Infant mortality among First Nations versus non-First Nations in British Columbia: temporal trends in rural versus urban areas, 1981–2000

Background Increasingly more First Nations (FN) people have moved from rural to urban areas. It is unknown how disparities in infant mortality among FN versus non-FN women have changed over time in urban versus rural areas. Methods We conducted a birth cohort-based study of all 877 925 live births (56 771 FN and 821 154 non-FN) registered in British Columbia, 1981-2000. Main outcomes included rates, risk differences, and relative risks of neonatal, postneonatal, and overall infant death. Results Both neonatal and postneonatal mortality rates for FN infants showed a steady decline in rural areas but a rise-and-fall pattern in urban areas. Relative risks for overall infant death among FN versus non-FN infants declined steadily from 2.75 (95% CI: 2.04, 3.72) to 1.87 (95% CI: 1.24, 2.81) in rural areas from 1981-1984 to 1997-2000, but rose from 1.59 (95% CI: 1.27, 1.99) (1981-1984) to 2.80 (2.33-3.37) (1989-92) and then fell to 1.89 (1.44-2.49) (1997-2000) in urban areas. Risk differences for neonatal death among FN versus non-FN infants declined substantially over time in rural but not urban areas. The disparities in neonatal death among FN versus non-FN were largely explained by differences in preterm birth, while the disparities in postneonatal death were not explained by observed maternal and pregnancy characteristics. Conclusions Reductions in disparities in infant mortality among FN versus non-FN women have been less substantial and consistent over time in urban versus rural areas of British Columbia, suggesting the need for greater attention to FN maternal and infant health in urban areas.