Calculations of life expectancy and rates of death by disease rely on the collection and analysis of health records and census data, and registrations of births and deaths. These records are not always reliable, so their use to indicate trends is sometimes debated by experts in this field. They are, however, essential to an understanding of population changes.
The British passion for collecting and interpreting population statistics was brought to New Zealand from the 1840s by European settlers. In 19th-century Britain, there was great enthusiasm for identifying health and social trends, and quantifying death rates.
In England, national registration of births and deaths began in 1837. For death records, the person’s age and gender were recorded, and soon the cause of death was included as well. Dr William Farr helped develop this official data system and was the first to use it to analyse death statistics extensively. His basic statistical methods were still in use in the early 21st century.
The most powerful technique for analysing mortality was the life table, a tool dating from the 17th century. In life tables, records of birth and death rates were subjected to a formula to calculate life expectancy at particular times. By the late 19th century these tables were being computed in ways that resemble state-of-the-art practices in the 21st century.
Using population statistics, Farr identified what he called ‘healthy districts’, which tended to be rural areas. Cities were seen as overpopulated and filthy, and therefore unhealthy. Colonies such as New Zealand were regarded as distant healthy districts, so statistics about their inhabitants were of interest in Britain for comparative purposes.
In New Zealand, Pākehā births and deaths were officially recorded from 1848, and from 1875 fuller information about the person and their cause of death was collected for death certificates. By the 1870s virtually all Pākehā deaths were registered, so by that time the records could be usefully analysed. Only since the later 20th century, however, has the cause of death been described well enough to interpret fully.
From the 19th century, strenuous efforts were made by missionaries, travellers, physicians, district magistrates and census enumerators to record Māori population and health statistics. Official Māori birth and death records were kept from 1913. Despite these attempts, registration of Māori births and deaths did not occur reliably until after the Second World War. However, techniques to analyse populations with incomplete data can be applied to reconstruct Māori population history back to the 19th century.
Internationally, deaths caused by infections such as measles, smallpox and tuberculosis have declined and deaths caused by conditions associated with ageing or lifestyle, such as heart disease and lung cancer, have increased. This change in the types of diseases that cause death is called ‘the epidemiological transition’. It is usually accompanied by a reduction in childhood deaths and an increase in how long people live.
Like most societies across the world, New Zealand has experienced this shift in disease and death patterns. Over time, diseases of old age and lifestyle have replaced infections as the main types of sickness and primary causes of death.
New Zealand has had two major epidemiological transitions. For non-Māori the transition occurred very early, in the 19th century. For Māori, the transition happened much later, in the 20th century.
Epidemiological transition resulted in radical improvements in longevity. Some universal trends in life expectancy are seen in all epidemiological transitions.
Increase in life expectancy is one of the most significant historical developments to have occurred worldwide since the second half of the 18th century. Life expectancy then was 20–35 years. By the early 21st century it had nearly tripled, to 60–80 years and more.
In New Zealand in the 21st century the life expectancy of women is higher than that of men. In the past, men’s life expectancy could exceed that of women, notably during women’s childbearing years. This is common in societies with both high mortality and high fertility, and was particularly noticeable in Pākehā settler society in the 1870s and Māori society in the 1940s. It has been suggested that poorer female survival during the reproductive years is due to the physiological burden of childbearing. This weakens women so they die not only from complications of pregnancy and labour, but from other causes, notably tuberculosis.
New Zealand’s British settlers started their epidemiological transition – in which diseases of old age and lifestyle replace infections as the main cause of death – very early and passed through it ahead of other populations worldwide.
In the 1850s Arthur Thomson, surgeon major of the British Army’s 58th Regiment, which was stationed in northern New Zealand, analysed death rates and disease statistics and found that soldiers in New Zealand had lower rates of death than their counterparts in other parts of the empire, including the United Kingdom. He published his conclusions in a book, The story of New Zealand: past and present, savage and civilised (1859), and they have been supported by recent research.
Thomson believed that one reason for New Zealand’s lower death rates was its superior climate. Although that explanation is debatable, it was supported and elaborated by doctor Alfred Newman in an address to the New Zealand Institute (later the Royal Society) in 1882.
There are a number of possible reasons for settler New Zealand’s early epidemiological transition. Settlers had a better diet than their peers in Britain – perhaps due to the temperate climate, as fruit and vegetables could be grown year-round in most areas.
The colony had a high per-capita gross domestic product, and this general prosperity meant that individuals and families had a relatively high standard of living. This was enhanced by economic and social-welfare legislation in the 1890s and 1900s. Also, settlement was dispersed throughout the country, lessening the spread of infections. A rapid decline in family size in the settler population had beneficial effects on child health, and from the mid-1870s to mid-1890s there was a marked decline in child mortality.
Favourable living conditions had a cumulative effect, and life expectancy at birth for Pākehā rose markedly. Pākehā women in New Zealand were the first population in the world to reach a life expectancy of 55 years, in the late 1870s. In 1874 life expectancy was 48 for Pākehā men and 50 for Pākehā women, and by 1891 it was 55 for men and 58 for women. It was 58 for men and 60 for women in 1901, and 65 for men and 68 for women in 1931.
There is ongoing research to investigate whether another reason for the early epidemiological transition of British settlers could have been selective emigration to New Zealand of people from ‘healthy districts’ in Britain. However, initial results suggest that large numbers of settlers came from London and Scotland, which both had high mortality rates.
The Pākehā population also grew. By 1860 it was around 60,000, about the same as the Māori population. From this time it grew quickly, while the Māori population declined. By 1896, when the Māori population was around 42,000, its lowest point, the Pākehā population was 700,000, and it had reached 1 million by 1911.
Non-Māori life expectancy has continued to grow steadily since the Second World War. In 1951 life expectancy was 68 for men and 72 for women; in 1961 it was 69 and 75 respectively. In 1976 men could expect to live to 69 and women to 76, and in 1986 the figures were 71 for men and 77 for women. In 1996 the expectation was 75 for men and 81 for women; by 2013 it was 80 for men and 84 for women.
Māori started the epidemiological transition (in which diseases of old age and lifestyle replace infections as the main cause of death) much later than Pākehā, because of the effects of colonisation on their disease and death rates.
Evidence suggests that Māori life expectancy at the time of Captain James Cook’s visits to New Zealand (between 1769 and 1777) was similar to that in some of the most privileged 18th-century societies. Māori may have had a life expectancy at birth of about 30. After European contact, however, there was a major decline in Māori life expectancy. By 1891 the estimated life expectancy of Māori men was 25 and that of women was just 23.
The Māori population also declined steeply. It is estimated to have been about 100,000 in 1769. By 1840 it was probably between 70,000 and 90,000. At its lowest point in 1896 it was around 42,000.
There is a common belief that musket warfare between 1810 and 1840 caused heavy mortality among Māori. However, war deaths were not great in number compared with the deaths from other causes. From 1810 to 1840 there were around 120,000 deaths from illness and other ‘normal’ causes, an average of 4,000 a year. In the same period warfare caused perhaps 700 deaths per year.
Although the impact of introduced diseases was severe, Māori were dispersed over a wide area and so were less at risk than Pacific Islanders living on small islands. The first New Zealand-wide epidemic of measles in 1854 may have killed 7% of the Māori population. This is an alarming figure, but far below that for Fiji’s first outbreak, which killed an estimated 20% of their population.
Introduced diseases were the major reason for the Māori population decrease. In the 1890s the Māori population had fallen to about 40% of its pre-contact size. Decline accelerated after the Treaty of Waitangi was signed in 1840 and settlers began to arrive in greater numbers. This influx exposed Māori to new diseases, leading to severe epidemics.
Newly introduced illnesses that were common in Europe, such as measles, mumps and whooping cough, took a terrible toll among Māori, who had no immunity to them. In European populations, such diseases tended to affect mainly children. Among Māori, however, they affected both adults and children, often with devastating results. Introduced respiratory diseases, particularly bronchitis and tuberculosis, also killed large numbers of Māori in the 19th century.
The influx of settlers led to a demand for land, and from the 1840s Māori were under great pressure to sell their ancestral territories. Loss of Māori land – through confiscation following the 1860s wars, Crown purchase and the Native Land Court – led to the displacement of large numbers of Māori. Deprived of their land, tribes were in many instances reduced to poverty, with no option but to live in overcrowded and unhygienic conditions. Losing land, they also lost access to traditional food sources. Lack of resources, overcrowding and poor diet helped disease to take hold and spread.
In 1886 over 50% of Māori who died were children. When Whina Te Wake (later Whina Cooper) was born in the 1890s, 25% of Māori girls died before reaching nine months of age, and 50% before they turned seven. In comparison, fewer than 10% of Pākehā girls died before nine months, and only about 15% before the age of seven. Significantly fewer Māori girls survived to childbearing age, limiting future population growth.
After 1891 Māori life expectancy began to increase, reaching 35 for men and 30 for women in 1911. In the later 1890s the Māori population also began to grow, following a decrease in childhood deaths and an increase in the number of people surviving to have children.
Rapid population recovery occurred in the early 1900s, assisted by gains in immunity to diseases among Māori. Immunity improved over time, as a result of repeated exposure to European diseases. The effects of illness were increasingly less severe. Another factor was the spread of Māori-led health initiatives initiated by former students of Te Aute College, including the doctors Peter Buck (Te Rangi Hīroa) and Māui Pōmare.
In the first half of the 20th century Māori life expectancy continued to rise. This improvement owed much to the efforts of Peter Buck and Edward Ellison, who worked through the Division of Māori Hygiene which had been established in the Department of Health in 1921. In 1926 life expectancy at birth for Māori men was 42; for women it was 40. By 1945 Māori men could expect to live to 49 and women to 48. However, Māori life expectancy still lagged well behind that for Pākehā. There were several reasons.
Most Māori continued to live in communities in isolated rural areas. They remained vulnerable to severe epidemics of illnesses such as measles, often accompanied by diarrhoea, bronchitis, pneumonia and dysentery. The Māori death rate during the influenza pandemic of 1918 was eight times that of Pākehā. Serious epidemics occurred regularly in Māori communities until the 1940s.
Unlike many other countries, New Zealand did not suffer devastating diseases such as typhus, malaria or bubonic plague. An outbreak of smallpox in 1913 was contained by public health measures, and limited in its impact because many Māori had been vaccinated by missionaries. Māori doctor Peter Buck played a major role in responding to this epidemic. He later published a significant paper comparing numbers of deaths for vaccinated and un-vaccinated Māori.
Māori were also still severely disadvantaged socially and economically, with poorer housing and nutrition than Pākehā. Diseases such as tuberculosis were closely associated with socio-economic factors such as overcrowded housing.
From 1945 to 1966, the epidemiological transition of the Māori population accelerated. There was a major decline in infant mortality and in deaths at all ages from infectious diseases. Life expectancy increased. During the period there was a major shift of Māori from rural communities to urban centres, which gave them better access to health facilities. Māori also, like Pākehā, benefited from improvements in medical technology. Most significantly, targeted health and social security measures directed at housing and support for families together helped combat the scourge of tuberculosis.
Tuberculosis is a highly contagious disease that affects many parts of the body, but usually the lungs. In pulmonary tuberculosis, patients have chest pain, cough blood, and lose weight. They can easily infect other people by coughing, sneezing, speaking and spitting, and bad living conditions help the disease to spread. Until the development of antibiotics in 1946, there was no effective cure.
The rapid reduction in Māori tuberculosis mortality between 1945 and 1961, in a period when medical treatments were not yet fully developed, was a triumph for public health in New Zealand. In the 1930s Dr Harold Turbott carried out a health survey among Māori on the East Coast, which showed high levels of conditions that usually accompanied tuberculosis – poverty, malnutrition and overcrowded housing. The survey stimulated an attempt to reduce health inequalities between Māori and non-Māori, focusing especially on tuberculosis. Health policy was synchronised with social policy following the passage of the Social Security Act 1938. Measures included taking chest X-rays of 10% of Māori each year, sending people with tuberculosis to sanatoriums, and giving families of tuberculosis patients nutritional supplements, income support and top priority for state housing assistance.
As well as a continuing increase in life expectancy there was a gender shift. Until 1945 Māori men had a greater life expectancy than women, although for some cohorts of men bursts of improvement in life expectancy were followed by periods when life expectancy decreased slightly. From 1951 this changed, reflecting the Pākehā pattern of women tending to live longer than men. In 1951 Māori life expectancy was 54 for men and 56 for women, and by 1961 it was 59 for men and 61 for women. In 1976 it was 63 for men and 68 for women, rising to 67 for men and 71 for women in 1996. Analysis of the life expectancy of particular birth cohorts suggests that Māori born in the early 1940s, especially men, were more likely to die by the time they reached their sixties than non-Māori.
The life-expectancy gap between Māori and Pākehā narrowed considerably from the 1970s. However, in the 21st century Māori life expectancy was still below non-Māori levels. In 2013 Māori men could expect to live to 73, compared with 80 for non-Māori men. Māori women had a life expectancy of 77, compared with 84 for non-Māori women.
In the 21st century Māori and Pākehā faced similar health issues. There had been a shift in causes of death, from communicable to non-communicable diseases. For both Pākehā and Māori, acute infectious, respiratory and diarrhoeal diseases and tuberculosis had given way to causes of death such as heart conditions, strokes and cancers. These chronic disorders, generally associated with old age, did occur in the past, but were more prominent in the 21st century because most people survived longer.
Proportions of non-communicable diseases causing death were changing. Public health measures were increasingly successful at reducing coronary heart disease and its risk factors. As a result, cardiovascular diseases were becoming less dominant causes of death, with cancers increasing in relative significance.
In the early 21st century, most people survived into the retirement age group, and long-term ill-health requiring intensive hospital care occurred typically amongst older people. Many middle-aged and older people required pharmaceutical interventions such as blood pressure medication, but their ability to cope with the physical challenges of daily life (often called ‘health expectancy’) was overwhelmingly reported as good, as in other OECD countries.
The radical but long-term changes in causes of death have had major implications for New Zealand health policies. Many health institutions and services were designed for conditions prevalent much earlier in the epidemiological transition. Meeting emerging situations was likely to be a major challenge.
Health expectancy is a measure of being able to undertake daily living tasks appropriate for a particular age. In the early 21st century Māori health expectancies in old age were close to those of Pākehā, but this was because their survival rates beyond late middle age were well below those of Pākehā, and only the hardy reached old age.
This was a challenge for health policy, which had to cater for the needs of the majority, yet respond to minority populations such as Māori, Pacific people and other disadvantaged groups.
In the 21st century most Māori and non-Māori of both sexes were surviving to middle age. But in late middle age and early old age, Māori levels of survival fell well below those of non-Māori. This is partly a consequence of higher levels of infectious diseases and inflammation among Māori during childhood. Out of any group of people born at the same time, only 38% of Māori men and 50% of Māori women would reach the age of 80, compared with 60% (men) and 71% (women) for New Zealanders of all ethnic groups combined. In the early 21st century Māori men and Pasifika men were increasingly likely to be using health services and this may have a positive impact on their health and life expectancy in the future.
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