The New Zealand Census Mortality and CancerTrends Study (NZCMS/CT) is part of the Health Inequalities Research Programme (HIRP), established in July 2005. The study mainly aims to measure mortality differences by ethnicity and socio-economic status in New Zealand. In order to do this, we have been working with Statistics New Zealand to anonymously and probabilistically link census records with mortality and cancer records, thereby creating cohort studies. This linkage has been achieved for all six censuses (1981, 1986, 1991, 1996, 2001, 2006) and mortality followed for three years (1981, 1986, 1991, 1996) or five years in the more recent cohorts (2001, 2006).
Analyses have been conducted on these cohorts to:
- Compare the strength of the relationship of ethnicity, socio-economic factors, and other social factors, with mortality and cancer incidence across time - the cohort studies a traverse period of major macro-economic and social change in New Zealand.
- Investigate the extent to which smoking acts as an intermediate variable in the relation between social factors and mortality.
- Investigate possible contextual effects for variables such as neighbourhood deprivation and income inequality on mortality and cancer incidence.
- Examine discrepancies in the coding of ethnic group between census and mortality data (the so-called numerator denominator bias).
The NZCMS/CT Data Explorer (funded by the Ministry of Health) aims to provide users of population-level public health data with a flexible tool to monitor and analyse trends in NZ mortality and cancer incidence over time. Due to its linkage with the Census, the NZCMS/CT data is rich with aggregate-level demographic information on mortality and cancer incidence in NZ.
The New Zealand Census Mortality and CancerTrends Study is funded by the Ministry of Health. Originally the New Zealand Census Mortality Study and the CancerTrends Study, as separate projects, received funding from the Health Research Council of New Zealand.