Low birth weight does not predict the ontogeny of relative leg length of infants and children: an allometric analysis of the NHANES III sample

Mining Candidate Genes and Identifying Risk Factors for Leg Disease in Broilers: A Mendelian Randomization Study

Clinical investigations have highlighted disruptions in bone metabolic processes and abnormal fluctuations in serum indicator levels during the onset of leg disease (LD) in broilers. However, the presence of a genetic causal relationship for this association remains undetermined. Therefore, the aim of this study is to discern the risk factors underlying LD development using 1235 sequenced white-feathered broilers. We employed Mendelian randomization (MR) analysis to assess the associations of bone strength (BS), bone mineral density (BMD), tibial bone weight (TBW), tibial bone length (TBL), tibial bone diameter (TBD), bone ash (BA), ash calcium (Ash Ca), ash phosphorus (Ash P), serum calcium (Ca), serum phosphorus (P), serum alkaline phosphatase (ALP), and serum osteoprotegerin (OPG) with the incidence of LD. Compelling evidence underscores a causal link between the risk of developing LD and decreased BMD (odds ratio (OR) = 0.998; 95% CI: 0.983, 0.993; P < 0.001) and narrower TBD (OR = 0.985, 95% CI: 0.975, 0.994, P = 0.002). Additionally, serum OPG concentrations (OR: 0.995, 95% CI: 0.992, 0.999, P = 0.008) were associated with BMD (OR = 0.0078, 95% CI = 0.0043 to 0.0140, P < 0.001), indicating a robust genetic relationship between ALP concentrations (OR: 0.988, 95% CI: 0.984, 0.993, P < 0.001) and TBD (OR = 0.0046, 95% CI = 0.0026, 0.0083, P < 0.001). Moreover, elevated serum Ca (OR: 0.564, 95% CI: 0.487, 0.655, P < 0.001) and P (OR: 0.614, 95% CI: 0.539, 0.699, P < 0.001) levels were associated with a narrower TBD. Elevated serum levels of Ca, P, ALP, and OPG contribute to disturbances in bone metabolism, while decreased BMD and narrower TBD are associated with a greater risk of developing LD in broilers. This discovery elucidates the metabolic risk factors for LD in broilers and could provide information on LDs, such as osteoporosis, in humans.

Implications of leg length for metabolic health and fitness

Background and objectives

Several studies have linked longer legs with favorable adult metabolic health outcomes and greater offspring birth weight. A recent Mendelian randomization study suggested a causal link between height and cardiometabolic risk; however, the underlying reasons remain poorly understood.

Methodology

Using a cross-sectional design, we tested in a convenience sample of 70 healthy young women whether birth weight and tibia length as markers of early-life conditions associated more strongly with metabolically beneficial traits like organ size and skeletal muscle mass (SMM) than a statistically derived height-residual variable indexing later, more canalized growth.

Results

Consistent with the 'developmental origins of health and disease' hypothesis, we found relatively strong associations of tibia length-but not birth weight-with adult organ size, brain size, SMM and resting energy expenditure measured by magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry and indirect calorimetry, respectively.

Conclusions and implications

Building on prior work, these results suggest that leg length is a sensitive marker of traits directly impacting metabolic and reproductive health. Alongside findings in the same sample relating tibia length and height-residual to MRI-measured pelvic dimensions, we suggest there may exist a degree of coordination in the development of long bone, lean mass and pelvic traits, possibly centered on early, pre-pubertal growth periods. Such phenotypic coordination has important implications for fitness, serving to benefit both adult health and the health of offspring in subsequent generations.

Children of the abyss: Investigating the association between isotopic physiological stress and skeletal pathology in London during the Industrial Revolution

OBJECTIVE

This project sought to investigate whether an association may be observed between isotopic stress indicators and skeletal evidence of pathological conditions.

MATERIALS

Deciduous and permanent teeth of 15 non-adults from two contemporaneous mid-19th century London burial grounds (City Bunhill, Lukin Street).

METHODS

δ¹³C and δ¹⁵N was measured in the incrementally sectioned dentine collagen. Isotopic profiles for each individual included death during tooth development.

RESULTS

Individuals with skeletal evidence of chronic pathological conditions (e.g., rickets, tuberculosis) exhibited raised δ¹⁵N values of 0.5-1.7‰ in the months prior to death. Isotopic change consistent with chronic physiological stress prior to death was also recorded in two individuals with no skeletal evidence of disease. An offset was observed between co-forming bone and dentine δ¹⁵N values in both populations, indicating that bone and dentine are not recording the same isotopic changes.

CONCLUSIONS

Isotopic change consistent with chronic physiological stress was observed in both those with and without skeletal evidence of disease, suggesting that adaptation to chronic stress in childhood was not uncommon within these 19th century London populations.

SIGNIFICANCE

Chronic physiological stress prior to death may be seen in the incrementally sampled dentine of non-adults who die during tooth formation.

LIMITATIONS

The temporal resolution of current dentine micro-sampling methods may mask or minimise visibility of shorter-term periods of stress or dietary change.

SUGGESTIONS FOR FURTHER RESEARCH

Future research should further explore the relationship between specific skeletal pathologies and isotopic evidence for stress.

Developmental origins of variability in pelvic dimensions: Evidence from nulliparous South Asian women in the United Kingdom

OBJECTIVES

Pelvic growth may be sensitive to early-life nutrition, with implications for maternal risk of obstructed labor. However, the "developmental origins" of adult pelvic variability require further investigation. We tested whether adult pelvic dimensions are associated with two components of height, indexing different periods of linear growth: tibia length, a proxy for early postnatal growth, and height-residual (height regressed on tibia length), a proxy for later growth. We also tested whether adult pelvic dimensions are associated with birth weight, a marker of nutritional investment in utero.

METHODS

In this cross-sectional study, data were obtained on 68 nulliparous young women of South Asian ancestry. Pelvic dimensions (bi-iliac and bi-acetabular breadth, anteroposterior pelvic inlet and outlet, interspinous and intertuberous diameter) were measured using magnetic resonance imaging. Height and tibia length were measured manually. Birth weight and gestational age were obtained by recall. Multivariable regression models were fitted with a given pelvic dimension regressed on height-residual, tibia, and birth weight, with the latter adjusted for gestational age.

RESULTS

Controlling for birth weight, height-residual was predictive of bi-acetabular breadth, bi-iliac breadth, and the pelvic inlet, while tibia length significantly predicted all dimensions except interspinous diameter. Controlling for the linear growth variables, birth weight was predictive of bi-iliac breadth only.

CONCLUSIONS

Markers of linear growth during both early and later development were associated with adult pelvic dimensions, whereas size at birth was poorly predictive. Efforts to reduce stunting in early life may facilitate the attainment of maximum potential growth for both height and the pelvis.

Early-life nutritional status and metabolic syndrome: gender-specific associations from a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

OBJECTIVE

In the present study we investigated gender-specific associations of low birth weight (LBW) and shorter relative leg length with metabolic syndrome (MetS) after adjusting for sociodemographic characteristics and health-related behaviours. We also investigated whether these associations are independent of age at menarche and BMI at 20 years old.

DESIGN

Cross-sectional analysis.

SUBJECTS

Baseline data from 12 602 participants (35-74 years) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), 2008-2010.

SETTING

MetS was defined according to the revised National Cholesterol Education Program Adult Treatment Panel III guidelines. LBW (<2·5 kg) and age- and sex-standardized relative leg length (high, medium and low) were the explanatory variables studied. The strength of the associations between the explanatory variables and MetS was estimated by Poisson regression with robust variance.

RESULTS

MetS prevalence was 34·2 %; it was more prevalent in men (36·8 %) than in women (32·2 %). In multivariate analysis, LBW was associated (prevalence ratio; 95 % CI) with MetS only in women (1·28; 1·24, 1·45). Shorter leg length was associated with MetS in both men (1·21; 1·09, 1·35 and 1·46; 1·29, 1·65 for low and medium lengths, respectively) and women (1·12; 1·00, 1·25 and 1·40; 1·22, 1·59 for low and medium lengths, respectively). Additional adjustments for age at menarche and BMI at 20 years old did not change the associations.

CONCLUSIONS

Poor nutritional status as estimated by LBW and lower leg length in childhood was associated with a higher prevalence of MetS, although LBW was a significant factor only among women.

Body composition and the monitoring of non-communicable chronic disease risk

There is a need for simple proxies of health status, in order to improve monitoring of chronic disease risk within and between populations, and to assess the efficacy of public health interventions as well as clinical management. This review discusses how, building on recent research findings, body composition outcomes may contribute to this effort. Traditionally, body mass index has been widely used as the primary index of nutritional status in children and adults, but it has several limitations. We propose that combining information on two generic traits, indexing both the ‘metabolic load’ that increases chronic non-communicable disease risk, and the homeostatic ‘metabolic capacity’ that protects against these diseases, offers a new opportunity to improve assessment of disease risk. Importantly, this approach may improve the ability to take into account ethnic variability in chronic disease risk. This approach could be applied using simple measurements readily carried out in the home or community, making it ideal for M-health and E-health monitoring strategies.

Blood pressure and the capacity-load model in 8-year-old children from Nepal: Testing the contributions of kidney size and intergenerational effects

Objectives

Growth patterns in early life are increasingly linked with subsequent cardio-metabolic risk, but the underlying mechanisms require elucidation. We have developed a theoretical model of blood pressure, treating it as a function of homeostatic metabolic capacity, and antagonistic metabolic load. We sought to differentiate prenatal and postnatal components of metabolic capacity, and to identify intergenerational contributions to offspring capacity and load.

Methods

We followed up at 8 years a cohort of children originally recruited into a randomized trial of maternal micronutrient supplementation in pregnancy. Maternal anthropometry was measured at recruitment. Offspring anthropometry was measured at birth, 2 years and 8 years. Offspring blood pressure, kidney size, and body composition were measured at 8 years. Regression analysis was used to investigate potential associations of maternal phenotype, birth phenotype, and current body composition with kidney size and blood pressure.

Results

Blood pressure was positively associated with body fat, but negatively associated with birth weight and relative leg length. Kidney size was positively associated with birth weight but not with relative leg length. Adjusting for adiposity, blood pressure was independently negatively associated with birth weight, relative leg length, and kidney length. Maternal height and BMI predicted offspring size at birth and at 8 years, but not blood pressure.

Conclusions

Our data provide support for the capacity-load model of blood pressure in Nepalese children. Fetal and postnatal growth and kidney dimensions all contribute to metabolic capacity. Maternal phenotype contributed to offspring capacity and load, but these associations did not propagate to blood pressure.

Relationships between neonatal weight, limb lengths, skinfold thicknesses, body breadths and circumferences in an Australian cohort

Background

Low birth weight has been consistently associated with adult chronic disease risk. The thrifty phenotype hypothesis assumes that reduced fetal growth impacts some organs more than others. However, it remains unclear how birth weight relates to different body components, such as circumferences, adiposity, body segment lengths and limb proportions. We hypothesized that these components vary in their relationship to birth weight.

Methods

We analysed the relationship between birth weight and detailed anthropometry in 1270 singleton live-born neonates (668 male) from the Mater-University of Queensland Study of Pregnancy (Brisbane, Australia). We tested adjusted anthropometry for correlations with birth weight. We then performed stepwise multiple regression on birth weight of: body lengths, breadths and circumferences; relative limb to neck-rump proportions; or skinfold thicknesses. All analyses were adjusted for sex and gestational age, and used logged data.

Results

Circumferences, especially chest, were most strongly related to birth weight, while segment lengths (neck-rump, thigh, upper arm, and especially lower arm and lower leg) were relatively weakly related to birth weight, and limb lengths relative to neck-rump length showed no relationship. Skinfolds accounted for 36% of birth weight variance, but adjusting for size (neck-rump, thigh and upper arm lengths, and head circumference), this decreased to 10%. There was no evidence that heavier babies had proportionally thicker skinfolds.

Conclusions

Neonatal body measurements vary in their association with birth weight: head and chest circumferences showed the strongest associations while limb segment lengths did not relate strongly to birth weight. After adjusting for body size, subcutaneous fatness accounted for a smaller proportion of birth weight variance than previously reported. While heavier babies had absolutely thicker skinfolds, this was proportional to their size. Relative limb to trunk length was unrelated to birth weight, suggesting that limb proportions at birth do not index factors relevant to prenatal life.

Leg length is associated with lower values of inflammatory markers in older Chinese: The Guangzhou Biobank Cohort Study

BACKGROUND

In developed western populations, longer legs are a biomarker of better childhood conditions and negatively associated with cardiovascular disease risk factors. These associations are less obvious in non-western settings. However, early life is also a key immune system development phase.

AIM

To examine the associations of height, leg length, sitting height and leg length/sitting height ratio with inflammatory markers (white blood, lymphocyte and granulocyte cell counts and C-reactive protein (CRP)) in a developing population of southern China.

SUBJECTS AND METHODS

This study used multivariable linear regression to examine the adjusted associations in 30,499 Chinese (50+ years).

RESULTS

Height z-score was associated with lower white blood, lymphocyte and granulocyte cell counts. Leg length z-score was associated with lower white blood, lymphocyte and granulocyte cell counts and CRP. Sitting height z-score was associated with lower white blood and granulocyte cell counts, but not with lymphocyte cell count or CRP. Leg length/sitting height ratio z-score was associated with lower white blood, lymphocyte and granulocyte cell counts and CRP.

CONCLUSION

Factors enabling more early growth may also lead to changes in immunity that are associated with reduced CVD risk.

Influence of Adult Knee Height, Age at First Birth, Migration, and Current Age on Adult Physical Function of Bangladeshi Mothers and Daughters in the United Kingdom and Bangladesh

In the United Kingdom, Bangladeshi women have the lowest self-reported levels of physical activity and some of the highest levels of metabolic disease of all ethnic groups. To better understand these risks for poor health we employed life course and intergenerational hypotheses to predict lower body physical function in a sample of 121 Bangladeshi mothers (40–70 years old) and one of their adult daughters (17–36 years old) living in Bangladesh or in the UK. For the mothers, older age and shorter knee height predicted reduced lower body physical function. Knee height is a biomarker of nutrition and health status between birth and puberty. Age at first birth did not have a significant effect. For daughters, older age and migration to the UK predicted reduced lower body physical function. We controlled for total stature and fatness in all analyses. UK-born daughters were taller than BD-born daughters living in the UK, mostly due to differences in knee height. These new findings support previous research indicating that early life health and adequate nutritional status, along with appropriate adult physical activity and diet, may decrease risks for poor physical function, morbidity, and premature mortality.

Childhood height and birth weight in relation to future prostate cancer risk: a cohort study based on the copenhagen school health records register

BACKGROUND

Adult height has been positively associated with prostate cancer risk. However, the exposure window of importance is currently unknown and assessments of height during earlier growth periods are scarce. In addition, the association between birth weight and prostate cancer remains undetermined. We assessed these relationships in a cohort of the Copenhagen School Health Records Register (CSHRR).

METHODS

The CSHRR comprises 372,636 school children. For boys born between the 1930s and 1969, birth weight and annual childhood heights-measured between ages 7 and 13 years-were analyzed in relation to prostate cancer risk. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI).

RESULTS

There were 125,211 males for analysis, 2,987 of who were subsequently diagnosed with prostate cancer during 2.57 million person-years of follow-up. Height z-score was significantly associated with prostate cancer risk at all ages (HRs, 1.13 to 1.14). Height at age 13 years was more important than height change (P = 0.024) and height at age 7 years (P = 0.024), when estimates from mutually adjusted models were compared. Adjustment of birth weight did not alter the estimates. Birth weight was not associated with prostate cancer risk.

CONCLUSIONS

The association between childhood height and prostate cancer risk was driven by height at age 13 years.

IMPACT

Our findings implicate late childhood, adolescence, and adulthood growth periods as containing the exposure window(s) of interest that underlies the association between height and prostate cancer. The causal factor may not be singular given the complexity of both human growth and carcinogenesis.

Nutritional status of Maya children, their mothers, and their grandmothers residing in the City of Merida, Mexico: revisiting the leg-length hypothesis

OBJECTIVES

To test the hypothesis that leg length-relative-to-stature is a more sensitive indicator of nutrition and health than is total height (HT) or sitting height (SH) in a sample of 109 triads of urban Maya children (6.0-8.99 years), their mothers, and maternal grandmothers from Merida, Mexico.

METHODS

From September 2011 to June 2012, the following factors were obtained from all participants: (1) HT, SH, and leg length (LL); (2) the sitting height ratio (SHR = [SH × 100]/HT), relative leg length index (RLLI = [LL × 100]/height), and percentiles and z-scores of HT, SH, and LL were calculated; and (3) the percentages of stunting for children or very short ZHT for the adults, short ZSH, and short ZLL: HT-for-age, SH-for-age, or LL-for-age below the 5th percentile of the reference were calculated. Correlations were performed to examine the association between z-scores of HT, SH, and LL among three generations.

RESULTS

Stunting in children was 11% (short ZLL = 29%, short ZSH = 7%). Short ZHT was present in 71% of mothers (short ZLL = 54%, short ZSH = 50%) and 90% of grandmothers (short ZLL = 69%, short ZSH = 83%). Significant correlations in ZHT, ZSH, and ZLL were found in mother-to-child and grandmother-to-mother, with the strongest correlations for ZLL.

CONCLUSIONS

These findings support the hypothesis for children and mothers. Based on ZLL, there is evidence that childhood and nutrition have improved somewhat for each younger generation. Persistent environmental adversity during growth resulted in growth deficits for LL and SH for the mothers and grandmothers.