Results

A total of 35 377 young people aged 15–34 years were discharged from hospital after sustaining a head injury between 1990–1994. An 8% decline in hospitalisation rates was observed over the study period, decreasing from 489/100 000 (CI 477–499) in 1990 to 447/100 000 (CI 438–459) in 1994. Men sustained a disproportionate number of head injuries (28 611; 81%). Head injuries were most commonly caused by assaults (40%), followed by falls (23%), strikes (19%), road traffic accidents (12%), pedestrian accidents (2%), and “other” causes (3%).

Assault was the commonest cause of head injury hospitalisation in men at all ages, and in women after 20 years of age (table 1). Falls were a commoner cause of head injury hospitalisation than assault among women aged 15–19 years (30%). Men had consistently and significantly higher rates of hospital discharge resulting from assault than women at all ages (p<0.01).

Rates of discharge attributable to assault increased with increasing deprivation score for both men and women (p<0.01). This pattern was repeated at all ages. Men in deprivation category 7 experienced rates of hospital discharge four times higher than men in deprivation category 1. Similarly, women in deprivation category 7 experienced rates of hospital discharge six times higher than women in deprivation category 1 (p<0.01).

Discussion

If hospitalisations reflect incidence, assault is the major cause of head injury among young people in Scotland. Assaults accounted for 40% of all hospitalisations due to head injury in this age group between 1990–1994. Rates of hospitalisation were particularly high among young men compared with young women. Young people of both sexes residing in areas of relatively greater deprivation had rates of hospitalisation significantly higher than those living in more affluent areas.

There are problems associated with the exclusive reliance on hospital discharge data. These include the distorting effect of excluding fatal and minor injuries, the influence of hospital admission policies on the sociodemographic characteristics of inpatients, and the unknown extent of diagnostic misclassification. These data are, however, the most comprehensive available on head injury in Scotland. While routine surveillance of intentional injuries at accident and emergency departments in the UK is advocated to provided data on violence related injuries, these systems are rare.5

Alcohol use is well documented as a contributory factor in assaults.6-8 However, the routine data sources used in this study do not provide sufficient detail on the injury event to elicit the extent of alcohol use among assault victims or their assailants. A recent prospective study of Accident and Emergency patients in Scotland suggests that alcohol had been consumed by over two thirds of assault victims in the six hours before the attack.6 Over 90% of assailants and 80% of victims were men (mean age 28 years). Similarly, a UK survey of facial injuries showed that over half of assaults were related to alcohol consumption.7 In Western Australia, a significant association was found between night time assaults and alcohol consumption.8

In summary, these data indicate that assault is the commonest cause of head injury hospitalisation in Scottish young people, with men residing in socially deprived areas at particularly high risk. The underlying explanations and possible contributing factors (including alcohol) require further investigation to plan, formulate and evaluate appropriate preventive responses.