Growth status among low‐income Mexican and Mexican‐American elementary school children

Objectives:

Childhood obesity remains a problem among Latino children in the United States. Acculturation to an American diet and sedentary lifestyle may be causative factors. The research purpose was to assess child growth status, including sitting height, in relation to acculturation among Mexican and Mexican‐American children.

Methods:

Anthropometric measures of weight, height, and sitting height were taken in a cross‐sectional survey of Mexican and Mexican‐American elementary school children (N = 484) in Phoenix, Arizona. Height‐for‐age (HAZ), weight‐for‐age (WAZ), and body mass index (BMI) Z‐scores were calculated based on the Centers for Disease Control 2000 growth reference. Sitting height Z‐scores (SHZ) were determined from the NHANES III reference values. Questions about language usage were asked of the children as a proxy for acculturation. Differences in growth measures and acculturation between those born in the United States or Mexico were evaluated by chi‐square or t‐tests.

Results:

The mean HAZ value (?0.23) was close to the reference median. There were no significant differences in HAZ or SHZ by birth country or gender. WAZ values for boys were significantly higher than for girls. More girls (64%) than boys (54%) had normal BMIs. More Mexican‐born boys (28%) were obese than Mexican‐born girls (17%; P = 0.026) in comparison to the US‐born boys (31%) and girls (24%; P = n.s.). Acculturation scale score and male gender predicted a small percentage of the variation in BMIZ.

Conclusions:

Environmental and cultural factors that promote obesity among low‐income Mexican and Mexican‐American children are similar regardless of birth country but boys may be at greater risk of obesity than girls. Am. J. Hum. Biol. 2012. © 2012 The Authors. American Journal of Human Biology published by Wiley Periodicals LLC.

     

Effects of a mixed‐subsistence diet on the growth of Hadza children

Introduction: We investigated the preliminary effects of dietary changes on the anthropometric measurements of child and adolescent Hadza foragers. Methods: We conducted a cross‐sectional study comparing height and weight of participants (aged 0‐17 years) at two time points, 2005 (n = 195) and 2017 (n = 52), from two locations: semi‐nomadic “bush camps” and sedentary “village camps”. World Health Organization (WHO) calculators were used to generate standardized z‐scores for weight‐for‐height (WHZ), weight‐for‐age (WAZ), height‐for‐age (HAZ), and BMI‐for‐age (BMIFAZ). Cross tabulations were constructed for each measurement variable as a function of z‐score categories and the variables year, location, and sex. Results: Residency in a village, and associated mixed‐subsistence diet, was associated with favorable growth, including greater WAZ (P < .001), HAZ (P < .001), and BMIFAZ (P = .004), but not WHZ (P = .717). Regardless of residency location, participants showed an improved WAZ (P = .021) and HAZ (P < .001) in the 2017 study year. We found no sex differences. Discussion and Conclusion: These preliminary findings suggest that a mixed‐subsistence diet may confer advantages over an exclusive wild food diet, a trend also reported among other transitioning foragers.     

Sex differences in fetal growth responses to maternal height and weight

Sex differences in fetal growth have been reported, but how this happens remains to be described. It is unknown if fetal growth rates, a reflection of genetic and environmental factors, express sexually dimorphic sensitivity to the mother herself. This analysis investigated homogeneity of male and female growth responses to maternal height and weight. The study sample included 3,495 uncomplicated singleton pregnancies followed longitudinally. Analytic models regressed fetal and neonatal weight on tertiles of maternal height and weight, and modification by sex was investigated (n = 1,814 males, n = 1,681 females) with birth gestational age, maternal parity, and smoking as covariates. Sex modified the effects of maternal height and weight on fetal growth rates and birth weight. Among boys, tallest maternal height influenced fetal weight growth before 18 gestational weeks of age (P = 0.006), and prepregnancy maternal weight and body mass index subsequently had influence (P < 0.001); this was not found among girls. Additionally, interaction terms between sex, maternal height, and maternal weight identified that males were more sensitive to maternal weight among shorter mothers (P = 0.003) and more responsive to maternal height among lighter mothers (P ≤ 0.03), compared to females. Likewise, neonatal birth weight dimorphism varied by maternal phenotype. A male advantage of 60 g occurred among neonates of the shortest and lightest mothers (P = 0.08), compared to 150 and 191 g among short and heavy mothers, and tall and light‐weight mothers, respectively (P = 0.01). Sex differences in response to maternal size are under‐appreciated sources of variation in fetal growth studies and may reflect differential growth strategies. Am. J. Hum. Biol., 2010. © 2009 Wiley‐Liss, Inc.     

Fetal growth restriction and 18‐year growth and nutritional status: Aboriginal birth cohort 1987–2007

The main objective of the work is to compare the growth and nutritional status of Australian Aboriginal term infants born with (n = 81) and without fetal growth restriction (n = 260). A prospective birth cohort study of 341 Aboriginal babies from the Top End of the Northern Territory of Australia was recruited at birth (1987–1990) and re‐examined at a mean age of 18.3 years (2006–2008) for outcome measures of growth and nutrition status. Those with growth restriction at birth were 3 cm shorter (P = 0.0026) and 9 kg lighter (P = 0.0001) with head circumferences 0.95 cm smaller (P = 0.0008) than those without growth restriction. The proportions of growth restricted participants with body mass index <18.5 kg/m² were significantly greater (P = 0.028), and those with BMI > 25 kg/m² and with fat percentage >85th percentile were significantly smaller (P = 0.012 and 0.004, respectively). In this cohort, those Aboriginal babies born smaller and lighter have remained smaller and lighter at 18 years of age. However, the highest risk of later chronic noncommunicable disease has been reported in subjects who were born small and become relatively larger in later life. The continued study of this Aboriginal birth cohort will give us an opportunity to determine if and when in later life the effects of birth weight are modified by environmental nutritional factors. Am. J. Hum. Biol., 2011. © 2010 Wiley‐Liss, Inc.     

“Month of birth effect” does not alter longitudinal growth in an experimental animal model

Previous cross-sectional human and animal data collected in the southern hemisphere suggest that month of birth influences growth throughout life; individuals born between August and January (spring/summer) were larger than individuals born between February and July (fall/winter) throughout their life cycle. It has been suggested that there is some form of annual global variation which may be caused by extraterrestrial factors. The present study, utilizing an experimental animal model, investigated the “month of birth effect” in the northern hemisphere on the somatic and skeletal growth of rabbits. The study sample consisted of 135 laboratory bred and reared New Zealand white rabbits (Oryctolagus cuniculus) from 62 different litters; spring/summer rabbits (n = 75) were born between February and July; fall/winter rabbits (n = 60) were born between August and January. Serial longitudinal body mass and craniofacial radiographic growth data were collected at 10, 25, 42, 84, and 126 days of age. Results from a two-way ANOVA showed no significant (P > 0.05) differences in the month of birth main effect or in the age × month of birth interaction for either somatic or skeletal growth. Results from the present study do not support the “month of birth effect” hypothesis. It was concluded that variations in growth patterns are more likely controlled by local environmental factors such as hemispheric seasonality in photoperiod or temperature, and not by more exotic factors such as the earth's orbital trajectory around the sun or global energy fields. Am. J. Hum. Biol. 9:481–486, 1997. © 1997 Wiley-Liss, Inc.     

Serum insulin‐like growth factor‐I concentrations in late middle age: no association with birthweight in three UK cohorts

Background: Small body size at birth and during infancy is associated with an increased risk of adult osteoporosis and cardiovascular disease. Fetal programming of the growth hormone–insulin‐like growth factor (GH‐IGF) axis may provide a mechanism for these epidemiological findings. Aims: To determine whether measurements of GH and IGF‐I in late middle age were related to size at birth and in infancy. Methods: Overnight urinary GH excretion and fasting serum IGF‐I were measured in 309 men and 193 women from Hertfordshire (born 1920–1930) for whom birthweight and weight at 1 year were recorded. Serum IGF‐I was measured in men and women from Preston (n = 254, born 1935–1943) and Sheffield (n = 215, born 1939–1940) whose birthweight and other birth measurements were recorded. Results: Urinary GH and serum IGF‐I were not related to birthweight, other measurements at birth, or weight at 1 year. Conclusion: In contrast to previous studies in children or young adults, these data do not support the hypothesis that IGF‐I concentrations are programmed by intra‐uterine events, as assessed by birthweight, in late middle age.     

Differences in body composition and cardiovascular and Type 2 diabetes risk factors between migrant and British‐born British Pakistani women

There is a high prevalence of cardiovascular disease and Type 2 diabetes in people of South Asian origin living in affluent western countries. We do not know whether or how risk factors for these diseases change in subsequent generations born in the west. Findings that birth‐weight is inversely associated with abdominal obesity and risk of cardiovascular disease and Type 2 diabetes in later life suggest that those born in the west may have lower levels of risk than migrants. We assessed 30 migrants from Pakistan to the UK, 30 British‐born British Pakistani women, and 25 British‐born women of European origin. British‐born British Pakistani women were taller (P = 0.05), had a lower waist to hip ratio (P = 0.04), lower mean fasting glucose levels (P = 0.03), lower mean triglyceride levels (P = 0.03), and higher mean HDL levels (P < 0.001) than migrant British Pakistani women. Levels of fasting insulin, HOMA‐IR, and blood pressure were not significantly different in the two British Pakistani groups. Thus, we found healthier levels of several cardiovascular and Type 2 diabetes risk factors in British‐born British Pakistani women than in migrant British Pakistani women. These findings might be related to the effects of early environment or to other factors, such as differences in health behaviors. British‐born British Pakistani women also differed from British‐born European women, having a more adverse body composition, but healthier levels of HDL cholesterol and blood pressure. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.     

Anatomical basis of laparoscopic medial‐to‐lateral mobilization of the descending colon

In laparoscopic colorectal resection, the medial‐to‐lateral approach has been largely adopted. This approach can be initiated by the division of either the inferior mesenteric artery (IMA) or the inferior mesenteric vein (IMV). This cadaveric study aimed to establish the feasibility of IMV dissection as the initial landmark of medial‐to‐lateral left colonic mobilization for evaluating the size of the peritoneal window between the IMV at the lower part of the pancreas and the origin of the IMA (IMA‐IMV distance) and the point of origin of the IMA compared to the lower edge of the third part of the duodenum (IMA‐D3 distance). These distances were recorded on 30 fresh cadavers. The IMA‐D3 distance was 0.4 ± 2.2 cm (mean ± SD). The IMA originated from the aorta at the level of or below the D3 in 21 cases (70%). The IMA‐IMV distance was 5.5 ± 1.8 cm and was greater or equal to 5 cm (large window) in 21 cases (70%). IMA‐IMV distance was correlated with IMA‐D3 showing that a large window was inversely correlated with a low IMA origin (P < 0.001). IMA‐D3 distance was not correlated with weight, height and sex. IMA‐IMV distance was largerin male (6.7 ± 0.9 vs. 4.9 ± 1.8, P = 0.001) and correlated with weight, (r = 0.60, 95%CI = 0.03–0.10, P < 0.001) and height (r = 0.54, 95%CI = 0.05–0.21, P = 0.002). IMV can be used as the initial landmark for laparoscopic medial‐to‐lateral dissection in two‐thirds of cases. A too‐small window can require first IMA division. The choice between the two different medial‐to‐lateral approaches could be made by evaluating the anatomical relationship between IMA, IMV, and D3. Clin. Anat., 2013. © 2013 Wiley Periodicals, Inc.     

The effect of menarcheal age on anthropometric,limb length,and bone measures in Hutterite and non‐Hutterite women

The age women reach menarche may affect bone length and mass. Some studies show an earlier menarcheal age (MA) results in a shorter stature and increased body fat. We hypothesized that Hutterite women have a shorter height and limb length, but greater bone mass and areal bone mineral density (aBMD) than non‐Hutterites. Results are from a secondary analysis of 344 (198 Hutterite) healthy, pre‐menopausal women aged 20?40 years who participated in the South Dakota Rural Bone Health Study. Bone measures were obtained by DXA (spine, hip and total body) and pQCT (4 and 20% distal radius). MA correlated with year of birth (r = ?0.10, P = 0.08) indicating a trend toward a younger MA for women born in more recent years. MA was inversely associated with current weight (r = ?0.11, P < 0.05), percent body fat (r = ?0.16, P < 0.01), femoral neck BMC (r = ?0.18, P = 0.003), femoral neck aBMD (r = ?0.21, P < 0.001), hip aBMD (r = ?0.22, P < 0.001) and trabecular volumetric BMD (vBMD) (r = ?0.14, P = 0.03). Hutterite women had a younger MA than non‐Hutterite women (12.3 ± 1.3 vs. 13.0 ± 1.3 yr, P < 0.001). In final regression models controlling for diet and activity patterns, Hutterite compared to non‐Hutterite women had shorter standing height (162 ± 0.4 vs. 166 ± 0.4 cm, P < 0.001), forearm length (258 ± 0.8 vs. 261 ± 0.9 mm, P = 0.04); and leg length (76 ± 0.2 vs. 77 ± 0.3 cm, P < 0.01) as hypothesized, but MA did not predict these outcomes. In conclusion, younger MA in Hutterite women did not explain their shorter standing height and limb lengths, but total hip aBMD was inversely associated with MA and greater in Hutterite than non‐Hutterite women. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.     

Growth patterns in early childhood and final attained stature: Data from five birth cohorts from low‐ and middle‐income countries

Growth failure is cumulative, and short stature is associated with multiple indices of reduced human capital. Few studies have been able to address in a single analysis both consideration of the timing of growth failure and comparison across populations. We analyzed data from birth cohorts in Brazil, Guatemala, India, the Philippines, and South Africa (n = 4,659). We used data on length at birth (available for three of the five cohorts), 12 mo, 24 mo, and mid‐childhood to construct cohort‐ and sex‐ specific conditional length measures. We modeled adult height as a function of conditional length in childhood. The five cohorts experienced varying degrees of growth failure. As adults, the Brazil sample was 0.35 ± 0.89 standard deviations (SD) below the World Health Organization reference, while adult Guatemalans were 1.91 ± 0.87 SD below the reference. All five cohorts experienced a nadir in height for age Z‐score at 24 mo. Birth length (in the three cohorts with this variable), and conditional length at 12 mo (in all five cohorts) were the most strongly associated with adult height. Growth in the periods 12–24 mo and 24 mo to mid‐childhood showed inconsistent patterns across tertiles of adult height. Despite variation in the magnitude of cumulative growth failure across cohorts, the five cohorts show highly consistent age‐specific associations with adult stature. Growth failure prior to age 12 mo was most strongly associated with adult stature. These consistencies speak to the importance of interventions to address intrauterine growth failure and growth failure in the first 12 mo of life. Am. J. Hum. Biol. 2010. © 2009 Wiley‐Liss, Inc.     

Perinatal factors associate with vertebral size and shape but not lumbar lordosis in 10‐year‐old children

The intrauterine environment is known to influence foetal development and future health. Low birthweight has been linked to smaller vertebral canals in children and decreased adulthood spine bone mineral content. Perinatal factors affecting lumbar spine curvature have not yet been considered but could be important for adult spinal health, as lumbar movement during lifting, a risk factor for backpain, is associated with lordosis. To investigate this, lumbar spine magnetic resonance images at age 10 years and perinatal and maternal data (birthweight, placental weight, gestation length, crown‐heel length, maternal age, height, weight and smoking status) from 161 children born in Aberdeen in 1988–1989 were acquired. Statistical shape modelling, using principal component analysis, quantified variations in lumbar spine shape and resulting modes of variation were assessed in combination with perinatal data using correlations and analyses of covariance, adjusted for potential confounders. Spine modes 1–3 (SM1–SM3) captured 75% of the variation in lumbar spine shape. The first and third modes described the total amount (SM1) and evenness of curvature distribution (SM3). SM2 accounted for variations in antero‐posterior vertebral diameter relative to vertebral height, increasing positive scores representing a larger relative diameter. Adjusting for gestation length and sex, SM2 positively correlated with birthweight (r = 0.25, P < 0.01), placental weight (r = 0.20, P = 0.04), crown‐heel length (r = 0.36, P < 0.001) and maternal weight (r = 0.19, P = 0.04), and negatively with maternal age (r = ?0.22, P = 0.02). SM2 scores were lower in girls (P < 0.001) and in the low birthweight group (P = 0.02). There were no significant differences in SM1 and SM3 scores between birthweight groups, boys and girls or children of smokers (31%) and non‐smokers (69%). In conclusion, s ome perinatal factors were associated with vertebral body morphology but had little effect on lumbar curvature.     

Early rapid growth,early birth: Accelerated fetal growth and spontaneous late preterm birth

The past two decades in the United States have seen a 24% rise in spontaneous late preterm delivery (34–36 weeks) of unknown etiology. This study tested the hypothesis that fetal growth was identical prior to spontaneous preterm (n = 221, median gestational age at birth 35.6 weeks) and term (n = 3706) birth among pregnancies followed longitudinally in Santiago, Chile. The hypothesis was not supported: Preterm‐delivered fetuses were significantly larger than their term‐delivered peers by mid‐second trimester in estimated fetal weight, head, limb, and abdominal dimensions, and they followed different growth trajectories. Piecewise regression assessed time‐specific differences in growth rates at 4‐week intervals from 16 weeks. Estimated fetal weight and abdominal circumference growth rates slowed at 20 weeks among the preterm‐delivered, only to match and/or exceed their term‐delivered peers at 24–28 weeks. After an abrupt growth rate decline at 28 weeks, fetuses delivered preterm did so at greater population‐specific sex and age‐adjusted birth weight percentiles than their peers from uncomplicated pregnancies (P < 0.01). Growth rates predicted birth timing: one standard score of estimated fetal weight increased the odds ratio for late preterm birth from 2.8 prior to 23 weeks, to 3.6 (95% confidence interval, 1.82–7.11, P < 0.05) between 23 and 27 weeks. After 27 weeks, increasing size was protective (OR: 0.56, 95% confidence interval, 0.38–0.82, P = 0.003). These data document, for the first time, a distinctive fetal growth pattern across gestation preceding spontaneous late preterm birth, identify the importance of mid‐gestation for alterations in fetal growth, and add perspective on human fetal biological variability. Am. J. Hum. Biol., 2009. © 2008 Wiley‐Liss, Inc.     

Birth order, atopy, and symptoms of allergy and asthma among inner-city children attending Head Start in New York City

Background In past research, children with older siblings were more likely than others to wheeze at age 2 years, but less likely by age 6 years. Higher infection transmission and a down‐regulated allergic immune response as a result of these infections, respectively, were suggested as the causes. However, in a study of children aged 0–3 years in a low‐income urban community in New York City, USA, with high asthma prevalence, we observed no birth‐order effect. Objective To evaluate the association between birth order and atopy and respiratory symptoms in 4‐year‐old children attending Head Start programs in NYC. Methods Respiratory symptoms were assessed by questionnaire for 1005 children (mean age 4.0 years) living in high asthma prevalence neighbourhoods. Serum was collected from a subgroup of the children (n=494) and specific IgE responses to dust mite, cockroach, mouse, and cat allergens were measured. Results Prevalence of specific IgE (0.35 IU/mL) did not differ significantly among first (35%), second (35%), and later‐born children (28%) (P=0.23). Increasing birth order was associated with increasing prevalence of respiratory symptoms in the prior year, including wheeze (first 20%, second 27%, third or later 35%; P<0.001), being awakened at night by cough (28%, 33%, 38%; P=0.005), emergency department visits (14%, 17%, 21%; P=0.02) and hospitalizations for difficulty breathing (6.1%, 6.6%, 10%; P=0.04). The associations of birth order with respiratory symptoms were statistically significant only for the non‐seroatopic children and those without an asthmatic parent. Conclusions Non‐seroatopic children with older siblings were more likely than those without older siblings to have respiratory symptoms at age 4 years. Although the stability of these associations over time remains to be determined, the differences in findings between this study and our previous NYC birth cohort study suggest that patterns of asthma development may vary even among low‐income populations within the same city.     

Enzyme activities in the tibialis anterior muscle of young moderately active men and women: relationship with body composition,muscle cross‐sectional area and fibre type composition

The aims of this study were (i) to assess the differences between men and women in maximal activities of selected enzymes of aerobic and anaerobic pathways involved in skeletal muscle energy production, and (ii) to assess the relationships between maximal enzyme activities, body composition, muscle cross‐sectional area (CSA) and fibre type composition. Muscle biopsies were obtained from the tibialis anterior (TA) muscle of 15 men and 15 women (age 20–31 years) with comparable physical activity levels. The muscle CSA was determined by magnetic resonance imaging (MRI). Maximal activities of lactate dehydrogenase (LDH), phosphofructokinase (PFK), β‐hydroxyacyl‐coenzyme A dehydrogenase (HAD), succinate dehydrogenase (SDH) and citrate synthase (CS), were assayed spectrophotometrically. The proportion, mean area and relative area (proportion × area) of type 1 and type 2 fibres were determined from muscle biopsies prepared for enzyme histochemistry [myofibrillar adenosine triphosphatase (mATPase)]. The men were significantly taller (+6.6%; P < 0.001) and heavier (+19.1%; P < 0.001), had significantly larger muscle CSA (+19.0%; P < 0.001) and significantly larger areas and relative areas of both type 1 and type 2 fibres (+20.5–31.4%; P = 0.007 to P < 0.001). The men had significantly higher maximal enzyme activities than women for LDH (+27.6%; P = 0.007) and PFK (+25.5%; P = 0.003). There were no significant differences between the men and the women in the activities of HAD (+3.6%; ns), CS (+21.1%; P = 0.084) and SDH (+7.6%; ns). There were significant relationships between height and LDH (r = 0.41; P = 0.023), height and PFK (r = 0.41; P = 0.025), weight and LDH (r = 0.45; P = 0.013), and weight and PFK (r = 0.39; P = 0.032). The relationships were significant between the muscle CSA and the activities of LDH (r = 0.61; P < 0.001) and PFK (r = 0.56; P = 0.001), and between the relative area of type 2 fibres and the activities of LDH (r = 0.49; P = 0.006) and PFK (r = 0.42; P = 0.023). There were no significant relationships between HAD, CS and SDH, and height, weight, muscle CSA and fibre type composition, respectively. These data indicate that the higher maximal activities of LDH and PFK in men are related to the height, weight, muscle CSA and the relative area of type 2 fibres, which are all significantly larger in men than women.     

The sex‐shift in single disease and multimorbid asthma and rhinitis during puberty ‐ a study by MeDALL

Background

Cross‐sectional studies suggested that allergy prevalence in childhood is higher in boys compared to girls, but it remains unclear whether this inequality changes after puberty. We examined the sex‐specific prevalence of asthma and rhinitis as single and as multimorbid diseases before and after puberty onset in longitudinal cohort data.

Methods

In six European population‐based birth cohorts of MeDALL, we assessed the outcomes: current rhinitis, current asthma, current allergic multimorbidity (ie, concurrent asthma and rhinitis), puberty status and allergic sensitization by specific serum antibodies (immunoglobulin E) against aero‐allergens. With generalized estimating equations, we analysed the effects of sex, age, puberty (yes/no) and possible confounders on the prevalence of asthma and rhinitis, and allergic multimorbidity in each cohort separately and performed individual participant data meta‐analysis.

Findings

We included data from 19 013 participants from birth to age 14‐20 years. Current rhinitis only affected girls less often than boys before and after puberty onset: adjusted odds ratio for females vs males 0.79 (95%‐confidence interval 0.73‐0.86) and 0.86 (0.79‐0.94), respectively (sex‐puberty interaction P = .089). Similarly, for current asthma only, females were less often affected than boys both before and after puberty onset: 0.71, 0.63‐0.81 and 0.81, 0.64‐1.02, respectively (sex‐puberty interaction P = .327). The prevalence of allergic multimorbidity showed the strongest sex effect before puberty onset (female‐male‐OR 0.55, 0.46‐0.64) and a considerable shift towards a sex‐balanced prevalence after puberty onset (0.89, 0.74‐1.04); sex‐puberty interaction: P < .001.

Interpretation

The male predominance in prevalence before puberty and the “sex‐shift” towards females after puberty onset were strongest in multimorbid patients who had asthma and rhinitis concurrently.     

Muscularity in adult humans: Proportion of adipose tissue‐free body mass as skeletal muscle

Muscularity, or the proportion of adipose tissue‐free body mass (ATFM) as skeletal muscle (SM), provides valuable body composition information, especially for age‐related SM loss (i.e., sarcopenia). Limited data from elderly cadavers suggest a relatively constant SM/ATFM ratio, 0.540 ± 0.046 for men (mean ± SD, n = 6) and 0.489 ± 0.049 for women (n = 7). The aim of the present study was to examine the magnitude and constancy of the SM/ATFM ratio in healthy adults. Whole‐body SM and ATFM were measured using multi‐scan magnetic resonance imaging. The SM/ATFM ratio was 0.528 ± 0.036 for men (n = 139) and 0.473 ± 0.037 for women (n = 165). Multiple regression analysis indicated that the SM/ATFM ratio was significantly influenced by sex, age, body weight, and race. The four factors explained 50% of the observed between individual variation in the SM/ATFM ratio. After adjusting for age, body weight, and race, men had a larger SM/ATFM ratio than women. Both older men and women had a lower SM/ATFM ratio than younger subjects, although the relative reduction was greater in men. After adjustment for sex, age, and body weight, there were no significant differences in the SM/ATFM ratios between Asian, Caucasian, and Hispanic subjects. In contrast, African‐American subjects had a significantly greater SM/ATFM ratio than subjects in the other three groups. In addition, the SM/ATFM ratio was significantly lower in AIDS patients than corresponding values in healthy subjects. Am. J. Hum. Biol. 13:612–619, 2001. © 2001 Wiley‐Liss, Inc.     

Body size and human energy requirements: Reduced mass‐specific total energy expenditure in tall adults

Mammalian resting energy expenditure (REE) increases as ～weight^0.75 while mass‐specific REE scales as ～weight^?0.25. Energy needs for replacing resting losses are thus less relative to weight (W) in large compared with small mammals, a classic observation with biological implications. Human weight scales as ～height² and tall adults thus have a greater weight than their short counterparts. However, it remains unknown if mass‐specific energy requirements are less in tall adults; allometric models linking total energy expenditure (TEE) and weight with height (H) are lacking. We tested the hypothesis that mass‐specific energy requirements scale inversely to height in adults by evaluating TEE (doubly labeled water) data collected by the National Academy of Sciences. Activity energy expenditure (AEE) was calculated from TEE, REE (indirect calorimetry), and estimated diet‐induced energy expenditure. Main analyses focused on nonmorbidly obese subjects ≤50 yrs of age with non‐negative AEE values (n = 404), although results were directionally similar for all samples. Allometric models, including age as a covariate, revealed significantly (P < 0.05) greater REE, AEE, and TEE as a function of height (range H^1.5–1.7) in both men and women. TEE/W scaled negatively to height (～H^?0.7, P < 0.01) with predicted mass‐specific TEE (kcal/kg/d) at ±2 SD for US height lower in tall compared with short men (40.3 vs. 46.5) and women (37.7 vs. 42.7). REE/W also scaled negatively to height in men (P < 0.001) and women (P < 0.01). Results were generally robust across several different analytic strategies. These observations reveal previously unforeseen associations between human stature and energy requirements that have implications for modeling efforts and provide new links to mammalian biology as a whole. Am. J. Hum. Biol. 2010. © 2009 Wiley‐Liss, Inc.     

Associations of long‐chain polyunsaturated fatty acid concentrations with birth outcome in term Indian mothers and their neonates

The purpose of this study was to examine the maternal and cord long‐chain polyunsaturated fatty acid (LCPUFA) concentrations and their associations with birth outcome in term deliveries. Pregnant women (n = 253) delivering at term were divided into two groups based on their babies' birth weights (1) normal birth weight (NBW), that is, ≥2.5 kg (n = 190) and (2) low‐birth weight (LBW), that is, <2.5 kg (n = 63). Each group is further divided into two groups according to the baby's sex, that is, male NBW (M‐NBW), female NBW (F‐NBW), male LBW (M‐LBW), and female LBW (F‐LBW) groups. Maternal plasma docosahexaenoic acid and erythrocyte arachidonic acid (AA) levels were lower (P < 0.05 for both), while cord plasma docosahexaenoic acid and erythrocyte AA levels were higher (P < 0.05 for both) in LBW group when compared to the NBW group. Maternal erythrocyte AA levels were positively associated with birth weight (P = 0.001), while cord plasma docosahexaenoic acid levels were negatively (P = 0.05) associated with birth weight. Reduced maternal and increased cord LCPUFA levels exist in mothers delivering LBW babies, especially in mothers delivering female babies, indicative of sex‐specific effects. Am. J. Hum. Biol., 2011. © 2010 Wiley‐Liss, Inc.     

Clinicopathological factors associated with BRAF‐V600E mutation in colorectal serrated adenomas

Serrated adenomas are genetically heterogeneous, and the histological classification into sessile serrated (SSA) adenoma and traditional serrated adenoma (TSA) does not reflect the molecular landscape. The objective of this study was to assess clinical or pathological factors associated with BRAF‐V600E mutation in serrated adenomas. Systematic review and meta‐analysis was performed by searching electronic databases from January 2011 to January 2019 for studies assessing the association of BRAF‐V600E mutation with clinical or pathological features of serrated adenomas. Odds ratio (OR) was calculated for each factor; a P‐value <0.05 was considered significant. Forty studies assessing 3511 serrated adenomas (2375 SSAs and 1136 TSAs) were included. BRAF‐V600E mutation was significantly associated with proximal localisation (OR = 2.71; P < 0.00001) and CIMP‐H status (OR = 4.81; P < 0.0001) in both SSA and TSA, with polyp size <10 mm (OR = 0.41; P = 0.02) in TSA, and with endoscopic pit pattern II‐O (OR = 13.11; P < 0.00001) and expression of MUC5A5 (OR = 4.43; P = 0.003) and MUC6 (OR = 2.28; P < 0.05) in SSA. Conversely, BRAF mutation was not associated with age <70 years (OR = 1.63; P = 0.34), age <60 years (OR = 0.86; P = 0.79), female sex (OR = 0.77; P = 0.12), flat morphology (OR = 1.52; P = 0.16), presence of any dysplasia (OR = 1.01; P = 0.59), serrated dysplasia (OR = 1.23; P = 0.72) and invasive cancer (OR = 0.67; P = 0.32), nuclear β‐catenin expression (OR = 0.73; P = 0.21) and p53 overexpression (OR = 1.24; P = 0.82). In conclusion, BRAF‐V600E mutation is associated with proximal localisation and CIMP‐H status in both SSA and TSA, with size <10 mm only in TSA, and with expression of MUC5A5 and MUC6 and endoscopic pit pattern II‐O at least in SSA. In serrated adenomas, BRAF‐V600E mutation does not seem to be associated with age and sex, with the prevalence of dysplasia and cancer and with the morphology of the dysplastic component.     

Tibetan protection from intrauterine growth restriction (IUGR) and reproductive loss at high altitude

Chronic hypoxia at high altitude restricts fetal growth, reducing birth weight and increasing infant mortality. We asked whether Tibetans, a long‐resident high‐altitude population, exhibit less altitude‐associated intrauterine growth restriction (IUGR) and prenatal or postnatal reproductive loss than Han (ethnic Chinese), a group that has lived there for a shorter period of time. A population sample was obtained, comprising 485 deliveries to Tibetan or Han women over an 18‐month period at 8 general hospitals or clinics located at 2,700–4,700 m in the Tibet Autonomous Region, China. Birth weight, gestational age, and other information were recorded for each delivery. Prenatal and postnatal mortality were calculated using information obtained from all pregnancies or babies born to study participants. Tibetan babies weighed more than the Han, averaging 310 g heavier at altitudes 2,700–3,000 m (95% CI = 126, 494 g; P < 0.01) and 530 g heavier at 3,000–3,800 m (210, 750 g; P < 0.01). More Han than Tibetan babies were born prematurely. Prenatal and postnatal mortality rose with increasing elevation and were 3‐fold higher across all altitudes in the Han than the Tibetans (P < 0.05). Tibetans experience less altitude‐associated IUGR than Han and have lower levels of prenatal and postnatal mortality. When the relationships between birth weight and altitude are compared among these and other high‐altitude populations, those living at high altitude the longest have the least altitude‐associated IUGR. This may suggest the occurrence of an evolutionary adaptation. Am. J. Hum. Biol. 13:635–644, 2001. © 2001 Wiley‐Liss, Inc.