Healthy Canadian infants and toddlers are heavier and longer than the World Health Organization Child Growth Standards according to a new study by researchers at the Institute for Clinical Evaluative Sciences and St. Michael’s Hospital.

In 2006, the WHO released universal CGS, intended to describe the optimal growth of children. The WHO Multicentre Growth Reference Study took place between 1997 and 2003, and included children from Brazil, Ghana, India, Norway, Oman and the United States, who were deemed to be free of health or environmental constraints on growth, such as maternal smoking or malnutrition.

“Measuring a child’s weight and height is an important and routine aspect of monitoring early growth, but the WHO Child Growth Standards may not reflect the growth of healthy Canadian children,” said Dr. Joel Ray, lead author on the study and a researcher at ICES and the Li Ka Shing Knowledge Institute of St. Michael's Hospital.

The study published in the journal Paediatric and Perinatal Epidemiology compared the WHO standards to the growth of 9,964 healthy Ontarian children up to 2–years–old between April 1, 2002, and March 31, 2013, including various feeding practices and maternal place of birth.

The study found:

• Canadian children were markedly longer than the WHO standards before 18 months, regardless of feeding practice.
• Canadian children had a higher 50th percentile (i.e., median) weight at birth, and again, after 6 months
• By age 2 years, the 50th percentile weight of Canadian males was 823 grams heavier than the WHO standards 50th percentile.

The researchers add that the differences in percentiles of weight, length and Body Mass Index of young Canadian children compared to the WHO standards, regardless of infant feeding practice may impact how the “normal” growth of Canadian children is interpreted.