Social inequalities and hospital admission for unintentional injury in young children in Scotland: A nationwide linked cohort study

Abstract

Background: Unintentional injury is a leading cause of death/disability, with more disadvantaged children at greater risk. Understanding how inequalities vary by injury type, age, severity, and place of injury, can inform prevention.

Methods: For all Scotland-born children 2009-2013 (n=195,184), hospital admissions for unintentional injury (HAUI) were linked to socioeconomic circumstances (SECs) at birth: area deprivation via the Scottish Index of Multiple Deprivation (SIMD), mother's occupational social class, parents' relationship status. HAUI was examined from birth-five, and during infancy. We examined HAUI frequency, severity, injury type, and injury location (home vs. elsewhere). We estimated relative inequalities using the relative indices of inequality (RII, 95% CIs), before and after adjusting for demographics and other non-mediating SECs.

Findings: More disadvantaged children were at greater risk of any HAUI from birth-five, RII: 1•59(1•49-1•70), 1•74(1•62-1•86), 1•97(1•84-2•12) for area deprivation, maternal occupational social class, and relationship status respectively. These attenuated after adjustment (1•15 [1•06-1•24], 1.22 [1•12-1•33], 1.32 [1•21-1•44]). Inequalities were greater for severe (vs. non-severe), multiple (vs. one-off) and home (vs. other location) injuries. Similar patterns were seen in infancy, excluding SIMD-inequalities in falls, where infants living in more disadvantaged neighbourhoods were at lower risk (0•79 [0•62-1•00]). After adjustment, reverse SIMD-gradients were also observed for all injuries and poisonings.

Interpretation: Children living in more disadvantaged households are more likely to be injured across multiple dimensions of HAUI in Scotland. Upstream interventions which tackle family-level disadvantage may be most effective at reducing childhood HAUI.

Funding: Wellcome Trust, Medical Research Council, Scottish Government Chief Scientist Office.

Fig. 1

Directed acyclic graphs for the proposed causal relationship between socio-economic circumstances* and hospital admission for unintentional injury * Graph A: Area deprivation, Graph B: occupational social class, Graph C: relationship status of parents ** Because the direction between occupational social class and relationship status is uncertain, a conservative approach was taken, assuming that relationship status is a cause of occupational social class in B and that occupational social class is a cause of relationship status in C.

Fig. 2

Flow diagram showing creation of analytic sample. CHI: Community Health Index; NRS: National Records of Scotland; SMR02: Scottish Morbidity Record 02; SBR: Scottish Birth Record; SIMD: Scottish Index of Multiple Deprivation.

Fig. 3

Unadjusted and adjusted* RIIs of hospital admission for unintentional injury from birth to age five, for injury types that could not be reported at specific ages due to statistical disclosure *Adjusted for sex of child, number of births in pregnancy, country of birth of mother, age of mother at first live birth, number of older siblings, SEC exposures (area deprivation was adjusted for occupational social class and relationship status; relationship status was adjusted for occupational social class; occupational social class was adjusted for relationship status).

Fig. 4

Unadjusted and adjusted* RIIs of hospital admission for unintentional injury all injuries, type of injury and physical location in infants *Adjusted for sex of child, number of births in pregnancy, country of birth of mother, age of mother at first live birth, number of older siblings, SEC exposures (area deprivation was adjusted for occupational social class and relationship status; relationship status was adjusted for occupational social class; occupational social class was adjusted for relationship status)

Fig. 5

Unadjusted and adjusted* RIIs of hospital admission for unintentional injury from age one to five, by type of injury and SEC *Adjusted for sex of child, number of births in pregnancy, country of birth of mother, age of mother at first live birth, number of older siblings, SEC exposures (area deprivation was adjusted for occupational social class and relationship status; relationship status was adjusted for occupational social class; occupational social class was adjusted for relationship status)