“…The greatest differences in morbidity and mortality between indigenous and non-indigenous children were reported by four Canadian studies that used an ecological study design,3 50 – 52 measuring indigenous status at the area, as opposed to the individual, level 3 50 51. Four studies differentiated by age groups,3 19 24 31 (see online supplement table S2), two of these from the USA reported higher mortality inequalities in the youngest age groups (under 1-year-olds and 1–4-year-olds) compared with 1–9 and 10–19-year–olds, respectively 19 24. By comparison, a recent study from the USA reported lower mortality inequalities in the under 1-year-olds and 1–4–year-olds, compared with the 5–14-year–olds,31 and a Canadian study showed no age pattern in the size of inequalities in the analysis of hospital data 3…”