The shrinking health advantage: unintentional injuries among children and youth from immigrant families

With the proliferation of global migration, increasing attention is being paid to health outcomes of immigrants in developed countries. Immigrants tend to arrive with better health than their native born counterparts. This healthy immigrant effect has been demonstrated across multiple health systems, in several countries, and for a number of conditions [1–7]. With increasing duration of residence in a host country, this health benefit can shrink as immigrants adopt behaviours and exposures more similar to the native population. This latter observation, demonstrated in adult populations, has been termed the “convergence hypothesis” [4, 8, 9].

The notion of the healthy immigrant effect has been less well studied in children and young adults but has been shown for immunizations [10], mental health [1, 11], and substance use [1]. The convergence hypothesis, however, has not been evaluated at a population-based level for pediatric health outcomes. Moreover, in adults, there is considerable variation in the effects of immigration on health and its subsequent convergence towards the native population depending on the health outcome and region of origin [8, 9].

Injury remains one of the leading causes of death, hospitalization, and emergency department (ED) visits for children and youth in North America and Europe [12, 13]. Most injuries are preventable, and injury reduction strategies, when targeted and implemented appropriately, are successful [14–16]. Immigrants have a lower risk of unintentional injury than Canadian born children [17–19]. Though there is some cause-specific variability, this has been demonstrated across all causes of injury [19]. The evidence for the extent to which the lower risk of injury persists with increasing duration of residence in a new country for children and young adults from immigrant families is not known. As immigrant populations acculturate, their risk-taking behaviours or exposures may change. Investigating patterns of injury across immigrant populations with increasing time since migration can help provide a more comprehensive picture of contributing factors to injury risk in this large and growing population. With better understanding of unintentional injury risk in immigrants, strategies can be developed for injury prevention, education, behaviour modification, and policy development so that immigrants can maintain their health advantage.

We sought to examine patterns of unintentional injury in children and youth from immigrant families in a large, diverse Canadian province with a single payer health care system where 20% of the population are immigrants [20]. Our specific objectives were to describe the epidemiology of unintentional injury-related emergency department visits, hospitalizations, and deaths overall and according to cause of injury in recent, intermediate-term, and long-term children and youth from immigrant families and by region of origin; and to test the association of unintentional injury and duration of residence and region of origin in children from immigrant families in Ontario, Canada.

In this large population-based cross-sectional study, we report longer duration of residence in Canada is associated with an increased risk of unintentional injuries in children and young adults from immigrant families. This was observed across most causes of injury, except for drowning and scald burns where the highest rates of injury were among newcomers (≤ 5 years in Canada). Risk of unintentional injury was lowest in immigrants from South and East Asia and highest in those from Europe and the Americas.

The rates of unintentional injury in our cohort of immigrants are much lower than published rates for pediatric injuries in the general child and youth population of Ontario [17], supporting a healthy immigrant effect. Our study is the first to report a loss of this health advantage over time, with immigrant injury risk converging towards levels of the general Canadian population. This is particularly important given the amenability of injury risk to appropriately targeted safety interventions [13].

The shrinking health benefit of immigrants over time may be explained by a number of factors. As immigrants acculturate, they may introduce changes to their parenting style, including direct supervision of children. With settlement and integration, children and youth may have increased exposures such as more time spent in motor vehicles with less time spent exploring urban areas as pedestrians. The worsening injury rates in immigrants may reflect adoption of unhealthy, risk taking behaviours known to contribute to injury, such as drug and alcohol use [13] or involvement with gang-related firearm violence [27, 28]. There may also be changes in access to primary care, which has been shown to be worse over time from migration [29]. This may reduce opportunities for preventative counselling on injuries and safe play over time in Canada. Similarly, barriers to care-seeking including initial distrust in or use of the health care system may preclude recent immigrants from visiting a hospital for injuries. Conversely, our findings of increasing falls, cuts, and overexertion may indicate improved access to play spaces with increased physical activity or participation in sport by immigrants as they integrate into life in Canada.

The observed rates of cause-specific injuries by duration of residence are not unexpected. Research from Denmark has shown that while pediatric immigrants have lower risk of injury, a higher proportion scald and hot oil burns occurred in immigrants compared with native Danes [23]. More time spent at home cooking and preparing foods by immigrants, especially within newcomers, may explain this finding. Drowning rates among newcomers may be related to lack of knowledge about safe swim environments and highlights an area in need of intervention. Relatively high rates of suffocation were observed in recent immigrants. Recent immigrants may have inferior understanding of North American or European product safety guidelines such as crib safety (placing infant supine, avoiding drop-side rails, and not using loose bedding in cribs or blind cord safety), all of which can lead to entrapment or strangulation and subsequent suffocation [13]. Understanding the variability in the influence of duration of residence over time on cause-specific injuries will be important to study as injury prevention strategies are developed. For example, the unchanged rates of bicycle, pedestrian, and machinery injuries may reflect the countering protective effects of being a recent immigrant and changes in exposures over time in Canada. This remains to be studied.

We observed significant differences in risk of injury by region of origin. In particular, South and East Asian immigrant populations had very low rates of injury. Others have described significant variability in rates of injury mortality by region of origin [5] though comparisons to Asian immigrant populations have not previously been reported. Interestingly, South and East Asian immigrants have among the highest in-country unintentional injury rates across the globe (49.0 injuries per 100 000 population), with rates second only to African countries [13]. Clearly, this risk is not brought with them through immigration. Our observations may be related to selection factors in those who immigrate to Canada as well as cultural differences in risk taking behaviours and exposures that reduce overall risk of unintentional injury upon arrival in Canada.

The risk of all-cause and most cause-specific unintentional injuries in immigrant children and youth rises with increasing duration of residence in Canada. This important finding indicates there is a need to understand why this is occurring and to develop strategies, which may include providing education about water and cooking safety for recent immigrants, to maintain the immigrant health advantage over time after migration. This must be done while balancing the desire to support active living and healthy child development.