The contribution of childhood cardiorespiratory fitness and adiposity to inflammation in young adults

Secular trends of cardiorespiratory fitness in children and adolescents over a 35-year period: Chronicle of a predicted foretold

Background

In the context of concerns regarding the cardiorespiratory fitness (CRF) of youth populations, the aims of this study were: (1) to update reference values for the VO₂max for school-aged Canadians and (2) to document secular trends in CRF after a 35-year interval.

Methods

Between September 2014 and April 2017, the CRF of 3725 students (53.2% boys; 6.0 to 17.9 yrs) was determined using the 20-m shuttle run test. The sample was collected in 36 different schools from six cities of Québec (Canada).

Results

Median values of VO₂max decreased with age in both sexes (p ≤ 0.05). By the age of 10, more than 20% of boys showed VO₂max values below the recommended value (42 ml·kg^-1·min^-1). At the age of 17, that proportion reached 56.8%. A similar proportion of 12 yrs girls (20%) were under the recommended minimal value (37 ml·kg^-1·min^-1) and that value reached 69.9% at the age of 17. Compared to 1982, the VO₂max at age 17 has declined by 18% for boys and 12% for girls. The situation is worse in terms of functional capacity (number of stages completed) with an overall decrease of more than 30%.

Conclusion

This study demonstrates that, compared to data obtained using the same methodology 35 years ago, the CRF and functional capacity of children and adolescents has declined to levels that should raise concerns from a public health perspective. Thus, the development of strategies to promote a physically active lifestyle in youth is more relevant than ever.

Improving cardiorespiratory fitness protects against inflammation in children: the IDEFICS study

BACKGROUND

Muscular and cardiorespiratory fitness (MF and CRF) have been related to inflammation. Thus, the aim of this study was to assess the relationship between fitness and high-sensitivity C-reactive protein (hs-CRP) in European children both in the cross-sectional and longitudinal analysis.

METHODS

Three hundred and fifty-seven children (46.2% males) aged 2-9 years with hs-CRP measured, data from MF and CRF, diet quality, objectively measured physical activity (PA) and screen time at baseline and follow-up after 2 years were included. Body mass index z-score (zBMI), waist circumference (WC) and fat mass index (FMI) were assessed. MF and CRF were also dichotomized as follows: low-medium quartiles (Q1-Q3) and highest quartile (Q4).

RESULTS

At follow-up, children with the highest CRF (Q4) showed a lower probability of having high hs-CRP. In the longitudinal analysis, children who improved their CRF over time showed a significantly lower probability (p < 0.05) of being in the highest hs-CRP category at follow-up, independently of the body composition index considered: odds ratio (OR) = 0.22 for zBMI, OR = 0.17 for WC, and OR = 0.21 for FMI.

CONCLUSIONS

Improving CRF during childhood reduces the odds of an inflammatory profile, independently of body composition and lifestyle behaviours. These highlight the importance of enhancing fitness, especially CRF, to avoid an inflammatory state in children.

IMPACT

Improvements in the cardiorespiratory profile during childhood could reverse an unfavourable inflammatory status. There is a longitudinal and inverse association between CRF and inflammation in children. This is the first longitudinal study assessing the relationship between fitness and inflammation during childhood that takes also into account the lifestyle behaviours. Results from the present study suggest a protective role of fitness already in childhood. Efforts to improve fitness in children should be aimed at as inflammation could trigger future cardiovascular disease.

Improvements in Physical Fitness are Associated with Favorable Changes in Blood Lipid Concentrations in Children

Although accumulating evidence suggests the benefits of cardiorespiratory fitness and muscular fitness, little knowledge exists on how other physical fitness (PF) components are associated with cardiovascular disease (CVD) risk markers in children. Additionally, much of the relevant evidence is from longitudinal studies with CVD risk markers at a single time point (i.e., baseline) rather than changes in PF. The purpose of the present study was to examine whether initial 1-year changes in different performance measures of PF (i.e., endurance performance, muscular strength/endurance, flexibility, agility, and speed) can predict the subsequent changes (2-year change) in blood lipid concentrations in children. This 2-year longitudinal study included a total of 251 Japanese children (mean age 9.2 ± 0.4). PF tests were performed to comprehensively evaluate the participant's fitness levels (handgrip strength [upper body muscular strength], bent-leg sit-ups [muscular endurance], sit-and-reach [flexibility], side-step [agility], 20-meter shuttle run [endurance performance], 50-meter sprint [speed], standing long jump [lower body muscular strength], and softball throw [explosive arm strength and throwing ability]). Fasting lipid profile was assayed for triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and non-HDL-C concentration. Multilevel linear regressions were used to examine the associations between the preceding changes (over 1-year) in PF and subsequent changes (over 2-years) in blood lipid concentrations. We also examined the simultaneous associations between 2-year changes in PF and 2-year changes in blood lipid concentrations. For boys, preceding improvement in handgrip strength was negatively associated with TG concentration (β = -0.260, p = 0.030); improvements in bent-leg sit-ups were negatively associated with clustered lipid scores (β = -0.301, p = 0.038) and non-HDL-C (β = -0.310, p = 0.044); and improvements in 50m sprinting were associated with subsequent changes in non-HDL-C (β = 0.348, p = 0.006) and LDL-C (β = 0.408, p = 0.001). For girls, improvements in handgrip strength was negatively associated with TG concentration (β = -0.306, p = 0.017); and improvements in standing long jump were negatively associated with non-HDL-C (β = -0.269, p = 0.021) and LDL-C (β = -0.275, p = 0.019). For boys and girls, there were no significant simultaneous associations between 2-year changes in PF and 2-year changes in blood lipid concentrations. In conclusion, preceding change in physical fitness in relation to change in blood lipid concentration likely reflect a physiological adaptation to growth and maturation since these associations diminished in the subsequent year.

The impact of body weight trajectory from childhood on chronic inflammation in adulthood: The Bogalusa Heart Study

IMPORTANCE

The impact of long-term burden of excessive body weight, beginning in childhood, on inflammatory status in adulthood has been poorly described.

OBJECTIVE

To characterize the longitudinal body mass index (BMI) trajectory from childhood and examine its relationship with inflammatory status in adulthood.

METHODS

We included 1285 adults who had 4-15 repeat measurements of BMI from childhood to adulthood. The area under the curve (AUC) of growth curves was calculated to characterize long-term burden (total AUC) and trends (incremental AUC) of BMI.

RESULTS

After adjusting for covariates, higher values of BMI in terms of childhood and adulthood, as well as total and incremental AUC, were strongly associated with elevated levels of adult C-reactive protein (CRP) in the four race-sex groups. There were significant differences in linear and nonlinear curve parameters between the normal and high CRP groups for all race-sex groups (P < 0.01). Compared with participants who had consistently low BMI in both childhood and adulthood, participants with high BMI in adulthood had higher CRP levels (P < 0.001), irrespective of their childhood BMI status; participants with high BMI in childhood but low BMI in adulthood had similar adult CRP levels.

INTERPRETATION

The impact of excessive body weight on inflammation is cumulative and exacerbated over time. The influence of childhood overweight/obesity on inflammatory status in adulthood can be alleviated by reducing adiposity in adulthood.

Cardiorespiratory Fitness Predicted by Fibrinogen and Leptin Concentrations in Children with Obesity and Risk for Diabetes: A Cross-Sectional Study and a ROC Curve Analysis

Obesity is defined as abnormal or excessive fat accumulation that presents a risk to health. The ability to exercise is affected by adiposity, and this mechanism involves low-grade chronic inflammation and homeostatic stress produced mainly in adipocytes, which can result in abnormal adipokine secretion. To date, the gold standard for cardiorespiratory fitness assessment is considered to be the maximum oxygen uptake (VO_2max). The aim of the present study was to assess the prognostic value of hematological parameters of childhood obesity, as potential predictors of cardiorespiratory fitness (VO_2max), using a sample of children and adolescents with obesity and risk for diabetes. A total of 84 clinically healthy children and adolescents were recruited, of which 21 were considered lean, 22 overweight and 41 obese, with a mean age of 12.0 ± 1.9, 11.4 ± 2.0, and 11.2 ± 2.1 years old, in each weight status category, respectively. Age and sex did not differ between groups. Hematologic testing was performed after 12 h of fasting including glucose, serum lipids, insulin, hc-CRP, adiponectin, leptin and fibrinogen levels. Cardiorespiratory capacity for exercise was assessed to determine VO_2max, using a cycle ergometer. The VO_2max was negatively correlated with progressive strength to the BMIz (-0.656, p ≤ 0.001), hs-CRP (r = -0.341, p ≤ 0.002), glucose (r = -0.404, p ≤ 0.001) and insulin levels (r = -0.348, p ≤ 0.001), the homeostasis model assessment of insulin resistance (HOMA-IR) (r = -0.345, p ≤ 0.002), as well as to the leptin (r = -0.639, p ≤ 0.001) and fibrinogen concentrations (r = -0.520, p ≤ 0.001). The multivariate analysis revealed that only leptin and fibrinogen concentrations could predict the VO_2max adjusted for the BMIz of participants. The receiver operating characteristic (ROC) curve for the diagnostic accuracy of leptin, hs-CRP and fibrinogen concentrations for the prediction of VO_2max revealed a good diagnostic ability for all parameters, with leptin being the most promising one (area under the curve (AUC): 99%). The results verify that in children with obesity, VO_2max may be predicted from hematological parameters (leptin and fibrinogen), possibly bypassing more invasive methods.

Association of Cardiorespiratory Fitness Levels During Youth With Health Risk Later in Life: A Systematic Review and Meta-analysis

IMPORTANCE

Although the associations between cardiorespiratory fitness (CRF) and health in adults are well understood, to date, no systematic review has quantitatively examined the association between CRF during youth and health parameters later in life.

OBJECTIVES

To examine the prospective association between CRF in childhood and adolescence and future health status and to assess whether changes in CRF are associated with future health status at least 1 year later.

DATA SOURCES

For this systematic review and meta-analysis, MEDLINE, Embase, and SPORTDiscus electronic databases were searched for relevant articles published from database inception to January 30, 2020.

STUDY SELECTION

The following inclusion criteria were used: CRF measured using a validated test and assessed at baseline and/or its change from baseline to the end of follow-up, healthy population with a mean age of 3 to 18 years at baseline, and prospective cohort design with a follow-up period of at least 1 year.

DATA EXTRACTION AND SYNTHESIS

Data were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Random-effects models were used to estimate the pooled effect size.

MAIN OUTCOMES AND MEASURES

Anthropometric and adiposity measurements and cardiometabolic health parameters.

RESULTS

Fifty-five studies were included with a total of 37 563 youths (46% female). Weak-moderate associations were found between CRF at baseline and body mass index (r = -0.11; 95% CI, -0.18 to -0.04; I2 = 59.03), waist circumference (r = -0.29; 95% CI, -0.42 to -0.14; I2 = 69.42), skinfold thickness (r = -0.34; 95% CI, -0.41 to -0.26; I2 = 83.87), obesity (r = -0.15; 95% CI, -0.23 to -0.06; I2 = 86.75), total cholesterol level (r = -0.12; 95% CI, -0.19 to -0.05; I2 = 75.81), high-density lipoprotein cholesterol (HDL-C) level (r = 0.11; 95% CI, 0.05-0.18; I2 = 69.06), total cholesterol to HDL-C ratio (r = -0.19; 95% CI, -0.26 to -0.13; I2 = 67.07), triglyceride levels (r = -0.10; 95% CI, -0.18 to -0.02; I2 = 73.43), homeostasis model assessment for insulin resistance (r = -0.12; 95% CI, -0.18 to -0.06; I2 = 68.26), fasting insulin level (r = -0.07; 95% CI, -0.11 to -0.03; I2 = 0), and cardiometabolic risk (r = -0.18; 95% CI, -0.29 to -0.07; I2 = 90.61) at follow-up. Meta-regression analyses found that early associations in waist circumference (β = 0.014; 95% CI, 0.002-0.026), skinfold thickness (β = 0.006; 95% CI, 0.002-0.011), HDL-C level (β = -0.006; 95% CI, -0.011 to -0.001), triglyceride levels (β = 0.009; 95% CI, 0.004-0.014), and cardiometabolic risk (β = 0.007; 95% CI, 0.003-0.011) from baseline to follow-up dissipated over time. Weak-moderate associations were found between change in CRF and body mass index (r = -0.17; 95% CI, -0.24 to -0.11; I2 = 39.65), skinfold thickness (r = -0.36; 95% CI, -0.58 to -0.09; I2 = 96.84), obesity (r = -0.21; 95% CI, -0.35 to -0.06; I2 = 91.08), HDL-C level (r = 0.05; 95% CI, 0.02-0.08; I2 = 0), low-density lipoprotein cholesterol level (r = -0.06; 95% CI, -0.11 to -0.01; I2 = 58.94), and cardiometabolic risk (r = -0.08; 95% CI, -0.15 to -0.02; I2 = 69.53) later in life.

CONCLUSIONS AND RELEVANCE

This study suggests that early intervention and prevention strategies that target youth CRF may be associated with maintaining health parameters in later life.

Cardiorespiratory Fitness in Childhood and Adolescence Affects Future Cardiovascular Risk Factors: A Systematic Review of Longitudinal Studies

BACKGROUND

Although cardiorespiratory fitness (CRF) in childhood and adolescence may be linked to future cardiovascular health, there is currently limited evidence for a longitudinal association.

OBJECTIVES

To provide a systematic review on the prospective association between CRF in childhood and adolescence and cardiovascular disease (CVD) risk factors at least 2 years later.

METHODS

Using a systematic search of Medline, Embase, and SPORTDiscus, relevant articles were identified by the following criteria: generally healthy children and adolescents between 3 and 18 years of age with CRF assessed at baseline, and a follow-up period of ≥ 2 years. The outcome measures were CVD risk factors. We appraised quality of the included articles with STROBE and QUIPS checklists.

RESULTS

After screening 7524 titles and abstracts, we included 38 articles, assessing 44,169 children and adolescents followed up for a median of 6 years. Eleven articles were of high quality. There was considerable heterogeneity in methodology, measurement of CRF, and outcomes, which hampered meta-analysis. In approximately half of the included articles higher CRF in childhood and adolescence was associated with lower body mass index (BMI), waist circumference, body fatness and lower prevalence of metabolic syndrome in later life. No associations between CRF in childhood and adolescence and future waist-to-hip ratio, blood pressure, lipid profile, and glucose homeostasis were observed.

CONCLUSION

Although about half of the included articles reported inverse associations between CRF in childhood and adolescence and future BMI, body fatness, and metabolic syndrome, evidence for other CVD risk factors was unconvincing. Many articles did not account for important confounding factors such as adiposity. Recommendations for future research include standardizing the measurement of CRF, i.e. by reporting VO_2max, using standardized outcome assessments, and performing individual patient data meta-analyses.

Childhood adiposity, adult adiposity, and the ACE gene insertion/deletion polymorphism: evidence of gene-environment interaction effects on adult blood pressure and hypertension status in adulthood

BACKGROUND

Genetic variants may modify the associations of adiposity measures with blood pressure (BP) and hypertension. The insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene is an attractive candidate.

AIMS

To examine interaction effects between I/D polymorphism and adiposity measures (BMI, waist circumference, waist-to-hip ratio, and skinfold thickness) during childhood and adulthood in relation to adult BP and hypertension.

METHODS

Data were available for 4835 participants from three prospective cohort studies. Multivariable linear regression models for adult SBP and DBP, and multivariable logistic regression models for hypertension were fit that included interaction effects between child or adult adiposity and I/D polymorphism.

RESULTS

Evidence for interaction effects on BP/hypertension were found across the three studies. Compared with childhood measures, the effect modification appeared to be more consistent when using adult adiposity. In particular, the adverse effects of greater adult waist circumference on increasing adult SBP and DBP appeared to be larger among carriers of ACE DD (or GG) [adjusted linear regression coefficients 0.26, 95% CI (0.21-0.31) and 0.28 (0.24-0.32) for SBP and DBP, respectively] and ID (or AG) genotypes [0.25 (0.21-0.29) and 0.25 (0.21-0.28), respectively], whereas those with II (or AA) genotypes had smaller effects [0.15 (0.09-0.21) and 0.19 (0.13-0.23)].

CONCLUSION

ACE genetic variation may modify the effect of adult adiposity on increasing BP and risk of hypertension in adulthood. Individuals with ACE DD (or GG) and/or ID (or AG) genotypes, compared with those with II (or AA) genotype, appear more vulnerable to the impact of excess adiposity.

Association of cardiorespiratory fitness and adiposity with inflammatory biomarkers in young adults

OBJECTIVES

Cardiorespiratory fitness (fitness) has been inversely associated with inflammation, but whether the association is attributed to fitness itself or lower levels of adiposity remains uncertain in young adults. The purpose of this study was to determine the association of fitness and adiposity with inflammation in young adults.

METHODS

A cross-sectional study was conducted with 88 participants aged 20-34 years. Fitness was assessed by a submaximal treadmill walking test. Adiposity was assessed by body mass index (BMI) and waist circumference (WC). Inflammation was measured by plasma C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels using immunoassays. Biological data were log₁₀ transformed. A separate multiple regression analysis was conducted with each inflammatory biomarker as a dependent variable. Covariates (sex, oral contraceptive use, and education level) were adjusted.

RESULTS

Fitness was inversely associated with log₁₀ CRP after adjustment for covariates but not after adjusting for BMI or WC. Fitness was inversely associated with log₁₀ IL-6 after adjustment for WC and covariates (β = -0.341, P = .049) but not after adjusting for BMI. Fitness × WC interaction (partial eta²  = 0.056, P = .033) indicated that high fitness was more strongly associated with low log₁₀ IL-6 in young adults with high WC than those with low WC.

CONCLUSIONS

Although adiposity has a stronger association than fitness with CRP and IL-6, higher levels of fitness could be essential for maintaining low levels of IL-6, especially in the presence of high levels of central adiposity.