Suicide in the Canary Islands, 1977-1983

Accidents and undetermined deaths: re-evaluation of nationwide samples from the Scandinavian countries

Background

National mortality statistics should be comparable between countries that use the World Health Organization’s International Classification of Diseases. Distinguishing between manners of death, especially suicides and accidents, is a challenge. Knowledge about accidents is important in prevention of both accidents and suicides. The aim of the present study was to assess the reliability of classifying deaths as accidents and undetermined manner of deaths in the three Scandinavian countries and to compare cross-national differences.

Methods

The cause of death registers in Norway, Sweden and Denmark provided data from 2008 for samples of 600 deaths from each country, of which 200 were registered as suicides, 200 as accidents or undetermined manner of deaths and 200 as natural deaths. The information given to the eight experts was identical to the information used by the Cause of Death Register. This included death certificates, and if available external post-mortem examinations, forensic autopsy reports and police reports.

Results

In total, 69 % (Sweden and Norway) and 78 % (Denmark) of deaths registered in the official mortality statistics as accidents were confirmed by the experts. In the majority of the cases where disagreement was seen, the experts reclassified accidents to undetermined manner of death, in 26, 25 and 19 % of cases, respectively. Few cases were reclassified as suicides or natural deaths. Among the extracted accidents, the experts agreed least with the official mortality statistics concerning drowning and poisoning accidents. They also reported most uncertainty in these categories of accidents. In a second re-evaluation, where more information was made available, the Norwegian psychiatrist and forensic pathologist increased their agreement with the official mortality statistics from 76 to 87 %, and from 85 to 88 %, respectively, regarding the Norwegian and Swedish datasets. Among the extracted undetermined deaths in the Swedish dataset, the two experts reclassified 22 and 51 %, respectively, to accidents.

Conclusion

There was moderate agreement in reclassification of accidents between the official mortality statistics and the experts. In the majority of cases where there was disagreement, accidents were reclassified as undetermined manner of death, and only a small proportion as suicides.

Are suicide deaths under-reported? Nationwide re-evaluations of 1800 deaths in Scandinavia

OBJECTIVE

Valid mortality statistics are important for healthcare planning and research. Suicides and accidents often present a challenge in the classification of the manner of death. The aim of this study was to analyse the reliability of the national suicide statistics by comparing the classification of suicide in the Scandinavian cause of death registers with a reclassification by 8 persons with different medical expertise (psychiatry, forensic pathology and public health) from each of the 3 Scandinavian countries.

METHODS

The cause of death registers in Norway, Sweden and Denmark retrieved available information on a sample of 600 deaths in 2008 from each country. 200 were classified in the registers as suicides, 200 as accidents or undetermined and 200 as natural deaths. The reclassification comprised an assessment of the manner and cause of death as well as the level of certainty.

RESULTS

In total, 81%, 88% and 90% of deaths registered as suicide in the official mortality statistics were confirmed by experts using the Swedish, Norwegian and Danish data sets, respectively. About 3% of deaths classified as accidents or natural deaths in the cause of death registers were reclassified as suicides. However, after a second reclassification based on additional information, 9% of the natural deaths and accidents were reclassified as suicides in the Norwegian data set, and 21% of the undetermined deaths were reclassified as suicides in the Swedish data set. In total, the levels of certainty of the experts were 87% of suicides in the Norwegian data set, 77% in the Swedish data set and 92% in Danish data set; the uncertainty was highest in poisoning suicides.

CONCLUSIONS

A high percentage of reported suicides were confirmed as being suicides. Few accidents and natural deaths were reclassified as suicides. Hence, reclassification did not increase the overall official suicide statistics of the 3 Scandinavian countries.

The reliability of suicide statistics: a systematic review

BACKGROUND

Reliable suicide statistics are a prerequisite for suicide monitoring and prevention. The aim of this study was to assess the reliability of suicide statistics through a systematic review of the international literature.

METHODS

We searched for relevant publications in EMBASE, Ovid Medline, PubMed, PsycINFO and the Cochrane Library up to October 2010. In addition, we screened related studies and reference lists of identified studies. We included studies published in English, German, French, Spanish, Norwegian, Swedish and Danish that assessed the reliability of suicide statistics. We excluded case reports, editorials, letters, comments, abstracts and statistical analyses. All three authors independently screened the abstracts, and then the relevant full-text articles. Disagreements were resolved through consensus.

RESULTS

The primary search yielded 127 potential studies, of which 31 studies met the inclusion criteria and were included in the final review. The included studies were published between 1963 and 2009. Twenty were from Europe, seven from North America, two from Asia and two from Oceania. The manner of death had been re-evaluated in 23 studies (40-3,993 cases), and there were six registry studies (195-17,412 cases) and two combined registry and re-evaluation studies. The study conclusions varied, from findings of fairly reliable to poor suicide statistics. Thirteen studies reported fairly reliable suicide statistics or under-reporting of 0-10%. Of the 31 studies during the 46-year period, 52% found more than 10% under-reporting, and 39% found more than 30% under-reporting or poor suicide statistics. Eleven studies reassessed a nationwide representative sample, although these samples were limited to suicide within subgroups. Only two studies compared data from two countries.

CONCLUSIONS

The main finding was that there is a lack of systematic assessment of the reliability of suicide statistics. Few studies have been done, and few countries have been covered. The findings support the general under-reporting of suicide. In particular, nationwide studies and comparisons between countries are lacking.

Is the time of suicide a random choice? A new statistical perspective

The problem of the time distribution of suicide has aroused the interest of many authors, but their findings often appear uncertain and contradictory. These inconsistencies can be partially explained by both the choice of the sample and the statistical method used for the analysis. In this study, in order to reveal expected and unexpected periodicities in the time distribution of suicides, we analyzed a small but complete and very homogeneous sample of suicides which occurred in the Mountain District of the Metauro River Valley in Italy in the period 1960-1994. A recent circular statistics technique, the "maximization of mean vector length" was used. We found no significant weekly and lunar patterns, but significant seasonal and intraseasonal cycles, with peaks in March and at the beginning of each season. The superposition of these two significant cyclic trends was also studied.

Use of statistical techniques in studies of suicide seasonality, 1970 to 1997

The effect of seasons on suicides has been suggested repeatedly. In order to reveal a true seasonal pattern, an appropriate statistical technique, which is sensitive to a specific type of cyclic variation in the data, must be chosen. This study is a review of the use of statistical techniques for seasonality and of some important characteristics of study samples that were evaluated from 46 original suicide seasonality articles published in major psychiatric journals. The results showed that statistical techniques were applied in a majority of articles, but they were commonly lacking regarding analyses, which compared seasonal patterns among subgroups of a population. In recent studies more sophisticated statistical techniques were utilized for seasonality, like spectral analyses, as compared with earlier studies, in which the emphasis was on chi-square tests. Lack of reporting essential features of the data, such as the sample size and monthly values of suicides, were frequent. The calendar effect was adjusted only in 11 studies. Some recommendations concerning the methodological and reporting issues are summarized for future articles on the seasonal affect on suicides.

Elevated suicide rates on the first workday: a replication in Israel

This study verified variations in suicide rates throughout the days of the week among Israel Defense Force soldiers during 1974 - 2001. Results confirmed the findings of most previous studies. The first workday was associated with a 60% increase in suicide rate among young men. This increase was not observed among female reserve or professional soldiers. This finding might indicate a particular susceptibility of men to contextual and situational factors. The explanation of the increased suicide risk on the first workday stresses such processes as the broken-promise effect as well as difficulty in facing the demands of service and transitions from the weekend to the workweek.

Timing of completed suicides among residents of Olmsted County, Minnesota, 1951-1985

Previous studies of suicide timing may have been biased by incomplete ascertainment of suicides and by delays between the suicidal act and subsequent death. Those potential biases were assessed and minimized in this population-based study by using the unique resources of the Rochester Epidemiology Project in Olmsted County, Minnesota. Using these more accurate data, we confirmed previous reports of no excess suicides on birthdays (+/- 3 days), or during 3 United States national holidays. While most prior reports found excess post-holiday suicides and suicide peaks on Mondays, those findings were not observed in Olmsted County. Because 93% of deaths occurred on the date of the suicidal act, using date of death instead of the actual date of suicide is sufficient for most research purposes.

Suicide in the Canary Islands: standardized epidemiological study by age, sex, and marital status

The authors analyze the distribution of suicides according to the variables of sex, age and marital status in the Canary Islands, during the period 1977-1983, by means of a register that they themselves created in order to correct serious deficiencies in the official data. There were notable differences between men and women, and the tendencies observed in each case are also very different. The authors argue that this makes it necessary to separate the sexes in the epidemiological studies on suicide. The advantages and disadvantages of the direct and indirect methods in the standardization of the specific suicide rates are discussed. The specific rates related to marital status are standardized according to age and, likewise, the specific rates related to age are standardized according to marital status, for each sex. Once confounding factors are controlled, it becomes clear that there is a direct relationship between age and suicide. After adjusting for age, it is noted that the pattern of risk for different marital status categories varies by sex.