Trends in colorectal cancer mortality by ethnicity and socio‐economic position in New Zealand, 1981‐99: one country, many stories

Abstract

Background:Ethnicity and socio‐economic position are important determinants of colorectal cancer (CRC) mortality. In this paper, we determine trends in colorectal cancer mortality by ethnicity and socioeconomic position in New Zealand. 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 CRC mortality by income and education. For ethnicity, we used routine unlinked Census and mortality data, but with correction factors applied for undercounting of Mǎori and Pacific deaths. Results:Ethnicity: CRC mortality trends varied markedly. There were small (10‐20%) decreases among non‐Mǎori non‐Pacific people, a 50% increase among Mǎori, and up to 10‐fold increase among Pacific people. By 1996‐99, all three ethnic groups had similar CRC mortality. Socio‐economic position:For females, differences in CRC mortality by education and income increased over time e. g. poor females had a 40% higher CRC mortality than rich females in 1996‐99, compared with no difference in 1981‐84 (p for trend 0.04). In men, increases in inequality were seen by income but not education. Conclusion:The observed ethnic trends probably reflect differential trends in exposure to etiological risk factors. Social inequalities in colorectal cancer mortality appear to be increasing.

The Maori, Behavior, Modern Diets and Colorectal Cancers

“…Schiffman (1988), discounted Caldararo's central proposal where sitting down (squatting) allowed the passage of more fecal matter in his small sample, but verified Caldararo's theory that this behavior would result in more fecapentane excretion and thus less exposure to mutagenic activity. This would be consistent with recent findings, including Shaw et al (2006). This is especially likely given the failure to find a dietary explanation.…”

“…One element that is absent from the review is how behavior may affect fecal water pH and the time exposure of colon tissue to its components. Shaw, et al (2006) recently published a paper on colorectal cancers in New Zealand. Caldararo (1988) did some fieldwork in Polynesia in the 1980s and tried to understand the low rates of colorectal cancers reported then by physicians in the Maori population (e.g., Smith, et al, 1985).…”

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Survival disparities in Indigenous and non-Indigenous New Zealanders with colon cancer: the role of patient comorbidity, treatment and health service factors

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