The effect of eradicating poverty on childhood unintentional injury mortality in New Zealand: a cohort study with counterfactual modelling
- 1 Department of Public Health, University of Otago, Wellington, New Zealand;
- 2 School of Population Health, University of Auckland, New Zealand
- E-mail: amanda.dsouza{at}paradise.net.nz
- Received 21 July 2007
- Accepted 15 February 2008
- Published Online First 15 April 2008
Abstract
Objective To examine the effect of household income on unintentional injury mortality in children and model the potential impact of eradicating income poverty as an injury prevention strategy.
Design National retrospective cohort study linking census to mortality records.
Setting New Zealand during a three-year period following the 1991 census.
Participants Children aged 0 to 14 years on census night.
Main outcome measures Odds ratios for unintentional injury death by equivalised household income category and proportional reductions (population attributable risk) in unintentional injury mortality from modelled scenarios of nil poverty.
Results One third of children lived in households earning less than 60% of the national median household income. Age-adjusted odds of death from unintentional injury were higher for children from any income category compared to the highest, and were most elevated for children from households earning less than 40% of the national median income (Odds ratio 2.81, 95% CI 1.73 to 4.55). Adjusting for ethnicity, household education, family status and labour force status halved the effect size (OR 1.83, 1.02 to 3.28). 30% of injury mortality was attributable to low or middle household income using the highest income category as reference. Altering the income distribution to eradicate poverty, defined by a threshold of 50% or 60% of the national median income, in this model reduced injury mortality by a magnitude of 3.3 to 6.6%.
Conclusions Household income is related to a child's risk of death from unintentional injury independent of measured confounders. Most deaths attributable to low income occur amongst households that are not defined as 'in poverty'. The elimination of poverty may reduce childhood unintentional injury mortality by 3.3 to 6.6%.
