Varying evolution of the New Zealand lung cancer epidemic by ethnicity and socioeconomic position (1981–1999)

Aim Tobacco use and resultant health effects have been described as an epidemic that
progresses through the population. This paper aims to describe and explain trends in
lung cancer mortality by ethnicity and socioeconomic position in New Zealand
between 1981–1999.
Methods Cohort studies of the entire New Zealand population for 1981–84, 1986–89,
1991–94, and 1996–99 (linking census and mortality datasets) allowed direct
determination of trends in lung mortality by income and education. For ethnicity, we
used unlinked census and mortality data—but with correction factors applied for
undercounting of Maori and Pacific deaths.
Results Lung cancer mortality decreased in males and increased in females over the
time period studied. In males, socioeconomic inequality persisted despite a decline in
mortality in all socioeconomic groups. In females, a disproportionate increase in the
mortality of lower socioeconomic groups compared to higher socioeconomic groups
resulted in an increase in inequality. Divergent trends by ethnic group resulted in an
increase in ethnic inequalities between 1981 and 1996 in both males and females.
Conclusions There are significant and growing ethnic and socioeconomic inequalities
in lung cancer mortality in New Zealand. In the current absence of concerted public
health action these inequalities will probably widen in future decades.