Provisional all-ages suicide statistics for 2003

NEW ZEALAND HEALTH INFORMATION SERVICE

Home > health statistics > suicide facts

Provisional all-ages suicide statistics for 2003

This information is also available as a PDF file (724 kB)

Key points:
Suicide deaths in 2003

A total of 515 people died by suicide, compared with 465 in 2002.
The age-standardised suicide rate was 11.5 deaths per 100,000 population, compared with 10.8 in 2002.
The three-year moving average age-standardised rate of suicide for the total population increased to a peak of 14.0 deaths per 100,000 population for the 1995–1997 and 1996–1998 periods. It then decreased until the most recent period (2001–2003).
Males continue to have a higher age-standardised suicide rate than females (16.9 compared with 6.2 per 100,000 population respectively). From 1995, there was a decline in the male rate, and then after 2000 there was a general increase in the female rate.
The all-ages sex ratio for the suicide rate in New Zealand was 2.7 male suicides to every female suicide per 100,000 population.
The age-standardised rate of suicide was higher for Māori than for non-Māori. For Māori males and females the age-standardised rates were 21.1 and 6.4 deaths respectively per 100,000 population, and for non-Māori males and females they were 15.6 and 5.9 deaths per 100,000 population respectively.
For life-cycle age groups, for females, 15–24-year-olds had the highest age-specific suicide rate (11.0 per 100,000 population), while for males, 25–44-year-olds had the highest age-specific suicide rate (28.4 per 100,000 population).
New Zealand’s all-ages suicide rate was the sixth highest among selected OECD countries for males, and the fourth highest for females.
The least deprived areas of New Zealand had a suicide rate of 8.8 per 100,000 population compared with 13.2 per 100,000 population in the most deprived areas of New Zealand.
Trends by ethnicity, age group and region will be further explored in the publication Suicide Trends, due for release later in 2006. Three-year moving averages will be used in this document.

Hospitalisation for intentional self-harm in 2002/03

The age-standardised hospitalisation rate for suicide and intentional self-harm for the total population was 131.5 per 100,000 population, compared with 128.2 in 2001/02.
The sex ratio for hospitalisation for suicide and intentional self-harm in New Zealand was 2.1 female hospitalisations to every male hospitalisation per 100,000 population.

Technical notes: data
Source

All data in this publication was sourced from the New Zealand Health Information Service (NZHIS), except for two figures. Figure 1 data was sourced from the Injury Prevention Research Unit, University of Otago, and the international rates in Figure 13 were sourced from the World Health Organization (WHO).

Suicide deaths

The suicide mortality data contained in this report is provisional 2003 data for all ages. There are a small number of deaths (18) still subject to coroners’ findings, for which a cause of death has not yet been assigned. Final data will be released by the NZHIS.

Hospitalisation for suicide and intentional self-harm

Hospitalisation for intentional self-harm is an internationally recognised proxy measure for attempted suicide. It is a measure of the number of people who intentionally harmed themselves and were admitted to hospital. People who intentionally harm themselves and later die in hospital are included.

Data is collected from inpatient and day patient hospital admissions. Hospitalisation discharge data in this report is for the 2002/03 financial yea (1 July – 30 June).

People who intentionally harm themselves but are not admitted to hospital are not included; for example, those people treated by a general practitioner (GP) or an emergency department but not admitted to hospital.

When comparing data for hospitalisation for intentional self-harm between years, caution should be exercised due to changes in coding and treatment practices. In 1999 and 2000, New Zealand introduced the ICD-10-AM international classification of disease for morbidity and mortality statistics. This resulted in a modified inclusion criterion for the diagnosis of intentional self-harm. From 2000/01 psychiatric hospital discharges, previously excluded from the data, were included, greatly increasing the number of discharges recorded.

In addition, new treatments for overdose have increased the number of people treated on an outpatient basis; previously such cases would have been included in the hospitalisation data.

Some of the regional differences in hospitalisation for intentional self-harm rates between District Health Boards (DHBs) are due to different practices in reporting and patient management.

ICD codes

The ICD-9 codes used for both mortality and hospitalisations were E950–E959. The ICD-10 codes used were X60–X84.

Technical notes: definitions

Age-specific rates

An age-specific rate refers to the frequency with which suicide occurs relative to the number of people in a defined age group. Age-specific rates are presented for both five-year and life-cycle age groups.

Age-standardised rates or rate ratios

Age-standardised rates are rates that have been adjusted to take account of differences in the age distribution of the population over time or between different groups (eg, different ethnic groups).

Age-standardised rate ratios are the ratio of the two rates, taking into account differences in the group size and age structure.

The standard population used was Segi–s world population. The International Comparisons section used the WHO World population.

Deaths by suicide

Classification of a death as suicide is subject to a coroner–s inquiry, and only on completion of an inquest can a death be officially classified as suicide. In some cases the inquest will be heard over a year after the death, particularly if there are other factors surrounding the death that need to be investigated first, meaning that the suicide may be counted in a different year from the one in which it occurred.

District Health Board rates

Age-standardised rates were calculated for each District Health Board (DHB). Deaths from the years 2001 to 2003 were averaged to provide sufficient numbers to calculate robust rates. For hospitalisations for suicide and intentional self-harm, sufficient numbers allowed rates for a single year (the 2002/03 financial year) to be calculated.

New Zealand Deprivation Index

The New Zealand Deprivation Index 2001 (NZDep2001) (see Further reading) was used as the key indicator of socioeconomic status. It is an area-based index of deprivation based on Census 2001 variables (eg, income, house ownership and qualifications) and calculated at meshblock level and also at census area unit (CAU) level. In this report, 1996 domicile codes were mapped forward to the 2001 domicile code (boundaries for 2001 domicile codes and 2001 CAUs are the same) for the assignation of deprivation. NZDep2001 CAUs were divided into five quintiles, where quintile 1 is the least deprived and quintile 5 the most deprived.

Suicide numbers, rates and ratios

The number of suicide deaths refers to the actual number of people who have died by suicide.

The rate of suicide refers to the frequency with which suicide occurs relative to the number of people in a defined population and a defined time period.

Rate ratios indicate how many times suicide is reported in one population group compared to another.

Three-year moving average

Three-year moving average age-standardised rates are the average age-standardised rates for rolling three-year periods, that is, 1983–1985, 1984–1986, 1985–1987, etc. The three-year moving averages are plotted on the mid-point year. For example, the 2001–2003 three-year moving average is plotted on the year 2002. Rates based on individual years tend to exhibit pronounced variation. By using the three-year moving average this variation is ‘smoothed’ for graphical presentation. This also allows for the underlying trends over time to be more clearly illustrated.

Three-year moving averages will be used in the Suicide Trends publication, which will be released in 2006.

Introduction

Top Back

NEW ZEALAND HEALTH INFORMATION SERVICE