Part 2: National trends in longevity and mortality

This part presents a summary of mortality and longevity trends of the total population, Māori population and non-Māori population of New Zealand. Official complete life tables for New Zealand were first produced for the period 1880–1892, although these were for the non- Māori population only. For periods from 1950–1952, complete life tables have been prepared for the total New Zealand and Māori populations, in addition to life tables for the non-Māori population. It is important to note that changes to ethnic concepts, deaths measures and population measures affect the historical comparability of these life tables, particularly those relating to the Māori population (see Part 1: Background, including table 1.01).

Age distribution of deaths

There were 82,550 deaths of New Zealand residents registered during the 2000–2002 period, comprising 41,756 male deaths and 40,794 female deaths. More than three-quarters of these deaths were of people aged 65 years and over (figure 2.01). The proportion of male deaths occurring at age 65 years and over increased from 57 percent in 1950–1952 to 73 percent in 2000–2002, while the percentage of female deaths occurring at age 65 years and over increased from 62 to 82 percent over the same period.

In the 2000–2002 period, there were more male deaths in the 65–79 year age group than in the 80 years and over age group. In contrast, the number of female deaths at age 80 years and over was almost double the number of female deaths in the 65–79 year age group.

Children (those under 15 years) accounted for 2 percent of deaths in 2000–2002, whereas they accounted for 11 percent of deaths in 1950–1952 and 5 percent of deaths in 1975–1977. Infants (under one year old) account for about two-thirds of the deaths of children. Ages between 15 and 29 years accounted for another 2 percent of deaths in 2000–2002, with 72 percent of these being male.

Figure 2.01

Cumulative Deaths by Age and Sex
Total population
1950–1952 and 2000–2002

New Zealand life expectancy

Life expectancy at birth was 76.3 years for males and 81.1 years for females in 2000–2002 (table 2.01 and figure 2.02). Male life expectancy increased by 1.9 years from 74.4 years in 1995–1997. Female life expectancy increased by 1.4 years from 79.7 years in 1995–1997. The five-yearly increase in male life expectancy between 1995–1997 and 2000–2002 was the highest recorded during the last century. Over the last quarter of a century (1975–1977 to 2000–2002), male life expectancy at birth increased by 7.3 years. This compares with an increase of only 1.8 years in the previous 25 years, during which male life expectancy at birth decreased slightly between 1960–1962 and 1965–1967 (as a result of an increase in mortality rates from heart disease, cancer and motor vehicle accidents). Female life expectancy at birth increased by 5.7 years between 1975–1977 and 2000–2002. Like males, the female gain was greater than that seen in the previous 25-year period, when female life expectancy at birth increased by 4.2 years.

Figure 2.02

Life Expectancy at Birth
1901–2002

Note: Life tables before 1950 were prepared for the non-Māori population only.

Figure 2.03

Five-yearly Change in Life Expectancy at Birth
Total population
1950–2002

Māori and non-Māori life expectancy

The 2000–2002 life tables indicate that a newborn Māori boy can expect to live 69.0 years and a newborn Māori girl 73.2 years (table 2.01). This is an increase of 2.4 years for males and 1.9 years for females over the revised 1995–1997 figures of 66.6 years and 71.3 years for males and females, respectively.

For non-Māori in 2000–2002, a newborn boy can expect to live 77.2 years and a newborn girl 81.9 years. This is an increase of 1.8 years for males and 1.3 years for females over the revised 1995–1997 figures of 75.4 years for non-Māori males and 80.6 years for non-Māori females.

Māori and non-Māori life expectancy figures for 1995–1997 and 2000–2002 are not directly comparable with figures for 1990–1992 and earlier. This is mainly because of the impact of the new ethnicity question on the birth and death registration forms which were implemented in September 1995. More details on the new forms are contained in Part 1 (Background) of this report.

Table 2.01

Life Expectancy at Selected Ages
Total, Māori and non-Māori populations
1950–2002

Māori/non-Māori differentials in life expectancy

During the period 1995–1997 to 2000–2002, Māori life expectancy increased more than non-Māori life expectancy. As a result, the non-Māori advantage over Māori in life expectancy at birth has narrowed slightly (table 2.02). Revised life tables for 1995–1997 suggest the difference was 8.8 years for males and 9.3 years for females. This has decreased by about half a year to 8.2 years for males and 8.8 years for females in 2000–2002.

Table 2.02

Difference between Māori and Non-Māori Life Expectancy
at Selected Ages
1950–2002

Male-female difference in life expectancy

Prior to 1975–1977, female life expectancy generally increased faster than that for males. As a result, the difference between female and male life expectancy at birth increased from 4.1 years in 1950–1952 to a peak of 6.4 years in 1975–1977 (table 2.03). Since then, male life expectancy has been increasing faster and in 2000–2002 the difference had narrowed to 4.8 years. The life expectancy at birth of males in 2000–2002 was attained 20 years earlier by females.

Table 2.03

Difference between Male and Female Life Expectancy
at Selected Ages, total population
1950–2002

Females also have a longevity advantage over males among both Māori and non-Māori. For the Māori population, male life expectancy increased more than female life expectancy between the periods 1995–1997 and 2000–2002. As a consequence the female longevity advantage decreased from 4.7 years in 1995–1997 to 4.2 years in 2000–2002. Among non-Māori, females can expect to outlive males by 4.8 years in 2000–2002, down from 5.2 years in 1995–1997.

The closing gap between male and female life expectancy has also been observed overseas, such as in Australia where the gap peaked at about seven years in the 1970s and early 1980s, but has declined to just over five years in 2000–2002 (Australian Bureau of Statistics, 2003b). Similarly, the difference between male and female life expectancies at birth in the United Kingdom decreased from 6.0 years in 1980–1982 to 4.7 years in 2000–2002 (Government Actuary's Department, 2004).

International comparison of life expectancy

Life expectancy at birth in New Zealand is higher than in the United States and the United Kingdom (table 2.04). However New Zealand male life expectancy is about two years lower than in Hong Kong and Japan and about a year lower than in Australia. The difference is greater for female life expectancy, with New Zealand almost four years lower than Hong Kong and Japan and one and a half years lower than Australia. Despite the lower life expectancy compared with some countries, higher life expectancy gains in New Zealand over the last five-year period mean the gap has closed. In fact the high gains over the last five-year period have seen New Zealand life expectancy surpass that for the Netherlands, and New Zealand female life expectancy also surpass that for the United Kingdom. Between 1995–1997 and 2000–2002, newborn male New Zealanders gained about an extra year of life compared with Sweden, Japan and the Netherlands, while newborn females gained about an extra year of life compared with the Netherlands and the United Kingdom.

Table 2.04

International Comparison of Life Expectancy at Birth

Age contribution to longevity differences

It is possible to determine the contribution that each age group has made to longevity differences between periods or between populations (eg Māori and non-Māori). This comparison involves calculating and comparing "hypothetical or temporary" life expectancies at each age. Hypothetical life expectancy is the average number of years that a group of people will live from age x to x + i years (where i is the age interval). For further methodological details on this process see Arriaga (1984).

The gains in life expectancy at birth between 1995–1997 and 2000–2002 were due largely to the reduction in death rates among the late working ages (50–64 years) and retirement ages (65–79 years). Reduced death rates among young adults (15–29 years) and the very old (80 years and over, especially females) also made a significant contribution (figure 2.04).

Figure 2.04

Age Contribution to Longevity Gain
Total population
1995–1997 to 2000–2002

Over a longer timeframe, between 1975–1977 and 2000–2002, it was also the late working ages (50–64 years) and retirement ages (65–79 years) which provided the majority of the gain in life expectancy (figure 2.05). Reduced death rates among infants, the middle ages (30–49 years) and females aged 80 years and over were also significant.

Figure 2.05

Age Contribution to Longevity Gain
Total population
1975–1977 to 2000–2002

Between the periods 1995–1997 and 2000–2002, about half of the gain in Māori life expectancy resulted from reductions in mortality rates at the late working and retirement ages (50–79 years) (figure 2.06). Significant contributions also resulted from mortality reductions for those aged 30–49 years and from young adult males (15–29 years).

Figure 2.06

Age Contribution to Longevity Gain
Māori population
1995–1997 to 2000–2002

About three-quarters of the difference between Māori and non-Māori life expectancy in 2000–2002 was due to lower non-Māori death rates at ages 45–79 years (figure 2.07). The difference partly reflects different rates of smoking and diabetes, as well as socio-economic differences. According to the 1996/1997 New Zealand Health Survey, Māori people were more than twice as likely to have been diagnosed with diabetes than European people, and nearly half of all Māori adults reported that they were current smokers compared with 23 percent of European adults (Ministry of Health, 1999). Similarly, the 1996 Census reported that 44 percent of Māori aged 15 years and over were regular smokers, compared with 21 percent of non-Māori (Statistics New Zealand, 1997a).

Figure 2.07

Age Contribution to Māori/Non-Māori Longevity Difference
2000–2002

Age-specific death rates

Total population

The New Zealand life table is not unusual by international standards. It is characterised by relatively high death rates in the first year of life (5 to 6 deaths per 1,000 live births). Death rates decrease to their lowest among ages 8–11 years then increase to a bulge around 20 years of age, especially for males (figure 2.08). Death rates then change little until the mid-30s for males and the late 20s for females, when they begin to increase gradually with age. There is 1 death per 100 people at about 60 years of age for males and 65 years of age for females. By about 85 years of age, death rates have reached 1 death per 10 people. Females experience lower death rates than males at all ages.

Figure 2.08
Age-specific Death Rates
Total population
2000–2002

Change between 1950–1952 and 2000–2002

Between 1950–1952 and 2000–2002, male and female death rates decreased at all ages. However, the decreases were not uniform across age or time (figures 2.09–2.11). Between 1950–1952 and 1975–1977, male death rates actually increased slightly at ages 17–21 years and at some ages between 48 and 88 years. The increase in male death rates around 20 years of age accentuated the 'accident hump' at age 15–29 years, so-called because accidents (especially motor vehicle accidents) were the leading cause of death at those ages. An accident hump was also evident among female death rates around 20 years of age in 1975–1977, although this was smaller than for males. These humps were still apparent in 1995–1997 but had become little more than a 'bulge' by 2000–2002.

Figure 2.09

Male Age-specific Death Rates
Total population
1950–1952, 1975–1977 and 2000–2002

Figure 2.10

Female Age-specific Death Rates
Total population
1950–1952, 1975–1977 and 2000–2002

Figure 2.11

Death Rates at Selected Ages
Total population
1950–2002
Males Females

Between 1950–1952 and 1975–1977, female death rates declined more than male death rates at almost all ages above 15 years (figure 2.12). Female death rates decreased by more than 20 percent at most ages, and by an average of 38 percent under 40 years. For males, the largest percentage decreases occured under 15 years of age, while little change was recorded between 40 and 90 years of age. Male death rates around 20 years of age increased.

Figure 2.12

Decrease in Age-specific Death Rates
Total population
1950–1952 to 1975–1977

The pattern of change in age-specific death rates between 1975–1977 and 2000–2002 was broadly similar for males and females (figure 2.13). For both sexes, all ages experienced declines in death rates over this period. As for 1950–1952 to 1975–1977, the largest percentage decreases in death rates between 1975–1977 and 2000–2002 occurred in the youngest ages. Over this 25-year period, death rates declined by 44–67 percent under 13 years of age. The smallest percentage decreases for males were experienced around 30 years of age, which conversely experienced high percentage decreases in death rates between 1950–1952 and 1975–1977. As with the previous 25-year period, the change in female death rates between 1975–1977 and 2000–2002 was more consistent across age than for males, averaging about 40 percent.

Figure 2.13

Decrease in Age-specific Death Rates
Total population
1975–1977 to 2000–2002

Māori and non-Māori

Non-Māori experience lower death rates than Māori at all ages (figure 2.14). Among males aged in their 50s and females aged in their 50s and 60s, Māori death rates are roughly three times that of non-Māori.

Chance of survival

Based on the 2000–2002 mortality experience, 95 percent of newborn babies can expect to reach 50 years of age (figure 2.15). After that, the chance of survival decreases rapidly, with a faster decline for males than for females. About 84 percent of newborn boys and 89 percent of newborn girls can expect to live to 65 years of age. About half of newborn boys are expected to reach 80 years of age, compared with almost two-thirds of newborn girls. The chance of reaching 100 years is about 1 in 200 for newborn boys and 1 in 50 for newborn girls.

Figure 2.15

Chance of Survival from Birth to Selected Ages
2000–2002

According to the 2000–2002 life tables, about 96 percent of newborn non-Māori babies can expect to reach 50 years of age compared with about 92 percent of newborn Māori babies (table 2.05). As age increases, the decrease in the chance of survival is more pronounced for Māori than for non-Māori. About half of newborn non-Māori boys are expected to reach age 80 years, compared with one-quarter of newborn Māori boys. For females, 67 percent of newborn non-Māori girls are expected to reach age 80 years, compared with 38 percent of newborn Māori girls.

Infant mortality

The New Zealand infant mortality rate has fallen markedly over the last 50 years. For males, the infant mortality rate decreased from 31.1 deaths per 1,000 live births in 1950–1952 to 7.2 deaths per 1,000 live births in 1995–1997, and further to 6.1 deaths per 1,000 live births in 2000–2002 (table 2.06). Females experienced a similar improvement, from 25.4 deaths per 1,000 live births in 1950–1952 to 6.3 deaths per 1,000 live births in 1995–1997, and further to 5.2 deaths per 1,000 live births in 2000–2002. The improvement in infant mortality is due to reductions in both the endogenous (related to the birth process) and exogenous (related to external circumstances) components of mortality in the first year of life.

Table 2.06
Infant Mortality Rate
Total population, 1950–2002

The 2000–2002 New Zealand infant mortality rates are a little higher than those in Australia (5.6 for males and 4.6 for females) and the United Kingdom (6.0 for males and 4.8 for females) for the same period. They are nearly twice those in Japan, which recorded only 3.3 deaths per 1,000 live births for males and 2.8 deaths per 1,000 live births for females in 2001. However the New Zealand rates are lower than those in the United States, which recorded 7.5 deaths per 1,000 live births for males and 6.1 deaths per 1,000 live births for females in 2001.

Causes of death

Diseases of the circulatory system (eg heart attacks, strokes) are the major cause of death in New Zealand. In the year ended December 2000 (the latest year for which cause of death data has been processed by the New Zealand Health Information Service), 41 percent of all deaths were due to this cause (figure 2.16). Cancer was the next biggest cause of death, accounting for 29 percent of deaths, followed by diseases of the respiratory system (8 percent) and accidents/poisonings/violence (6 percent). Diabetes, diseases of the nervous and digestive systems, mental disorders and other causes made up the remaining 16 percent.

Figure 2.16
Deaths by Cause
Total population, 2000

Eighty-six percent of deaths from circulatory diseases in 2000 were of people aged 65 years and over. Over the last two decades, mortality rates from circulatory diseases have dropped by 40 percent for males aged 65 years and over and 29 percent for females aged 65 years and over. For those aged 45–64 years the decreases have been greater, at 64 and 62 percent for males and females, respectively (table 2.07).

Table 2.07
Mortality Rates by Cause of Death
Total population
1980–2000

In contrast, mortality rates from cancer have shown different trends. For those aged 65 years and over, the rates in 2000 were higher than those recorded two decades earlier – up 8 percent for males and up 10 percent for females. For those aged 45–64 years, the rates have decreased by 31 and 23 percent for males and females, respectively, since 1980–1982. Cancer is the leading cause of death for people aged 45–64 years, accounting for 46 percent of deaths in 2000.

For people aged 15–24 years, accidents/poisonings/violence accounted for about 80 percent of male deaths and 60 percent of female deaths in 2000. Male deaths outnumbered female deaths from this cause by about 4 to 1 among the 15–24 year age group. Mortality rates from accidents/poisonings/violence have dropped by 31 percent for males and 38 percent for females aged 15–24 years since 1980–1982.