Parents may be connected to their children much more than they realize.

Previous studies have explored correlations about death and have found that adults have an increased risk of dying prematurely after the death of a spouse or child. However, not many have tried to take a look at how a parent's death could affect a child.

Titled "Mortality after Parental Death in Childhood: A Nationwide Cohort Study from Three Nordic Countries," a study released in the PLOS Medicine journal gathered national registry data, tracking down all the children born between 1968 and 2008 in Denmark, 1973 and 2006 in Sweden and 1987 and 2006 in Finland.

More than seven million people were included in the study, some of which were tracked for up to 42 years. Based on findings, children who lost a parent after six months of age and before turning 18 had 50 percent more risk of dying during the period of the study. At even greater risk are children whose parent passed away due to unnatural causes, but those at greatest risk were those whose parent committed suicide. Out of all the participants, 189,094 lost a parent between the period specified.

A total of 39,683 participants died during the follow-up period and researchers are excluding lack of health care or access to material needs as reasons for death because the participants were living in high-income countries. Therefore, increased risks of death are likely to be caused by genetic susceptibility as well as long-term effects of the death of a parent on the social well-being and health of a participant.

"Parental death in childhood was associated with a long-lasting increased mortality risk from both external causes and diseases, regardless of age and sex of the child and the deceased parent, cause of parental death, as well as population characteristics like socioeconomic background," concluded the research. This also means that healthcare and social support must be provided to the bereaved children, a task that may require a long period of time.

Children who died on the same day as their parents or those who died within 30 days of a parent passing away were mostly due to crime or an accident, so they were not included in the study.

The study was carried out by researchers from Denmark's Aarhus University, Sweden's Karolinska Institute and Finland's National Institute for Health and Welfare. Authors include: Jiong Li, Mogens Vestergaard, Carsten Obel, Sven Cnattingius, Mika Gissler and Jørn Olsen.