Principal component analysis reveals gender-specific predictors of cardiometabolic risk in 6th graders

Nonalcoholic Fatty Liver Disease and Continuous Metabolic Syndrome in Adolescents with Overweight/Obesity

INTRODUCTION

Nonalcoholic fatty liver disease is the leading cause of pediatric chronic liver disease. Although nonalcoholic fatty liver disease is closely associated with obesity, its relationship with metabolic syndrome in children is not fully understood. The main aim of this study was to evaluate the association between nonalcoholic fatty liver disease and a combination of cardiometabolic risk factors in adolescents with overweight/obesity, using a pediatric metabolic syndrome score (PsiMS) to predict metabolic syndrome.

METHODS

A retrospective cohort study was conducted. Subjects with overweight/obesity aged 10 to 17 followed at two clinical centers in Portugal (2018 - 2021) were enrolled. The independent association of nonalcoholic fatty liver disease with PsiMS, and of other potential predictors, was tested through multiple regression analyses. Receiver operator characteristic curve analysis was performed to estimate the optimal cutoff of PsiMS to discriminate metabolic syndrome.

RESULTS

Eighty-four subjects were included (median age at baseline 11.5 years). The prevalence rate of nonalcoholic fatty liver disease was 51% and the prevalence rate of metabolic syndrome was 7%. The mean PsiMS was 2.05 ± 0.48 at the first evaluation, and 2.11 ± 0.52 at the last evaluation (mean follow-up time was 15 months). The nonalcoholic fatty liver disease group had significantly (p < 0.05) higher weight and body mass index z-scores, higher rate of severe obesity and higher waist circumference percentile. PsiMS was highly accurate in predicting metabolic syndrome (area under the curve = 0.96), with an optimal cutoff of 2.46 (sensitivity 100%, specificity 89%). In the univariate analysis, no statistically significant association was observed between nonalcoholic fatty liver disease and PsiMS. In the multiple regression analysis, female sex had a negative association with PsiMS (first and last evaluation). Independent predictors of a higher PsiMS at first evaluation were: ≥ 2 metabolic syndrome criteria, body mass index z-score, insulin resistance and dyslipidemia. At the last evaluation, independent predictors of a higher PsiMS were: nonalcoholic fatty liver disease, baseline PsiMS and body mass index increase from baseline.

CONCLUSION

The results suggest a good performance of the PsiMS to assess metabolic syndrome and that nonalcoholic fatty liver disease is associated with PsiMS at follow-up.

Machine Learning Methods in Real-World Studies of Cardiovascular Disease

Objective:Cardiovascular disease (CVD) is one of the leading causes of death worldwide, and answers are urgently needed regarding many aspects, particularly risk identification and prognosis prediction. Real-world studies with large numbers of observations provide an important basis for CVD research but are constrained by high dimensionality, and missing or unstructured data. Machine learning (ML) methods, including a variety of supervised and unsupervised algorithms, are useful for data governance, and are effective for high dimensional data analysis and imputation in real-world studies. This article reviews the theory, strengths and limitations, and applications of several commonly used ML methods in the CVD field, to provide a reference for further application.

Methods:This article introduces the origin, purpose, theory, advantages and limitations, and applications of multiple commonly used ML algorithms, including hierarchical and k-means clustering, principal component analysis, random forest, support vector machine, and neural networks. An example uses a random forest on the Systolic Blood Pressure Intervention Trial (SPRINT) data to demonstrate the process and main results of ML application in CVD.

Conclusion:ML methods are effective tools for producing real-world evidence to support clinical decisions and meet clinical needs. This review explains the principles of multiple ML methods in plain language, to provide a reference for further application. Future research is warranted to develop accurate ensemble learning methods for wide application in the medical field.

Sex-specific correlates of metabolic syndrome risk in college-aged young adults

Objective: To identify the sex-specific prevalence of metabolic syndrome (MetS) risk factors and their physiological, psychosocial, and behavioral correlates in a college-aged population. Participants and methods: Cross-sectional assessment of MetS risk factors and potential correlates occurred in 379 first-year students (aged 18.34 ± 0.49 years, 67.3% female). Multivariable linear regression assessed the relationships between potential correlates and continuous MetS risk scores, derived from principal component analysis. Results: MetS risk factors were present in 58.4% of females and 68.5% of males, with 2.4% and 3.2% having defined MetS. In females, percent body fat (β = 0.46, p < 0.001), stress (β = 0.12, p = 0.031), % kcal from sugar (β = 0.18, p = 0.001), and moderate-to-vigorous physical activity (β=-0.12, p = 0.036) were associated with risk score. Whereas, correlates in males included percent body fat (β = 0.54, p < 0.001), C-reactive protein (β = 0.15, p = 0.045), and AUDIT alcohol consumption score (β = 0.15, p = 0.033). Conclusion: The sex-specific prevalence of MetS risk factors and correlates suggest that primary prevention strategies on college campuses should also follow a sex-specific approach.

Continuous metabolic syndrome severity score and the risk of CVD and all-cause mortality

BACKGROUND

The dualistic diagnostic criteria for metabolic syndrome overlooked the severity of metabolic syndrome, and the relationships between the severity of metabolic syndrome and adverse health conditions are poorly characterized. We therefore aimed to investigate the associations of metabolic syndrome severity with incident cardiovascular disease (CVD)/all-cause mortality.

METHODS

A total of 116,772 participants from the Kailuan study were followed up biennially between 2006 and 2018. The severity of metabolic syndrome was evaluated using a continuous metabolic syndrome severity score (MetS score). Cox proportional hazards model was used to examine the association between MetS score and the risk of CVD and all-cause mortality. Restricted cubic spline analyses were performed to explore the dose-response associations.

RESULTS

We found that the risk of CVD and all-cause mortality increased consistently with the MetS score. In the multivariable-adjusted model, the hazard ratios of CVD and all-cause mortality were 2.05 (95% CI 1.86-2.25) and 1.45 (95% CI 1.35-1.56), respectively, in those subjects>75th percentile compared with those <25th percentile. Additionally, a J-shaped dose-response relationship was found between MetS score and the risk of all-cause mortality (p_nonlinearity  <.001), while a linear relationship between MetS score and the risk of CVD was observed in this study (p_nonlinearity  = .737).

CONCLUSIONS

This study suggests significant dose-response relationships between MetS score and the risk of CVD/mortality. Subjects without metabolic syndrome but with a relatively high MetS score should raise their awareness and pay more attention to the possible increased risk of CVD events.

Lifestyle and awareness of cholesterol blood levels among 29159 community school children in Italy

BACKGROUND AND AIM

Lifestyle habits including indoor and outdoor activities among community school children, adherence to the Mediterranean diet and awareness about total cholesterol blood levels represent determinant factors in cardiovascular disease (CVD) prevention. The aim of this study was to analyze the relationship between adherence to the Mediterranean diet, total cholesterol blood levels, body composition and hours per day spent in in-house or outdoor among 29,159 Italian 6-14 years-old community school children (50% boys). The KidMed questionnaire, modified to handle missing information on olive oil consumption, was used to assess the adherence to the Mediterranean diet among participants.

METHODS AND RESULTS

Associations between variables were tested according to 3 classes of the Mediterranean diet adherence score using analysis of variance. Participants with high adherence to Mediterranean diet were few (1%). Overall awareness of total cholesterol blood levels was low among children (4.5%), slightly higher among parents (26.2 and 24.1% in mothers and fathers, respectively). Among Mediterranean diet adherent children, BMI was significantly (p < 0.001) smaller than among the non-Mediterranean or intermediate adherent children as were the total hours spent per day watching television or playing with videogames (p < 0.001) whereas the hours/day in sport or outdoor activities were more (p < 0.001). These results were confirmed by multiple linear regression with KidMed scored 0 to 8 as dependent variable.

CONCLUSION

Although awareness of total cholesterol blood levels and adherence to the Mediterranean diet are rare among community school children, only among these a healthier lifestyle was practiced with a tendency to lower CVD risks. These results are important as the first sized experience of this type in Italy.

Cardiovascular disease risk factor clustering in children and adolescents: a prospective cohort study

OBJECTIVE

The early identification of predictors related to cardiovascular disease risk factor clustering (CVD-RFC) can help prevent chronic disease. We aimed to identify the risk factors for CVD-RFC in adolescents.

METHODS

A prospective longitudinal cohort study design was used to obtain data included in these analyses from school-aged children who participated in the Korean Child-Adolescent Study 2008-2014. A total of 1309 children aged 6-15 years were enrolled. We compared the participants based on the presence or absence of CVD-RFC and examined the cumulative incidence of CVD-RFC.

RESULTS

Of the total 1309 children, 410 (31.32%) had CVD-RFC in adolescence. A higher average household income ≥3 million Korean Republic won (KRW)/month (3-5 million KRW/month: HR 0.75 (95% CI 0.58 to 0.97); ≥5 million KRW/month: HR 0.58 (95% CI 0.44 to 0.77)) was associated with a lower CVD-RFC incidence, while the presence of parental CVD history (HR 1.28 (95% CI 1.04 to 1.57)), overweight or obesity (HR 3.83 (95% CI 3.05 to 4.80)) and shorter sleep duration of 8-9 hour/day (HR 1.80 (95% CI 1.05 to 3.07)) and <8 hour/day (HR 1.93 (95% CI 1.11 to 3.34)) had higher CVD-RFC incidences.

CONCLUSIONS

Obesity in childhood, short sleep duration and parental factors such as low socioeconomic status and parental history of CVD are significant risk factors for the development of CVD-RFC in adolescents. Efforts to create awareness regarding sufficient sleep duration in children via intervention programmes targeting cardiometabolic health in children and special attention to lifestyle modifications and socioeconomic components of the family should be considered.

Body Mass Index, Waist Circumference, and the Clustering of Cardiometabolic Risk Factors in Early Childhood

BACKGROUND

Obesity has its origins in early childhood; however, there is limited evidence of the association between anthropometric indicators and cardiometabolic risk factors in young children. Our aim was to evaluate the associations between body mass index (BMI) and waist circumference (WC) in relation to cardiometabolic risk factors and to explore the clustering of these factors.

METHODS

A cross-sectional study was conducted in children aged 1-5 years through TARGet Kids! (n = 2917). Logistic regression was used to evaluate associations between BMI and WC z-scores and individual traditional and possible non-traditional cardiometabolic risk factors. The underlying clustering of these measures was evaluated using principal components analysis (PCA).

RESULTS

Child obesity (BMI z-score >2) was associated with high (>90th percentile) leptin [odds ratio (OR) 8.15, 95% confidence interval (CI) 4.56, 14.58] and insulin (OR = 1.76; 95% CI 1.05, 2.94). WC z-score >1 was associated with high insulin (OR 1.59, 95% CI 1.11, 2.28), leptin (OR 5.48, 95% CI 3.48, 8.63) and 25-hydroxyvitamin D < 75 nmol/L (OR 1.39, 95% CI 1.08, 1.79). BMI and WC were not associated with other traditional cardiometabolic risk factors, including non-High Density Lipoprotein (HDL) cholesterol, and glucose. Among children 3-5 years (n = 1035) the PCA of traditional risk factors identified three components: adiposity/blood pressure, metabolic, and lipids. The inclusion of non-traditional risk factors identified four additional components but contributed minimally to the total variation explained.

CONCLUSIONS

Anthropometric indicators are associated with selected cardiometabolic risk factors in early childhood, although the clustering of risk factors suggests that adiposity is only one distinct component of cardiometabolic risk. The measurement of other risk factors beyond BMI and WC may be important in defining cardiometabolic risk in early childhood.

Continuous Metabolic Syndrome Scores for Children Using Salivary Biomarkers

Background

Binary definitions of the metabolic syndrome based on the presence of a particular number of individual risk factors are limited, particularly in the pediatric population. To address this limitation, we aimed at constructing composite and continuous metabolic syndrome scores (cmetS) to represent an overall measure of metabolic syndrome (MetS) in a large cohort of metabolically at-risk children, focusing on the use of the usual clinical parameters (waist circumference (WC) and systolic blood pressure (SBP), supplemented with two salivary surrogate variables (glucose and high density lipoprotein cholesterol (HDLC). Two different approaches used to create the scores were evaluated in comparison.

Methods

Data from 8,112 Kuwaiti children (10.00 ± 0.67 years) were used to construct two cmetS for each subject. The first cmetS (cmetS-Z) was created by summing standardized residuals of each variable regressed on age and gender; and the second cmetS (cmetS-PCA) was defined as the first principal component from gender-specific principal component analysis based on the four variables.

Results

There was a graded relationship between both scores and the number of adverse risk factors. The areas under the curve using cmetS-Z and cmetS-PCA as predictors for severe metabolic syndrome (defined as the presence of ≥3 metabolic risk factors) were 0.935 and 0.912, respectively. cmetS-Z was positively associated with WC, SBP, and glucose, but inversely associated with HDLC. Except for the lack of association with glucose, cmetS-PCA was similar to cmetS-Z in boys, but had minimum loading on HDLC in girls. Analysis using quantile regression showed an inverse association of fitness level with cmetS-PCA (p = 0.001 for boys; p = 0.002 for girls), and comparison of cmetS-Z and cmetS-PCA suggested that WC and SBP were main contributory components. Significant alterations in the relationship between cmetS and salivary adipocytokines were demonstrated in overweight and obese children as compared to underweight and normal-weight children.

Conclusion

We have derived continuous summary scores for MetS from a large-scale pediatric study using two different approaches, incorporating salivary measures as surrogate for plasma measures. The derived scores were viable expressions of metabolic risk, and can be utilized to study the relationships of MetS with various aspects of the metabolic disease process.

Strength capacity and cardiometabolic risk clustering in adolescents

OBJECTIVES

The purpose of this study was to determine the gender-specific independent association between muscular strength and cardiometabolic risk clustering in a large cohort (n = 1421) of children.

METHODS

Principal component analysis was used to determine the pattern of risk clustering and to derive a continuous aggregate score (MetScore) from various cardiometabolic risk components: percent body fat (%BF), fasting glucose, blood pressure, plasma triglycerides levels, and HDL-cholesterol. Gender-stratified risk and MetScore were assessed by using general linear models and logistic regression for differences between strength tertiles, as well as independent associations with age, BMI, estimated cardiorespiratory fitness (CRF), physical activity, and muscular strength (normalized for body mass).

RESULTS

In both boys (n = 670) and girls (n = 751), there were significant differences in cardiometabolic profiles across strength tertiles, such that stronger adolescents had lower overall risk. Age, BMI, cardiorespiratory fitness, physical activity participation, and strength were all individually correlated with multiple risk components, as well as the overall MetScore. However, in the adjusted model, only BMI (β = 0.30), physical inactivity (β = 0.30), and normalized strength capacity (β = -1.5) emerged as significant (P < .05) predictors of MetScore. %BF was the strongest loading coefficient within the principal component analysis-derived MetScore outcome.

CONCLUSIONS

Normalized strength is independently associated with lower cardiometabolic risk in boys and girls. Moreover, %BF was associated with all cardiometabolic risk factors and carried the strongest loading coefficient. These findings bolster the importance of early strength acquisition and healthy body composition in childhood.

Effect of physical activity on vascular characteristics in young children

BACKGROUND

Physical activity has long been proposed as an important modifiable cardiovascular risk factor in adults. We assessed whether physical activity already has an effect on childhood vasculature.

METHODS

In the Wheezing-Illnesses-Study-in-Leidsche-Rijn birth cohort, we performed vascular ultrasound to measure carotid intima-media thickness (cIMT) and functional properties (distensibility, elastic modulus) at 5 and 8 years of age. Child typical physical activities were inquired using a questionnaire completed by parents. Linear regression was used with physical activity level, expressed as a standardized value of time-weighted metabolic equivalent (MET) as the independent variable and vascular properties as dependent variables with further confounder adjustment and evaluation for possible body mass index and sex effect modifications.

RESULTS

In 595 5-year-old children and in 237 of those who had reached the age of 8 years, we did not find statistically significant associations between total time-weighted MET and each vascular parameter, neither in pooled nor stratified analysis. However, sport activities were associated with thinner cIMT (-3.20 µm/SD, 95% CI -6.34, -0.22, p = 0.04) at 5 years of age; a similar pattern was seen for organized sport. This effect was strongest in children in the highest body mass index tertile (-5.38 µm/SD, 95% CI -10.54, -0.19, p = 0.04). At the age of 8 years, higher sport level tended to be associated with higher vascular distensibility (2.64 × 10(3) kPa/SD, 95% CI -0.18, 5.45, p = 0.07) although this was not statistically significant.

CONCLUSIONS

Sport activity may have beneficial effects on arteries of young children, particularly those with higher relative body weight.

Massively parallel synthetic promoter assays reveal the in vivo effects of binding site variants

Gene promoters typically contain multiple transcription factor binding sites (TFBSs), which may vary in affinity for their cognate transcription factors (TFs). One major challenge in studying cis-regulation is to understand how TFBS variants affect gene expression. We studied the in vivo effects of TFBS variants on cis-regulation using synthetic promoters coupled with a thermodynamic model of TF binding. We measured expression driven by each promoter with RNA-seq of transcribed sequence barcodes. This allowed reporter genes to be highly multiplexed and increased our statistical power to detect the effects of TFBS variants. We analyzed the effects of TFBS variants using a thermodynamic framework that models both TF-DNA interactions and TF-TF interactions. We found that this system accurately estimates the in vivo relative affinities of TFBSs and predicts unexpected interactions between several TFBSs. Our results reveal that binding site variants can have complex effects on gene expression due to differences in TFBS affinity for cognate TFs and differences in TFBS specificity for noncognate TFs.

Assessment of endothelial dysfunction in childhood obesity and clinical use

The association of obesity with noncommunicable diseases, such as cardiovascular complications and diabetes, is considered a major threat to the management of health care worldwide. Epidemiological findings show that childhood obesity is rapidly rising in Western society, as well as in developing countries. This pandemic is not without consequences and can affect the risk of future cardiovascular disease in these children. Childhood obesity is associated with endothelial dysfunction, the first yet still reversible step towards atherosclerosis. Advanced research techniques have added further insight on how childhood obesity and associated comorbidities lead to endothelial dysfunction. Techniques used to measure endothelial function were further brought to perfection, and novel biomarkers, including endothelial progenitor cells, were discovered. The aim of this paper is to provide a critical overview on both in vivo as well as in vitro markers for endothelial integrity. Additionally, an in-depth description of the mechanisms that disrupt the delicate balance between endothelial damage and repair will be given. Finally, the effects of lifestyle interventions and pharmacotherapy on endothelial dysfunction will be reviewed.