Normal weight metabolically unhealthy phenotype in youth: Do definitions matter?

Maternal diet quality during pregnancy is associated with biomarkers of metabolic risk among male offspring

AIMS/HYPOTHESIS

Limited data exist on the association between maternal diet quality during pregnancy and metabolic traits in offspring during early childhood, which is a sensitive period for risk of obesity-related disorders later in life. We aimed to examine the association of maternal diet quality, as indicated by the Healthy Eating Index-2010 (HEI), in pregnancy with offspring metabolic biomarkers and body composition at age 4-7 years.

METHODS

We used data from 761 mother-offspring pairs from the Healthy Start study to examine sex-specific associations of HEI >57 vs ≤57 with offspring fasting glucose, leptin, cholesterol, HDL, LDL, percentage fat mass, BMI z score and log-transformed insulin, 1/insulin, HOMA-IR, adiponectin, triacylglycerols, triacylglycerols:HDL, fat mass, and sum of skinfolds. Multivariable linear regression models accounted for maternal race/ethnicity, age, education, smoking habits during pregnancy and physical activity, and child's age.

RESULTS

During pregnancy, mean (SD) HEI score was 55.0 (13.3), and 43.0% had an HEI score >57. Among boys, there was an inverse association of maternal HEI with offspring glucose, insulin, HOMA-IR and adiponectin. For instance, maternal HEI >57 was associated with lower fasting glucose (-0.11; 95% CI -0.20, -0.02 mmol/l), and lower concentrations of: insulin by 15.3% (95% CI -24.6, -5.0), HOMA-IR by 16.3% (95% CI -25.7, -5.6) and adiponectin by 9.3% (95% CI -16.1, -2.0). Among girls, there was an inverse association of maternal HEI with insulin and a positive association with LDL. However, following covariate adjustment, all estimates among girls were attenuated to the null.

CONCLUSIONS/INTERPRETATION

Greater compliance with the USA Dietary Guidelines via the HEI may improve the maternal-fetal milieu and decrease susceptibility for poor metabolic health among offspring, particularly boys. Future studies are warranted to confirm these associations and determine the underlying mechanisms.

Alternative pediatric metabolic syndrome definitions impact prevalence estimates and socioeconomic gradients

BACKGROUND

There is no consensus regarding the definition of pediatric metabolic syndrome (MetS). This study assessed the impact of alternative definitions on the prevalence, children identified, and association with socioeconomic status (SES).

METHODS

Data were from the prospective multigenerational Dutch Lifelines Cohort Study. At baseline, 9754 children participated, and 5085 (52.1%) with average follow-up of 3.0 (SD = 0.75) years were included in the longitudinal analyses; median ages were 12 (IQR = 10-14) and 14 years (IQR = 12-15), respectively. We computed MetS prevalence according to five published definitions and measured the observed proportion of positive agreement. We used logistic regression to assess the SES-MetS association, adjusted for age and sex. Longitudinal models were also adjusted for baseline MetS.

RESULTS

MetS prevalence and positive agreement varied between definitions, from 0.7 to 3.0% and from 0.34 (95% CI: 0.28; 0.41) to 0.66 (95% CI: 0.58; 0.75) at baseline, respectively. We consistently found a socioeconomic gradient; in the longitudinal analyses, each additional year of parental education reduced the odds of having MetS by 8% (95% CI: 1%; 14%) to 19% (95% CI: 7%; 30%).

CONCLUSIONS

Alternative MetS definitions had differing prevalence estimates and agreed on 50% of the average number of cases. Additionally, regardless of the definition, low SES was a risk factor for MetS.

IMPACT

Little is known about the impact of using different definitions of pediatric metabolic syndrome on study results. Our study showed that the choice of pediatric metabolic syndrome definition produces very different prevalence estimates. We also showed that the choice of definition influences the socioeconomic gradient. However, low socioeconomic status was consistently a risk factor for having pediatric metabolic syndrome. In conclusion, studies using different definitions of metabolic syndrome could be reasonably compared when investigating the association with socioeconomic status but not always validly when comparing prevalence studies.

Obesity, metabolic syndrome, and primary hypertension

Primary hypertension is the dominant form of arterial hypertension in adolescents. Disturbed body composition with, among other things, increased visceral fat deposition, accelerated biological maturation, metabolic abnormalities typical for metabolic syndrome, and increased adrenergic drive constitutes the intermediary phenotype of primary hypertension. Metabolic syndrome is observed in 15-20% of adolescents with primary hypertension. These features are also typical of obesity-related hypertension. Metabolic abnormalities and metabolic syndrome are closely associated with both the severity of hypertension and the risk of target organ damage. However, even though increased body mass index is the main determinant of blood pressure in the general population, not every hypertensive adolescent is obese and not every obese patient suffers from hypertension or metabolic abnormalities typical for metabolic syndrome. Thus, the concepts of metabolically healthy obesity, normal weight metabolically unhealthy, and metabolically unhealthy obese phenotypes have been developed. The risk of hypertension and hypertensive target organ damage increases with exposure to metabolic risk factors which are determined by disturbed body composition and visceral obesity. Due to the fact that both primary hypertension and obesity-related hypertension present similar pathogenesis, the principles of treatment are the same and are focused not only on lowering blood pressure, but also on normalizing body composition and metabolic abnormalities.

Determinants of new onset cardiometabolic risk among normal weight children

OBJECTIVE

To identify determinants for the development of "normal weight metabolically unhealthy" (NWMU) profiles among previously metabolically healthy normal weight children.

METHODS

The QUALITY cohort comprises youth 8-10 years of age with a parental history of obesity (n = 630). Of these, normal weight children with no metabolic risk factors were identified and followed up 2 years later (n = 193). Children were classified as NWMU if they remained normal weight but developed at least one cardiometabolic risk factor. They were classified as normal weight metabolically healthy otherwise. Multivariable logistic regression models were used to identify whether adiposity (anthropometrics and DXA), lifestyle habits (physical activity, screen time, vegetables, and fruit- and sugar-sweetened beverages intake), fitness, and family history of cardiometabolic disease were associated with new onset NWMU.

RESULTS

Of the 193 normal weight and metabolically healthy children at baseline, 45 (23%) became NWMU 2 years later (i.e., 48% had elevated HDL cholesterol, 13% had elevated triglycerides, and 4% had impaired fasting glucose). Changes in adiposity between baseline and follow-up were associated with an increased risk of NWMU for all adiposity measures examined (e.g., for ∆zBMI OR = 3.95; 95% CI: 1.76, 8.83). Similarly, a 2-year change in screen time was associated with incident NWMU status (OR = 1.24; 95% CI 1.04, 1.49).

CONCLUSIONS

Children who increase their adiposity levels as they enter puberty, despite remaining normal weight, are at risk of developing cardiometabolic risk factors. Studies examining long-term consequences of NWMU profiles in pediatrics are needed to determine whether changes in screening practice are warranted.

Extracellular Matrix Remodeling of Adipose Tissue in Obesity and Metabolic Diseases

The extracellular matrix (ECM) is a network of different proteins and proteoglycans that controls differentiation, migration, repair, survival, and development, and it seems that its remodeling is required for healthy adipose tissue expansion. Obesity drives an excessive lipid accumulation in adipocytes, which provokes immune cells infiltration, fibrosis (an excess of deposition of ECM components such as collagens, elastin, and fibronectin) and inflammation, considered a consequence of local hypoxia, and ultimately insulin resistance. To understand the mechanism of this process is a challenge to treat the metabolic diseases. This review is focused at identifying the putative role of ECM in adipose tissue, describing its structure and components, its main tissue receptors, and how it is affected in obesity, and subsequently the importance of an appropriate ECM remodeling in adipose tissue expansion to prevent metabolic diseases.

Metabolic Abnormalities in Normal Weight Children Are Associated with Increased Visceral Fat Accumulation, Elevated Plasma Endotoxin Levels and a Higher Monosaccharide Intake

Being overweight has been identified as the main risk factor for the development of metabolic disorders in adults and children. However, recent studies suggest that normal weight individuals are also frequently affected by metabolic abnormalities with underlying mechanisms not yet fully understood. The aim of the present study was to determine if dietary pattern and markers of intestinal permeability, as well as inflammation, differ between normal weight healthy children and normal weight children suffering from metabolic abnormalities. In total, 45 normal weight children aged 5–9 years were included in the study, of whom nine suffered from metabolic abnormalities. Anthropometric data, dietary intake and markers of inflammation, as well as intestinal permeability, were assessed in fasting blood samples. Neither BMI nor BMI-SDS differed between groups; however, children with metabolic abnormalities had a significantly larger waist circumference (+~5 cm) and a higher leptin to adiponectin ratio. While plasma leptin levels are significantly higher in normal weight children with metabolic abnormalities, neither TNF α nor sCD14, adiponectin, PAI-1 or IL-6 plasma levels differed between groups. Despite similar total calorie and macronutrient intake between groups, mean total fructose and total glucose intake (resulting mainly from sugar sweetened beverages, fruits and sweets) were higher in children with metabolic abnormalities than in healthy children. Time spent physically active was significantly higher in healthy normal weight children whereas time spent physically inactive was similar between groups. Furthermore, bacterial endotoxin levels were significantly higher in the peripheral plasma of normal weight children with metabolic abnormalities than in healthy normal weight children. Our results suggest that metabolic disorders in normal weight children are associated with a high monosaccharide intake and elevated bacterial endotoxin as well as leptin plasma levels, the latter also discussed as being indicative of visceral adiposity.