[Decreasing incidence of suicide in the Netherlands, with changing methods].

OBJECTIVE

To determine time trends in the incidence of suicide mortality and in the methods used during the period 1970-2007, and to determine the resulting number of lost life years.

DESIGN

Retrospective dynamic cohort study in the Dutch population.

METHOD

Analyses were based on national register data (from the Statistics Netherlands) concerning suicide numbers and methods, and demographic characteristics of the population. Data were standardized for age and sex using the direct method, with the Dutch population of 2007 as a reference. Time trends were calculated using the Poisson regression model.

RESULTS

Since 1983 the standardized incidence of suicide decreased by 38% (95% confidence interval (95% CI): 36-40) from 14.8 per 100,000 in the peak year of 1983 to 8.3 per 100,000 in 2007. In the age group of 20-59 years the decrease was considerably stronger for women than for men, with rates of 47% (95% CI: 44-51) and 18% (95% CI: 14-22), respectively. The strongest decline was found in the group aged 60 years and over, with a decrease of 58% (95% CI: 55-60). There was a decrease in drowning as the suicide method, while the incidence of hanging increased. Over 43,000 life years were lost to suicide in the Netherlands in 2007. Of the total number of years lost, 82% occurred in the age group of 20 to 59 years.

CONCLUSION

The number of suicides in the Netherlands has declined substantially since 1983. Factors that may have contributed to this development remain unknown at present.