Prevalence of childhood adversity

The DANLIFE cohort includes all children born in Denmark since 1980, which so far totals more than two million people. Using the nationwide Danish registers, we have measured a wide range of stressful childhood adversities in DANLIFE (see the specific adversities and their definitions here). Parental separation (29%), parental long-term unemployment (25%), and parental somatic illness (12%), are so far the most frequently experienced adversities before 18 years of age, while parental drug abuse (2%), sibling psychiatric illness (1%), and sibling death (1%) have been the least common adversities. However, in the large population sample of DANLIFE, even these small proportions correspond to several thousand individuals (e.g., 10,543 individuals younger than 18 had experienced the death  of a sibling).

The proportions exposed to the specific childhood adversities varied substantially between the specific adversities, from 29% exposed to parental separation to only 1% exposed to sibling death.
Proportion of the DANLIFE cohort population who have been exposed to specific childhood adversities before the age of 18.

Social gradient in the accumulation of childhood adversities

Almost half (47%) of the study population did not experience any adversities before age 18, while one in 10 people experienced three or more of the 12 specific adversities at least once before their 18th birthday. We identified a strong social gradient in the accumulation of childhood adversities: e.g., 20% of the children who were born to mothers with a low level of education (≤9 years of education) had been exposed to three or more adversities before age 18 whereas only 4% of the children born to mothers with a high level of education (>12 years of education) had experienced similar exposures. The mean number of adversities experienced was 1.5 amongst persons whose mothers had low levels of education and 0.5 amongst children whose mothers had high levels of education.

20% of children born to mothers with a low level of education had been exposed to three or more adversities before age 18, compared with only 8% and 4% among children born to mothers with a middle and high level of education, respectively.
The accumulation of childhood adversities (three or more) amongst children whose mothers had low (≤9 years), medium (10–12 years), and high (>12 years) levels of education at the time of birth.

Read the full paper published in BMJ Open here