Use of growth charts for assessing and monitoring growth in Canadian infants and children: Executive summary

Growth assessment is the single most useful tool for defining health and nutritional status at both the individual and population level. This is because disturbances in health and nutrition, regardless of their etiology, almost always affect growth. Growth monitoring strives to improve nutrition, reduce the risk of inadequate nutrition, educate caregivers, and produce early detection and referral for conditions manifested by growth disorders. At the population health level, cross-sectional surveys of anthropometric data help define health and the nutritional status for purposes of program planning, implementation and evaluation. Growth monitoring is also used in all settings to assess the response to intervention.

Recent changes to commonly used growth charts, including the addition of charts for body mass index (BMI), have raised questions about which growth charts to use for Canadian children and how to apply BMI in the paediatric population.

This statement is intended for use as a practice guideline for medical practitioners and clinical and community health professionals. The desired outcome is the provision of recommendations that will promote consistent practices in monitoring growth and assessing atypical patterns of linear growth and weight gain in infants, children and adolescents. The recommendations are graded (Table 1) based on the available evidence from searches of the MEDLINE, CINAHL and EBM review databases using the following key words: anthropometry, child growth, child health, failure to thrive, growth, growth assessment, growth charts, growth monitoring, height and nutritional status.

Table 1.

Grades for recommendations

Level of evidence	Description
A	There is good evidence to recommend this action
B	There is fair evidence to recommend this action
C	The existing evidence is conflicting and does not allow making a recommendation for or against this action; however, other factors may influence decision-making
D	There is fair evidence to recommend against this action
E	There is good evidence to recommend against this action
I	There is insufficient evidence in quantity or quality to make a recommendation; however, other factors may influence decision-making

Adapted with permission from Canadian Task Force on Preventive Health Care. New grades for recommendations from the Canadian Task Force on Preventive Health Care. CMAJ 2003;169:207-8. <www.cmaj.ca/cgi/collection/task_force_on_preventive_health_care>.

Evidence demonstrating the benefits of growth monitoring on clinical outcomes is quite limited. This likely reflects the paucity of research, rather than providing proof against such rewards. More research is needed in this area and, as data becomes available in the future, recommendations contained in this document should be re-examined.

RECOMMENDATIONS

• Serial measurements of recumbent length (birth to two to three years) or height (two years and older), weight and head circumference (birth to two years) should be part of scheduled well-baby and well-child health visits. This will help identify disturbances in rates of weight gain or physical growth. Although the ideal number of health maintenance visits for children has not been established, current recommendations are that they be organized according to the immunization schedule, with additional visits within the first month and also at nine months of age (ie, within one to two weeks of birth; at one, two, four, six, nine, 12, 18 and 24 months; and at four to six years). The frequency for monitoring older children and adolescents is not known. However, it seems reasonable to continue monitoring growth on an annual basis at primary care visits for the early identification and referral of a child whose growth appears abnormal. More frequent monitoring may be indicated in cases where potential or real growth concerns are identified or a child’s response to therapy is being monitored. Children who are not brought for the recommended well-baby and well-child health visits should be measured during unwell visits (I recommendation).

• To yield accurate measurements, weights and measures should be obtained using calibrated, well-maintained quality equipment and standardized measurement techniques. An individual child’s measurements should be recorded in the data table of a consistent growth chart appropriate for the child’s age and sex, and then plotted to identify any disturbances in height or weight gain. When plotting anthropometric measurements of premature infants, corrected age should be used at least until 24 to 36 months of age. To identify major shifts in growth patterns, interpretation of plotted measurements should consider their percentile rank, their relationship to each other, recommended cut-off values, parental heights (for stature measurements) and comparison with previous percentile ranks (B recommendation). The American Centers for Disease Control and Prevention (CDC) provides suggested guidelines and training modules on their Web site at <www.cdc.gov/nchs/about/major/nhanes/growthcharts/charts.htm>.

• Growth charts from the CDC (<www.cdc.gov/nchs/about/major/nhanes/growthcharts/charts.htm>) are recommended for use by Canadian family physicians, paediatricians, dietitians, nurses and other health professionals until internationally diverse growth charts have been reviewed and are available in Canada (I recommendation). The World Health Organization (WHO) is currently developing charts that provide international representation of children (birth to five years old) being raised according to recommended health practices.

• Health care providers are encouraged to take the time to teach children and their caregivers how to interpret the growth chart (I recommendation).

• Growth of breastfed infants can be evaluated on the CDC growth charts by taking into account the type of feeding. Health care providers should be aware of the potential differences in growth between breastfed and formula-fed infants (B recommendation).

• BMI-for-age is recommended to screen children two years or older to identify those who may be at risk for conditions and illnesses related to excess body fat (B recommendation). BMI is an anthropometric index of weight and height, defined as body weight in kilograms divided by height in metres squared.

  $$\mathbf{\text{BMI}}\hspace{0.17em}=\hspace{0.17em}\mathbf{\text{weight}}\hspace{0.17em}(\mathbf{\text{kg}})/\mathbf{\text{height}}\hspace{0.17em}({\mathbf{\text{m}}}^2)$$

• For Canadian children, the CDC BMI-for-age charts are recommended for use in clinical and community settings. Use of the international BMI chart is recommended when comparing prevalence data for BMI for international populations (I recommendation).

• Traditional measures of underweight, such as percent ideal body weight or weight-for-length/stature percentile (available for use up to approximately five years of age), continue to be recommended until the validity of using BMI to assess underweight is established (to calculate percent ideal body weight (% IBW), plot length or height on growth chart to identify length- or height-forage percentile, locate IBW as the weight at the same percentile as the height, for the same age and sex, divide actual weight by ideal body weight and multiply by 100 [% IBW=actual weight/IBW×100]). Alternatively, in children two years and older, BMI-for-age may be used to screen for underweight, with an awareness of the existing limited experience of its role in underweight assessment (I recommendation).

• The following cut-offs are recommended as guidance for further assessment, referral or treatment, but not as diagnostic criterion for labelling children:

  • shortness or stunting: length-for-age or height-for-age less than the third percentile (I recommendation);
  • underweight or wasting: BMI-for-age less than the fifth percentile, body weight 89% or less of ideal or weight-for-length/stature less than the third percentile (charts available from birth to five years) (I recommendation);
  • overweight: 85th percentile < BMI-for-age < 95th percentile (I recommendation),
  • obesity: BMI-for-age at 95th percentile or higher (B recommendation).

• Given the rising prevalence of paediatric obesity and the associated short- and long-term health risks, routine screening for obesity is recommended as part of the paediatric health maintenance visit (I recommendation).

• Children suspected to be overweight, with a BMI-forage more than or at the 85th percentile with complications of obesity, or with a BMI-for-age more than or at the 95th percentile, with or without complications, should undergo evaluation and possible treatment (I recommendation). A family-centred approach is recommended to promote healthy eating and physical activity and reduce sedentary activity (B recommendation).

• A Canadian Paediatric Nutrition Surveillance System should be developed for organized and ongoing collection of anthropometric measurements to follow the growth and nutritional status of Canadian children and to describe key indicators of their nutritional status. Data could be used for program planning, targeting, development, and evaluation of health and nutrition interventions such as breastfeeding rates. It could also be used to monitor progress toward health objectives for Canada. Collaboration with key stakeholders in the health sector is needed.

• Research is required in the following areas: benefits of growth monitoring, optimum frequency for growth monitoring, validity of using BMI-for-age to assess underweight, development of a weight classification system for Canadian children, and effective strategies for prevention and treatment of paediatric obesity.

Implications

Recent revisions to growth references have provided an excellent opportunity to heighten the awareness of health care professionals about the importance of routine and accurate growth monitoring and the appropriate use and interpretation of growth charts and BMI for children. Implications for health care professionals include:

• The need for accessible training for practitioners on performing accurate and reliable anthropometric measurements using the new CDC growth charts, and calculating and interpreting BMI in children and adolescents.

• The demand for resources including accurate (and sometimes portable) measuring equipment, population health strategies for the prevention of excessive weight gain, treatment programs for paediatric obesity, and health care professionals trained in behaviour modification therapy.

• The need for professional organizations and health agencies to collaborate by publicizing the gravity of the obesity epidemic and reminding their members to address the problem with the public. This includes maximizing the limited community resources to realize healthy outcomes for children.

These same groups can collectively lobby for:

1. a Canadian Paediatric Nutrition Surveillance System to monitor the nutritional status and growth of our children; and

2. a national multisector strategy to address the prevention and treatment of obesity in children and adolescents. This would include promoting healthy eating, decreasing sedentary activity, and increasing physical activity for all school-age children and their families.

RECOMMENDED RESOURCES

• Growth Charts – Centers for Disease Control and Prevention, National Center for Health Statistics. CDC growth charts: United States <www.cdc.gov/nchs/about/major/nhanes/growthcharts/charts.htm>.

• Accurate Measurement Techniques – Maternal and Child Health Bureau Training Modules <depts.washington.edu/growth>

• A Health Professional’s Guide for Using Growth Charts – search key words “growth charts” at <www.dietitians.ca/resources/resourcesearch.asp>

• How Well Is My Child Growing – Questions and Answers for Parents – search key words “growth charts” at <www.dietitians.ca/resources/resourcesearch.asp>