Mandibular fractures in Far North Queensland: an ethnic comparison.

Background: No previous published Australian study on the epidemiology of mandibular fractures has comprehensively shown the differences existing between indigenous and nonindigenous populations. Cairns Base Hospital, which services both the metropolitan city of Cairns and remote regions of Far North Queensland, provides the perfect environment for investigating such differences.

Methods: A retrospective study of all patients presenting to Cairns Base Hospital with mandibular fractures over the 3-year period between January 1999 and January 2002 was undertaken.

Results: A total of 444 mandibular fractures occurred in 276 patients. The indigenous population of 7.6% in Cairns (17.9% in Far North Queensland) represented 49% of all patients. Assaults (74%) were the principal cause. The second most common mechanism was sporting injuries (17%), followed by motor vehicle accidents (5%) and falls (4%). In the indigenous female population, 93% arose from assaults, of which 57% were documented as domestic violence. The nonindigenous population had a defined peak in the third decade of life, with fractures in 47% of men and 38% of women occurring then. However, the indigenous group had a sustained peak between 11 and 40 years of age, with 94% of fractures occurring within this period. The male to female ratio was 6:1 in nonindigenous (3:1 indigenous). The side of predilection was L:R = 1:1 in nonindigenous (L:R = 3:1 indigenous). Recurrent mandibular trauma was documented in 4% of nonindigenous (18% of indigenous). Within the nonindigenous, all women and 90% men sought medical attention within 2 days of injury. In contrast, 38% indigenous men and 20% indigenous women delayed their initial presentation for 3 days or more (P < 0.001).

Conclusion: Clinically and statistically significant differences exist between the two ethnic groups. It is proposed that these differences are possible indicators that high rates of interpersonal violence exist in a community.