Intentional injuries of children and young people in the Northern region 2023

Intentional injuries in children fall into two broad categories: Injuries from self-harm (including poisoning, cutting, and asphyxiation) and injuries resulting from assault, abuse, or neglect. This report presents hospitalisation data for all types of intentional injuries, but it is likely to substantively underestimate the true burden of these injuries given that many cases will go unreported and/or will not reach hospital. Hospitalisations recorded as childhood neglect typically occur in conjunction with assault codes; hospitalisations for neglect alone occur in numbers too low to be analysed separately but, again, this is unlikely to reflect the actual burden of neglect.

An important subcategory of abuse is abusive head trauma (AHT). This type of injury disproportionately affects the youngest children at a highly vulnerable time of their physical development and has far-reaching, long-term consequences.

National trend data suggest that overall intentional injury rates among children and young people have increased. This is largely attributable to self-harm events. However, there are marked differences in trend patterns when analysed by type of injury, age, and sex. Rates of self-harm among females aged 15–24 years have nearly tripled over the last ten years (from 307 per 100,000 in 2012 to 900 per 100,000 in 2022) and far exceed (by roughly 3 times) rates in males over the same period.

Historically, assaults have accounted for the majority of intentional injuries among young men (15–24 years) but rates of assault in this group have been decreasing over recent years and are now comparable to rates of self-harm in this group. For males aged 14 years or younger, rates of all types of intentional injury have remained consistent over time, however, self-harm events have been increasing slowly but steadily over recent years. The age of 11–12 years signals the start of a marked disparity in the rates of self-harm between girls and boys.

Children of Asian/Indian ethnicity have the lowest rates of self-harm of any ethnic group. For Māori, rates of hospitalisation for self-harm range between 141 and 208 per 100,000 for males and between 467 and 689 per 100,000 for females with no apparent difference by level of deprivation. Rates for European/Other children and young people correlate more closely to level of deprivation with a marked trend for increasing rates of self-harm with increasing deprivation, especially for males.

In the years between 2018 and 2022, the most common method of self-harm was poisoning, accounting for more than three-quarters of all hospitalisations in children aged 14 years or younger (around 3,000 events) and those aged 15–24 years (around 17,000 events). Acetaminophen-containing drugs (e.g., paracetamol) are the most frequently used agents. Rates of poisoning were between 8 and 10 times higher than rates of self-inflicted wounds to the arm, the next most common method of self-harm. Overall, self-harm rates are higher than the national rate for Waikato, Bay of Plenty, Taranaki, Whanganui, Hutt Valley, Capital & Coast, Nelson Marlborough, and Southern districts.

The pattern of assault of children in Aotearoa is closely related to age. Two age groups are notable; infants less than one year of age and adolescents/young adults (especially males) aged 15 years and older. Rates of hospitalisation for those children who fall between these ages (1–14 years) are less than 26 per 100,000. Similar to the trends for self-harm hospitalisations, children of Asian/Indian ethnicity have the lowest rates of hospitalisation for assault. Māori and Pacific boys and young men living in areas with the two lowest levels of deprivation experience the highest rates of assault (≥ 250 per 100,000). There are marked gradients according to level of deprivation for all children of both Māori and European/Other ethnicity; between the least and most deprived quintiles there is more than a 2-fold increase in rates of assault. Districts with rates of hospitalisation for assault higher than the national rate for young men aged 15–24 years are Te Tai Tokerau, Counties Manukau, Bay of Plenty, Lakes, Tairāwhiti Gisborne, Taranaki, Hawke’s Bay, Whanganui, and Hutt Valley.

Abusive head trauma (AHT) refers to brain injury potentially caused by a range of factors, including (but not limited to) shaking and/or impact by or against an object. Just over three-quarters of all cases occur in infants aged less than one year. In this age group, the 5-year rolling average hospitalisation rate is between 20 and 45 cases per 100,000. Structural disadvantage (e.g., experience of colonialism, racism) and poverty are key risk factors for AHT; for all ethnic groups, children from the most disadvantaged quintile have rates of hospitalisation for AHT that are at least 2-fold higher than those living in the least disadvantaged circumstances. For tamariki Māori, there is a 4-fold difference. Children living in Te Waipounamu experience the lowest rates of hospitalisation for AHT compared to other regions in Aotearoa, most likely reflecting the demographic characteristics of the southern population.

The epidemiology of injury from self-harm and assault in Aotearoa indicates high rates of unmet need, especially for youth (15–24-year-olds). Mental health services that are specifically designed for children and young people should be a priority. Alongside service provision is the need to tackle the wider determinants of health. Poverty continues to be an important driver of injuries stemming from assault.