Dear Hajime,
Your observations in Japan are mirrored in Australia; that there is a mortality gradient based on social deprivation. We have statutory Child Mortality Review committees in each state, which are charged with reviewing each death and assigning causation, and identifying preventable factors. This committee structure has been operational for about 40 years.
Over the last 2 decades we have identified the complex causal pathway to child deaths, which often includes an underlying condition, an acute intercurrent event, and social and economic disadvantage.
A mortality gradient based on sociodemographic characteristics exists in all countries, and within all countries in which this has been studied. In Victoria (one of the southern states in Australia) the mortality gradient is 1.5 to 2, based on a population measure called the Relative Index of Social Disadvantage, which classifies each post-code (suburb, village, town) into quintiles of RISD. This means children and adolescents in the most disadvantaged quintile are 1.5 to 2 times as likely to die as those in the most advantaged quintile. The causes of deaths disproportionate among those with social disadvantage include: sudden unexpected death in infancy (SUDI or SIDS), accidents / trauma, suicide, epilepsy, asthma, infections, malignancy, congenital problems and other chronic health conditions.
In analysing each death we try to record specific adverse social circumstances, including:
Unsafe home environment
Out of home care
Neglect
Lost to medical follow-up
Delayed presentation
Unvaccinated child
Lack of adequate adult supervision
Homeless family or extreme poverty
Domestic violence in family
Evidence of parental alcohol or drug abuse
Previous sibling death in family
Known to child protection services
Victorian report
CCOPMM 2024 annual report - For births and perinatal, maternal and child and adolescent deaths in Victoria in 2023<https://www.safercare.vic.gov.au/sites/default/files/2025-11/CCOPMM%2020...
And the report from the Northern Territory, which I think grapples with the social context very well:
Child Deaths Review and Prevention Committee annual report<https://agd.nt.gov.au/media/docs/annual-reports/cdrpc-annual-reports/cdr...
WHO has a framework for mortality auditing, which is a little different if done at a hospital level compared to at a state jurisdictional level. But it may also be useful:
Improving the quality of paediatric care: an operational guide for facility-based audit and review of paediatric mortality<https://iris.who.int/items/4dc2f21a-b6d1-4692-8e65-d957f53720cf>
New WHO guidelines on paediatric mortality and morbidity auditing<https://adc.bmj.com/content/archdischild/104/9/831.full.pdf>
And yes, suicide is a major cause of mortality in adolescents, and the tragic end of the much larger problem of unaddressed mental health issues, or adverse social circumstances. The factors we see in suicides include family dislocation or dysfunction, bullying, sexual abuse, social media pressures, loneliness, low self-esteem, impulsivity, and despair. As a review body, we often have an incomplete understanding of the full background to suicides, for understandable reasons. This is a more complicated topic than there is scope here to discuss.
With kind regards,
Trevor
CHIFA profile:
Trevor Duke is Director of the Centre for International Child Health at the University of Melbourne, Australia which is a WHO Collaborating Centre for Research and Training in Child and Neonatal Health. The Centre is extensively involved with WHO's Child Survival Strategy and Hospital Care Quality Improvement approach. Trevor works closely with countries throughout the Asia-Pacific region, particularly Papua New Guinea and the Solomon Islands on child health policy, research and health worker training. trevor.duke AT rch.org.au