Physical fitness and C-reactive protein level in children and young adults: the Columbia University BioMarkers Study

Cross-sectional associations between physical fitness and biomarkers of inflammation in children-The PANIC study

BACKGROUND

Systemic low-grade inflammation has been proposed as an underlying pathophysiological mechanism for cardiometabolic diseases. We investigated the associations of physical fitness with a systemic low-grade inflammatory state in a population sample of children.

METHODS

Altogether 391 children aged 6-9 years were examined. Cardiorespiratory fitness (maximal power output, W_max ) was assessed by a maximal cycle ergometer test and neuromuscular fitness by hand grip strength, sit-up, standing long jump, 50-meter shuttle run, static balance, sit-and-reach, and box and block tests. Body fat percentage (BF%) and lean mass (LM) were assessed by dual-energy X-ray absorptiometry (DXA). High sensitivity C-reactive protein (hs-CRP), leptin, leptin receptor, high molecular weight adiponectin (HMW-adiponectin), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and glycoprotein acetyls (GlycA) were assessed from fasting blood samples. The modified inflammatory score (IS) was calculated using the population-specific z-scores and formula (^z hs-CRP + ^z leptin + ^z IL-6 + ^z TNF-α + ^z GlycA)-^z leptin receptor-^z HMW-adiponectin. The data were analyzed using linear regression analyses.

RESULTS

Higher W_max /kg of body mass (β = -0.416, 95% CI = -0.514 to -0.318), higher number of completed sit-ups (β = -0.147, 95% CI = -0.244 to -0.049), a longer distance jumped in the standing long jump test (β = -0.270, 95% CI = -0.371 to -0.169), and a shorter time in the 50-meter shuttle run test (β = 0.123, 95% CI = 0.022 to 0.223) were associated with lower IS. None of these associations remained statistically significant after adjustment for BF%.

CONCLUSIONS

Higher physical fitness is associated with a more favorable inflammatory biomarker profile in children. However, the associations were explained by BF%.

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.

Do documented records and retrospective reports of childhood maltreatment similarly predict chronic inflammation?

BACKGROUND

Childhood adversities have been associated with chronic inflammation and risk for cardiovascular disease. With some exceptions, existing knowledge of this relationship is based on retrospective self-reports, potentially subject to recall bias or memory problems. We seek to determine whether childhood maltreatment is associated with higher C-reactive protein (CRP) later in life and whether individuals with official and retrospective self-reports of maltreatment and men and women show similar increases in risk.

METHODS

Data are from in-person interviews in 2009-2010 with 443 offspring (mean age = 23.4) of parents in a longitudinal study of the consequences of childhood maltreatment. Official reports of maltreatment were abstracted from 2011-2013 Child Protective Services records. Eleven measures were used to assess self-reported maltreatment retrospectively. Seventeen percent of offspring had official reports, whereas self-reported prevalence rates ranged from 5.4% to 64.8%. CRP was assessed through blood spot samples. Regression models were used to estimate the effect of maltreatment on inflammation, adjusting for age, sex, race, parent occupational status, current depression, smoking, and heavy drinking.

RESULTS

Individuals with official reports of child maltreatment and, specifically, physical abuse, had significantly higher levels of CRP than non-maltreated individuals. Maltreated females showed elevated CRP, independent of control variables, whereas no significant association was observed in males. Retrospective self-report measures of child maltreatment did not predict elevated CRP.

CONCLUSIONS

Individuals with documented histories of childhood maltreatment are at increased risk for chronic inflammation and may benefit from targeted interventions. The results strengthen inferences about the effects of childhood maltreatment on inflammation in females.

The Relationship Between Antioxidants and Inflammation in Children With Attention Deficit Hyperactivity Disorder

Introduction

Recent studies have identified Attention Deficit Hyperactivity Disorder (ADHD) as an inflammatory condition associated with immunological and oxidative responses. Therefore, it is necessary to examine these processes in these patients. The present study aimed at investigating the relationship between the dietary intake of antioxidants, Superoxide Dismutase (SOD) activity, and the serum levels of inflammatory factors in ADHD students.

Methods

This retrospective case-control study was conducted on 64 ADHD children aged 6 - 13 years. The demographic questionnaire, Food Frequency Questionnaire, and Baecke Physical Activity Questionnaire were used for data collection. SOD activity and the serum level of inflammatory factors (homocysteine, interleukin-6, and C-reactive Protein (CRP)) were measured in all patients. According to the CRP values, 32 patients were included in the case group (CRP≥1 mg/L) and 32 patients in the control group (0≤CRP<1 mg/L).

Results

There was no significant difference between the two groups in age, sex, weight, height, and body mass index. In the case group, the mean SOD activity (P=0.034), the physical activity (P=0.04), zinc intake (P=0.02), and homocysteine levels were higher than the control group (P=0.001). Of all studied variables, the best predictors were homocysteine (OR: 1.34, 95% CI: 1.082-1.670, P=0.029) and physical activity (OR: 0.85, 95% CI: 0.761-0.952, P=0.022) respectively, whereas other variables were not significant predictors.

Conclusion

The present study showed that the level of inflammatory factors in the case group was significantly higher than the control group. Homocysteine and physical activity can predict the inflammation status induced by CRP.

Physical-activity trajectories during childhood and lung function at 15 years: findings from the ALSPAC cohort

Background

Although physical activity has many known health benefits, its association with lung function in childhood/adolescence remains unclear. We examined the association of physical-activity trajectories between 11 and 15 years with lung function at 15 years in 2266 adolescents.

Methods

A population-based cohort of 14 305 singleton births alive at 1 year was recruited in the UK population-based Avon Longitudinal Study of Parents and Children cohort. Physical activity (counts/minute and moderate-to-vigorous physical activity) was assessed for 7 days using an accelerometer at 11, 13 and 15 years. We identified sex-specific physical-activity trajectories applying K-means for longitudinal data in children with at least two accelerometer measurements (n = 3584). We then estimated the sex-specific associations of these trajectories with post-bronchodilation lung-function parameters using multivariable linear-regression models (n = 2266, 45% boys).

Results

Fewer than 7% of participants met the WHO physical-activity recommendations (i.e. daily average of at least 60 minutes of moderate-to-vigorous physical activity). Boys were substantially more active than girls. In both sexes, we identified three distinct physical-activity trajectories (‘low’: 39.8% boys, 45.8% girls; ‘moderate’: 42.9% boys, 41.4% girls; and ‘high’ physical activity: 17.3% boys, 12.8% girls). Girls in the moderate and high physical-activity trajectories had 0.11 L [95% confidence interval (CI): 0.04–0.19] and 0.15 L (95% CI: 0.03–0.26) higher forced vital capacity than their less-active peers. No association was observed in boys.

Conclusions

Higher childhood physical activity relates to higher lung-function levels in adolescent girls. A better understanding of the mechanisms underlying this association should be pursued.

Higher Cardiorespiratory Fitness Levels May Attenuate the Detrimental Association between Weight Status, Metabolic Phenotype and C-Reactive Protein in Adolescents-A Multi-Cohort Study

Results from several studies show that only obese, unfit subjects, but not obese, fit subjects, are at higher mortality risk than are normal-weight fit subjects. The aim of the study was two-fold: (1) to examine the differences in C-reactive protein levels across different metabolic phenotypes (healthy and unhealthy) of weight status and (2) ascertain whether high levels of cardiorespiratory fitness (CRF) attenuate the association of C-reactive protein and metabolic phenotypes of weight status. This was a pooled study, which included data from three cross-sectional projects (1706 youth (921 girls) aged 12-18 years). We used a Shuttle run test to assess CRF. Adolescents were classified into six metabolic phenotypes (healthy and unhealthy) of weight status (non-overweight, overweight and obese), based on age- and sex-specific cutoff points for triglycerides, systolic blood pressure, HDL-cholesterol, glucose and body mass index. High-sensitivity assays were used to obtain the C-reactive protein as inflammatory biomarker. After adjustment for potential confounders (age, sex, pubertal stage and country), the analysis of covariance (ANCOVA) shows that C-reactive protein is directly associated with metabolic phenotypes of weight status. Subjects with obesity, regardless of their metabolic profile, had higher levels of C-reactive protein Z-score. In addition, (after adjustments for potential confounders) a two-way ANCOVA showed that high levels of CRF attenuated the associations of C-reactive protein levels in metabolic healthy non-overweight and in adolescents with obesity. In conclusion, higher CRF levels may attenuate the detrimental association between obesity and C-reactive protein independently of metabolic phenotype. Findings from this study are important for prevention, clinical practice on issues associated with adiposity and metabolic disorders.

Effect of Yoga on Lipid Profile and C-reactive Protein in Women

BACKGROUND

Few scientific studies have been conducted about the effect of yoga on biochemical variables such as total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and C-reactive protein (CRP) to lay a scientific foundation regarding benefits of yoga, but its effect is not clearly detected yet. This study was conducted to assess the effect of yoga on lipid profile and CRP in women.

METHODS

This research was designed as an interventional study. After reviewing inclusion and exclusion criteria, selected biochemical variables such as TC, HDL-C, LDL-C, TG, and CRP were measured for each participant. Yoga instruction was done three times a week for 26 weeks by an experienced yoga instructor. After 26 weeks of yoga intervention, the above-mentioned dependent variables were assessed. SPSS Ver. 16 was used for data analysis.

RESULTS

After a 26-week follow-up for participants, only 24 women had the necessary criteria to be included in the study. The mean TG was 157.33 ± 68.416 mg/dL and 134.33 ± 58.80 mg/dL before and after the intervention (P = 0.108), respectively. The mean TC was 234.83 ± 48.47 mg/dL and 183.33 ± 55.09 mg/dL before and after the intervention (P = 0.014), respectively. The mean HDL-C was 31.58 ± 14.22 mg/dL and 38.25 ± 13.5 mg/dL before and after the intervention (P = 0.118), respectively. The mean LDL-C was 171.75 ± 42.69 mg/dL and 142.91 ± 36.4 mg/dL before and after the intervention (P = 0.030), respectively. The mean CRP was 0.57 ± 0.22 mg/L and 0.71 ± 0.77 mg/L before and after the intervention (P = 0.779), respectively.

CONCLUSIONS

The result showed that yoga reduced TC and LDL-C significantly, but had no significant effect on TG, HDL-C, and CRP.

Elevated Inflammatory Status and Increased Risk of Chronic Disease in Chronological Aging: Inflamm-aging or Inflamm-inactivity?

Age-associated hyper-inflammation or "inflamm-aging" has been linked to the development of chronic diseases and characterized as an unavoidable aspect of aging. However, the inflamm-aging model does not adequately address the potential anti-inflammatory effects of exercise training and the potential for exercise to ameliorate several age-related diseases. In this brief review, we introduce a new paradigm-inflamm-inactivity-that describes a potent counter-measure to age-associated inflammatory illness.

Does Physical Activity-Based Intervention Improve Systemic Proinflammatory Cytokine Levels in Overweight or Obese Children and Adolescents? Insights from a Meta-Analysis of Randomized Control Trials

OBJECTIVES

The purpose of this research was to conduct a meta-analysis of the role that physical activity (PA) plays in influencing the critical proinflammatory cytokine levels associated with overweight/obese children and adolescents to explore the effectiveness of exercise intervention within this population.

METHODS

With searches of the PubMed, EMBASE, and CENTRAL databases, we updated our meta-analysis up to November 2018. The randomized controlled trials (RCT) evaluated the ability of exercise training to increase the following factors in children and/or adolescents classified as obese or overweight: tumor necrosis factor (TNF)-α, interleukin (IL)-6, and C-reactive protein (CRP).

RESULTS

Eleven RCT comprising 623 children and/or adolescents who were obese or overweight (i.e., 393 with PA and 230 controls) were suitable for use in this study. The meta-analysis showed that PA in general was associated with a significant reduction of CRP levels (mean difference = -0.45 mg/L, p = 0.02) in overweight/obese children and adolescents. Based on 115 overweight and obese youths, this study suggests that PA does not significantly mitigate IL-6 levels (mean difference = -0.39 pg/mL, p = 0.08), although there was a trend towards a reduction. Additionally, no close connection was observed between PA and TNF-α levels at 0.04 pg/mL (p = 0.78). Moreover, meta-regression analysis revealed a statistical association between CPR levels and changes in BMI or changes in adiponectin; likewise, IL-6 levels dramatically impacted the effect of exercise on changes in adiponectin.

CONCLUSIONS

PA was associated with significantly reduced CRP levels, whereas there was no significant association with IL-6 or TNF-α in overweight/obese children or adolescents; however, there was a trend towards a reduction of IL-6.

The association of cardiorespiratory fitness with cardiometabolic factors, markers of inflammation, and endothelial dysfunction in Latino youth: findings from the Hispanic Community Children's Health Study/Study of Latino Youth

PURPOSE

To evaluate the relationship of cardiorespiratory fitness (CRF) with cardiovascular disease risk factors and a biomarker of endothelial dysfunction (e-selectin) among Hispanic/Latino youth.

METHODS

The study included 1380 Hispanic/Latino youths (8-16 years old) from the Hispanic Community Children's Health Study/Study of Latino Youth that enrolled from four cities (Bronx, Chicago, Miami, and San Diego). CRF was assessed by a 3-minute step test that uses postexercise heart rate to estimate maximal oxygen uptake. Regression models assessed differences in cardiometabolic markers across quartiles of CRF, adjusting for potential confounders.

RESULTS

CRF was higher among boys (mean: 57.6 mL per kg/min, 95% confidence interval, 56.8-58.4) compared to girls (mean: 54.7 mL per kg/min, 95% confidence interval, 53.9-55.5). Higher levels of CRF were associated with more favorable levels of cardiometabolic, inflammation, and endothelial dysfunction factors (P-values <.001) and independently of physical activity and sedentary time. Compared to the lowest quartile of CRF, the odds of having greater than or equal to two cardiovascular disease risk factors was lower at higher quartiles of CRF, after adjustment for potential confounders.

CONCLUSIONS

Among Hispanic/Latino youth, CRF appears to be a strong protective factor for endothelial dysfunction and cardiometabolic risk factors. Strategies to improve CRF may be a useful approach for improving cardiovascular health in youth.

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.

Gender Differences in C-Reactive Protein and Muscle Strengthening Activity

BACKGROUND

Few studies have examined the gender differences between C-reactive protein (CRP) and muscle strengthening activity (MSA).

METHODS

The sample (n = 7533) included U.S. adult (≥20 years of age).participants in the 1999-2004 National Health and Nutrition Examination Survey (NHANES). Created categories of MSA participation included no MSA (referent group), some MSA (≥1 to <2 days/week), and meeting the 2008 Department of Health and Human Services (DHHS) recommendation (≥2 days/week). The dependent variable was elevated CRP (>3 to 10 mg/L).

RESULTS

Analysis revealed significantly lower odds of having elevated CRP for women reporting some MSA (OR 0.64; 95% CI 0.44-0.93, P = .0191). Significantly lower odds of men having elevated CRP was observed in those reporting MSA volumes meeting the DHHS recommendation (OR 0.72; 95% CI 0.59-0.88, P = .0019). Following adjustment for waist circumference (WC) these odds remained significant in men but not women.

CONCLUSIONS

These results suggest that WC may mediate the associations between MSA and CRP and this relationship may be stronger in women.

Proteína C-reativa, atividade física e aptidão cardiorrespiratória em adolescentes portugueses: um estudo transversal

O objetivo deste estudo foi investigar a associação da atividade física (AF) e aptidão cardiorrespiratória com os níveis de concentração proteína C-reativa (PCR) em adolescentes. Fizeram parte da amostra 386 adolescentes Portugueses (n = 207, feminino), de 12-18 anos avaliados no ano de 2012. AF foi avaliada com acelerômetros e a aptidão cardiorrespiratória pelo teste de Vai- e-vem da bateria de testes fitnessgram. Amostras sanguíneas foram obtidas após jejum de 10 horas e posteriormente avaliaram-se os níveis de concentração de PCR por alta sensibilidade. Foram encontradas associações significativas entre a PCR e a aptidão cardiorrespiratória no gênero feminino (r = -0,313; p < 0.001) e masculino (r = -0,163; p < 0,05), porém quando ajustadas pelo IMC essas associações permaneceram significativas apenas no gênero feminino (r = -0,215; p < 0,001). Para associações entre PCR e AF não se encontraram associações estatisticamente significativas em ambos os gêneros. Assim a PCR aparentemente se associa de forma negativa com a aptidão cardiorrespiratória, mas de forma diferenciada em função do gênero, sendo que no feminino parece menos dependente do IMC.

Association of Sarcopenic Obesity with Higher Serum High-Sensitivity C-Reactive Protein Levels in Chinese Older Males--A Community-Based Study (Taichung Community Health Study-Elderly, TCHS-E)

The prevalence of obesity and sarcopenia is high among the elderly. The simultaneous occurrence of these two disorders results in sarcopenic obesity. Research suggests that inflammation has an important role in the pathogenesis of obesity and sarcopenia. This study explores the impact of sarcopenic obesity on inflammatory markers, including interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), and tumor necrosis factor-alpha (TNF-α). This study is a community-based cross-sectional study. The study sample consisted of 844 community-dwelling people aged 65 years and older (448 men and 396 women). Sarcopenia was characterized by low muscle mass (skeletal muscle index < 6.87 and 5.46 kg/m² for men and women, respectively), and obesity was characterized by excess body fat (body fat percentage greater than the 60th percentile of the study sample by sex [27.82% in men and 37.61% in women]). Older individuals identified with sarcopenic obesity were those who had both sarcopenia and obesity. Inflammatory markers such as IL-6, hs-CRP, and TNF-α were measured. The prevalence rates of obesity only, sarcopenia only, and sarcopenic obesity were 32.94%, 11.85%, and 7.23%, respectively. No difference was observed in the serum levels of IL-6 and TNF-α among the four groups of combined sarcopenia and obesity status. After multivariate adjustment, the serum hs-CRP levels in the obesity only and in the sarcopenic obesity groups were 0.14 and 0.16 mg/dL among males, respectively, which were significantly higher than that in the normal group (P=0.012 and 0.036). Our results provide evidence that obesity and sarcopenic obesity are associated with increased levels of serum hs-CRP among males.

Fatness but Not Fitness Relative to the Fat-Free Mass Is Related to C-Reactive Protein in 18 Year-Old Adolescents

Introduction

The interaction between fatness, fitness, and C-reactive protein (CRP) in adolescents is not well characterized but may be important to prevent low grade inflammation. The purpose of this study was to assess the relationship between adiposity, different expressions of fitness, and CRP in late adolescence using direct measures of fitness and fatness.

Methods

Anthropometric measurements were taken on 245 eighteen-year-old participants (116 girls). Fasting CRP, glucose, and insulin were measured and homeostatic model assessment (HOMA) calculated. Body composition was estimated via dual energy X-ray absorptiometry. Fitness was assessed with maximal oxygen uptake (VO₂max) during a treadmill test and also expressed relative to the fat-free mass (VO₂max_FFM).

Results

Prevalence of overweight/obesity based on body mass index (BMI) was 20.7% and 25.6% among girls and boys, respectively (p = 0.407), but 42.5% and 58.1% when based on body fat percentage (%fat, p = 0.015). Higher proportion of boys (81.3%) than girls (54.5%) were highly fit (p<0.001), but the percentage of girls with high levels of CRP was greater (12.1% vs 6.2%, p = 0.028). Adiposity, indicated with BMI, waist circumference, fat mass, android fat mass (aFM), or %fat, was positively associated with CRP independent of VO₂max (r = 0.13-0.18, p<0.05) and VO₂max_FFM (r = 0.24-0.32, p<0.001). VO₂max, was negatively associated with CRP independent only of BMI and waist circumference (r = -0.21, p = 0.001), but not %fat, fat mass or aFM (r = -0.08 to -0.12, p>0.05). VO₂max_FFM was unrelated to CRP with (r = -0.07 to -0.11, p>0.05) or without (r = -0.10, p = 0.142) adjustment for adiposity. Additional adjustment for HOMA did not change any of the relationships, although the coefficients were attenuated.

Conclusions

Fatness has a greater association with CRP than fitness in late adolescence. However, VO₂max_FFM, which is truly independent of adiposity, is unrelated to CRP, indicating that the effects of fitness might be mediated via the fatness component embedded in fitness expressed relative to body mass.

Cross-Sectional and Prospective Associations between Physical Activity and C-Reactive Protein in Males

Background

There is conflicting evidence about the association between physical activity and inflammatory markers. Few prospective studies are available, particularly from low and middle-income countries. This study was aimed at assessing the cross-sectional and prospective associations between physical activity and C-reactive protein (CRP) levels in males belonging to the 1982 Pelotas (Brazil) Birth Cohort Study.

Methods

The sample comprised 2,213 males followed up at the ages of 18 and 23 years. We performed high sensitivity CRP assays; we used a cut-off of 3 mg/L in categorical analyses. We measured physical activity by self-report at ages 18 and 23 years. Body mass index and waist circumference were studies as possible mediators.

Results

CRP levels above the 3mg/L cut-off were found in 13.3% (95%CI: 11.7; 14.8) of the individuals. We found no evidence for an association between physical activity (leisure-time or all-domains) and either continuous (geometrical mean) or categorical CRP. We confirmed these null findings in (a) prospective and cross-sectional analyses; (b) trajectories analyses.

Conclusions

There was no association between CRP levels and physical activity levels in early adulthood in a large birth cohort. Little variability in CRP at this early age is the likely explanation for these null findings.

Relation between leukocyte count, adiposity, and cardiorespiratory fitness in pubertal adolescents

Objective

To compare the total and differential leukocyte count in obese and normal-weight adolescents, and to verify their possible relations with cardiorespiratory fitness and adiposity indicators.

Methods

A cross-sectional study conducted with 139 adolescents (107 obese and 32 normal weight) aged between 13 and 18 years. Cardiorespiratory fitness was determined by direct gas analysis during an incremental treadmill test. Total leukocytes and subsets were estimated by flow cytometry. Body composition was assessed by dual-energy X-ray absorptiometry. The t-test for independent samples was used for comparison between groups. The relation between leukocytes, cardiorespiratory fitness and adiposity indicators was verified by Pearson’s correlation and multiple linear regression (adjusted for age and body mass index) tests.

Results

Obese adolescents had higher leukocyte (8.12±2.36u/L x 10³; p=0.001), neutrophil (4.33±1.86u/L x 10³; p=0.002), and monocyte (0.70±0.22u/L x 10³; p=0.002) counts compared to the levels of normal weight subjects. After the necessary adjustments, cardiorespiratory fitness had a negative association with leukocytes, neutrophils, and monocytes in boys.

Conclusion

Obese adolescents had higher total and differential leucocyte count when compared to normal weight individuals. We also observed a weak positive association between adiposity and total leukocyte, monocyte, and neutrophil counts, and in boys, a negative association between cardiorespiratory fitness and total count of leukocytes, monocytes, and neutrophils.

Post-effort chances in C-reactive protein level among soccer players at the end of the training season

Numerous literature data point out the differences in immunological parameters as a result of physical effort and the relation of those changes to the subject's fitness level. This study was aimed at the assessment of soccer players' condition and adaptation to physical effort based on the changes in C-reactive protein (CRP) blood level. C-reactive protein, total protein, and albumin plasma levels before and after 60-minute-long outdoor running were determined among 16 (8 men and 8 women) soccer players. Statistically significant increase in total blood protein level was observed in both studied groups. However, there were no statistically significant changes in albumin level in soccer players' blood. Determination of CRP showed that the exercise test caused changes in its level among both women and men; yet, statistically significant increase in CRP level was found only in women's blood. The different influence of effort on CRP plasma level may be explained by the involvement of various mechanisms in regulation of acute-phase responses in different conditions. It was found in our study that CRP level could be a valuable tool to assess the metabolic response to aerobic exercise.

Resistance exercise training-induced decrease in circulating inflammatory CD14+CD16+ monocyte percentage without weight loss in older adults

PURPOSE

Exercise training reduces systemic inflammation in weight-stable people, but concurrent diet-induced body weight loss is not well studied. We hypothesized that resistance training would decrease inflammatory monocyte percentage and improve biomarkers associated with disease risk, independent of weight loss.

METHODS

Forty physically inactive (PI) subjects (58.0 ± 5.7 years; BMI 30.1 ± 4.3 kg m(-2)) completed baseline testing, and 26 of these subjects completed 12-week of resistance training exercises while consuming either their usual, weight-maintenance diet (RE, n = 14) or an energy-restricted diet (RE-ER, n = 12). Nine physically active (PA) subjects served as a comparison group (60.1 ± 6.1 years; BMI 25.8 ± 3.1 kg m(-2)).

RESULTS

At baseline, circulating CD14+CD16+ monocyte percentage, C-reactive protein, and cholesterol were higher in PI vs. PA. Post-intervention, RE subjects had a ~35 % decrease in circulating CD14+CD16+, and a lower LPS-stimulated TNFα and IL-6 production, while RE-ER subjects had lower cholesterol than RE.

CONCLUSIONS

These findings indicate that resistance training is an effective means for older, overweight adults to reduce systemic inflammation. The unexpected lack of response with concurrent energy restriction underscores the need for further research on the use of resistance training and diet to reduce inflammation.

Clinical application of C-reactive protein in stroke prevention: bright and dark sides of the moon

In different study populations, several studies have shown that modest C-reactive protein elevation, in the range of apparently healthy individuals, is a strong predictor of future vascular events. Willcox and colleagues summarize the epidemiological and clinical observations that have led to the enthusiastic suggestion that determination of serum C-reactive protein levels could also be used as an adjunct for risk assessment in primary and secondary prevention of cerebrovascular disease. Currently, high-sensitivity C-reactive protein assays as a screening test to ascertain individuals at risk of cerebrovascular disease does not provide an accurate determination of the risk of stroke likelihood, and adequate evidence that early detection improves health outcomes and that an early intervention is likely to have a beneficial impact. High-sensitivity C-reactive protein assays as a screening test, only provide inadequate evidence to be considered as an effective cerebrovascular screening test, especially in the elderly.

Adiposity, aerobic fitness, muscle fitness, and markers of inflammation in children

PURPOSE

The purpose of this study was to describe levels of inflammation markers in Norwegian children and to examine the associations of adiposity, aerobic fitness, and muscle fitness with markers of inflammation.

METHODS

In 2005-2006, 1467 nine-year-olds were randomly selected from all regions in Norway. The participation rate was 89%. The inflammatory markers evaluated included C-reactive protein (CRP), leptin, adiponectin, plasminogen activator inhibitor-1, tumor necrosis factor-α, hepatocyte growth factor, resistin, and interleukin-6. We assessed muscular strength by measuring explosive, isometric, and endurance strength. Aerobic fitness was measured directly during a maximal cycle ergometer test. Adiposity was expressed as waist circumference (WC).

RESULTS

The girls had significantly higher levels of CRP, leptin, adiponectin, and resistin and lower levels of tumor necrosis factor-α compared with the boys. We observed a graded association of CRP and leptin levels across quintiles of WC, aerobic fitness, and muscle fitness (P ≤ 0.001 for all participants). The regression analyses revealed that WC, aerobic fitness, and muscle fitness were independently associated with the CRP (WC β = 0.158, P < 0.001; aerobic fitness β = -0.190, P < 0.001; muscle fitness β = -0.122, P < 0.002) after adjustments for sex, age, Tanner pubertal stage, and the other independent variables. The same pattern was observed for leptin levels (WC β = 0.406, P < 0.001; aerobic fitness β = -0.298, P < 0.001; muscle fitness β = -0.064, P < 0.036).

CONCLUSIONS

These data represent a reference material with respect to inflammatory markers. Our results show that adiposity, aerobic fitness, and muscle fitness were independently associated with the CRP and leptin levels.

Managing cardiovascular risk in overweight children and adolescents

The scientific, medical, and lay communities are currently confronted with a serious medical and public health problem related to the marked non-remitting worldwide epidemic of obesity. This ever-increasing prevalence of obesity is accompanied by a host of inherently associated co-morbidities. As a result, obesity is fast becoming the major cause of premature death in the developed world. As pediatric and adult cardiologists, we have seen a dramatic increase in office referrals of overweight and obese children and adolescents, who already have obesity-related degenerative disease processes such as hypertension, dyslipidemia, the metabolic syndrome, and type 2 diabetes mellitus, as well as manifestations of early preclinical atherosclerotic cardiovascular disease, not previously observed in this age group. This article presents a review of the literature and recent scientific statements and recommendations issued by the American Heart Association (AHA) and the American Academy of Pediatrics (AAP) regarding the metabolic abnormalities associated with obesity, including newer identification and treatment strategies for obesity, dyslipidemia, and early subclinical coronary artery disease seen in high-risk children and adolescents.

Elevated salivary C-reactive protein predicted by low cardio-respiratory fitness and being overweight in African children

Introduction

C-reactive protein (CRP) is a sensitive marker of systemic inflammation and is an independent risk factor for cardiovascular disease. The aim of the study was to examine the relationship between salivary CRP, cardio-respiratory fitness and body composition in a paediatric population.

Methods

This was a cross-sectional study of 170 black South African children (age 9.41 ± 1.55 years, 100 females, 70 males) in grades 3 to 7. Unstimulated whole saliva samples were obtained for the analysis of CRP. Height, mass, skin-fold thickness, resting blood pressure, and waist and hip circumference measurements were obtained. Cardio-respiratory fitness was assessed using a 20-m multi-stage shuttle run. Children were classified as overweight/obese according to the Center for Disease Control and Prevention (CDC) body mass index (BMI) percentile ranking, and meeting percentage body fat recommendations, if percentage body fat was ≤ 25% in boys and ≤ 32% in girls. The cut-off point for low cardio-respiratory fitness was a predicted aerobic capacity value ≤ the 50th percentile for the group. Contributions of low cardio-respiratory fitness, overweight/obesity, and not meeting percentage body fat recommendations, to elevated salivary CRP (≥ 75th percentile) concentration and secretion rate were examined using binary logistic regression analysis with a backward stepwise selection technique based on likelihood ratios.

Results

Poor cardio-respiratory fitness was independently associated with elevated salivary CRP concentration (OR 3.9, 95% CI: 1.7–8.9, p = 0.001). Poor cardio-respiratory fitness (OR 2.7, 95% CI: 1.2–6.1, p = 0.02) and overweight/obesity (BMI ≥ 85th percentile) (OR 2.5, 95% CI: 1.1–5.9, p = 0.03) were independent predictors of elevated salivary CRP secretion rate.

Conclusion

The results suggest a strong association between poor cardio-respiratory fitness and/or overweight/obesity and inflammatory status in children, based on elevated salivary CRP levels.

Novel risk factors of cardiovascular disease and their associations between obesity, physical activity and physical fitness

The prevalence of cardiovascular disease (CVD) is increasing around the globe and is the leading cause of death around the world. Though once thought of as an adult problem, it is now recognised that the early manifestations of disease may occur during childhood. Numerous risk factors have been linked to CVD with much of the research focusing on understanding the prevalence and relationship of traditional risk factors such as dyslipidemia, smoking, diabetes mellitus, hypertension, obesity, psychosocial stress, poor diet, physical inactivity and alcohol consumption to the early etiology of disease. While this line of investigation has greatly enhanced our understanding of the relationship between these risk factors and disease, they do not fully explain all cardiovascular events. To enhance our understanding and help with the management of CVD, investigations that involve the measurement of traditional as well as novel risk factors may be necessary. Public health strategies that aim to reduce the prevalence of obesity and overweight encourage youth to increase their physical activity levels as a means of protecting against poor cardiometabolic profiles. Interventions that increase physical activity levels and improve cardiorespiratory fitness cause a reduction in certain CVD risk factors but the lack of agreement between findings makes it impossible to give precise recommendations that will ensure CVD risk reduction. Yet it is important that research continues in order to establish the most appropriate means of improving the health and well-being of those at most risk of future CVD.

Cardiorespiratory fitness, metabolic risk, and inflammation in children

The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4  ±  0.4 years). Data was obtained for children's anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk (P < 0.001) and CRP (P < 0.007), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood.

APOE genotype and cardio-respiratory fitness interact to determine adiposity in 8-year-old children from the Tasmanian Infant Health Survey

APOE plays a well established role in lipid metabolism. Animal model evidence suggests APOE may also be associated with adiposity, but this has not been thoroughly investigated in humans. We measured adiposity (BMI, truncal fat mass, waist circumference), physical activity (PA), cardiorespiratory fitness and APOE genotype (E2, E3, E4) in 292 8-year-old children from the Tasmanian Infant Health Survey (TIHS), an Australian population-based prospective birth cohort. Our aims were to examine the association of APOE with child adiposity, and to examine the interplay between this association and other measured factors. We found that APOE was associated with child lipid profiles. APOE was also associated with child adiposity measures. The association was E4 allele-specific, with adiposity lower in the E4-containing group (BMI: Mean difference -0.90 kg/m²; 95% confidence intervals (CI) -1.51, -0.28; p = 0.004). The association of APOE4 with lower BMI differed by fitness status (difference in effect p = 0.002), and was more evident among the less fit (mean difference -1.78 kg/m²; 95% CI -2.74, -0.83; p<0.001). Additionally, associations between BMI and lipids were only apparent in those of lower fitness who did not carry APOE4. Similar overall findings were observed when truncal fat mass and waist circumference were used as alternative adiposity measures. APOE4 and cardiorespitatory fitness could interact to influence child adiposity. In studies addressing the genetic determinants of childhood obesity, the context of child fitness should also be taken into account.

Cardiovascular disease, SCI and exercise: unique risks and focused countermeasures

PURPOSE

To summarise the spinal cord injury (SCI) specific profile of three cardiovascular disease risk factors (CVD): fasting dyslipidaemia, postprandial lipidaemia and vascular inflammation and to summarise exercise prescriptions that may attenuate each.

METHOD

NA.

RESULTS

NA.

CONCLUSIONS

At least three CVD risk factors have unique profiles in the SCI population. Fasting dyslipidaemia is characterised in the SCI population by depressed HDL cholesterol and normal or low total cholesterol. In the post-prandial state, persons with SCI exhibit an exaggerated triglyceride rise and delayed clearance compared to non-disabled persons. Finally, vascular inflammation, as indexed by C-reactive protein, is markedly elevated in SCI. Exercise may improve each, although the specific prescriptions differs. Fasting dyslipidaemia responds to 8 weeks of moderate intensity aerobic exercise performed 5 days weekly for 30 min daily. Post-prandial lipaemia treatment requires daily moderate or vigorous aerobic exercise, as the effect dissipates day by day. The daily exercise duration is proportional to fitness level, with total caloric expenditure emphasised rather than time. Finally, attenuating vascular inflammation in non-disabled persons requires moderate or vigorous exercise performed for ≥12 months, 5 days weekly for ≥45 min; with aerobic exercise plus resistance training more effective than aerobic exercise alone.

Significant differences between serum CRP levels in children in different categories of physical activity: the PLAY study

Summary

Low-grade systemic inflammation is emerging as a component of the metabolic syndrome. The purpose of this study was to assess the association between serum C-reactive protein (CRP), physical activity and body composition in 193 black children aged 13 to 18 years from a South African township. Demographic information and anthropometric measurements were taken, and fasting blood samples were analysed for high-sensitivity serum CRP. Body fat was measured by air displacement plethysmography.

There was a trend towards higher serum CRP in the boys with a higher percentage body fat. After multiple regression analyses, waist circumference in the girls was significantly associated with serum CRP. In the boys, there was an inverse correlation between percentage body fat and fitness, and between fitness and serum CRP. Significant differences were found between serum CRP in the different physical activity categories, with lower serum CRP in the girls in the higher physical activity group. Obesity should be prevented in South African children by encouraging physical activity.

Adiposity, activity, fitness, and C-reactive protein in children

PURPOSE

The purpose of this study was to examine the relative association of physical activity, cardiorespiratory fitness (CRF), and adiposity with C-reactive protein (CRP) in prepubescent children.

METHODS

Forty-five prepubescent children (age = 9.4 ± 1.6 yr; 26 boys) were assessed for adiposity (percent fat) via dual-energy x-ray absorptiometry, CRF with a peak graded exercise test, physical activity using pedometers, and systemic inflammation via serum CRP.

RESULTS

Adiposity was positively correlated with CRP (body mass index, r = 0.61; percent fat, r = 0.59, P < 0.001), whereas step count and CRF were inversely associated with CRP (r = -0.49 and -0.37, respectively, all P values < 0.05). Compared across fitness or physical activity and adiposity groups, the low-fit/high-fat and the low-activity/high-fat groups had higher CRP than both low-fat groups. There was also a main effect of physical activity (P < 0.01) but not fitness on CRP. Regression analyses revealed that percent fat (ß = 0.59, P = 0.002) and physical activity (ß = -0.35, P = 0.011) were the only independent predictors of CRP, explaining 16.0% and 10.0% of the variance, respectively.

CONCLUSIONS

Adiposity is positively related to serum CRP in prepubescent children, independent of the effects of fitness or physical activity. In addition, physical activity is inversely associated with CRP levels. This research identified habitual physical activity and adiposity as focal points for the design of interventions attempting to reduce chronic systemic inflammation in children.

Impact of intensive school-based nutrition education and lifestyle interventions on insulin resistance, β-cell function, disposition index, and subclinical inflammation among Asian Indian adolescents: a controlled intervention study

OBJECTIVE

The present study was designed to assess the impact of intensive and repetitive nutrition education and lifestyle interventions on insulin resistance, β-cell function, disposition index (DI), and subclinical inflammation in Asian Indian adolescents (15-17 years) residing in North India.

METHOD

In this prospective study, two matched schools were randomly allocated to the intervention (n = 56; 31 boys and 25 girls) or control group (n = 50; 30 boys and 20 girls). The intervention consisted of seven components: (1) Dissemination of health-related information through lectures and focused group discussions, (2) planning of activities such as quizzes, (3) individual counseling of students, (4) promotion of physical activity, (5) change in the canteen menu to healthier alternatives, (6) conducting health camps involving parents and teachers, and (7) training of student volunteers for sustainability of the program in school. Impact of intervention was studied on surrogate markers of insulin resistance, β-cell function, disposition index, and subclinical inflammation.

RESULTS

At 6 months follow-up, significantly higher (P = 0.037) mean value of homeostasis model assessment denoting β-cell function (HOMA-βCF) was seen in the intervention group compared to the control group, whereas high sensitivity C-reactive protein (hs-CRP) was significantly lowered (P < 0.001). The increase (30.3 ± 73.4; P < 0.037) observed in the DI in adolescents in the intervention group was significantly higher compared to the control group. The Pearson's coefficient of correlation in the intervention group showed that the Δ-decrease in mean waist circumference was significantly correlated (r = 0.267, P < 0.05) with Δ-decrease in homeostasis model assessment of insulin resistance (HOMA-IR).

CONCLUSION

The intervention model developed by us could be used for amelioration of insulin resistance with potential of preventing type 2 diabetes mellitus in Asian Indian adolescents.

Physical fitness, adiposity, and metabolic risk factors in young college students

PURPOSE

The purpose of this study was to assess anthropometry, physical fitness, and serum glucose and lipid levels in college students and to determine the relative impact of fitness level compared with body composition on blood chemistries related to metabolic syndrome.

METHODS

College students (n = 564; means +/- SD: age = 19.4 +/- 1.1 yr) participating in the Tufts University Longitudinal Health Study between 2000 and 2007 were examined for the relative impact of fitness level compared with body composition on serum glucose, triglycerides, HDL, LDL, and total cholesterol controlling for age and ethnicity.

RESULTS

In this college population, 16.2% were overweight or obese, whereas 60% had body fat percentages above desirable levels. Higher percent body fat was associated with increased cholesterol and LDL in both men and women, and with increased triglyceride and decreased HDL in women (P < 0.05). Increased fitness was associated with increased HDL and decreased triglycerides in women and decreased serum glucose in men (P < 0.05). When dichotomized into "fit" and "unfit" groups, students who were fit demonstrated more optimal levels of serum glucose and lipids independent of percent body fat (P < 0.05).

CONCLUSIONS

Several metabolic risk factors are already evident in a young college population, and both increased body fatness and decreased physical fitness were associated with metabolic risk. Being physically fit can confer an added benefit to a healthy body composition. It is therefore important to encourage both healthy weights and fitness in late adolescence as each play important and independent roles in biochemical parameters associated with increased chronic disease risk.

Physical activity, exercise and low-grade systemic inflammation

Prospective studies have shown that chronic low-grade inflammation may contribute to the pathogenesis of the most common chronic diseases and in particular CVD. Obesity has repeatedly been associated with moderately raised levels of inflammation, and this observation has led to the view that obesity is characterised by a state of chronic low-grade inflammation. There is now great interest in elucidating how physical activity and exercise modulate inflammation. This review summarises the current research addressing the influence of physical activity and exercise in mitigating the risks of obesity and diseases such as type-II diabetes and CVD, through its action on the low-grade inflammatory state. Most research on this topic hypothesised that the association between physical activity and inflammatory markers is independent of fatness, but very few studies have proven this. Given that physical activity and obesity are often inversely related, it is not clear as to whether the anti-inflammatory health benefits of a physically active lifestyle are due to exercise per se or result from favourable changes in the body composition.

Stunting, adiposity, and low-grade inflammation in African adolescents from a township high school

OBJECTIVE

The objective of this study was to compare the inflammatory status of children with differences in nutritional status.

METHODS

This was a cross-sectional study of 184 African children aged 13-18 y from a low socioeconomic background that compared stunted with non-stunted and lean with over-fat (percentage of body fat above normal cutoff points) children. Fasting serum tumor necrosis factor-alpha, interleukin-6, C-reactive protein, and insulin were measured using high-sensitivity methods. Body composition was assessed using anthropometry and air-displacement plethysmography. T tests for parametric data and the Mann-Whitney test for non-parametric data were used to compare groups. Regression analyses and principal components analyses were done to assess relations between body composition and biochemical variables.

RESULTS

Of all participants 18% were stunted. Serum tumor necrosis factor-alpha of stunted girls was higher than in non-stunted girls. More of the stunted boys were over-fat compared with their non-stunted counterparts. Regression analyses showed that insulin resistance, diastolic blood pressure, and C-reactive protein contributed significantly to interleukin-6 in boys. Serum C-reactive protein, waist circumference, and body mass index clustered together in factor analysis in boys. Serum interleukin-6, waist-hip ratio, and tumor necrosis factor-alpha clustered together in factor analysis in girls.

CONCLUSION

An association between adiposity and stunting and between adiposity low-grade inflammation was found in this study. Interventions for stunted children focus mainly on correction of undernutrition by providing feeding schemes. Attention should, however, also be paid to changes in body composition over time to prevent excessive abdominal fat accumulation and risk for cardiovascular diseases later in life.

Prevalence of metabolic syndrome and insulin resistance among Egyptian adolescents 10 to 18 years of age

BACKGROUND

The prevalence and magnitude of childhood obesity are increasing dramatically.

OBJECTIVES

To examine the effect of varying social, demographic, dietary, and activity factors on the prevalence of metabolic syndrome and its relation to insulin resistance, C-reactive protein, and homocysteine levels in a large, representative sample of Egyptian adolescents.

METHODS

Our survey included 4250 adolescents (from 10 to 18 years of age; male subjects comprised 42.5% of participants) from 7 governorates representing Egypt. Baseline measurements included blood pressure, fasting blood glucose, plasma lipids, C-reactive protein, and homocysteine levels. Because the body mass index varies according to age, we standardized the value for age and sex with the use of conversion to percentiles.

RESULTS

The overall prevalence of the metabolic syndrome was 7.4% with no sex or area of residence predilection. Results showed that adolescents with the full criteria of metabolic syndrome (ie, three criterion or more) constituted nearly one fourth of those exhibiting high values of different components, except for systolic blood pressure, where they were 42%, and TG, where they were 31%. Family history of obesity and diabetes mellitus increase the odds for metabolic syndrome significantly (1.68 and 1.3, respectively) as well as inactivity. A high level of C-reactive protein was reported among affected adolescents. Homocysteine level did not have an influence.

CONCLUSIONS

The prevalence of the metabolic syndrome is considerable among obese adolescents. Proinflammatory markers associated with an increased risk of adverse cardiovascular outcomes are already present in these youth.

The interleukin-1 cluster, dyslipidaemia and risk of myocardial infarction

Coronary heart disease (CHD) is among the most serious worldwide health problems. Recent genetic studies have robustly identified a number of polymorphic loci throughout the genome that are associated with disease risk but it is certain that more remain to be discovered. It is well established that inflammation plays a key role in the pathophysiology of CHD. Determining whether or not polymorphisms in genes involved in the inflammatory cascade affect the risk of CHD is of considerable interest with respect to understanding the direction of the causal arrow between increased expression of inflammatory genes and CHD. Establishing an association between the variation in inflammatory genes and CHD would provide conceptual support for the use of appropriately specific anti-inflammatory agents in CHD prevention and, potentially, suggest new therapeutic targets. This month in BMC Medicine, Benjamin Brown and colleagues adopt a family-based case-control association study design to address this question. In a large number of CHD cases and healthy sibling controls genotyped for 51 mainly coding single nucleotide polymorphisms (SNPs), they find evidence for the association of a common haplotype at the Interleukin-1 (IL-1) cluster with CHD which appears to be stronger in younger cases without hypercholesterolaemia. They also find suggestive evidence for an association between this same haplotype and hypercholesterolaemia. If replicated in other cohorts, these results could be of substantial importance in advancing the understanding of the way in which inflammatory genes affect coronary heart disease risk.See the associated research paper by Brown et al: http://www.biomedcentral.com/1741-7015/8/5.

Prevenção primária de doenças cardiovasculares na obesidade infantojuvenil: efeito anti-inflamatório do exercício físico

A pandemia da obesidade juvenil e do sedentarismo está relacionada com o maior risco de doenças cardiovasculares no futuro. Ambas com fisiopatologia inflamatória, essas condições têm atraído significativa atenção científica. O início dos eventos que agridem o endotélio vascular pode ocorrer na infância, porém, sinais clínicos da aterosclerose geralmente só aparecem na fase adulta. O tecido adiposo é hoje reconhecido por seu papel ativo, induzindo a produção de citocinas pró e anti-inflamatórias, como o fator de necrose tumoral-alfa, as interleucinas 1, 6 e 10, a proteína C-reativa e outras. Há várias evidências de que os níveis sanguíneos dessas citocinas se encontram mais altos em indivíduos com excesso de peso, inclusive crianças e adolescentes. A prevenção precoce, desde a infância, apresenta-se como a melhor maneira de evitar os danos da obesidade na fase adulta, enquanto o potencial da prática regular de exercícios físicos tem se mostrado surpreendente. Sua ação anti-inflamatória se manifesta através de menores concentrações séricas de interleucina 6, de proteína C-reativa e leptina, além de aumentos na adiponectina. Observa-se escassez de estudos randomizados e controlados avaliando as relações entre obesidade, inflamação e exercícios para a população jovem. Com resultados às vezes controversos, a maioria das conclusões é procedentede estudos com adultos. O objetivo desta revisão é avaliar o papel anti-inflamatório, e assim cardioprotetor, da atividade física regular na obesidade infantojuvenil.

A cross-sectional study of food group intake and C-reactive protein among children

BACKGROUND

C-reactive protein (CRP), a marker of sub-clinical inflammation, is a predictor of future cardiovascular diseases. Dietary habits affect serum CRP level however the relationship between consumption of individual food groups and CRP levels has not been established.

METHODS

This study was designed to explore the relation between food intake and CRP levels in children using data from the cross-sectional 1999-2002 National Health and Nutrition Examination Surveys. CRP level was classified as low, average or high (<1.0, 1.0-3.0, and >3.0 mg/L, respectively). Adjusted mean daily intakes of dairy, grains, fruit, vegetables, and meat/other proteins in each CRP category were estimated using multivariate analysis of covariance modeling. The effect modification by age (5-11 years vs. 12-16 years), gender and race/ethnicity was explored. We examined whether total or central body fat (using BMI Z-scores and waist circumference) explained any of the observed associations.

RESULTS

A total of 4,010 children and adolescents had complete information on diet, CRP and all covariates of interest and were included in the analyses. Individuals with high CRP levels had significantly lower intake of grains (p < 0.001) and vegetables (p = 0.0002). Selected individual food subgroups (e.g., fluid milk and "citrus, melon and berry" consumption) were more strongly associated with lower CRP than were their respective major food groups. Consumption of meat/other proteins did not influence CRP levels. The addition of body composition variables to the models attenuated the results for all food groups to varying degrees.

CONCLUSION

Children and adolescents with higher CRP levels had significantly lower intakes of grains and vegetables. The associations between selected childhood dietary patterns and CRP levels seem largely mediated through effects on body composition.

Paediatric obesity, physical activity and the musculoskeletal system

The current epidemic of paediatric obesity is consistent with a myriad of health-related comorbid conditions. Despite the higher prevalence of orthopaedic conditions in overweight children, a paucity of published research has considered the influence of these conditions on the ability to undertake physical activity. As physical activity participation is directly related to improvements in physical fitness, skeletal health and metabolic conditions, higher levels of physical activity are encouraged, and exercise is commonly prescribed in the treatment and management of childhood obesity. However, research has not correlated orthopaedic conditions, including the increased joint pain and discomfort that is commonly reported by overweight children, with decreases in physical activity. Research has confirmed that overweight children typically display a slower, more tentative walking pattern with increased forces to the hip, knee and ankle during 'normal' gait. This research, combined with anthropometric data indicating a higher prevalence of musculoskeletal malalignment in overweight children, suggests that such individuals are poorly equipped to undertake certain forms of physical activity. Concomitant increases in obesity and decreases in physical activity level strongly support the need to better understand the musculoskeletal factors associated with the performance of motor tasks by overweight and obese children.

A randomized controlled trial of Kung Fu training for metabolic health in overweight/obese adolescents: the "martial fitness" study

Twenty overweight/obese adolescents underwent six months of Kung Fu or placebo (Tai Chi) training, 3x.wk(-1). Outcomes included fasting insulin and insulin resistance, lipids, glucose and HbA(1c), and C-reactive protein (CRP). CRP decreased significantly (p = 0.03) in both groups over time at six months. Although insulin sensitivity did not change, HbA(1c) tended to decrease over time (p = 0.09), again with no group difference (p = 0.60). Reduced CRP was related to increased upper body strength (p = 0.01). Increased lean body mass was related to reductions in HbA(1c), insulin resistance, triglycerides, and total cholesterol. Improvements in lean body mass appear to have a potential role in favorable metabolic outcomes, independent of changes in fat mass. Further research in this area is warranted before definite conclusions can be drawn about the efficacy of martial arts training for metabolic outcomes in this cohort.

Criterion-related validity of the one-mile run/walk test in children aged 8-17 years

We assessed the criterion-related validity of Cureton's equation for estimating peak oxygen consumption (VO(2peak)) from the one-mile run/walk test in endurance-trained children aged 8-17 years. Altogether, 66 physically active white children and adolescents (32 girls, 34 boys) completed a graded exercise test to volitional exhaustion and the one-mile run/walk test. Cureton's equation was used to estimate VO(2peak), and was assessed using several error measures. Agreement between measured VO(2peak) and estimated VO(2peak) was analysed by the Bland and Altman method. The correlation coefficient between measured VO(2peak) and one-mile run/walk time was -0.59 (P < 0.001) and that between measured and estimated VO(2peak) was 0.70 (P < 0.001). The mean difference between measured and estimated VO(2peak) was 10 ml . kg(-1) . min(-1) (95% CI = 9.2-11.8; P < 0.001). The standard error of the estimate was 3 ml . kg(-1) . min(-1), and the percentage error was 32%. There was a positive association between the measured and estimated VO(2peak) difference and the measured and estimated VO(2peak) mean, which indicates that the higher the VO(2peak) the higher the error of the estimate. These findings did not change markedly when the analyses were performed by sex, age group or body mass status. These results suggest that Cureton's equation systematically underestimates VO(2peak) in endurance-trained children with high VO(2peak).

Hs-CRP is associated with weight, BMI, and female sex but not with endothelial function in children with type 1 diabetes

BACKGROUND

Atherosclerosis is an inflammatory process, and high-sensitivity C-reactive protein (Hs-CRP), a marker of inflammation, predicts cardiovascular events in adults. Vascular endothelial and smooth muscle dysfunction, measurable precursors of atherosclerosis, begin in childhood. Therefore, we sought to determine if Hs-CRP is associated with vascular endothelial and smooth muscle dysfunction in children with type 1 diabetes mellitus (T1DM) and healthy control subjects.

METHODS

Hs-CRP and endothelial function assessed by flow-mediated dilatation (FMD) and smooth muscle function assessed by glyceryl-trinitrate (GTN)-induced dilatation were measured in 121 subjects with T1DM aged 14.1 (2.9) yr, of whom 31 were also studied at 4 and 8 wk, and in 33 healthy controls aged 14.2 (3.6) yr.

RESULTS

Hs-CRP did not differ between subjects with T1DM and healthy, age-matched controls. In both controls and subjects with T1DM, Hs-CRP did not relate to FMD or GTN at baseline or at intervals over 8 wk in T1DM. Hs-CRP did not change over time. In T1DM, but not healthy controls, Hs-CRP related to body mass index (BMI) z-score (r = 0.47, p < 0.001), weight z-score (r = 0.41, p < 0.001), and female sex (p = 0.008).

CONCLUSIONS

Hs-CRP is not associated with early vascular dysfunction in children with T1DM. However, in children and adolescents with T1DM, Hs-CRP was associated with female sex and children with higher BMI, suggesting that these groups may be at greater cardiovascular risk. Maintenance of a healthy BMI may be important in the prevention of vascular disease of T1DM.

Fitness level and body composition are associated with inflammation in non-obese children

Childhood obesity and poor fitness are associated with insulin resistance (IR), risk for coronary heart disease (CHD), and type 2 diabetes mellitus. Elevated markers of inflammation (e.g., C-reactive protein [CRP]) are independent predictors of CHD. Whether higher percent body fat and poor fitness in non-obese children are associated with evidence of inflammation and IR is unclear. We evaluated 75 children with non-obese body mass index (BMI) for age (<95th percentile), ages 11-14 years for fasting insulin, glucose, adiponectin, CRP, body composition, and maximum oxygen-consumption (VO2max). CRP correlated positively with body composition (BMI z-score, p = 0.00062; percent body fat, p = 0.00007; and total body fat in grams, p = 0.00006) and negatively with VO2max, p = 0.036. Using multivariate analysis, VO2max and percent body fat were both independent predictors of CRP. Fasting insulin and insulin resistance as assessed by QUICKI did not correlate with CRP, fitness, or fatness in these non-obese children. Adiponectin showed no significant correlations, and gender did not influence correlation analyses. We conclude that in non-obese children, low fitness and higher body fat are both associated with inflammation (i.e., higher levels of CRP). This observation strengthens the importance of promoting both fitness and healthy body composition in all children.

Increasing physical activity in preschool: a pilot study to evaluate animal trackers

OBJECTIVE

This report describes a pilot study to evaluate Animal Trackers (AT), a preschool program designed to (1) increase structured physical activity (PA) during the preschool day; (2) increase practice of gross motor skills; (3) provide teachers with an easy-to-use PA program regardless of teacher experience; and (4) implement a teacher walking intervention.

DESIGN

Pilot observational study in volunteer preschools.

SETTING

Nine preschools in New Mexico.

PARTICIPANTS

Two-hundred seventy 3- to 5-year-old children and 32 teachers.

INTERVENTION

Daily 10-minute classroom activities for children.

MAIN OUTCOME MEASURE

Implementation and duration of AT activities, teacher preparation time, and added weekly time spent in structured PA.

ANALYSIS

Process evaluation to track program implementation, and pre-post measures to assess outcomes.

RESULTS

AT activities were implemented 4.1 times per week (11.4 minutes/activity), with 7 minutes teacher preparation time. Overall, AT added 47 minutes of structured PA per week for children.

CONCLUSIONS AND IMPLICATIONS

The AT program increased structured PA time in preschools. Teachers felt that AT was developmentally appropriate; that children enjoyed the activities; and that the children's motor skills improved. Results of the pilot study are encouraging, since research suggests that even small increases in PA could help prevent obesity.