Risk factors for suicide in Denmark

Diet and lifestyle 7. feb 2023 3 min Postdoctoral Fellow Megan Davies Written by Kristian Sjøgren

Researchers investigated the risk factors for suicide in Denmark. Having a mother with a mental disorder and having a dead father were associated most strongly with the risk of suicide, and the level of education and type of jobs in the immediate neighbourhood were less important determinants.

The World Health Organization (WHO) has asked the world’s countries to focus more thoroughly on measures that can reduce the number of people dying by suicide. Knowing the factors that are associated or not associated with the risk of suicide is therefore important.

Researchers investigated this in a study showing that whether the mother has a mental disorder and whether the father has died is strongly associated with the risk of suicide.

Conversely, the neighbourhood of residence is not very relevant, in contrast to the results of previous studies.

“We need to determine where to start with interventions to lower the risk of suicide. Investing in areas that do not substantially alter the risk while ignoring areas that do makes no sense. We therefore need specific data, which we provide in this study,” explains Megan Davies, Postdoctoral Fellow, Department of Public Health, University of Copenhagen.

The research, which was carried out at the Big Data Centre for Environment and Health (BERTHA) at Aarhus University, has been published in Psychological Medicine.

Denmark had the world’s highest suicide rate

Megan Davies and colleagues investigated whether specific factors are associated with an increased or reduced risk of suicide.

This involved examining how mental disorders in the family, attempted suicide, the death of any parents, the level of education, the type of work and the ethnic origin of people in the immediate neighbourhood are associated with the risk of suicide.

The researchers examined 1,723 deaths by suicide in Denmark from 1982 to 2015.

Denmark is an interesting country for research into suicide, because it had the most suicides per 100,000 population in the 1980s.

“This rate has declined since then, but there is still a long way to go because the number of people dying by suicide is still relatively high,” says Megan Davies.

Mother’s schizophrenia associated with the highest risk of suicide

The results generally show that having a mental disorder in the family or the death of a parent was more strongly associated with the risk of suicide than neighbourhood.

A person’s mother having a diagnosis of schizophrenia had the greatest association with the risk of suicide, more than doubling the risk to 129%. Similarly, the death of a person’s father also more than doubled the risk.

Whether the mother had died did not affect the risk as much, and whether the father had, or did not have schizophrenia did not affect the risk at all.

“The association between a mother’s mental health and the risk of suicide is not surprising. However, the fact that there is such a big difference between which parent has a mental disorder and which parent has died is surprising. Other research has shown that the death of a parent tends to be associated with an increased risk of suicide among children of the same sex. Identifying risk factors for suicide therefore requires examining the parents separately,” explains Megan Davies.

Neighbourhood very weakly associated with risk of suicide

The researchers found that neighbourhood is not that strongly associated with the risk of suicide.

If the neighbourhood has many people with low education, the risk only increased by 7%. Neighbourhoods with a higher proportion of manual workers increased the risk by 8%.

Conversely, the risk was 7% lower if the neighbourhood had many residents born outside Denmark. In addition, high population density in the neighbourhood was associated with 11% lower risk.

“However, the risk of suicide differs very little by neighbourhood and is therefore not a significant determinant of risk in Denmark,” says Megan Davies.

Poverty affects men’s risk more severely than women

Megan Davies explains that the study found surprising conclusions, since previous studies elsewhere indicated that people’s neighbourhood relatively strongly influences the risk of suicide.

This is not the case in Denmark. The researchers examined neighbourhood characteristics more closely while controlling for other important risk factors for suicide, and this enabled them to identify the effect of neighbourhood more precisely.

According to the researchers, the results highlight areas for focusing interventions to reduce the risk.

This may involve monitoring the children of mothers with schizophrenia more closely and starting interventions early if danger signals emerge. The same applies to the children who had a father who died during their childhood.

“People who live in neighbourhoods with many people close to the poverty line have a slightly increased risk. Neighbourhood may affect women and men differently, with men appearing to have a higher risk of suicide than women if they live in a high-poverty neighbourhood. However, identifying this is more difficult because men generally have a higher risk of death by suicide than women,” concludes Megan Davies.

My main research interests centre around health inequalities and outcomes amongst different social groups. I am also interested in mental health and i...

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