowledge and eating habits of female athletes, but its effect on body composition represents an area where much remains to be explored.

Understanding the interplay between adiposity and histopathological features of colorectal tumours is crucial for advancing strategies in disease management. We conducted a retrospective cohort study over an 8-year period (2007–2015), including patients who underwent surgical resection for colorectal cancer (CRC). Body composition was assessed via computed tomography (CT) at the level of the third lumbar vertebra, with visceral adipose tissue (VATd) and subcutaneous adipose tissue (SATd) radiodensities stratified into tertiles. Systemic inflammatory status was evaluated using the neutrophil-to-lymphocyte ratio (NLR). Logistic regression was employed to analyse the relationship between variables, using OR with 95 % CI. The Cox proportional hazards model assessed hazard ratios (HR) with 95 % CI. A total of 231 patients were included (48·9 % men, 51·1 % women), with 93·6 % in CRC stages II and III. Multivariate analyses demonstrated that CRC stages II and III (OR = 5·15, 95 % CI: 1·60, 16·62; OR = 5·16, 95 % CI: 1·59, 16·77) and low VATd (1st and 2nd tertiles; OR = 2·43, 95 % CI: 1·30, 4·53) were associated with the presence of desmoplasia. In the multivariate Cox analyses, only stage III disease (HR = 4·77, 95 % CI: 1·09, 20·89) and moderate to accentuated fibrous stroma (HR = 1·90, 95 % CI: 1·03, 3·46) were identified as predictors of reduced overall survival. These findings suggest that increased visceral adiposity may contribute to the development of a desmoplastic tumour microenvironment. Moreover, the presence of moderate to accentuated fibrous stroma is significantly associated with poorer long-term survival in patients with CRC.

The World Cancer Research Fund and the American Institute for Cancer Research recommend a plant-based diet to cancer survivors, which may reduce chronic inflammation and excess adiposity associated with worse survival. We investigated associations of plant-based dietary patterns with inflammation biomarkers and body composition in the Pathways Study, in which 3659 women with breast cancer provided validated food frequency questionnaires approximately 2 months after diagnosis. We derived three plant-based diet indices: overall plant-based diet index (PDI), healthful plant-based diet index (hPDI) and unhealthful plant-based diet index (uPDI). We assayed circulating inflammation biomarkers related to systemic inflammation (high-sensitivity C-reactive protein [hsCRP]), pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) and anti-inflammatory cytokines (IL-4, IL-10, IL-13). We estimated areas (cm2) of muscle and visceral and subcutaneous adipose tissue (VAT and SAT) from computed tomography scans. Using multivariable linear regression, we calculated the differences in inflammation biomarkers and body composition for each index. Per 10-point increase for each index: hsCRP was significantly lower by 6·9 % (95 % CI 1·6%, 11·8%) for PDI and 9·0 % (95 % CI 4·9%, 12·8%) for hPDI but significantly higher by 5·4 % (95 % CI 0·5%, 10·5%) for uPDI, and VAT was significantly lower by 7·8 cm2 (95 % CI 2·0 cm2, 13·6 cm2) for PDI and 8·6 cm2 (95 % CI 4·1 cm2, 13·2 cm2) for hPDI but significantly higher by 6·2 cm2 (95 % CI 1·3 cm2, 11·1 cm2) for uPDI. No significant associations were observed for other inflammation biomarkers, muscle, or SAT. A plant-based diet, especially a healthful plant-based diet, may be associated with reduced inflammation and visceral adiposity among breast cancer survivors.

Pregnancy and lactation change women’s body composition (BC), but few longitudinal studies have investigated postpartum BC trajectories. We aimed to investigate maternal and infant predictors of maternal body fat (BF), fat mass (FM), fat-free mass (FFM) and BMI trajectories during lactation. Longitudinal study with 234 Brazilian mother–infant dyads followed at 1·0–3·49, 3·5–5·99 and 6·0–8·5 months postpartum. Maternal BC was estimated using bioelectrical impedance at all follow-up points. Longitudinal mixed–effects models with interaction terms with time (weeks postpartum) were employed. FFM declined significantly over weeks postpartum (β = −0·02 kg; 95 % CI –0·03, −0·01). Pre-pregnancy overweight women experienced an increase in all body components (BF: β = 4·91 %, 95 % CI 3·79, 6·04; FM: β = 6·46 kg, 95 % CI 5·26, 7·67; FFM: β = 3·72 kg, 95 % CI 2·80, 4·65) and BMI (β = 4·51 kg/m2, 95 % CI 3·91, 5·12). Multiparous women showed BMI increases (β = 0·76 kg/m2, 95 % CI 0·11, 1·41), and those who delivered by caesarean had FFM (β = 1·87 kg, 95 % CI 0·67, 3·07) and BMI (β = 1·39 kg/m2, 95 % CI 0·61, 2·18) increases. Women who birthed girls had reductions in FM (β = −1·24 kg, 95 % CI –2·41, −0·07) and FFM (β = −0·93 kg, 95 % CI –1·84, −0·01). Interactions occurred between maternal age ≥ 30 years, higher family income, multiparity and infant sex for BC and BMI trajectories. Maternal age, pre-pregnancy BMI, parity, family income, mode of delivery and infant sex predict maternal BC and BMI trajectories.

An assessment of systemic inflammation and nutritional status may form the basis of a framework to examine the prognostic value of cachexia in patients with advanced cancer. The objective of the study was to examine the prognostic value of the Global Leadership Initiative on Malnutrition criteria, including BMI, weight loss (WL) and systemic inflammation (as measured by the modified Glasgow Prognostic Score (mGPS)), in advanced cancer patients. Three criteria were examined in a combined cohort of patients with advanced cancer, and their relationship with survival was examined using Cox regression methods. Data were available on 1303 patients. Considering BMI and the mGPS, the 3-month survival rate varied from 74 % (BMI > 28 kg/m2) to 61 % (BMI < 20 kg/m2) and from 84 % (mGPS 0) to 60 % (mGPS 2). Considering WL and the mGPS, the 3-month survival rate varied from 81 % (WL ± 2·4 %) to 47 % (WL ≥ 15 %) and from 93 % (mGPS 0) to 60 % (mGPS 2). Considering BMI/WL grade and mGPS, the 3-month survival rate varied from 86 % (BMI/WL grade 0) to 59 % (BMI/WL grade 4) and from 93 % (mGPS 0) to 63 % (mGPS 2). When these criteria were combined, they better predicted survival. On multivariate survival analysis, the most highly predictive factors were BMI/WL grade 3 (HR 1·454, P = 0·004), BMI/WL grade 4 (HR 2·285, P < 0·001) and mGPS 1 and 2 (HR 1·889, HR 2·545, all P < 0·001). In summary, a high BMI/WL grade and a high mGPS as outlined in the BMI/WL grade/mGPS framework were consistently associated with poorer survival of patients with advanced cancer. It can be readily incorporated into the routine assessment of patients.

We investigated associations between ‘healthy dietary pattern’ scores, at ages 36, 43, 53 and 60–64 years, and body composition at age 60–64 years among participants from the MRC National Survey of Health and Development (NSHD). Principal component analyses of dietary data (food diaries) at age 60–64 years were used to calculate diet scores (healthy dietary pattern scores) at each age. Higher scores indicated healthier diets (higher consumption of fruit, vegetables and wholegrain bread). Linear regression was used to investigate associations between diet scores at each age and height-adjusted dual-energy X-ray absorptiometry-measured fat and lean mass measures at age 60–64 years. Analyses, adjusting for sex and other potential confounders (age, smoking history, physical activity and occupational class), were implemented among 692 men and women. At age 43, 53 and 60–64 years, higher diet scores were associated with lower fat mass index (FMI) and android:gynoid fat mass ratio; for example, in fully adjusted analyses, a standard deviation (sd) increase in diet score at age 60–64 years was associated with an SD difference in mean FMI of −0·18 (95 % CI: −0·25, −0·10). In conditional analyses, higher diet scores at ages 43, 53 and 60–64 years (than expected from diet scores at younger ages) were associated with lower FMI and android:gynoid fat mass ratio in fully adjusted analyses. Diet scores at age 36 years had weaker associations with the outcomes considered. No associations regarding appendicular lean mass index were robust after full adjustment. This suggests that improvements in diet through adulthood are linked to beneficial effects on adiposity in older age.

The prevalence of poor linear growth among African children with perinatally acquired HIV remains high. There is concern that poor linear growth may to lead to later total and central fat deposition and associated non-communicable disease risks. We investigated associations between height-for-age Z score (HAZ) and total and regional fat and lean mass measured by dual-energy X-ray absorptiometry, expressed as internal population Z scores, among 839 Zimbabwean and Zambian perinatally HIV-infected male and female adolescents aged 11–19 years. Stunting (HAZ < –2) was present in 37 % of males and 23 % of females. HAZ was strongly positively associated with total, trunk, arm and leg fat mass and lean mass Z scores, in analyses controlling for pubertal stage, socio-economic status and HIV viral load. Associations of linear growth with lean mass were stronger than those with fat outcomes; associations with total and regional fat were similar, indicating no preferential central fat deposition. There was no evidence that age of starting antiretroviral therapy was associated with HAZ or body composition. Non-suppressed HIV viral load was associated with lower lean but not fat mass. The results do not support the hypothesis that poor linear growth or stunting are risk factors for later total or central fat deposition. Rather, increased linear growth primarily benefits lean mass but also promotes fat mass, both consistent with larger body size. Nutritional and/or HIV infection control programmes need to address the high prevalence of stunting among perinatally HIV-infected children in order to mitigate constraints on the accretion of lean and fat mass.

The expensive-tissue hypothesis (ETH) posited a brain–gut trade-off to explain how humans evolved large, costly brains. Versions of the ETH interrogating gut or other body tissues have been tested in non-human animals, but not humans. We collected brain and body composition data in 70 South Asian women and used structural equation modelling with instrumental variables, an approach that handles threats to causal inference including measurement error, unmeasured confounding and reverse causality. We tested a negative, causal effect of the latent construct ‘nutritional investment in brain tissues’ (MRI-derived brain volumes) on the construct ‘nutritional investment in lean body tissues’ (organ volume and skeletal muscle). We also predicted a negative causal effect of the brain latent on fat mass. We found negative causal estimates for both brain and lean tissue (−0.41, 95% CI, −1.13, 0.23) and brain and fat (−0.56, 95% CI, −2.46, 2.28). These results, although inconclusive, are consistent with theory and prior evidence of the brain trading off with lean and fat tissues, and they are an important step in assessing empirical evidence for the ETH in humans. Analyses using larger datasets, genetic data and causal modelling are required to build on these findings and expand the evidence base.

This study verified the accuracy of the international BMI references and the allometric BMI reference to diagnose obesity in children and adolescents from the USA. Data from 17 313 subjects were obtained from the National Health and Nutrition Examination Survey between the years 1999–2006 and 2011–2018. Fat Mass Index, Allometric Fat Mass Index and fat mass/fat-free mass were calculated. Receiver operating characteristic curve, AUC, sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were estimated to evaluate the accuracy of the growth references for diagnosing obesity. The International Obesity Task Force, MULT BMI 17 years, MULT BMI 18 years and allometric BMI 19 years achieved the best sensitivity-specificity trade-off for boys, with sensitivities ranging from 0·92 to 0·96 and specificities of 0·94, with positive likelihood ratio of 15·51, 16·17, 13·46 and 18·01, respectively. The negative likelihood ratios were notably low, ranging from 0·04 to 0·08. In girls, the International Obesity Task Force, MULT BMI 17 years and MULT allometric BMI 17 years also demonstrated high sensitivity (0·95–0·97) and specificity (0·92), with positive likelihood ratio values of 11·54, 11·82 and 11·77, respectively and low negative likelihood ratio values (0·03–0·05). In summary, these international growth references presented satisfactory performance to diagnose obesity. However, the MULT growth reference performed better, and the MULT allometric BMI was the only indicator capable of detecting that girls have a higher proportion of fat mass than boys for the same index values. These findings suggest that the MULT growth reference may be a better tool to assess the nutritional status of children and adolescents internationally.

The relationship between frailty and glycemic control in older adults with diabetes remains uncertain, mainly due to the fact that previous studies have not accounted for measures of body composition. In older adults with diabetes, we examined the association between three types of frailty measures and glycemic control, while accounting for fat-free mass (FFM) and waist circumference (WC). Eighty older adults (age ≥65, 27 women and 53 men, mean age 80.5 ± 0.6 years) had gait speed, Cardiovascular Health Study Index (CHSI), Rockwood Clinical Frailty Scale (RCFS), and glycosylated hemoglobin (HgA1C) measured. HgA1C showed a negative association only with CHSI (standardized β = −0.255 ± 0.120, p = 0.038), but no association with gait speed or the RCFS. Even after accounting for FFM and WC, we demonstrated a negative association between glycated hemoglobin and increasing frailty in older adults with diabetes.

Cerebral palsy (CP), or to use the Te Reo term “Hōkai Nukurangi”, is an umbrella name for a group of permanent neurodevelopmental disorders, affecting movement and posture(1), and is the most common childhood onset physical disability globally. The available literature on the nutritional status of children with CP describes high rates of malnutrition, however data appears to be skewed towards children of higher levels of impairment impacting functional independence. Less is known about the nutritional status of children with lower levels of impairment. The aim of the “Eat, Sleep, Play-CP” study was to evaluate total energy intake, total protein intake and the timing of protein intake in relation to physical activity for children with CP across all functional levels living in Aotearoa New Zealand. Children with CP aged 5-12 years were invited to participate in an observational assessment of dietary intake using parent reported 24-hour dietary recall (Intake 24) on three non-consecutive days, accompanied by a questionnaire capturing self-reported sleep and physical activity patterns. Body composition was assessed via whole body dual energy X-ray absorptiometry scan. Nine participants (6 males, median age: 10 years, n = 2 Māori), across Gross Motor Function Classification System levels I-IV, and Eating and Drinking Classification System levels I-III took part in the study. The median total energy intake was 7267kJ/d (range 5355-10731.96kJ/d), and median protein intake was 67g/d (range 49-111g/d). According to the Nutrient Reference Values for Australia and New Zealand (NRV)(2), 3 of the 9 participants (33%) were within the recommended range for energy intake according to their age and reported physical activity levels. Of the other 6, 4 were below and 2 were above the recommended ranges. All 9 met the recommended protein intake (NRV). Participants had a median percentage body fat of 40% (range 20-46%), and non-fat mass of 58% (range 52-76%). Five participants fell within the overweight or obese range for their age and sex, three of whom were within the recommended range of total energy daily intake according to NRVs. This outcome may indicate that for some children with CP, recommendations could be over-estimating the actual requirements. These early results may bring in to question current practice around guidance for energy intake requirements for children with CP and their whānau to support healthy body composition. Further investigations are needed to establish whether specific energy intake guidelines are required for children with CP.

The prevalence of childhood obesity is increasing globally(1). While BMI is commonly used to define obesity, it is unable to differentiate between fat and muscle mass, leading to calls to measure body composition specifically(2). While several tools are available to assess body composition in infancy, it is unclear if they are directly comparable. Among a subset of healthy infants born to mothers participating in a randomised controlled trial of a preconception and antenatal nutritional supplement(3), measurements were made at ages 6 weeks (n = 58) and 6 months (n = 70) using air displacement plethysmography (ADP), whole-body dual-energy X-ray absorptiometry (DXA), and bioelectrical impedance spectroscopy (BIS). Estimates of percentage fat mass (%FM) were compared using Cohen’s kappa statistic (κ) and Bland-Altman analysis (4,5). There was none to weak agreement when comparing tertiles of %FM (κ = 0.15–0.59). When comparing absolute values, the bias (i.e., mean difference) was smallest when comparing BIS to ADP at 6 weeks (+1.7%). A similar bias was observed at 6 months when comparing DXA to ADP (+1.8%). However, when comparing BIA to DXA at both ages, biases were much larger (+7.6% and +4.7% at 6 weeks and 6 months, respectively). Furthermore, there was wide interindividual variance (limits of agreement [LOA] i.e., ± 1.96 SD) for each comparison. At 6 weeks, LOA ranged from ± 4.8 to ± 6.5% for BIA vs. DXA and BIA vs. ADP, respectively. At 6 months, LOA were even wider, ranging from ± 7.3 to ± 8.1% (DXA vs. ADP and BIA vs. DXA, respectively). Proportional biases were apparent when comparing BIS to the other tools at both ages, with BIS generally overestimating %FM more among infants with low adiposity. In addition to differences according to tool type, within-tool factors impacted body composition estimation. For ADP measurements, the choice of FFM density reference (Fomon vs. Butte) had minimal impact; however, choice of DXA software version (GE Lunar enCORE basic vs. enhanced) and BIS analysis approach (empirical equation vs. mixture theory prediction) led to very different estimates of body composition. In conclusion, when comparing body composition assessment tools in infancy, there was limited agreement between three commonly used tools. Therefore, researchers and clinicians must be cautious when conducting longitudinal analyses or when comparing findings across studies, as estimates are not comparable across tools.

The purpose of this study was to compare single- and multi-frequency bioimpedance (BIA) devices against dual-energy X-ray absorptiometry (DXA) for appendicular lean mass (ALM) and muscle quality index (MQI) metrics in Hispanic adults. One hundred thirty-one Hispanic adults (18–55 years) participated in this study. ALM was measured with single-frequency bioimpedance analysis (SFBIA), multi-frequency bioimpedance analysis (MFBIA) and DXA. ALMTOTAL (left arm + right arm + left leg + right leg) and ALMARMS (left arm + right arm) were computed for all three devices. Handgrip strength (HGS) was measured using a dynamometer. The average HGS was used for all MQI models (highest left hand + highest right hand)/2. MQIARMS was defined as the ratio between HGS and ALMARMS. MQITOTAL was established as the ratio between HGS and ALMTOTAL. SFBIA and MFBIA had strong correlations with DXA for all ALM and MQI metrics (Lin’s concordance correlation coefficient values ranged from 0·86 (MQIMFBIA-ARMS) to 0·97 (Arms LMSFBIA); all P < 0·001). Equivalence testing varied between methods (e.g. SFBIA v. DXA) when examining the different metrics (i.e. ALMTOTAL, ALMARMS, MQITOTAL and MQIARMS). MQIARMS was the only metric that did not differ from the line of identity and had no proportional bias when comparing all the devices against each other. The current study findings demonstrate good overall agreement between SFBIA, MFBIA and DXA for ALMTOTAL and ALMARMS in a Hispanic population. However, SFBIA and MFBIA have better agreement with DXA when used to compute MQIARMS than MQITOTAL.

Different starch-to-protein ratios were compared among neutered and spayed domiciled cats. Male and female obese and non-obese cats were fed kibble diets ad libitum for 4 months high in starch (HS (38 % crude protein (CP)): starch 32 %, protein 38 %; DM basis) or high in protein (HP (55 % CP): starch 19 %, protein 55 %) but similar in energy and fat in a crossover design. Physical activity was evaluated using an accelerometer, and body composition (BC), energy expenditure (EE) and water turnover (WT) using the doubly labelled water method. Results were compared in a 2 diet × 2 sex × 2 body condition factorial arrangement. Cats fed the HS (38 % CP) diet maintained a constant body weight, but lean mass (LM) tended to be reduced in female obese but to be increased in male non-obese (P < 0·08) and increased in female non-obese cats (P = 0·01). The HP (55 % CP) diet induced an increase in cat body weight and LM (P < 0·05) without altering BC proportion. EE tended to be higher in males (351 (se 8) kJ/kg0·67/d) than females (330 (se 8) kJ/kg0·67/d; P = 0·06), was unaffected by diet or BC, decreased as age increased (R2 0·44; P < 0·01) and increased as physical activity increased (R2 0·58; P < 0·01). WT was higher for the HP (55 % CP) diet (P < 0·01) and increased with EE (R2 0·65; P < 0·01). The HS (38 % CP) diet favoured body weight control during 4 months of ad libitum feeding. Caution is necessary to balance protein in diets of female obese cats over 5 years, as they may have low energy and food intake, with LM loss.

Research indicates that green tea extract (GTE) supplementation is beneficial for a range of conditions, including several forms of cancer, CVD and liver diseases; nevertheless, the existing evidence addressing its effects on body composition, oxidative stress and obesity-related hormones is inconclusive. This systematic review and meta-analysis aimed to investigate the effects of GTE supplementation on body composition (body mass (BM), body fat percentage (BFP), fat mass (FM), BMI, waist circumference (WC)), obesity-related hormones (leptin, adiponectin and ghrelin) and oxidative stress (malondialdehyde (MDA) and total antioxidant capacity (TAC)) markers. We searched proper databases, including PubMed/Medline, Scopus and Web of Science, up to July 2022 to recognise published randomised controlled trials (RCT) that investigated the effects of GTE supplementation on the markers mentioned above. A random effects model was used to carry out a meta-analysis. The heterogeneity among the studies was assessed using the I2 index. Among the initial 11 286 studies identified from an electronic database search, fifty-nine studies involving 3802 participants were eligible to be included in this meta-analysis. Pooled effect sizes indicated that BM, BFP, BMI and MDA significantly reduced following GTE supplementation. In addition, GTE supplementation increased adiponectin and TAC, with no effects on FM, leptin and ghrelin. Certainty of evidence across outcomes ranged from low to high. Our results suggest that GTE supplementation can attenuate oxidative stress, BM, BMI and BFP, which are thought to negatively affect human health. Moreover, GTE as a nutraceutical dietary supplement can increase TAC and adiponectin.

Systolic blood pressure (SBP) is significantly associated with body composition in children and adolescents. However, which one of the components of body composition is the dominant contributor to SBP in children and adolescents remains unclear. We, therefore, aimed to determine the dominant contributor to SBP among components of body composition in a large cohort of American children and adolescents derived from the National Health and Nutrition Examination Survey with cross-sectional analysis. In total, 13 618 children and adolescents (median age 13 years; 6107 girls) with available data on whole-body dual-emission X-ray absorptiometry measurements were included. Multiple linear regression showed that SBP was associated with higher total fat-free mass in boys (β = 0·49, P < 0·001) and girls (β = 0·47, P < 0·001) and with higher total fat mass only in boys (β = 0·12, P < 0·001) after adjustment for covariates. When taking fat distribution into consideration, SBP was associated with higher trunk fat mass (boys: β = 0·28, P < 0·001; girls: β = 0·15, P < 0·001) but negatively associated with leg fat mass (Boys: β = −0·14, P < 0·001; Girls: β = −0·11, P < 0·001), in both boys and girls. Dominance analysis showed that total fat-free mass was the dominant contributor to SBP (boys: 49 %; girls: 55·3 %), followed by trunk fat mass (boys: 32·1 %; girls: 26·9 %); leg fat mass contributed the least to SBP in boys (18·9 %) and girls (17·8 %). Our findings indicated that total fat-free mass was not only associated with SBP but also the most dominant contributor to SBP variation in American children and adolescents.