Need for Inuit-specific growth curves for accurate diagnosis and treatment

Inuit children in Nunavut, Canada, are being overdiagnosed for macrocephaly and underdiagnosed for microcephaly, two neurological conditions measured by head size, because of reliance on World Health Organization (WHO) growth curves, according to new research in CMAJ (Canadian Medical Association Journal) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.230905.

“Clinicians must be able to identify children with potential medical issues appropriately, without underdiagnosis or overdiagnosis at the extremes of head circumference measurements,” writes Dr. Kristina Joyal, a pediatric neurologist, University of Manitoba and University of Saskatchewan, with coauthors.

In a study that compared head circumferences of Inuit children in Nunavut with WHO head circumference charts, researchers used chart data on 1960 children born from 2010 to 2013. The study population represented 18 of 25 communities in the region. Most data were from children aged 0 to 36 months, and at all age points, head circumferences were significantly larger than the WHO comparators.

“We observed larger median head circumference values, distinct patterns of growth curves, higher rates of children with head circumferences greater than the 97th percentile (macrocephaly), and lower rates of children with measurements below the 3rd percentile (microcephaly).”

This can result in higher diagnoses of macrocephaly, with resulting travel, treatment, and other stressors in otherwise healthy children, and underdiagnosis of microcephaly, which can mean delayed attention to a medical condition.

Variance from WHO reference charts has also been documented in other groups, including Turkish, South Asian, Australian Aboriginal, Canadian Cree, Japanese, and other populations.

“This unnecessary overinvestigation perpetuates a system that continues to bring harm to Inuit people, given the historical context of racism, mistreatment, and experimentation by settler health care workers,” write the authors.

They call for population-specific growth curves for Inuit children, developed in partnership with local communities.

“Our findings likely have implications for other Inuit populations in Canada and the circumpolar regions. The implementation of growth curves relevant to this population would necessitate ongoing discussion with Inuit organizations, health care professionals, and public health officials in these regions,” the authors conclude.