Making NZ smoke-free will reduce ethnic death rate
Making NZ smoke-free will reduce ethnic death rate inequalities
Latest Otago University research published in world’s leading medical journal
Research published online today in the prestigious international medical journal, The Lancet, estimates that about 400 deaths per year among 45-74 year old Maori would be saved if New Zealand were to go smoke-free. And among the same number of non-Maori non-Pacific people, approximately 275 deaths per year would be saved.
“Our study found that five to 10 per cent of the gap in death rates between Maori and non-Maori non-Pacific 45-74 year olds during the late 1990s was due to tobacco smoking,” says Associate Professor Tony Blakely from the University of Otago’s Wellington School of Medicine and Health Sciences, and lead author of the study. “Smoking therefore plays an important part in the shockingly large differences in death rates between Maori and non-Maori non-Pacific.”
There were about 2,000 deaths per year among the approximately 100,000 Maori aged 45-74 in the late 1990s, and the researchers estimate that about 400 of these deaths were due to tobacco smoking. Among 100,000 non-Maori non-Pacific people aged 45-74 in the late 1990s there would have been about 750 deaths per year (less than half the Maori rate), and about 275 of these deaths would have been due to tobacco smoking.
“Making New Zealand smoke-free will be a win-win, preventing a substantial number of deaths among all ethnic groups and substantially reducing ethnic inequalities in death rates. It’s a policy no-brainer,” says Assoc Prof Blakely.
The importance of tobacco smoking stated, most of the difference in death rates between Maori and non-Maori non-Pacific people was due to other things. This study published in the Lancet, and the Decades of Disparity report published last month by these researchers, find that much of this difference – perhaps about half – was due to socio-economic factors like income, education, asset wealth and neighbourhood deprivation, he said.
The remainder of the differences in death rates between Maori and non-Maori non-Pacific Islands people will be due to a mixture of: unequal access to, and access through, health services; different exposures to healthy or disease producing environments (such as good quality housing, stressful situations, diet, exercise); and early childhood and early life experiences.
“Disparities in these factors, and in socioeconomic factors itself, are underpinned by historical and social processes that systematically disadvantage Maori such as colonisation, discrimination and racism,” Assoc Prof Blakely says.
Finally, the Lancet study finds that the contribution of tobacco to differences in death rates between Maori and non-Maori non-Pacific people, and by extension the contribution of tobacco to all Maori deaths, is less than previously estimated by the Ministry of Health using ‘standard’ international methods.
“It is clear that the previous estimate of about a third of all Maori deaths being due to tobacco is an overestimate,” Assoc Prof Blakely says.
There are two key reasons for this overestimate. First, the international standard method uses lung cancer rates to infer the percentage of all deaths due to smoking: lung cancer rates for Maori are greater than expected on the basis of active smoking alone. Second, the international standard method assumes that the relative increase in death rates for smokers compared to never smokers is the same for all population groups: but Blakely’s research team has recently shown that the relative increase in death rates is greater among non-Maori non-Pacific people than among Maori.
“However, our lowering of the previous Ministry of Health estimate of the contribution of tobacco to Maori mortality does not change the bottom-line,” continued Assoc Prof Blakely. “Tobacco smoking kills too many people in all ethnic groups, and kills a greater proportion of Maori than non-Maori non-Pacific people.”
The co-authors of this study were Drs Jackie Fawcett, Darren Hunt and Nick Wilson. The New Zealand Census Mortality Study (NZCMS), from which the work arose, was previously funded by the Health Research Council of New Zealand and now funded by the Ministry of Health and University of Otago. The NZCMS is conducted in collaboration with Statistics New Zealand.
Paper published online at the Lancet at: http://www.thelancet.com/journals/eop
SUPPORTING INFORMATION: How did the researchers arrive at their conclusions?
This paper in the Lancet is based on the New Zealand Census-Mortality Study (NZCMS). This study anonymously and probabilistically links mortality data to census data, thereby creating follow-up studies of the entire New Zealand census populations of 1981, 1986, 1991 and 1996 (and soon to be 2001). The 1981 and 1996 censuses asked about tobacco smoking.
Using the results published
in the Lancet today, assuming a 10% contribution of smoking
to the gap in death rates between Maori and non-Maori
non-Pacific people, and also using previous research on
smoking and mortality from the NZCMS 1 2, we have
constructed the graphic below. It shows many important
• the total death rate for 45-74 year old Maori is about 2000 per 100 000, over two and half times that for 45-74 year old non-Maori non-Pacific people of 750 per 100 000
• the death rate due to smoking among Maori (about 400 per 100 000) is greater than that among non-Maori non-Pacific people (about 275 per 100 000)
• the gap in death rates between the two ethnic groups is 1250 per 100 000 (2000 minus 750), and the contribution of smoking to this gap is about 125 per 100 000
• put simply, about 125 more deaths due to tobacco smoking occur among 100 000 Maori than among 100 000 non-Maori non-Pacific people.
1: Summarised death rates per 100 000 45-74 year olds for
non-Maori non-Pacific people, Maori, and the gap in death
rates between them, and the amount of each due to smoking:
males and females combined, based on 1996-99 NZCMS data
1. Hunt D, Blakely T, Woodward A, Wilson N. The
smoking-mortality association varies over time and by
ethnicity in New Zealand. Int J Epidemiol
2. Blakely T, Wilson N. The contribution of smoking to inequalities in mortality by education varies over time and by sex: Two national cohort studies, 1981-84 and 1996-99. Int J Epidemiol 2005;34(5):1054-1062.