Elsevier

The Lancet

Volume 368, Issue 9532, 22–28 July 2006, Pages 299-304
The Lancet

Articles
Physical activity and clustered cardiovascular risk in children: a cross-sectional study (The European Youth Heart Study)

https://doi.org/10.1016/S0140-6736(06)69075-2Get rights and content

Summary

Background

Atherosclerosis develops from early childhood; physical activity could positively affect this process. This study's aim was to assess the associations of objectively measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis.

Methods

We did a cross-sectional study of 1732 randomly selected 9-year-old and 15-year-old school children from Denmark, Estonia, and Portugal. Risk factors included in the composite risk factor score (mean of Z scores) were systolic blood pressure, triglyceride, total cholesterol/HDL ratio, insulin resistance, sum of four skinfolds, and aerobic fitness. Individuals with a risk score above 1 SD of the composite variable were defined as being at risk. Physical activity was assessed by accelerometry.

Findings

Odds ratios for having clustered risk for ascending quintiles of physical activity (counts per min; cpm) were 3·29 (95% CI 1·96–5·52), 3·13 (1·87–5·25), 2·51 (1·47–4·26), and 2·03 (1·18–3·50), respectively, compared with the most active quintile. The first to the third quintile of physical activity had a raised risk in all analyses. The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children.

Interpretation

Physical activity levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors.

Introduction

Physical activity guidelines for young people were first formulated in 1988 by the American College of Sports Medicine, which produced an opinion statement on the amount of physical activity needed for optimum functional capacity and health.1 The American College of Sports Medicine based their proposals on guidelines for adults and recommended that children and adolescents should achieve 20–30 min of vigorous exercise every day. In 1993, an international consensus conference on physical activity guidelines for adolescents was convened to develop empirically based guidelines.2

In 1998, the Health Education Authority in the UK commissioned a series of reviews of scientific paediatric publications that updated those of the international consensus conference and, after a similar consensus conference, proposed a different set of recommendations for the physical activity of young people.3 Their primary recommendation was that all young people should participate in physical activity of at least moderate intensity for 1 h per day and that young people who did little activity should participate in physical activity of at least moderate intensity for at least 0·5 h per day. Their secondary recommendation was that, if done at least twice a week, some of these activities should help to enhance and maintain muscular strength, flexibility, and bone health.3 Recently, Strong and co-workers did a systematic review of the evidence base for health and physical activity in school-age children.4 The conclusion of the review was close to the existing guidelines.

However, the evidence base for these guidelines is not strong enough to preclude the possibility that they could be biased. There is little evidence for a particular dose-response relation from which physical activity guidelines for children and adolescents can be obtained.5

There have been two major problems in the analysis of the association between physical activity and health in children. First, previous studies have relied on subjective measures of physical activity, since obtaining accurate measures of habitual physical activity is difficult, especially in children. Second, health outcomes are not well defined in children. Many studies have analysed the associations between physical activity and single cardiovascular disease risk factors, and these associations are often very weak. Clustering of cardiovascular disease risk factors has recently proved a better measure of cardiovascular health in children than single risk factors.6

Our aims were to examine different measures of accelerometry-assessed physical activity with clustering of cardiovascular disease risk factors and to examine whether a dose-response relation exists from which guidelines for young people can be obtained.

Section snippets

Setting

Data from the European Youth Heart Study were used.7 This investigation is a multicentre international study addressing the prevalence and cause of cardiovascular disease risk factors in children aged 9 and 15 years. Data from Estonia, Denmark, and Portugal were used.7 Study protocols were much the same in all countries and conformed to the international guidelines on biomedical research, and all research teams complied with the ethical procedures of that country. Written informed consent was

Results

Of the 1725 girls and 1592 boys who initially participated, only 1156 girls and 1045 boys had valid activity variables because of the criteria for valid accelerometer measurements. Of these children, 915 girls and 817 boys had complete data on risk factors, and these individuals form the basis of the present investigation. No difference was seen between individuals with complete data and those who were excluded with respect to age, height, weight, BMI, HDL cholesterol, sum of four skinfold, and

Discussion

The main findings of this study were a graded negative association between clustering of risk factors and physical activity. Risk was raised in the first to third quintile of physical activity compared with the most active quintile. Time spent at moderate and vigorous intensity activity (ie, above 2000 cpm, corresponding to a walking speed of around 4 km/h15, 16) in the fourth quintile was 116 min in 9 year olds and 88 min in 15 year olds, respectively. Thus, the current guidelines of at least

References (23)

  • WB Strong et al.

    Evidence based physical activity for school-age youth

    J Pediatr

    (2005)
  • LB Andersen et al.

    Biological cardiovascular risk factors cluster in Danish children and adolescents: the European Heart Study

    Prev Med

    (2003)
  • Physical fitness in children and youth

    Med Sci Sports Exerc

    (1988)
  • JF Sallis et al.

    Physical activity guidelines for adolescents: consensus statement

    Pediatr Exerc Sci

    (1994)
  • C Boreham et al.

    The physical activity, fitness and health of children

    J Sports Sci

    (2001)
  • C Riddoch et al.

    The European Youth Heart Study–cardiovascular disease risk factors in children: rationale, aims, design and validation of methods

    J Physical Activity Health

    (2005)
  • JM Tanner

    Growth at adolescence

    (1962)
  • DA Lawlor et al.

    Infant feeding and components of the metabolic syndrome: findings from the European Youth Heart Study

    Arch Dis Child

    (2005)
  • DR Matthews et al.

    Homeostasis model assessment—insulin resistance and beta-cell function from fasting plasma-glucose and insulin concentrations in man

    Diabetologia

    (1985)
  • S Brage et al.

    Reexamination of validity and reliability of the CSA monitor in walking and running

    Med Sci Sports Exerc

    (2003)
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