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Meta-Analysis
. 2012 Sep 25:345:e4759.
doi: 10.1136/bmj.e4759.

Cardiovascular disease risk in healthy children and its association with body mass index: systematic review and meta-analysis

Claire Friedemann  1 , Carl Heneghan, Kamal Mahtani, Matthew Thompson, Rafael Perera, Alison M Ward
Affiliations
Meta-Analysis

Cardiovascular disease risk in healthy children and its association with body mass index: systematic review and meta-analysis

Claire Friedemann et al. BMJ. .

Abstract

Objectives: To describe the association and its magnitude between body mass index category, sex, and cardiovascular disease risk parameters in school aged children in highly developed countries.

Design: Systematic review and meta-analysis. Quality of included studies assessed by an adapted version of the Cochrane Collaboration's risk of bias assessment tool. Results of included studies in meta-analysis were pooled and analysed by Review Manager version 5.1.

Data sources: Embase, PubMed, EBSCOHost's cumulative index to nursing and allied health literature, and the Web of Science databases for papers published between January 2000 and December 2011.

Review methods: Healthy children aged 5 to 15 in highly developed countries enrolled in studies done after 1990 and using prospective or retrospective cohort, cross sectional, case-control, or randomised clinical trial designs in school, outpatient, or community settings. Included studies had to report an objective measure of weight and at least one prespecified risk parameter for cardiovascular disease.

Results: We included 63 studies of 49 220 children. Studies reported a worsening of risk parameters for cardiovascular disease in overweight and obese participants. Compared with normal weight children, systolic blood pressure was higher by 4.54 mm Hg (99% confidence interval 2.44 to 6.64; n=12 169, eight studies) in overweight children, and by 7.49 mm Hg (3.36 to 11.62; n=8074, 15 studies) in obese children. We found similar associations between groups in diastolic and 24 h ambulatory systolic blood pressure. Obesity adversely affected concentrations of all blood lipids; total cholesterol and triglycerides were 0.15 mmol/L (0.04 to 0.25, n=5072) and 0.26 mmol/L (0.13 to 0.39, n=5138) higher in obese children, respectively. Fasting insulin and insulin resistance were significantly higher in obese participants but not in overweight participants. Obese children had a significant increase in left ventricular mass of 19.12 g (12.66 to 25.59, n=223), compared with normal weight children.

Conclusion: Having a body mass index outside the normal range significantly worsens risk parameters for cardiovascular disease in school aged children. This effect, already substantial in overweight children, increases in obesity and could be larger than previously thought. There is a need to establish whether acceptable parameter cut-off levels not considering weight are a valid measure of risk in modern children and whether methods used in their study and reporting should be standardised.

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Conflict of interest statement

Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; CF receives a stipend from the Medical Research Council; CH teaches workshops on evidence based medicine, does media work, writes for the Guardian newspaper, attends World Health Organization meetings, and has coauthored toolkit books on statistics and evidence based medicine; MT received grant funding in 2011-12 to Oregon Health Sciences University from the United States Preventive Services task force, to a lead the evidence review for the task force’s review on screening for hypertension in children; AW attends WHO meetings; the University Department of Primary Care Health Sciences is part of the National Institutes for Health Research School of Primary Care Research, which provide financial support for senior staff who contributed to this paper; no other relationships or activities exist that could appear to have influenced the submitted work.

Figures

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Fig 1 Progression of papers through the review process
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Fig 2 Outcome of risk of bias assessment by paper. Studies labelled a and b refer to different papers by the same authors published in the same year
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Fig 3 Outcome of risk of bias assessment by type of bias
See this image and copyright information in PMC

Comment in

References

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