Early life origins of low-grade inflammation and atherosclerosis risk in children and adolescents

Fitness Levels and Gender Are Related With the Response of Plasma Adipokines and Inflammatory Cytokines in Prepubertal Children

Background and Aim

Changes in adipokines have been related with the development of metabolic syndrome, frequently associated with obesity, and other risk factors. Fitness seems to promote a healthy cardiovascular status and could be a protector factor, just from childhood. Therefore, the present study aimed to evaluate the relationship between fitness levels with plasma adipokines and inflammatory biomarkers in prepubertal children.

Methods

One hundred and thirty-seven healthy normal-weight prepubertal children were recruited from local schools and divided after performing the fitness tests, into two groups according to fitness level—low cardiovascular fitness group (LF) and equal or higher cardiovascular fitness group (HF). Anthropometric variables, blood pressure (BP) and plasma insulin, and leptin, resistin, adiponectin, tumor necrosis factor-alpha, hepatic growth factor, interleukin (IL)-8, monocyte chemoattractant protein-1, nerve growth factor (NGF), and plasminogen activator inhibitor-1 (PAI-1) were measured fasting in both groups to be compared. Univariate analysis of variance, comparative analysis, binary logistic regression, stepwise linear regression, and principal component analysis were conducted to evaluate the association between fitness, BMI, gender, and the biochemical parameters.

Results

Girls and boys with HF presented lower waist circumference Z-score, BMI Z-score, systolic BP (only boys) as well as lower levels of leptin and NGF compared with their respective LF group. Regarding the association between variables, fitness showed an inverse relationship with BMI Z-score, leptin, PAI-1, HOMA-IR, resistin, IL-8, and NGF.

Conclusion

An adequate level of fitness seems to protect against risk factors related to low-grade inflammation and altered adipokines that are related to the onset of obesity just from the prepubertal stage.

Birth Size as a Determinant of Cardiometabolic Risk Factors in Children

The association between birth size and cardiometabolic disease risk may be U-shaped. Being born small for gestational age (SGA) has a definitive association with later cardiovascular risk, but the impact of being born large for gestational age (LGA) on cardiometabolic health is more controversial. In addition to birth size, early postnatal growth pattern and later weight gain affect cardiometabolic risk in adulthood. Most SGA-born children have catch-up and LGA-born children have catch-down growth during the first years of life. The extent of this early compensatory growth may contribute to the adverse health outcomes. Both SGA- and LGA-born children are at an increased risk for overweight and obesity. This may have a long-term impact on cardiometabolic health as overweight tends to track to adulthood. Other cardiometabolic risk factors, including alterations in glucose metabolism, dyslipidemia, hypertension, and low-grade inflammation are associated with birth weight. Many of these risk factors are related to overweight or adverse fat distribution. Since later cardiometabolic risk is often mediated by early growth pattern and later overweight in SGA and LGA children, it is important to focus on staying normal weight throughout life. Hence, effective interventions to reduce cardiometabolic risk in LGA and SGA children should be developed.

Ability of 2 estimation methods of body fat percentage in identifying unfavorable levels of cardiometabolic biomarkers in adolescents: Results from the LabMed study

Background:

To assess and compare the ability of body fat percentage (BF%) estimated by 2 methods, bioelectrical impedance analysis (BIA) and by the Slaughter et al equations for triceps and subscapular skinfold thickness (SKF), in identifying unfavorable levels of several biomarkers of cardiometabolic risk.

Methods:

Cross-sectional school-based study with 529 apparently healthy adolescents (267 girls), aged 14.3 ± 1.7 years.

Results:

BF% estimated by both methods always showed higher areas under the curve (AUC) for each biomarker in girls than in boys (with the exception of BIA for leptin). BF% estimated by BIA and by SKF presented a discriminatory ability in identifying unfavorable levels in all biomarkers of cardiometabolic risk in girls; however, BF% estimated by BIA displayed the highest AUC (except for C-reactive protein). In boys, BF% estimated by SKF presented higher AUC for C-reactive protein, fibrinogen and erythrocyte sedimentation rate; and BF% estimated by BIA for complement C3 and leptin. Positive and significant associations between BIA and SKF with all biomarkers (P < .05) were found (except for SKF and complement C4 in girls, and SKF and fibrinogen and erythrocyte sedimentation rate in boys), after adjustments for pubertal stage, cardiorespiratory fitness, adherence to the Mediterranean diet and socioeconomic status.

Conclusions:

Overall, diagnostic performance was more accurate in girls. BF% estimated by BIA presented a slightly better overall discriminatory ability for each biomarker than BF% estimated by SKF in girls, while in boys no method clearly prevailed over the other.

Associations between anthropometric indicators in early life and low-grade inflammation, insulin resistance and lipid profile in adolescence

BACKGROUND AND AIMS

The long-term relations between excessive adiposity in early childhood and unfavourable cardiometabolic profiles in later ages are not yet completely understood. We aimed to assess the associations between birth weight (BW) and BMI from 6 months to 6 years of age, with biomarkers indicative of low-grade inflammation, insulin resistance and lipid profiles in adolescence.

METHODS AND RESULTS

Retrospective school-based study with 415 Portuguese adolescents (220 girls), mean age of 14.08 ± 1.6 years old. Anthropometric data from birth to 6 years old was extracted from individual child health book records. Actual weight and height were measured and BMI calculated. Participants were classified at each time point as normal weight or overweight according to WHO reference values. Biomarkers were obtained from venous blood samples. Linear regressions were used to explore the associations between the biomarkers and early life anthropometric indicators. From 2 years onwards, BMI associated positively with the inflammatory score and HOMA-IR in adolescence. Children who were overweight/obese from 2 to 6 years of age presented significantly higher inflammatory score and HOMA-IR later in adolescence. TC/HDL ratio was also positively associated with BMI from the age of 5 years onwards. The associations between BMI and cardiometabolic outcomes remained positive in adolescence, with overweight adolescents presenting a higher inflammatory score, HOMA-IR and TC/HDL than normal weight adolescents.

CONCLUSION

A high BMI from an early age was consistently associated with worse inflammatory and lipid profiles and insulin resistance in adolescence. No associations were found between BW and the same studied outcomes.

Sports participation and adiposity do not mediate the relationship between birth weight and arterial thickness in adolescents: ABCD Growth Study

OBJECTIVE

To analyse the relationship of altered birth weight with metabolic and cardiovascular outcomes among adolescents, as well as to identify if sports participation is able to attenuate or even eliminate the impact of birth weight on health outcomes.

METHODS

Cross-sectional study (Analysis of Behaviours of Children During Growth [ABCD Growth Study]). Adolescents with age ranging from 11 to 18 years old (14.7±2.1) stratified according to normal (n = 230) and altered (n = 35) birth weight composed the sample. Birth weight was self-reported by adolescent's parents. Sports participation was assessed by face-to-face interview. Carotid intima-media thickness (CIMT) and femoral intima-media thickness (FIMT) were measured using an ultrasound device. C-reactive protein levels were used to assess the inflammatory status. Blood pressure, Z score of metabolic risk (dyslipidemia and glucose), adiposity, and insulin resistance were covariates.

RESULTS

In the crude model, FIMT (p value = 0.037) and C-reactive protein (p value = 0.029) were affected by altered birth weight. In the adjusted models, altered birth weight affected FIMT (p value = 0.048; small effect size of 1.7%), independently of sports participation. For C-reactive protein, previous time of engagement in sports (p value = 0.001; small effect size of 4.8%) affected C-reactive protein, independently of birth weight.

CONCLUSION

Vascular structure seems to be affected by birth weight in adolescents, while its impact on inflammation seems to be attenuated by the regular engagement in sports.

Association of Exclusive Breastfeeding Duration With Systemic Inflammation Markers in Adolescents: A Cross-Sectional Study

BACKGROUND

Breastfeeding duration has been associated with less low-grade inflammation in healthy adolescents, but there is scarce information regarding obese subjects. This study aimed to evaluate whether exclusive breastfeeding is related to serum concentrations of inflammatory markers in a population of Spanish adolescents.

METHOD

A cross-sectional study was performed on 1,001 adolescents (13.2 ± 1.2 years) randomly recruited from schools in southeast Spain. Data on breastfeeding duration were collected via a parental questionnaire. Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were determined by enzyme-linked immunosorbent assay. C-reactive protein (CRP) was determined by solid-phase chemiluminescent immunometric assay.

RESULTS

Nonadjusted and adjusted multivariate correlation analyses confirmed a strong association ( p < .001, 95% confidence interval) between the three markers of inflammation and exclusive breastfeeding duration. No significant differences were observed for IL-6, TNF-α, and CRP serum concentrations among normal weight, overweight, and obese adolescents, except for IL-6 between normal weight and obese subjects. Likewise, no significant association was found between these markers of inflammation and body mass index (BMI) z-score.

CONCLUSIONS

We found a possible association between inflammatory markers and exclusive breastfeeding duration in adolescents, regardless of their BMI. This finding suggests that increased body weight or obesity might not mediate the association between breastfeeding and inflammation. These results contribute to the understanding of the relationship between breastfeeding and inflammatory markers in adolescents.

Ability of Measures of Adiposity in Identifying Adverse Levels of Inflammatory and Metabolic Markers in Adolescents

BACKGROUND

Overweight and obesity have been associated with a pro-inflammatory state. We aimed to assess the ability of different measures of overall and abdominal adiposity for identifying adverse levels of inflammatory and metabolic markers in adolescents.

METHODS

This is a cross-sectional analysis with 529 Portuguese adolescents (267 girls), mean age 14.3 ± 1.7 years. Weight, height, sitting height, waist circumference (WC), and body fat percentage (BF%) were measured; and BMI, waist-to-height ratio (WHtR), and waist-to-sitting-height ratio (WsHtR) were calculated. We measured C-reactive protein (CRP), fibrinogen, erythrocyte sedimentation rate (ESR), complements C3 and C4, leptin, and adiponectin levels. Receiver operating characteristic (ROC) curves were used to estimate the ability of the adiposity measures to discriminate between low/high values of biomarkers.

RESULTS

The highest areas under the ROC curves were presented by BF% for fibrinogen and complement C3 in both sexes and for ESR, complement C4, and adiponectin only in girls; by BMI for CRP in girls and for leptin in both sexes; by WHtR for leptin in both sexes and for CRP, fibrinogen, and adiponectin only in girls; by waist circumference for CRP, fibrinogen, and complement C3 only in boys and for complement C4 in girls; and by WsHtR for complement C3 in girls; p < 0.05 for all.

CONCLUSIONS

The measures that more often presented discriminatory power were, for overall adiposity, BF% in both sexes, and for abdominal adiposity, WHtR in girls and WC in boys. However, small differences in discriminatory capabilities don't allow us to clearly defend the adoption of a single measure above all others.

Late midlife C-reactive protein and interleukin-6 in middle aged danish men in relation to body size history within and across generations

OBJECTIVE

The aim was to estimate the effects of ponderal index at birth and body mass index (BMI) in early adulthood on C-reactive protein (CRP) and interleukin-6 (IL-6) and to quantify the effects through subsequent measures of body size. In a subanalysis, the contributions of maternal BMI to the inflammatory status of offspring were investigated.

METHODS

The study was based on 2,986 Danish males from the Copenhagen Aging and Midlife Biobank. Path analysis was employed to estimate direct and indirect effects.

RESULTS

A 10% higher maternal BMI was associated with 7% higher CRP and 3% higher IL-6 among offspring. A 10% higher ponderal index at birth was associated with 4% lower CRP in late midlife; this effect was only partially mediated by later growth. A 10% higher BMI in early adulthood was associated with 8% higher CRP and 4% higher IL-6 in late midlife. The findings suggest that weight gain in adulthood is associated with low-grade inflammation in late midlife.

CONCLUSIONS

Ponderal index at birth is associated with CRP in later life independently of adult BMI. The findings additionally suggest that preventing weight gain in early adulthood would be beneficial for inflammatory status in later life.

Developmental origins of chronic inflammation: a review of the relationship between birth weight and C-reactive protein

PURPOSE

The developmental origins of adult disease hypothesis suggests that the intrauterine environment may program postnatal health outcomes through mechanisms such as chronic inflammation. The purpose of this article was to review the literature on the association between infant birth weight and C-reactive protein (CRP), markers of the fetal environment and inflammation, respectively.

METHODS

We used PubMed, Google Scholar, Web of Science, ScienceDirect, the citation lists of the reviewed literature, and recommendations from experts in the field to identify potential articles. Inclusion criteria for the studies, regardless of study design, included human subjects, documented or self-reported infant birth weight, and a minimum of one measurement of CRP (during childhood, adolescence, or adulthood).

RESULTS

Several studies demonstrated a statistically significant inverse association between birth weight and CRP in adulthood, although in many cases only after controlling for markers of current adiposity. No studies significantly linked birth weight to CRP in childhood or adolescence.

CONCLUSIONS

Longitudinal studies, including multigenerational studies, are needed to further understand whether adult CRP has origins in the fetal environment.

Sex-specific impact of maternal-fetal risk factors on depression and cardiovascular risk 40 years later

Major depressive disorder (MDD) and cardiovascular disease (CVD) represent leading causes of morbidity and mortality worldwide. We tested the hypothesis that growth restriction and preeclampsia (referred to as fetal risk) are significant predictors of these conditions, with women at higher risk in adulthood. Adult offspring exposed to fetal risk factors and their discordant siblings were from two prenatal cohorts, whose mothers were followed through pregnancy and whom we recruited as adults 40 years later (n = 538; 250 males and 288 females). Subjects were psychiatrically diagnosed and underwent a stress challenge during which parasympathetic regulation was assessed by electrocardiogram, operationalized as high-frequency R-R interval variability (HF-RRV). Linear mixed models and generalized estimating equations were used to examine the relationship of fetal risk on HF-RRV, MDD and comorbidity of low HF-RRV (lowest 25th percentile) and MDD, including interactions with sex and socioeconomic status (SES). Fetal risk was significantly associated with low HF-RRV response (F = 3.64, P = 0.05), particularly among low SES (interaction: F = 4.31, P < 0.04). When stratified by MDD, the fetal risk impact was three times greater among MDD compared with non-MDD subjects (effect size: 0.21 v. 0.06). Females had a significantly higher risk for the comorbidity of MDD and low HF-RRV than males (relative risk (RR) = 1.36, 95% CI: 1.07-1.73), an association only seen among those exposed to fetal risk (RR = 1.38, 95% CI: 1.04-1.83). Findings suggest that these are shared fetal antecedents to the comorbidity of MDD and CVD risk 40 years later, an association stronger in females than in males.

Effect of particulate air pollution and passive smoking on surrogate biomarkers of endothelial dysfunction in healthy children

BACKGROUND

This study aimed to determine the association of ambient particulate matter (PM) on surrogate markers of endothelial function and inflammation in healthy children with or without exposure to second-hand smoke.

METHODS

This cross-sectional study was conducted in 2011 in Isfahan, which is the second largest and second most air-polluted city in Iran. The areas of the city with lowest and highest air pollution were determined, and in each area, 25 pre-pubescent boys with or without exposure to daily tobacco smoke at home were selected, i.e. 100 children were studied in total. Serum levels of C-reactive protein (CRP) and nitric oxide (NO) were measured.

RESULTS

Mean (SD) NO concentration was 7·87 (2·18) and 7·75 (2·04) μmol/L for participants not exposed and exposed to passive smoking, respectively, which is not statistically significant. The corresponding figures for CRP concentrations were 1·69 (0·89) and 2·13 (1·19) μg/ml (P = 0·04). Mean (SD) CRP concentration was significantly higher in children living in the highly polluted area than in those in the area of low pollution [2·11 (1·91) vs 1·60 (1·43) μg/ml, respectively, P = 0·02]. This difference was not significant for NO concentration. The regression analysis that examined the association between PM concentration (as independent variable) and CRP and NO levels (as dependent variables) in children not exposed to passive smoking demonstrated that increased PM was associated with a decrease in NO and an increase in CRP concentration. This finding shows that, regardless of passive smoking, PM10 concentration has a significant independent association with serum CRP and is inversely associated with NO levels.

CONCLUSION

The findings suggest that in healthy children PM concentration has a significant independent association with biomarkers of endothelial dysfunction and inflammation.

Association of adipokines with cardiovascular risk factors in low birth weight children: a case-control study

Our aim was to investigate plasma levels of adiponectin, monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) in low birth weight (LBW) children and to determine correlations among these adipokines and birth weight and cardiovascular disease risk factors. In a case-control study, the concentrations of adiponectin, MCP-1 and PAI-1 were measured in 180 schoolchildren (ages 6-11 years). MCP-1 and PAI-1 levels were significantly elevated in LBW children. Conversely, adiponectin concentration was significantly reduced in these children. Similar findings were observed after adjustment for current age, gender and abdominal circumference. Because the children with LBW had altered adipokine levels, as well as higher abdominal circumference, HOMA-IR and systolic blood pressure (SBP), we evaluated the correlation among these variables. These analyses showed that adiponectin levels were inversely correlated with systolic blood pressure (SBP) (r = -0.501; P < 0.001), HOMA-IR (r = -0.293; P = 0.023) and waist circumference (r = -0.317; P = 0.014). The proinflammatory markers were positively correlated with HOMA-IR (PAI-1: r = 0.358; P = 0.005) and waist circumference (PAI-1: r = 0.571; P < 0.001 and MCP-1: r = 0.267; P = 0.039).

CONCLUSION

Adipokines levels were correlated with cardiovascular risk factors in LBW children, and these compounds could be involved in the mechanism that links birth weight to the development of cardiovascular diseases in adulthood.

Early childhood poverty, immune-mediated disease processes, and adult productivity

This study seeks to understand whether poverty very early in life is associated with early-onset adult conditions related to immune-mediated chronic diseases. It also tests the role that these immune-mediated chronic diseases may play in accounting for the associations between early poverty and adult productivity. Data (n = 1,070) come from the US Panel Study of Income Dynamics and include economic conditions in utero and throughout childhood and adolescence coupled with adult (age 30-41 y) self-reports of health and economic productivity. Results show that low income, particularly in very early childhood (between the prenatal and second year of life), is associated with increases in early-adult hypertension, arthritis, and limitations on activities of daily living. Moreover, these relationships and particularly arthritis partially account for the associations between early childhood poverty and adult productivity as measured by adult work hours and earnings. The results suggest that the associations between early childhood poverty and these adult disease states may be immune-mediated.

Association of circulating visfatin concentrations with insulin resistance and low-grade inflammation after dietary energy restriction in Spanish obese non-diabetic women: role of body composition changes

BACKGROUND AND AIMS

To assess the influence of body composition changes on circulating serum visfatin after following 12 weeks of energy restricted diet intervention. We also examined the possible role of visfatin in glucose metabolism and in obesity-associated low-grade inflammation.

METHODS AND RESULTS

A total of 78 obese (BMI 34.0 ± 2.8 kg/m²) women aged 36.7±7 y volunteered to participate in the study. We measured by DXA body fat mass (FM) and lean mass (LM). Fasting serum visfatin, glucose, insulin, adiponectin, leptin, IL-1β, IL-6, IL-8, TNF-α and CRP concentrations were analyzed before and after the intervention and HOMA and QUIKI indexes were calculated. Mean weight loss 7.7 ± 3.0 kg and HOMA decreased in 24 ± 35%. Serum visfatin concentration change was negatively associated with LM difference (P < 0.05), whereas no significant relationship was observed with FM changes after energy restricted diet intervention. Changes in circulating serum visfatin levels were significantly and inversely associated with HOMA-IR (P < 0.01) and positively with QUICKI index (P < 0.02) after energy restricted diet intervention, regardless of achieved body weight loss. We did not find any significant association between changes in visfatin levels and IL-1β, IL-6, IL-8, TNF-α and CRP levels after dietary intervention (all P > 0.2).

CONCLUSION

Circulating visfatin concentration is associated with sensitivity improvement achieved after energy restricted diet intervention induced weight loss. Furthermore, LM changes could be an influencing factor on visfatin concentrations and consequently, on the improvement of insulin sensitivity after weight loss in obese non-diabetic women. Our findings did not provide any evidence for a role of visfatin increase on low-grade inflammation after weight loss.

Birth weight and subsequent adiposity gain in Swedish children and adolescents: a 6-year follow-up study

We examined whether birth weight (BW) predicts changes in body composition over a 6-year period in Swedish children and adolescents. For this purpose, a total of 247 children (55.5% girls) and 162 adolescents (60.5% girls) were included in the study and were followed up 6 years later. BW was obtained from parental records. We measured weight, height, waist circumference, and the bicep, tricep, subscapular, suprailiac, and medial calf skinfolds, and we calculated BMI, fat-free mass (FFM), and the sum of five skinfolds. Physical activity was assessed by accelerometry. Changes in pubertal status and baseline anthropometric estimates were used as confounders in all analysis. In the children cohort, we observed that BW was inversely associated with changes in BMI (β = -0.736, P = 0.002) and the sum of five skinfolds (β = -6.381, P = 0.009) regardless of confounders and physical activity, only in girls. We did not find any significant association between BW and adiposity gain estimates in the adolescent cohort. These findings give further support to the concept that low BW may have a programming effect of subsequent adiposity gain from childhood to adolescence. We also confirm the sex-related differences in the programming effect of body composition.

Exclusive breastfeeding duration and cardiorespiratory fitness in children and adolescents

BACKGROUND

Breastfeeding has been associated with a protective effect against cardiovascular disease. Higher cardiorespiratory fitness during childhood is associated with healthier cardiovascular profile later in life.

OBJECTIVES

The objective was to examine the association of exclusive breastfeeding duration with fitness in children and adolescents and to test the role of body composition and sociodemographic factors in this relation.

DESIGN

At the time of the study, exclusive breastfeeding duration was reported by mothers and grouped into 4 categories: exclusively formula fed or breastfed for <3, 3-6, or >6 mo. Fitness was determined by a maximal cycle-ergometer test in 1025 children (aged 9.5 ± 0.4 y) and in 971 adolescents (aged 15.5 ± 0.5 y) from Estonia and Sweden.

RESULTS

Longer duration of breastfeeding was associated with higher fitness regardless of confounders [+5.1% L/min; country, sex, age, pubertal status, and BMI (adjusted P < 0.001) or fat mass and fat-free mass (FFM) (+3.3%; adjusted P < 0.001)]. Further adjustment for birth weight, physical activity, and maternal educational level did not change the results (P = 0.001). The results were consistent in children and adolescents with low (P < 0.001) or high (P = 0.013) FFM, in nonoverweight (P < 0.001) or overweight (P = 0.002) children and adolescents, in offspring of nonoverweight (P < 0.001) or overweight (P = 0.003) mothers, in mothers with a low (P = 0.004) or high (P < 0.001) educational level, and in participants born within upper (P = 0.001), middle (P = 0.017), or lower (P = 0.007) tertiles of birth weight.

CONCLUSIONS

Longer exclusive breastfeeding has a beneficial effect on cardiorespiratory fitness in children and adolescents. Because early infant-feeding patterns are potentially modifiable, a better understanding of the possible programming effect of exclusive breastfeeding on cardiorespiratory fitness is of public health interest.

The effect of ponderal index at birth on the relationships between common LEP and LEPR polymorphisms and adiposity in adolescents

This study examined the effect of ponderal index (PI) at birth on the relationships between eight common polymorphisms of the leptin (LEP) and leptin receptor (LEPR) genes and adiposity in adolescents. A total of 823 European adolescents (45.4% girls) aged 14.8 ± 1.4 years were genotyped for the LEP (rs2167270, rs12706832, rs10244329, rs2071045, and rs3828942) and LEPR (rs1137100, rs1137101, and rs8179183) polymorphisms. The PI was calculated from parental reports of birth weight and length. Fat mass index (FMI) was calculated. Analyses were adjusted for relevant confounders. An "adiposity-risk-allele score" based on genotypes at the three single-nucleotide polymorphisms (SNPs) associated with adolescents' FMI in adolescents within the lower tertile of PI was calculated. The LEP rs10244329 and rs3828942 polymorphisms were associated with higher FMI only in adolescents within the lower PI tertile (+0.55 kg/m(2) per minor T allele, P = 0.040, and +0.58 kg/m(2) per major G allele, P = 0.028, respectively). The LEPR rs8179183 polymorphism was significantly associated with higher FMI in adolescents within the lower PI tertile (+0.87 kg/m(2) per minor C allele, P = 0.006). After correction for multiple comparisons, only the association between the LEPR rs8179183 and FMI persisted. However, each additional risk allele conferred 0.53 kg/m(2) greater FMI in adolescents within the lower tertile of PI (P = 0.008). In conclusion, our results suggest that those adolescents born with lower PI could be more vulnerable to the influence of the LEP rs10244329 and rs3828942 polymorphisms and LEPR rs8179183 polymorphism on total adiposity content. Due to the relatively small sample size, these findings should be replicated in further larger population samples.

Stability of the factorial structure of metabolic syndrome from childhood to adolescence: a 6-year follow-up study

Background

Metabolic syndrome (MS) is a clustering of cardiometabolic risk factors that is considered a predictor of cardiovascular disease, type 2 diabetes and mortality. There is no consistent evidence on whether the MS construct works in the same way in different populations and at different stages in life.

Methods

We used confirmatory factor analysis to examine if a single-factor-model including waist circumference, triglycerides/HDL-c, insulin and mean arterial pressure underlies metabolic syndrome from the childhood to adolescence in a 6-years follow-up study in 174 Swedish and 460 Estonian children aged 9 years at baseline. Indeed, we analyze the tracking of a previously validated MS index over this 6-years period.

Results

The estimates of goodness-of-fit for the single-factor-model underlying MS were acceptable both in children and adolescents. The construct stability of a new model including the differences from baseline to the end of the follow-up in the components of the proposed model displayed good fit indexes for the change, supporting the hypothesis of a single factor underlying MS component trends.

Conclusions

A single-factor-model underlying MS is stable across the puberty in both Estonian and Swedish young people. The MS index tracks acceptably from childhood to adolescence.

Body size at birth modifies the effect of fat mass and obesity associated (FTO) rs9939609 polymorphism on adiposity in adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

The present study was intended to examine whether ponderal index (PI) at birth modifies the effect of the fat mass and obesity associated (FTO) rs9939609 polymorphism on adiposity in European adolescents. A total of 628 adolescents aged 14·4 (se 1·3) years (56·8 % female) were recruited. PI was calculated from parental reports of birth weight and length (kg/m³), and the BMI (kg/m²), body fat percentage and fat mass index (FMI, kg/m²) were calculated. The rs9939609 polymorphism was genotyped and physical activity assessed by accelerometry. Sex, duration of pregnancy, pubertal status, centre and physical activity were used as confounders in all the analyses. The minor A allele of the FTO rs9939609 was significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) but not with PI. Significant interactions between PI and the rs9939609 polymorphism in terms of body fat percentage (P = 0·002) and FMI (P = 0·017) were detected. However, this polymorphism was only significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) in adolescents in the lower PI tertile. Indeed, both body fat percentage and FMI were higher in those adolescents in the lower PI tertile carrying the A allele of the FTO rs9939609 polymorphism than in those with the TT genotype (25·0 (se 0·8) v. 22·1 (se 1·0) %, adjusted P = 0·030 and 5·6 (se 0·3) v. 4·6 (se 0·4) kg/m2, P = 0·031, respectively). Our findings suggest that those adolescents born with lower PI could be more vulnerable to the influence of the A risk allele of the FTO polymorphism on total adiposity content.

Physical activity attenuates the effect of low birth weight on insulin resistance in adolescents: findings from two observational studies

OBJECTIVE

To examine whether physical activity influences the association between birth weight and insulin resistance in adolescents.

RESEARCH DESIGN AND METHODS

The study comprised adolescents who participated in two cross-sectional studies: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study (n = 520, mean age = 14.6 years) and the Swedish part of the European Youth Heart Study (EYHS) (n = 269, mean age = 15.6 years). Participants had valid data on birth weight (parental recall), BMI, sexual maturation, maternal education, breastfeeding, physical activity (accelerometry, counts/minute), fasting glucose, and insulin. Insulin resistance was assessed by homeostasis model assessment-insulin resistance (HOMA-IR). Maternal education level and breastfeeding duration were reported by the mothers.

RESULTS

There was a significant interaction of physical activity in the association between birth weight and HOMA-IR (logarithmically transformed) in both the HELENA study and the EYHS (P = 0.05 and P = 0.03, respectively), after adjusting for sex, age, sexual maturation, BMI, maternal education level, and breastfeeding duration. Stratified analyses by physical activity levels (below/above median) showed a borderline inverse association between birth weight and HOMA-IR in the low-active group (standardized β = -0.094, P = 0.09, and standardized β = -0.156, P = 0.06, for HELENA and EYHS, respectively), whereas no evidence of association was found in the high-active group (standardized β = -0.031, P = 0.62, and standardized β = 0.053, P = 0.55, for HELENA and EYHS, respectively).

CONCLUSIONS

Higher levels of physical activity may attenuate the adverse effects of low birth weight on insulin sensitivity in adolescents. More observational data, from larger and more powerful studies, are required to test these findings.

Breastfeeding in infancy is not associated with inflammatory status in healthy adolescents

It has been suggested that breast-feeding (BF) may be associated with a decreased risk of cardiovascular disease in adulthood. A low-grade inflammation is associated with an increased risk of cardiovascular disease, even in apparently healthy children. The objective of this study was to assess the potential modulating effect of BF on the inflammatory status of healthy adolescents. Information on BF (duration) was obtained from parental records in 484 of 1040 healthy European urban adolescents (56.4% females) that had a blood sample obtained as part of the Healthy Lifestyle in Europe by Nutrition and Adolescence study. Blood serum inflammatory markers were measured, including high sensitivity C-reactive protein, complement factors 3 and 4, ceruloplasmin, adhesion molecules (L-selectin and soluble endothelial selectin, soluble vascular cell adhesion molecule 1, and intercellular adhesion molecule 1), cytokines, TGFβ1, and white blood cells. After univariate analysis, a propensity score, including the potential confounding factors, was computed and used to assess the association between BF and selected inflammatory markers. BF was not significantly associated with any of the selected inflammatory markers after adjustment for gender and propensity score. In our study, BF was not associated with low-grade inflammatory status in healthy adolescents, suggesting that the potential cardiovascular benefits of BF are related to other mechanisms than modulation of inflammation or might become relevant at a later age. Groups at high risk for cardiovascular disease should be a target for further research concerning the effects of BF.

Intergenerational cardiovascular disease risk factors involve both maternal and paternal BMI

OBJECTIVE

To examine the association between parental BMI and offspring cardiovascular disease (CVD) risk factors.

RESEARCH DESIGN AND METHODS

The study comprised 940 children (9.5 +/- 0.4 years) and 873 adolescents (15.5 +/- 0.5 years). Parental weight and height were reported by the mother and the father, and BMI was calculated. CVD risk factors included total (sum of five skinfolds) and central (waist circumference) body fat, blood pressure, cardiorespiratory fitness, insulin sensitivity, total cholesterol, HDL cholesterol, triglycerides, and fibrinogen.

RESULTS

Maternal and paternal BMI were positively associated with total and central fatness in offspring (P < 0.001). BMIs of both parents were significantly related to fibrinogen levels (P < 0.02), but these associations disappeared when controlling for fatness. There was a positive relationship between maternal and paternal BMI and waist circumference in the offspring regardless of total adiposity and height (P < 0.001). Maternal BMI was negatively associated with offspring cardiorespiratory fitness independently of fatness (P < 0.02). These relationships persisted when overweight descendants were excluded from the analysis. There were no significant associations between parental BMI and the other CVD risk factors.

CONCLUSIONS

Both maternal and paternal BMI increase CVD risk factors of their offspring, characterized by total and central body fat, and higher maternal BMI was associated with poorer cardiorespiratory fitness. Our findings give further support to the concept that adiposity in parents transmits susceptibility to CVD risk to descendants, which is detectable even in the absence of overweight in offspring.