Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012

Abstract Background Suicide mortality and the rates by specific methods in a population may change over time in response to concurrent changes in relevant factors in society. This study aimed to identify significant changing points in method-specific suicide mortality from 1969 to 2012 in Norway. Me...

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Main Authors: Quirino Puzo, Ping Qin, Lars Mehlum
Format: Article
Language:English
Published: BMC 2016-03-01
Series:BMC Public Health
Subjects:
Online Access:http://link.springer.com/article/10.1186/s12889-016-2919-y
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author Quirino Puzo
Ping Qin
Lars Mehlum
author_facet Quirino Puzo
Ping Qin
Lars Mehlum
author_sort Quirino Puzo
collection DOAJ
description Abstract Background Suicide mortality and the rates by specific methods in a population may change over time in response to concurrent changes in relevant factors in society. This study aimed to identify significant changing points in method-specific suicide mortality from 1969 to 2012 in Norway. Method Data on suicide mortality by specific methods and by sex and age were retrieved from the Norwegian Cause-of-Death Register. Long-term trends in age-standardized rates of suicide mortality were analyzed by using joinpoint regression analysis. Results The most frequently used suicide method in the total population was hanging, followed by poisoning and firearms. Men chose suicide by firearms more often than women, whereas poisoning and drowning were more frequently used by women. The joinpoint analysis revealed that the overall trend of suicide mortality significantly changed twice along the period of 1969 to 2012 for both sexes. The male age-standardized suicide rate increased by 3.1 % per year until 1989, and decreased by 1.2 % per year between 1994 and 2012. Among females the long-term suicide rate increased by 4.0 % per year until 1988, decreased by 5.5 % through 1995, and then stabilized. Both sexes experienced an upward trend for suicide by hanging during the 44-year observation period, with a particularly significant increase in 15–24 year old males. The most distinct change among men was seen for firearms after 1988 with a significant decrease through 2012 of around 5 % per year. For women, significant reductions since 1985–88 were observed for suicide by drowning and poisoning. Conclusions The present study demonstrates different time trends for different suicide methods with significant reductions in suicide by firearms, drowning and poisoning after the peak in the suicide rate in the late 1980s. Suicide by means of hanging continuously increased, but did not fully compensate for the reduced use of other methods. This lends some support for the effectiveness of method-specific suicide preventive measures, such as restrictions to the access to firearms, which had been implemented in Norway during the relevant time period.
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spelling doaj.art-c445a4e48d9d442683eddac7b68fc2892022-12-22T02:56:48ZengBMCBMC Public Health1471-24582016-03-011611910.1186/s12889-016-2919-yLong-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012Quirino Puzo0Ping Qin1Lars Mehlum2National Centre for Suicide Research and Prevention, Faculty of Medicine, University of OsloNational Centre for Suicide Research and Prevention, Faculty of Medicine, University of OsloNational Centre for Suicide Research and Prevention, Faculty of Medicine, University of OsloAbstract Background Suicide mortality and the rates by specific methods in a population may change over time in response to concurrent changes in relevant factors in society. This study aimed to identify significant changing points in method-specific suicide mortality from 1969 to 2012 in Norway. Method Data on suicide mortality by specific methods and by sex and age were retrieved from the Norwegian Cause-of-Death Register. Long-term trends in age-standardized rates of suicide mortality were analyzed by using joinpoint regression analysis. Results The most frequently used suicide method in the total population was hanging, followed by poisoning and firearms. Men chose suicide by firearms more often than women, whereas poisoning and drowning were more frequently used by women. The joinpoint analysis revealed that the overall trend of suicide mortality significantly changed twice along the period of 1969 to 2012 for both sexes. The male age-standardized suicide rate increased by 3.1 % per year until 1989, and decreased by 1.2 % per year between 1994 and 2012. Among females the long-term suicide rate increased by 4.0 % per year until 1988, decreased by 5.5 % through 1995, and then stabilized. Both sexes experienced an upward trend for suicide by hanging during the 44-year observation period, with a particularly significant increase in 15–24 year old males. The most distinct change among men was seen for firearms after 1988 with a significant decrease through 2012 of around 5 % per year. For women, significant reductions since 1985–88 were observed for suicide by drowning and poisoning. Conclusions The present study demonstrates different time trends for different suicide methods with significant reductions in suicide by firearms, drowning and poisoning after the peak in the suicide rate in the late 1980s. Suicide by means of hanging continuously increased, but did not fully compensate for the reduced use of other methods. This lends some support for the effectiveness of method-specific suicide preventive measures, such as restrictions to the access to firearms, which had been implemented in Norway during the relevant time period.http://link.springer.com/article/10.1186/s12889-016-2919-ySuicideMethodsChanging trendsEpidemiologyJoinpoint analysis
spellingShingle Quirino Puzo
Ping Qin
Lars Mehlum
Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
BMC Public Health
Suicide
Methods
Changing trends
Epidemiology
Joinpoint analysis
title Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
title_full Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
title_fullStr Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
title_full_unstemmed Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
title_short Long-term trends of suicide by choice of method in Norway: a joinpoint regression analysis of data from 1969 to 2012
title_sort long term trends of suicide by choice of method in norway a joinpoint regression analysis of data from 1969 to 2012
topic Suicide
Methods
Changing trends
Epidemiology
Joinpoint analysis
url http://link.springer.com/article/10.1186/s12889-016-2919-y
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AT larsmehlum longtermtrendsofsuicidebychoiceofmethodinnorwayajoinpointregressionanalysisofdatafrom1969to2012