Genetic and Environmental Effects on Weight, Height, and BMI Under 18 Years in a Chinese Population-Based Twin Sample

Genetic knowledge and attitudes towards genetic testing among final-year medical students at a public university in Ecuador

Background

Genetics plays a crucial role in the field of medicine, offering numerous applications. However, health professionals often have insufficient knowledge in this area. Therefore, it is essential to provide appropriate genetics education during university studies.

Aim

This study aimed to assess the knowledge and attitudes towards genetic testing among final-year medical students at a public university in Ecuador.

Methods

A cross-sectional study was conducted involving final-year medical students from a public university in Ecuador. The third version of the Genetic Literacy and Attitudes Survey was administered between April and May 2022. The study examined sociodemographic characteristics, genetic knowledge, and attitudes towards genetic testing.

Results

The study included 153 medical students, of which 58.2% identified as female. Most participants fell within the age range of 22 to 25 years old (85.0%). Regarding genetic knowledge, three-quarters of the participants (75.2%) demonstrated intermediate proficiency, while only 9.80% possessed a high level of knowledge. Attitudes towards the clinical and therapeutic applications of genetics, scientific advancements, access to conventional medicine, and other related topics were found to be appropriate.

Conclusion

The findings suggest that most final-year medical students at a public university in Ecuador have intermediate genetic knowledge and hold appropriate attitudes towards genetic testing. However, higher education institutions should conduct a comprehensive analysis and restructure their curricula to better prepare students for the medical and technological challenges of the 21st century.

Obstetric and perinatal outcome in short-stature patients

OBJECTIVE

Scarce data exist regarding obstetric complications of short-stature patients. This study aimed to investigate obstetric and perinatal outcomes in women with short stature; specifically, to investigate whether short-stature patients are at an increased risk for cesarean delivery.

METHODS

A population-based cohort study was conducted, including all singletons born between the years 1991 and 2021 at a tertiary medical center. Obstetric and perinatal outcomes of short-stature patients were compared with those of non-short patients. A generalized estimation equation binary logistic model was constructed to adjust for confounders and maternal recurrence in the cohort.

RESULTS

The study population included 356 356 parturient; among them, 14 035 (3.9%) were short-stature patients. Short-stature patients had significantly higher rates of cesarean delivery (20.7% vs 13.7%, odds ratio = 1.64, 95% confidence interval 1.57-1.71, P < 0.001), induction of labor, pathologic presentations, prolonged second stage of labor, non-reassuring fetal monitoring, and meconium-stained amniotic fluid. Newborns of short-stature patients had a significantly higher risk of being small for gestational age as compared with those of non-short patients. In the generalized estimation equation models, the association between short stature and risk of cesarean delivery remained significant (adjusted odds ratio = 1.32, 95% confidence interval 1.27-1.38, P < 0.001), as well as the risk of small for gestational age newborns (adjusted odds ratio = 1.51, 95% confidence interval 1.40-1.63, P < 0.001), but not for the other adverse outcomes.

CONCLUSIONS

Maternal short stature is an independent risk factor for cesarean delivery and is associated with small for gestational age newborns.

Heritability of Psychological Traits and Developmental Milestones in Infancy: A Systematic Review and Meta-analysis

Importance

Although infancy is the most rapid period of postnatal growth and development, factors associated with variation in infant traits are not well understood.

Objective

To synthesize the large twin study literature partitioning phenotypic variance in psychological traits and developmental milestones in infancy into estimates of heritability and shared and nonshared environment.

Data Sources

PubMed, PsycINFO, and references of included publications were searched up to February 11, 2021.

Study Selection

Peer-reviewed publications using the classical twin design to study psychological traits and developmental milestones from birth to 2 years old were included.

Data Extraction and Synthesis

Data were extracted in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and categorized using the International Classification of Functioning, Disability and Health: Children and Youth Version. Data were pooled in 3-level random effects models, incorporating within-cohort variance in outcome measurement and between-cohort variance. Data were analyzed from March 2021 through September 2021.

Main Outcomes and Measures

The primary outcomes were monozygotic and dizygotic twin correlations. These were used to calculate genetic and shared and nonshared environment estimates.

Results

Among 139 publications that were systematically retrieved, data were available on 79 044 twin pairs (31 053 monozygotic and 47 991 dizygotic pairs), 52 independent samples, and 21 countries. Meta-analyses were conducted on psychological traits and developmental milestones from 106 publications organized into 10 categories of functioning, disability, and health. Moderate to high genetic estimates for 8 categories were found, the highest of which was psychomotor functions (pooled h2, 0.59; 95% CI, 0.25-0.79; P < .001). Several categories of traits had substantial shared environment estimates, the highest being mental functions of language (pooled c2, 0.59; 95% CI, 0.24-0.86; P = .001). All examined categories of traits had moderate or high nonshared environment estimates, the highest of which were emotional functions (pooled e2, 0.42; 95% CI, 0.33-0.50; P < .001) and family relationships (pooled e2, 0.42; 95% CI, 0.30-0.55; P < .001).

Conclusions and Relevance

These findings may be an important source of information to guide future gene discovery research, public perspectives on nature and nurture, and clinical insights into the degree to which family history and environments may estimate major domains of infant functioning, disability, and health in psychological traits and developmental milestones.

Morphofunctional and Hematological Characteristics of Health in Students from the Northern and Southern Regions of Kazakhstan

The study aimed at investigating morphofunctional and hematological features of the first-year students’ health condition. The health status for a total of 400 first-year students, who arrived for studying from the northern region (North Kazakhstan) and the southern region (Turkestan, Kyzylorda), was estimated during the study. The morphological (BMI, vital lung capacity, etc.) and hematological (the total number of red blood cells, white blood cells, the concentration of hemoglobin in the blood, etc.) indicators of the health status were investigated. By comparing the condition of physical health in students from both regions, a significant difference in main morphofunctional and hematological indices has been established. The functional indicators of the cardiovascular and respiratory systems were higher in students from the southern region, which reflects a good adaptive reaction to studying at a university, as well as new climatic and geographical conditions. Students from the southern region were reported to have lower red blood cell amounts and diagnosed with mild anemia compared to those from the northern region. Therefore, constant monitoring of the health condition among youth is required to develop effective tactics for the students’ smooth adjusting to living in new climatic conditions.

The current review of adolescent obesity: the role of genetic factors

Obesity, a complex, multi-factor and heterogeneous condition, is thought to result from the interaction of environmental and genetic factors. Considering the result of adolescence obesity in adulthood, the role of genetic factors comes to the fore. Recently, many genome-wide association studies (GWAS) have been conducted and many loci associated with adiposity have been identified. In adolescents, the strongest association with obesity has been found in single nucleotide polymorphisms (SNP) in the FTO gene. Besides FTO, GWAS showed consistent effects between variants in MC4R, TMEM18, TNNI3K, SEC16B, GNPDA2, POMC and obesity. However, these variants may not have similar effects for all ethnic groups. Although recently genetic factors are considered to contribute to obesity, relatively little is known about the specific loci related to obesity and the mechanisms by which they cause obesity.

An empirical study of factors associated with height-for-age z-scores of children aged 6-23 months in northwest Rwanda: the role of care practices related to child feeding and health

We aimed to identify the factors influencing child height-for-age z-scores (HAZ) as a measure of child nutritional status in Rwanda, and to examine the role of child feeding and health practices. We conducted a cross-sectional study involving 379 children (aged 6-23 months) and their mothers in northwest Rwanda. Data were collected using a pre-tested, structured questionnaire. An infant and young child feeding practices index (ICFI) and health practices index (HPI) were developed and categorised into tertiles, and linear regression analyses were performed to assess their association with child HAZ. Overall, mothers of non-stunted children exhibited better feeding and health practices than those of stunted children. ICFI was positively associated with child HAZ. We found an adjusted mean HAZ difference of 0·14 between children whose mothers were in high ICFI tertile compared with those in low tertile. Neither HPI nor any of its components were significantly associated with child HAZ. Other factors that were positively associated with child HAZ were infant birth weight (P < 0·001) and maternal height (P < 0·001). Child age, sex (male) (P < 0·05) and altitude (P < 0·05) were negatively associated with child HAZ. Diarrhoea (P < 0·05) and respiratory infections (P < 0·05) were negatively associated with HAZ in younger children aged 6-11 months. Policies to reduce stunting in this population must focus on both pre- and postnatal factors. Appropriate child feeding practices, particularly breast-feeding promotion and improvement in children's dietary diversity combined with measures to control infections should be given priority.

Development of a generalized model for kidney depth estimation in the Chinese population: A multi-center study

PURPOSE

To establish an accurate and reliable equation for kidney depth estimation in adult patients from different Chinese geographical regions.

METHOD

This multicenter study enrolled Eastern Asian Chinese patients with abdominal PET/CT scans at 26 imaging centers from six macro-regions across China in 3 years. Age, gender, height, weight, primary disease and its extent on PET scans of the participants were collected as potential predictive factors. Kidney depth on CT, defined as the average of the vertical distances from the posterior skin to the farthest anterior and closest posterior surfaces of each kidney, was measured as the standard reference. The new kidney depth model was constructed using a multiple regression model, and its performance was compared to those of three established models by computing the absolute value of estimation errors in comparison with CT-measured kidney depth.

RESULTS

A total of 2502 patients were enrolled and classified into training (n=1653) and testing (n = 849) subsets. In the training subset, two kidney depth models were constructed: Left (cm): 0.013×age+0.117×gender-0.044×height+0.087×weight+7.951, Right (cm): 0.005×age+0.013×gender-0.035×height+0.082×weight+7.266 (weight: kg, height: cm, gender = 0 if female, 1 if male). In the testing subset, one-way analysis of variance showed that the estimation errors of the new models did not significantly differ among the 6 regions. Bland-Altman analysis determined that new equations had lower estimated biases (left: 0.039 cm, right: 0.018 cm) compared with other existing models.

CONCLUSION

The new equations were highly accurate for kidney depth estimation in adults from all over China, with lower estimation errors compared to other established models.

The Chinese National Twin Registry: A Unique Data Source for Systems Epidemiology of Complex Disease

The Chinese National Twin Registry (CNTR), initiated in 2001, has now become the largest twin registry in Asia. From 2015 to 2018, the CNTR continued to receive Chinese government funding and had recruited 61,566 twin-pairs by 2019 to study twins discordant for specific exposures such as environmental factors, and twins discordant for disease outcomes or measures of morbidity. Omic data, including genetics, genomics, metabolomics, and proteomics, and gut microbiome will be tested. The integration of omics and digital technologies in public health will advance our understanding of precision public health. This review introduces the updates of the CNTR, including study design, sample size, biobank, zygosity assessment, advances in research and future systems epidemiologic research.

The Chinese National Twin Registry: a 'gold mine' for scientific research

The Chinese National Twin Registry (CNTR) currently includes data from 61 566 twin pair from 11 provinces or cities in China. Of these, 31 705, 15 060 and 13 531 pairs are monozygotic, same-sex dizygotic and opposite-sex dizygotic pairs, respectively, determined by opposite sex or intrapair similarity. Since its establishment in 2001, the CNTR has provided an important resource for analysing genetic and environmental influences on chronic diseases especially cardiovascular diseases. Recently, the CNTR has focused on collecting biologic specimens from disease-concordant or disease-discordant twin pairs or from twin pairs reared apart. More than 8000 pairs of these twins have been registered, and blood samples have been collected from more than 1500 pairs. In this review, we summarize the main findings from univariate and multivariate genetic effects analyses, gene-environment interaction studies, omics studies exploring DNA methylation and metabolomic markers associated with phenotypes. There remains further scope for CNTR research and data mining. The plan for future development of the CNTR is described. The CNTR welcomes worldwide collaboration.

New literacy challenge for the twenty-first century: genetic knowledge is poor even among well educated

We live in an age of rapidly advancing genetic research. This research is generating new knowledge that has implications for personal health and well-being. The present study assessed the level of genetic knowledge and personal engagement with genetics in a large sample (N = 5404) of participants. Participants received secondary education in 78 countries, with the largest samples from Russia, the UK and the USA. The results showed significant group differences in genetic knowledge between different countries, professions, education levels and religious affiliations. Overall, genetic knowledge was poor. The questions were designed to assess basic genetic literacy. However, only 1.2% of participants answered all 18 questions correctly, and the average score was 65.5%. Genetic knowledge was related to peoples' attitudes towards genetics. For example, those with greater genetic knowledge were on average more willing to use genetic knowledge for their personal health management. Based on the results, the paper proposes a number of immediate steps that societies can implement to empower the public to benefit from ever-advancing genetic knowledge.

Assessing the genetic correlations between early growth parameters and bone mineral density: A polygenic risk score analysis

OBJECTIVE

The relationships between early growth parameters and bone mineral density (BMD) remain elusive now. In this study, we performed a large scale polygenic risk score (PRS) analysis to evaluate the potential impact of early growth parameters on the variations of BMD.

METHODS

We used 2286 Caucasian subjects as cohort 1 and 3404 Framingham Heart Study (FHS) subjects as cohort 2 in this study. BMD at ulna & radius, hip and spine were measured using dual energy X-ray absorptiometry. BMD values were adjusted for age, sex, height and weight as covariates. Genome-wide single-nucleotide polymorphism (SNP) genotyping of the 2286 Caucasian subjects was performed using Affymetrix Human SNP Array 6.0. The GWAS datasets of early growth parameters were driven from the Early Growth Genetics Consortium, including birth weight (BW), birth head circumference (BHC), childhood body mass index (CBMI), pubertal height growth related indexes and tanner stage. Polygenic Risk Score (PRSice) and linkage disequilibrium (LD) score regression analysis were conducted to assess the genetic correlation between early growth parameters and BMD.

RESULTS

We detected significant genetic correlations in cohort 1, such as total spine BMD vs. CBMI (p value = 1.51 × 10^-4, rg = 0.4525), right ulna and radius BMD vs. CBMI (p value = 1.51 × 10^-4, rg = 0.4399) and total body BMD vs. tanner stage (p value = 7.00 × 10^-4, rg = -0.0721). For cohort 2, significant correlations were observed for total spine BMD vs. height change standard deviation score (SDS) between 8 years and adult (denoted as PGF + PGM) (p value = 3.97 × 10^-4, rg = -0.1425), femoral neck BMD vs. the timing of peak height velocity by looking at the height change SDS between age 14 years and adult (denoted as PTF + PTM) (p value = 7.04 × 10^-4, rg = -0.2185), and total spine BMD vs. PTF + PTM (p value = 6.86 × 10^-4, rg = -0.2180).

CONCLUSION

Our study results suggest that some early growth parameters could affect the variations of BMD.

WOMEN’S EMPOWERMENT AND GENDER INEQUALITY IN ADOLESCENT NUTRITIONAL STATUS: EVIDENCE FROM THE INDONESIAN FAMILY LIFE SURVEY

In contrast to the extensive knowledge on the association between women’s empowerment and the nutritional status of children under the age of five, relatively little is known about the influence of women’s empowerment on adolescents’ nutritional status. This study aimed to assess the association between women’s empowerment and gender inequalities in adolescent nutritional status. Data were from the Indonesian Family Life Survey (IFLS) covering the period 1997 to 2015, and consisted of 16,683 observations from 13,396 adolescents between the ages of 10 and 19 years born in 6781 families. Three indicators of women’s empowerment were used: mother’s education, mother’s bargaining power and mother’s working status. Multivariate linear regression with robust standard errors was used to examine whether and how these indicators of women’s empowerment influenced adolescent nutritional status. Interaction terms were added to analyse how the association between women’s empowerment and adolescent nutritional status differed by gender. The results showed that mother’s education and mother’s working status were significantly associated with adolescent nutritional status, particularly with height-for-age. Adolescents of well-educated mothers had a higher height-for-age while those who were raised by mothers with a blue-collar job had a lower height-for-age. Although no gender differences were found for height-for-age, gender differences for BMI-for-age were obvious, with boys having a lower BMI-for-age than girls. Interactions between indicators of mother’s empowerment and gender showed that the gender gap in BMI-for-age was smaller for adolescents of more educated mothers. However, further analyses of food consumption patterns showed that boys whose mothers were more educated consumed more fast food and had higher instant noodle consumption than girls, thus suggesting gender bias in new disguise.

A metric study of insole foot impressions in footwear of identical twins

Foot impressions are of utmost importance in crime scene investigations. Foot impressions are available in the form of barefoot prints, sock-clad footprints, and as impressions within footwear. Sometimes suspects leave their footwear at the crime scene, and the insole of this footwear may contain the foot impression of the suspect which may be important evidence linking him or her to the crime. The task of identification based on the analysis of footprints can be challenging when the footprints belonging to one of the identical twin is available for examination. The present study is based on the quantitative measures of the foot impressions in the footwear of adult identical twins. The study was conducted on four sets of female monozygotic twins from the United States of America. A total of 17 length and breadth measurements were taken on each foot impression. A combination of Reel Method and Extended Gunn Method was utilized to produce the measurements. The measurements of the foot impressions were compared among the twins on the right and the left side. Differences were found in the various footprint measurements among the twins. The study's sample size was not large enough to apply robust statistical tests, but the study is significant in that it presents the first detailed comparative analysis of a large number of measurements of insole foot impressions of adult twins. The observations derived from the study are likely to assist forensic investigations in cases involving the foot impressions of the twins.

Genetic and environmental effects on body mass index from infancy to the onset of adulthood: an individual-based pooled analysis of 45 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) study

BACKGROUND

Both genetic and environmental factors are known to affect body mass index (BMI), but detailed understanding of how their effects differ during childhood and adolescence is lacking.

OBJECTIVES

We analyzed the genetic and environmental contributions to BMI variation from infancy to early adulthood and the ways they differ by sex and geographic regions representing high (North America and Australia), moderate (Europe), and low levels (East Asia) of obesogenic environments.

DESIGN

Data were available for 87,782 complete twin pairs from 0.5 to 19.5 y of age from 45 cohorts. Analyses were based on 383,092 BMI measurements. Variation in BMI was decomposed into genetic and environmental components through genetic structural equation modeling.

RESULTS

The variance of BMI increased from 5 y of age along with increasing mean BMI. The proportion of BMI variation explained by additive genetic factors was lowest at 4 y of age in boys (a(2) = 0.42) and girls (a(2) = 0.41) and then generally increased to 0.75 in both sexes at 19 y of age. This was because of a stronger influence of environmental factors shared by co-twins in midchildhood. After 15 y of age, the effect of shared environment was not observed. The sex-specific expression of genetic factors was seen in infancy but was most prominent at 13 y of age and older. The variance of BMI was highest in North America and Australia and lowest in East Asia, but the relative proportion of genetic variation to total variation remained roughly similar across different regions.

CONCLUSIONS

Environmental factors shared by co-twins affect BMI in childhood, but little evidence for their contribution was found in late adolescence. Our results suggest that genetic factors play a major role in the variation of BMI in adolescence among populations of different ethnicities exposed to different environmental factors related to obesity.

Genetic and environmental influences on height from infancy to early adulthood: An individual-based pooled analysis of 45 twin cohorts

Height variation is known to be determined by both genetic and environmental factors, but a systematic description of how their influences differ by sex, age and global regions is lacking. We conducted an individual-based pooled analysis of 45 twin cohorts from 20 countries, including 180,520 paired measurements at ages 1-19 years. The proportion of height variation explained by shared environmental factors was greatest in early childhood, but these effects remained present until early adulthood. Accordingly, the relative genetic contribution increased with age and was greatest in adolescence (up to 0.83 in boys and 0.76 in girls). Comparing geographic-cultural regions (Europe, North-America and Australia, and East-Asia), genetic variance was greatest in North-America and Australia and lowest in East-Asia, but the relative proportion of genetic variation was roughly similar across these regions. Our findings provide further insights into height variation during childhood and adolescence in populations representing different ethnicities and exposed to different environments.