These researchers sought to determine whether excess winter mortality in New Zealand varies with social factors. Records from censuses in 1981, 1986, 1991, 1996 and 2001 were each linked to 3 years of subsequent mortality data to create five cohort studies of the New Zealand adult population (age 30–74 years at census). Complete data on social variables were recorded for 58,683 deaths. In logistic regression analysis adjusting for age, sex, census year, ethnicity and tenure, those in the lowest tertile of income were at increased risk of winter death compared to those in the highest tertile (OR, 1.13). Compared to home owners, people living in rented accommodation were at greater risk of winter death (OR, 1.05). Urban dwellers were also at significantly increased risk (OR, 1.05). The strongest associations were seen for infectious diseases.
