Assessing newborn body composition using principal components analysis: differences in the determinants of fat and skeletal size

Investigating neonatal health risk variables through cell-type specific methylome-wide association studies

Adverse neonatal outcomes are a prevailing risk factor for both short- and long-term mortality and morbidity in infants. Given the importance of these outcomes, refining their assessment is paramount for improving prevention and care. Here we aim to enhance the assessment of these often correlated and multifaceted neonatal outcomes. To achieve this, we employ factor analysis to identify common and unique effects and further confirm these effects using criterion-related validity testing. This validation leverages methylome-wide profiles from neonatal blood. Specifically, we investigate nine neonatal health risk variables, including gestational age, Apgar score, three indicators of body size, jaundice, birth diagnosis, maternal preeclampsia, and maternal age. The methylomic profiles used for this research capture data from nearly all 28 million methylation sites in human blood, derived from the blood spot collected from 333 neonates, within 72 h post-birth. Our factor analysis revealed two common factors, size factor, that captured the shared effects of weight, head size, height, and gestational age and disease factor capturing the orthogonal shared effects of gestational age, combined with jaundice and birth diagnosis. To minimize false positives in the validation studies, validation was limited to variables with significant cumulative association as estimated through an in-sample replication procedure. This screening resulted in that the two common factors and the unique effects for gestational age, jaundice and Apgar were further investigated with full-scale cell-type specific methylome-wide association analyses. Highly significant, cell-type specific, associations were detected for both common effect factors and for Apgar. Gene Ontology analyses revealed multiple significant biologically relevant terms for the five fully investigated neonatal health risk variables. Given the established links between adverse neonatal outcomes and both immediate and long-term health, the distinct factor effects (representing the common and unique effects of the risk variables) and their biological profiles confirmed in our work, suggest their potential role as clinical biomarkers for assessing health risks and enhancing personalized care.

Fetal fractional limb volumes in pregnancies following bariatric surgery

INTRODUCTION

Obesity rates have reached an epidemic level and bariatric surgery is the most effective method of sustainable weight loss. Pregnancy following bariatric surgery is associated with an increased prevalence of small babies. The objective of the study is to compare the fetal fat distribution, as assessed by fractional arm and thigh volume using three-dimensional ultrasonography, in pregnancies following maternal bariatric surgery with those without such history.

MATERIAL AND METHODS

This is a prospective, longitudinal, observational study conducted in a Maternity Unit in the UK. The study included 189 pregnant women; 63 with previous bariatric surgery [27 restrictive (13 with gastric band, 14 with sleeve gastrectomy) and 36 malabsorptive procedures] and 126 with no previous surgery but similar maternal booking body mass index. Fetal arm and thigh volume were obtained at 30-33 and 35-37 weeks' gestation and fractional limb volumes were calculated using a commercially available software. Women underwent a 75 g, 2 h oral glucose tolerance test at 28-31 weeks of gestation.

RESULTS

Overall, adjusted fetal arm and thigh volume were smaller in the post-bariatric, compared to the no surgery, group and this was more marked in women who had undergone a previous sleeve gastrectomy (P < .001 and P = .002, respectively) or a malabsorptive procedure (P < .001 for both). There was a strong positive correlation between maternal fasting/post-prandial (2 h) glucose levels, at the time of the oral glucose tolerance test, and arm and thigh volume at both 30-33 and 35-37 weeks (P < .01 for all).

CONCLUSIONS

The study has demonstrated that in the third trimester of pregnancy, fetuses of women with previous bariatric surgery have smaller fractional limb volumes, therefore less soft tissue, compared to fetuses of women without such surgery and this may be related to the lower maternal glucose levels seen in the former pregnancies.

Body Fatness and Cardiovascular Health in Newborn Infants

Birth weight is associated with cardiovascular disease, with those at both ends of the spectrum at increased risk. However, birth weight is a crude surrogate of fetal growth. Measures of body composition may more accurately identify high risk infants. We aimed to determine whether aortic wall thickening, cardiac autonomic control, and cardiac structure/function differ in newborns with high or low body fatness compared to those with average body fatness. 189 healthy singleton term born neonates were recruited and stratified by body fat percentiles (sex and gestation-specific). Infants with low body fat had higher aortic intima-media thickness (43 µm (95% confidence interval (CI) 7, 78), p = 0.02), lower heart rate variability (log total power, -0.5 (95% CI -0.8, -0.1), p = 0.008), and thicker ventricular walls (posterior wall thickness, 3.1 mm (95% CI 1.6, 4.6), p < 0.001) compared to infants with average body fatness. Infants with high body fat showed no differences in aortic intima-media thickness (-2 µm (95% CI -37, 33), p = 0.91) or cardiac structure compared to average body fatness, although stroke volume (-0.3 mL/kg (95% CI -0.6, -0.0), p = 0.003) and heart rate variability were lower (log total power, -0.8 (95% CI -1.1, -0.5), p < 0.001). The non-linear association of body fatness with heart rate variability was independent of birth weight. Infants born with low or high body fat have altered markers of cardiovascular health. Assessment of body fatness alongside birth weight may assist in identifying high risk individuals.

Creation of a predictive equation to estimate fat-free mass and the ratio of fat-free mass to skeletal size using morphometry in lean working farm dogs

AIMS To develop an equation that accurately estimates fat-free mass (FFM) and the ratio of FFM to skeletal size or mass, using morphometric measurements in lean working farm dogs, and to examine the association between FFM derived from body condition score (BCS) and FFM measured using isotope dilution. METHODS Thirteen Huntaway and seven Heading working dogs from sheep and beef farms in the Waikato region of New Zealand were recruited based on BCS (BCS < 3, 3-4, > 4) using a nine-point scale. Bodyweight, BCS, and morphometric measurements (head length and circumference, body length, thoracic girth, and fore and hind limb length) were recorded for each dog, and body composition was measured using an isotopic dilution technique. A new variable using morphometric measurements, termed skeletal size, was created using principal component analysis. Models for predicting FFM, leanST (FFM minus skeletal mass) and ratios of FFM and leanST to skeletal size or mass were generated using multiple linear regression analysis. RESULTS Mean FFM of the 20 dogs, measured by isotope dilution, was 22.1 (SD 4.4) kg and the percentage FFM of bodyweight was 87.0 (SD 5.0)%. Median BCS was 3.0 (min 1, max 6). Bodyweight, breed, age and skeletal size or mass were associated with measured FFM (p<0.001). There was a good correlation between predicted FFM and measured FFM (R²=0.96), and for the ratio of predicted FFM to skeletal size and measured values (R²=0.99). Correlation coefficients were higher for the ratio FFM and leanST to skeletal size than for ratios using skeletal mass. There was a positive correlation between BCS-derived fat mass as a percentage of bodyweight and fat mass percentage determined using isotope dilution (R²=0.65). CONCLUSIONS AND CLINICAL RELEVANCE As expected, the predictive equation was accurate in estimating FFM when tested on the same group of dogs used to develop the equation. The significance of breed, independent of skeletal size, in predicting FFM indicates that individual breed formulae may be required. Future studies that apply these equations on a greater population of working Huntaway and Heading dogs are needed to establish the utility of these equations on a large scale. Such studies could ascertain if there is a ratio for lean mass to skeletal size below which the risk of injury or disease increases. If these equations prove useful they would provide an objective and non-invasive measure to determine when welfare in individual dogs is compromised by underfeeding.

Macronutrient Balance and Dietary Glycemic Index in Pregnancy Predict Neonatal Body Composition

The influence of maternal macronutrient balance and dietary glycemic index (GI) on neonatal body composition has received little study. We hypothesized that the overall quantity and quality of macronutrients, particularly carbohydrate, in the maternal diet could have trimester-specific effects on neonatal growth and body composition in women at risk of gestational diabetes. Maternal diet was assessed using 3-day food records in mid (n = 96) and late (n = 88) pregnancy as part of the GI Baby 3 study. Neonatal body composition was assessed by air-displacement plethysmography within 48 h of birth, adjusted for length, and expressed as fat mass index (FMI) and fat-free mass index (FFMI). In mid pregnancy, higher maternal intake of carbohydrate energy was negatively correlated with infant FFMI (p = 0.037). In late pregnancy, higher dietary GI was associated with lower FFMI (p = 0.010) and higher carbohydrate energy predicted lower FMI (p = 0.034). Higher fat intake (%E) and saturated fat, but not protein, also predicted neonatal body composition (higher FFMI in mid pregnancy and higher FMI in late pregnancy). Depending on pregnancy stage, a high carbohydrate-low fat diet, particularly from high glycemic sources, may reduce neonatal indices of both lean mass and adiposity.

Relationships of maternal and paternal anthropometry with neonatal body size, proportions and adiposity in an Australian cohort

The patterns of association between maternal or paternal and neonatal phenotype may offer insight into how neonatal characteristics are shaped by evolutionary processes, such as conflicting parental interests in fetal investment and obstetric constraints. Paternal interests are theoretically served by maximizing fetal growth, and maternal interests by managing investment in current and future offspring, but whether paternal and maternal influences act on different components of overall size is unknown. We tested whether parents' prepregnancy height and body mass index (BMI) were related to neonatal anthropometry (birthweight, head circumference, absolute and proportional limb segment and trunk lengths, subcutaneous fat) among 1,041 Australian neonates using stepwise linear regression. Maternal and paternal height and maternal BMI were associated with birthweight. Paternal height related to offspring forearm and lower leg lengths, maternal height and BMI to neonatal head circumference, and maternal BMI to offspring adiposity. Principal components analysis identified three components of variability reflecting neonatal “head and trunk skeletal size,” “adiposity,” and “limb lengths.” Regression analyses of the component scores supported the associations of head and trunk size or adiposity with maternal anthropometry, and limb lengths with paternal anthropometry. Our results suggest that while neonatal fatness reflects environmental conditions (maternal physiology), head circumference and limb and trunk lengths show differing associations with parental anthropometry. These patterns may reflect genetics, parental imprinting and environmental influences in a manner consistent with parental conflicts of interest. Paternal height may relate to neonatal limb length as a means of increasing fetal growth without exacerbating the risk of obstetric complications. Am J Phys Anthropol 156:625–636, 2015.

Genetic influences on the association between fetal growth and susceptibility to type 2 diabetes

The fetal insulin hypothesis proposes that low birth weight and susceptibility to type 2 diabetes (T2D) could both be two phenotypes of the same genotype. Insulin is a key growth factor in utero, and T2D is characterized by insulin resistance and/or beta-cell dysfunction. Therefore, genetic variants impacting on insulin secretion and action are likely to alter both fetal growth and susceptibility to T2D. There are three lines of evidence in support of this hypothesis. (1) Studies of rare monogenic diabetes have shown mutations in a single gene, such as GCK or KCNJ11, can cause diabetes by reducing insulin secretion, and these mutations are also associated with reduced birth weight. (2) Epidemiological studies have indicated that children born to fathers with diabetes are born smaller. As the father cannot influence the intrauterine environment, this association is likely to reflect genes inherited by the fetus from the father. (3) The most compelling evidence comes from recent genome-wide association studies. Variants in the CDKAL1 and HHEX-IDE genes that predispose to diabetes, if present in the fetus, are associated with reduced birth weight. These data provide evidence for a genetic contribution to the association between low birth weight and susceptibility to T2D. This genetic background is important to take into consideration when investigating the impact of environmental determinants and developing strategies for intervention and prevention.

Maternal obesity and late effects on offspring metabolism

Objective : The aim of this study was to evaluate the late effects of maternal obesity induced by lesion of the ventromedial hypothalamus on offspring metabolism.Materials and methods : Thirty days after the bilateral lesion of the ventromedial hypothalamus, female rats were mated and divided into 2 groups of pregnant animals: Control (C) – false lesion (sham) and Obese (OB) – lesion. Three months after that, with the groups of mothers, offspring were divided into control and obese animals that received a normocaloric diet (C-N and OB-N), and control and obese animals that received a hypercaloric diet (C-H and OB-H). At 120 days of age, the animals were euthanized and their carcasses, feces and food were submitted to calorimetric analysis to determine energy balance and body composition.Results : During the growth period, offspring from obese mothers showed higher values of body weight and food intake than controls. Obese animals showed higher body weight gain and gross food efficiency than control animals in adulthood. The hypercaloric diet led to increased metabolizable energy intake, percentage of absorbed energy and energy expenditure in both groups. Body composition was only affected by the association of hypercaloric diet and maternal obesity that led to increased body fat.Conclusions : Maternal obesity has led to the development of later overweight in offspring, suggesting fetal programming. According to the trend presented, it is believed that the prolonged intake of hypercaloric diets in adult animals may, as an additional effect, induce worsening of the overweight induced by maternal obesity. Arq Bras Endocrinol Metab. 2014;58(3):301-7

Smaller pelvic size in pregnant adolescents contributes to lower birth weight

Adolescent pregnancy is associated with low birth weight. This has been explained by socioeconomic or emotional factors. However, an adolescent's pelvis may not be completely developed and this can contribute to impairing fetal growth. Our aim was to compare the relationship between pelvic size and birth weight among adolescents and adult mothers. A cross-sectional study was carried out at Instituto de Medicina Infantil Professor Fernando Figueira (IMIP), Brazil. We studied 125 healthy adolescents and 207 healthy adult women, all of whom were primiparous with a singleton term and low-risk pregnancy. The conjugate, intercristal and interspinous diameters were assessed by the Collins pelvimeter. The effect of pelvic size on the birth weight was evaluated using principal component analysis and multiple linear regression model. The mean pelvic size was smaller in adolescent mothers compared to adult ones (35.1 cm vs. 37.5 cm; p<0.001; t-test). After adjusting for other confounding variables, the predicted birth weights corresponding to these mean values of pelvic size were: 3020±27 g for adolescent mothers and 3145±26 g for adult mothers and showed a significant difference (p<0.001). We concluded that a pelvis that is less than fully developed in adolescents, as assessed by pelvic size, may contribute to lower birth weight in adolescent mothers.

Ethnic differences in neonatal body composition in a multi-ethnic population and the impact of parental factors: a population-based cohort study

BACKGROUND

Neonates from low and middle income countries (LAMIC) tend to have lower birth weight compared with Western European (WE) neonates. Parental height, BMI and maternal parity, age and educational level often differ according to ethnic background, and are associated with offspring birth weight. Less is known about how these factors affect ethnic differences in neonatal body composition.

OBJECTIVES

To explore differences in neonatal body composition in a multi-ethnic population, and the impact of key parental factors on these differences.

METHODS

A population-based cohort study of pregnant mothers, fathers and their offspring, living in Oslo, Norway. Gender- and gestational-specific z-scores were calculated for several anthropometric measurements, with the neonates of WE ethnic origin as reference. Mean z-scores for neonates with LAMIC origin, and their parents, are presented as outcome variables.

RESULTS

537 singleton, term neonates and their parents were included. All anthropometric measurements were smaller in neonates with LAMIC origin. Abdominal circumference and ponderal index differed the most from WE (mean z-score: -0.57 (95% CI:-0.69 to -0.44) and -0.54 (-0.66 to -0.44), and remained so after adjusting for parental size. Head circumference and skin folds differed less, and length the least (-0.21 (-0.35 to -0.07)). These measures became comparable to WEs when adjusted for parental factors.

CONCLUSIONS

LAMIC origin neonates were relatively "thin-fat", as indicated by reduced AC and ponderal index and relatively preserved length and skin folds, compared with neonates with WE origin. This phenotype may predispose to type 2 diabetes.

Maternal obesity: how big an impact does it have on offspring prenatally and during postnatal life?

Obesity is increasing at an epidemic rate in women of reproductive age. Not only does obesity during pregnancy lead to increased maternal health concerns, it is also linked to an increase in adiposity and components of the metabolic syndrome in the children and grandchildren of obese women. The potential transgenerational impact of maternal obesity on the health of future generations will undoubtedly result in increasing healthcare costs for society. This review will describe what is known about the specific impacts of maternal obesity on offspring in the human population as well as discuss how controlled animal experiments have shed light on the specific physiological mechanisms involved. Furthermore, preliminary experiments are presented describing potential dietary methods for preventing obesity-induced programming of offspring health concerns in postnatal life.

Maternal and infant factors associated with neonatal adiposity: results from the Tasmanian Infant Health Survey (TIHS)

OBJECTIVE

To examine the maternal and neonatal factors associated with offspring adiposity and the role of birth and placental weight as potential mediators in such associations.

DESIGN

The Tasmanian Infant Health Survey was a prospective cohort study conducted between 1988 and 1995 in Australia to investigate the cause of Sudden Infant Death Syndrome. This large infant cohort provides measurement of skinfolds on 7945 mothers and their offspring.

SUBJECTS

Participants included singletons born ≥37 weeks gestation who were at high risk of sudden infant death syndrome identified through a composite score that included birth weight, maternal age, neonatal gender, season of birth, duration of second-stage labor and intention to breastfeed.

MEASUREMENTS

Neonatal adiposity was assessed from skinfold measurements of the subscapular (SSF) and triceps folds (TSF) taken at birth. Maternal early-pregnancy body mass index (BMI) was calculated from self-reported height and weight. Neonatal data were extracted from birth records. Data relating to other environmental exposures were obtained from questionnaires administered when neonates were ∼4-days old.

RESULTS

In multivariable models, higher maternal adiposity, increasing maternal age, gestation age, delivery by Caesarian section and female gender were associated with larger SSF independent of placental and birth weight (P<0.001). Maternal age and delivery by Caesarian section were significantly associated with larger TSF, whereas gestational age and male gender were associated with thinner TSF independent of placental and birth weight. Higher early-pregnancy BMI, maternal weight gain, maternal age, parity and gestational age were significantly associated with larger placental and birth weight. Smoking during pregnancy was associated with smaller birth weight but not with placental weight.

CONCLUSION

In addition to birth weight, maternal adiposity and placental weight were important additional factors associated with neonatal adiposity.

Parental height differences predict the need for an emergency caesarean section

More than 30% of all pregnancies in the UK require some form of assistance at delivery, with one of the more severe forms of assistance being an emergency Caesarean section (ECS). Previously it has been shown that the likelihood of a delivery via ECS is positively associated with the birth weight and size of the newborn and negatively with maternal height. Paternal height affects skeletal growth and mass of the fetus, and thus might also affect pregnancy outcomes. We hypothesized that the effect of newborn birth weight on the risk of ECS would decrease with increasing maternal height. Similarly, we predicted that there would be an increase in ECS risk as a function of paternal height, but that this effect would be relative to maternal height (i.e., parental height differences). We used data from the Millennium Cohort Study: a large-scale survey (N = 18,819 births) with data on babies born and their parents from the United Kingdom surveyed 9 to 12-months after birth. We found that in primiparous women, both maternal height and parental height differences interacted with birth weight and predicted the likelihood of an ECS. When carrying a heavy newborn, the risk of ECS was more than doubled for short women (46.3%) compared to tall women (21.7%), in agreement with earlier findings. For women of average height carrying a heavy newborn while having a relatively short compared to tall partner reduced the risk by 6.7%. In conclusion, the size of the baby, the height of the mother and parental height differences affect the likelihood of an ECS in primiparous women.

Impact of maternal obesity on offspring obesity and cardiometabolic disease risk

The prevalence of obesity among pregnant women is increasing. In addition to the short-term complications of obesity during pregnancy in both mother and child, it is now recognised that maternal obesity has long-term adverse outcomes for the health of her offspring in later life. Evidence from both animal and human studies indicates that maternal obesity increases the risk for the offspring in developing obesity and altering body composition in child- and adulthood and, additionally, it also has an impact on the offspring's cardiometabolic health with dysregulation of metabolism including glucose/insulin homoeostasis, and development of hypertension and vascular dysfunction. Potential mechanisms include effects on the development and function of adipose tissue, pancreas, muscle, liver, the vasculature and the brain. Further studies are required to elucidate the mechanisms underpinning the programming of disease risk in the offspring as a consequence of maternal obesity. The ultimate aim is to identify potential targets, which may be amenable to prevention or early intervention in order to improve the health of this and future generations.

The maternal and fetal impacts of obesity and gestational diabetes on pregnancy outcome

Obesity has reached pandemic proportions and is of growing concern worldwide. Adverse health outcomes associated with a raised body mass index present the greatest challenge currently facing clinicians across all disciplines. Obesity is a chronic illness which is associated with metabolic disease, nutritional deficiency, musculoskeletal complications and cancer. These obesity-related health issues extend to pregnancy where they are responsible for producing a variety of medical and obstetric complications resulting in an increased incidence of maternal and fetal adverse outcomes. Management of diet, gestational diabetes and gestational and inter-gestational weight may improve outcomes in women who are obese during pregnancy. Specific recommendations for the management of obesity in pregnancy have recently been published.

Maternal metabolism and obesity: modifiable determinants of pregnancy outcome

BACKGROUND

Obesity among pregnant women is highly prevalent worldwide and is associated in a linear manner with markedly increased risk of adverse outcome for mother and infant. Obesity in the mother may also independently confer risk of obesity to her child. The role of maternal metabolism in determining these outcomes and the potential for lifestyle modification are largely unknown.

METHODS

Relevant studies were identified by searching PubMed, the metaRegister of clinical trials and Google Scholar without limitations. Sensitive search strategies were combined with relevant medical subject headings and text words.

RESULTS

Maternal obesity and gestational weight gain have a significant impact on maternal metabolism and offspring development. Insulin resistance, glucose homeostasis, fat oxidation and amino acid synthesis are all disrupted by maternal obesity and contribute to adverse outcomes. Modification of lifestyle is an effective intervention strategy for improvement of maternal metabolism and the prevention of type 2 diabetes and, potentially, gestational diabetes.

CONCLUSIONS

Maternal obesity requires the development of effective interventions to improve pregnancy outcome. Strategies that incorporate a detailed understanding of the maternal metabolic environment and its consequences for the health of the mother and the growth of the child are likely to identify the best approach.

Developmental programming resulting from maternal obesity in mice: effects on myocardial ischaemia-reperfusion injury

A comprehensive number of epidemiological and animal studies suggest that prenatal and early life events are important determinants for disorders later in life. Among them, prenatal stress (i.e. stress experienced by the pregnant mother with impact on the fetal ontogeny) has clear programming effects on the cardiovascular system. A fetus developing in adverse conditions becomes an adult who is susceptible to disease, which may include hypertension, insulin resistance, altered blood lipid levels and cardiovascular disease. Recent evidence demonstrates that maternal programming can occur in the absence of other adverse environmental factors. Obesity, which is becoming a problem of large proportions in Western countries, is a possible cause of programming. With over 30% of the population of the USA currently obese, many mothers suffer from obesity during their child-bearing years (in fact, these conditions are often aggravated during pregnancy). One of the targets of programming is the cardiovascular system, and reported consequences include hypertension, endothelial dysfunction and vascular abnormalities. The overall goal of our study was to investigate the susceptibility of the heart to ischaemia-reperfusion in an animal model of maternal obesity. Our data demonstrate that normal (non-mutant) offspring from obese agouti mouse dams had an increased susceptibility to ischaemia-reperfusion injury. These data may provide insights into the long-term cardiovascular consequences of programming.

A principal components approach to parent-to-newborn body composition associations in South India

Background

Size at birth is influenced by environmental factors, like maternal nutrition and parity, and by genes. Birth weight is a composite measure, encompassing bone, fat and lean mass. These may have different determinants. The main purpose of this paper was to use anthropometry and principal components analysis (PCA) to describe maternal and newborn body composition, and associations between them, in an Indian population. We also compared maternal and paternal measurements (body mass index (BMI) and height) as predictors of newborn body composition.

Methods

Weight, height, head and mid-arm circumferences, skinfold thicknesses and external pelvic diameters were measured at 30 ± 2 weeks gestation in 571 pregnant women attending the antenatal clinic of the Holdsworth Memorial Hospital, Mysore, India. Paternal height and weight were also measured. At birth, detailed neonatal anthropometry was performed. Unrotated and varimax rotated PCA was applied to the maternal and neonatal measurements.

Results

Rotated PCA reduced maternal measurements to 4 independent components (fat, pelvis, height and muscle) and neonatal measurements to 3 components (trunk+head, fat, and leg length). An SD increase in maternal fat was associated with a 0.16 SD increase (β) in neonatal fat (p < 0.001, adjusted for gestation, maternal parity, newborn sex and socio-economic status). Maternal pelvis, height and (for male babies) muscle predicted neonatal trunk+head (β = 0. 09 SD; p = 0.017, β = 0.12 SD; p = 0.006 and β = 0.27 SD; p < 0.001). In the mother-baby and father-baby comparison, maternal BMI predicted neonatal fat (β = 0.20 SD; p < 0.001) and neonatal trunk+head (β = 0.15 SD; p = 0.001). Both maternal (β = 0.12 SD; p = 0.002) and paternal height (β = 0.09 SD; p = 0.030) predicted neonatal trunk+head but the associations became weak and statistically non-significant in multivariate analysis. Only paternal height predicted neonatal leg length (β = 0.15 SD; p = 0.003).

Conclusion

Principal components analysis is a useful method to describe neonatal body composition and its determinants. Newborn adiposity is related to maternal nutritional status and parity, while newborn length is genetically determined. Further research is needed to understand mechanisms linking maternal pelvic size to fetal growth and the determinants and implications of the components (trunk v leg length) of fetal skeletal growth.

Multivariate statistical interpretation of laboratory clinical data

Laboratory aids are extensively used in the diagnosis of diseases, in preventive medicine, and as management tools. Reference values of clinically healthy people serve as a guide to the clinician in evaluating biochemical parameters. Determination of 21 biochemical parameters of healthy persons using standard methods of analysis. Cluster analysis and principal components analysis were applied on the above 21 biochemical parameters data. The application of a typical classification approach as cluster analysis proved that four major groups of similarity between all 21 clinical parameters are formed, which correspond to the authors assumption of the existence of several summarizing pattern of clinical parameters such as “enzyme,” “major component excretion”, “general health state,” and “blood specific” pattern. These patterns appear also in the subsets obtained by separation of the general dataset into “male”, “female”, “young”, and “adult” healthy groups. The results obtained from principal components analysis have additionally proved the validity of a similar assumption. The intelligent data analysis on the clinical parameter dataset has shown that when a complex system is considered as a multivariate one, the information about the system substantially increases. All these results support an idea that probably a general health indicator could be constructed taking into account the existing classification groups in the list of clinical parameters.