Opioid overdose mortality in Australia, 1964-1997: birth-cohort trends.

OBJECTIVE

To examine trends in rates of opioid overdose deaths from 1964 to 1997 in different birth cohorts.

DESIGN

Age-period-cohort analysis of national data from the Australian Bureau of Statistics.

MAIN OUTCOME MEASURES

Annual population rates of death attributed to opioid dependence or accidental opioid poisoning in people aged 15-44 years, by sex and birth cohort (in five-year intervals, 1940-1944 to 1975-1979).

RESULTS

The rate of opioid overdose deaths increased 55-fold between 1964 and 1997, from 1.3 to 71.5 per million population aged 15-44 years. The rate of opioid overdose deaths also increased substantially over the eight birth cohorts, with an incidence rate ratio of 20.70 (95% confidence interval, 13.60-31.46) in the 1975-1979 cohort compared with the 1940-1944 cohort. The age at which the cumulative rate of opioid overdose deaths reached 300 per million fell in successive cohorts (for men, from 28 years among those born 1955-1959 to 22 years among those born 1965-1974; for women, from 33 years among those born 1955-1959 to 27 years among those born 1965-1969).

CONCLUSIONS

Heroin use in Australia largely began in the early 1970s and rates of heroin use have markedly increased in birth cohorts born since 1950.