Early childhood growth is associated with cognitive function. However, the independent associations of fat mass (FM) and fat-free mass (FFM) with cognitive function are not well understood. We investigated associations of FM and FFM at birth and 0–5 years accretion with cognitive function at 10 years. Healthy-term newborns were enrolled in this cohort. FM and FFM were measured at birth, 1·5, 2·5, 3·5, 4·5 and 6 months and 4 and 5 years. Cognitive function was assessed using the Peabody Picture Vocabulary Test (PPVT) at 10 years. FM and FFM accretions were computed using statistically independent conditional accretion from 0 to 3 months, 3 to 6 months, 6 months to 4 years and 4 to 5 years. Multiple linear regression was used to assess associations. At the 10-year follow-up, we assessed 318 children with a mean (sd) age of 9·8 (1·0) years. A 1 sd higher birth FFM was associated with a 0·14 sd (95 % CI 0·01, 0·28) higher PPVT at 10 years. FFM accretion from 0 to 3 and 3 to 6 months was associated with PPVT at 10 years: β = 0·5 sd (95 % CI 0·08, 0·93) and β = −0·48 sd (95 % CI −0·90, −0·07, respectively. FFM accretion after 6 months showed no association with PPVT. Neither FM at birth nor 0–5 years accretion showed an association with PPVT. Overall, birth FFM, but not FM, was associated with cognitive function at 10 years, while the association of FFM accretion and cognitive function varied across distinct developmental stages in infancy. The mechanisms underlying this varying association between body composition and cognitive function need further investigation.

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.

HIV and severe wasting are associated with post-discharge mortality and hospital readmission among children with complicated severe acute malnutrition (SAM); however, the reasons remain unclear. We assessed body composition at hospital discharge, stratified by HIV and oedema status, in a cohort of children with complicated SAM in three hospitals in Zambia and Zimbabwe. We measured skinfold thicknesses and bioelectrical impedance analysis (BIA) to investigate whether fat and lean mass were independent predictors of time to death or readmission. Cox proportional hazards models were used to estimate the association between death/readmission and discharge body composition. Mixed effects models were fitted to compare longitudinal changes in body composition over 1 year. At discharge, 284 and 546 children had complete BIA and skinfold measurements, respectively. Low discharge lean and peripheral fat mass were independently associated with death/hospital readmission. Each unit Z-score increase in impedance index and triceps skinfolds was associated with 48 % (adjusted hazard ratio 0·52, 95 % CI (0·30, 0·90)) and 17 % (adjusted hazard ratio 0·83, 95 % CI (0·71, 0·96)) lower hazard of death/readmission, respectively. HIV-positive v. HIV-negative children had lower gains in sum of skinfolds (mean difference −1·49, 95 % CI (−2·01, −0·97)) and impedance index Z-scores (–0·13, 95 % CI (−0·24, −0·01)) over 52 weeks. Children with non-oedematous v. oedematous SAM had lower mean changes in the sum of skinfolds (–1·47, 95 % CI (−1·97, −0·97)) and impedance index Z-scores (–0·23, 95 % CI (−0·36, −0·09)). Risk stratification to identify children at risk for mortality or readmission, and interventions to increase lean and peripheral fat mass, should be considered in the post-discharge care of these children.

Early life exposures and growth patterns may affect long-term risk of chronic non-communicable diseases (NCD). We followed up in adolescence two Zambian cohorts (n 322) recruited in infancy to investigate how two early exposures – maternal HIV exposure without HIV infection (HEU) and early growth profile – were associated with later anthropometry, body composition, blood lipids, Hb and HbA1c, blood pressure and grip strength. Although in analyses controlled for age and sex, HEU children were thinner, but not shorter, than HIV-unexposed, uninfected (HUU) children, with further control for socio-demographic factors, these differences were not significant. HEU children had higher HDL-cholesterol than HUU children and marginally lower HbA1c but no other biochemical or clinical differences. We identified three early growth profiles – adequate growth, declining and malnourished – which tracked into adolescence when differences in anthropometry and body fat were still seen. In adolescence, the early malnourished group, compared with the adequate group, had lower blood TAG and higher HDL, lower grip strength (difference: −1·87 kg, 95 % CI −3·47, −0·27; P = 0·02) and higher HbA1c (difference: 0·5 %, 95 % CI 0·2, 0·9; P = 0·005). Lower grip strength and higher HbA1c suggest the early malnourished children could be at increased risk of NCD in later life. Including early growth profile in analyses of HIV exposure reduced the associations between HIV and outcomes. The results suggest that perinatal HIV exposure may have no long-term effects unless accompanied by poor early growth. Reducing the risk of young child malnutrition may lessen children’s risk of later NCD.

Marriage during childhood and adolescence adversely affects maternal and child health and well-being, making it a critical global health issue. Analysis of factors associated with women marrying ≥18 years has limited utility in societies where the norm is to marry substantially earlier. This paper investigated how much education Nepali women needed to delay marriage across the range of ages from 15 to ≥18 years. Data on 6,406 women aged 23-30 years were analysed from the Low Birth Weight South Asia Trial on the early-marrying and low-educated Maithili-speaking Madhesi population in Terai, Nepal. Multivariable logistic regression models assessed the associations of women’s education with marrying aged ≥15, ≥16, ≥17 and ≥18 years. Cox proportional hazards regression models quantified the hazard of marrying. Models adjusted for caste affiliation. Women married at median age of 15 years and three-quarters were uneducated. Women’s primary and lower-secondary education were weakly associated with delaying marriage, whether the cut-off to define early marriage was 15, 16, 17 or 18 years, with stronger associations for secondary education. Caste associations were weak. Overall, models explained relatively little of the variance in the likelihood of marriage at different ages. The joint effects of lower-secondary and higher caste affiliation and of secondary/higher education and mid and higher caste affiliation reduced the hazard of marrying. In early-marrying and low-educated societies, changing caste-based norms are unlikely to delay women’s marriage. Research on broader risk factors and norms that are more relevant for delaying marriage in these contexts is needed. Gradual increases in women’s median marriage age and increased secondary education may, over time, reduce child and adolescent marriage.

The study investigates sex differences in the prevalence of undernutrition in sub-Saharan Africa. Undernutrition was defined by Z-scores using the CDC-2000 growth charts. Some 128 Demographic and Health Surveys (DHS) were analysed, totalling 700,114 children under-five. The results revealed a higher susceptibility of boys to undernutrition. Male-to-female ratios of prevalence averaged 1.18 for stunting (height-for-age Z-score <−2.0); 1.01 for wasting (weight-for-height Z-score <−2.0); 1.05 for underweight (weight-for-age Z-score <−2.0); and 1.29 for concurrent wasting and stunting (weight-for-height and height-for-age Z-scores <−2.0). Sex ratios of prevalence varied with age for stunting and concurrent wasting and stunting, with higher values for children age 0–23 months and lower values for children age 24–59 months. Sex ratios of prevalence tended to increase with declining level of mortality for stunting, underweight and concurrent wasting and stunting, but remained stable for wasting. Comparisons were made with other anthropometric reference sets (NCHS-1977 and WHO-2006), and the results were found to differ somewhat from those obtained with CDC-2000. Possible rationales for these patterns are discussed.

There is limited information as to whether people who experience severe acute malnutrition (SAM) as young children are at increased risk of overweight, high body fat and associated chronic diseases in later life. We followed up, when aged 7–12 years, 100 Zambian children who were hospitalised for SAM before age 2 years and eighty-five neighbourhood controls who had never experienced SAM. We conducted detailed anthropometry, body composition assessment by bioelectrical impedance and deuterium dilution (D2O) and measured blood lipids, Hb and HbA1c. Groups were compared by linear regression following multiple imputation for missing variables. Children with prior SAM were slightly smaller than controls, but differences, controlling for age, sex, socio-economic status and HIV exposure or infection, were significant only for hip circumference, suprailiac skinfold and fat-free mass index by D2O. Blood lipids and HbA1c did not differ between groups, but Hb was lower by 7·8 (95 % CI 0·8, 14·7) g/l and systolic blood pressure was 3·4 (95 % CI 0·4, 6·4) mmHg higher among the prior SAM group. Both anaemia and high HbA1c were common among both groups, indicating a population at risk for the double burden of over- and undernutrition and associated infectious and chronic diseases. The prior SAM children may have been at slightly greater risk than the controls; this was of little clinical significance at this young age, but the children should be followed when older and chronic diseases manifest.

Functional benefits of the morphologies described by Bergmann's and Allen's rules in human males have recently been reported. However, the functional implications of ecogeographical patterning in females remain poorly understood. Here, we report the findings of preliminary work analysing the association between body shape and performance in female ultramarathon runners (n = 36) competing in hot and cold environments. The body shapes differed between finishers of hot and cold races, and also between hot race finishers and non-finishers. Variability in race performance across different settings supports the notion that human phenotype is adapted to different thermal environments as ecogeographical patterns have reported previously. This report provides support for the recent hypothesis that the heightened thermal strain associated with prolonged physical activity in hot/cold environments may have driven the emergence of thermally adaptive phenotypes in our evolutionary past. These results also tentatively suggest that the relationship between morphology and performance may be stronger in female vs. male athletes. This potential sex difference is discussed with reference to the evolved unique energetic context of human female reproduction. Further work, with a larger sample size, is required to investigate the observed potential sex differences in the strength of the relationship between phenotype and performance.

Both extinct and extant hominin populations display morphological features consistent with Bergmann's and Allen's Rules. However, the functional implications of the morphologies described by these ecological laws are poorly understood. We examined this through the lens of endurance running. Previous research concerning endurance running has focused on locomotor energetic economy. We considered a less-studied dimension of functionality, thermoregulation. The performance of male ultra-marathon runners (n = 88) competing in hot and cold environments was analysed with reference to expected thermoregulatory energy costs and the optimal morphologies predicted by Bergmann's and Allen's Rules. Ecogeographical patterning supporting both principles was observed in thermally challenging environments. Finishers of hot-condition events had significantly longer legs than finishers of cold-condition events. Furthermore, hot-condition finishers had significantly longer legs than those failing to complete hot-condition events. A degree of niche-picking was evident; athletes may have tailored their event entry choices in accordance with their previous race experiences. We propose that the interaction between prolonged physical exertion and hot or cold climates may induce powerful selective pressures driving morphological adaptation. The resulting phenotypes reduce thermoregulatory energetic expenditure, allowing diversion of energy to other functional outcomes such as faster running.

Lipid-based nutrient supplements (LNS) may be beneficial for malnourished HIV-infected patients starting antiretroviral therapy (ART). We assessed the effect of adding vitamins and minerals to LNS on body composition and handgrip strength during ART initiation. ART-eligible HIV-infected patients with BMI <18·5 kg/m2 were randomised to LNS or LNS with added high-dose vitamins and minerals (LNS-VM) from referral for ART to 6 weeks post-ART and followed up until 12 weeks. Body composition by bioelectrical impedance analysis (BIA), deuterium (2H) diluted water (D2O) and air displacement plethysmography (ADP), and handgrip strength were determined at baseline and at 6 and 12 weeks post-ART, and effects of LNS-VM v. LNS at 6 and 12 weeks investigated. BIA data were available for 1461, D2O data for 479, ADP data for 498 and handgrip strength data for 1752 patients. Fat mass tended to be lower, and fat-free mass correspondingly higher, by BIA than by ADP or D2O. At 6 weeks post-ART, LNS-VM led to a higher regain of BIA-assessed fat mass (0·4 (95 % CI 0·05, 0·8) kg), but not fat-free mass, and a borderline significant increase in handgrip strength (0·72 (95 % CI −0·03, 1·5) kg). These effects were not sustained at 12 weeks. Similar effects as for BIA were seen using ADP or D2O but no differences reached statistical significance. In conclusion, LNS-VM led to a higher regain of fat mass at 6 weeks and to a borderline significant beneficial effect on handgrip strength. Further research is needed to determine appropriate timing and supplement composition to optimise nutritional interventions in malnourished HIV patients.

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.