Exploring the relationship between socioeconomic status and dog-bite injuries through spatial analysis.

INTRODUCTION Despite a reported socioeconomic gradient in health, little is known about relationship between socioeconomic status (SES) and frequency of dog-bite injuries. The primary objective of this study was to compare the frequency of dog-bite injuries, using data on dog-bite injury hospitalizations (DBIH), across different SES areas in Manitoba, Canada. The secondary objective of the study was to assess if frequency and pattern of DBIHs are similar to those of non-canine bite injury hospitalizations (NCBIH) and rabies post-exposure prophylaxis (PEP). SES grouping in this study was defined through rurality and area-wide income quintile groups. METHODS Rural and urban Manitoba neighbourhoods were ranked according to average area-level incomes into five levels (quintiles) with equal numbers of people in each income level. Prevalence was defined as the number of cases of hospitalizations (whether dog-bite injury or non-canine bite injury) or PEP reported in the years 1984-2006, divided by the total population during the same time period and expressed as the number of cases per 100 000 population per SES grouping. The 95% confidence intervals (CI) were calculated using the approach for Poisson distribution. RESULTS During 1984-2006, Manitoba's prevalence (CI) of DBIH (3.19 (2.97, 3.41) per 100 000 population) was lower than prevalence of NCBIH (4.08 (3.84, 4.32)) and PEP (7.24 (6.92, 7.57)). Prevalence of DBIH was higher in rural than in urban areas (DBIH: 3.58 (3.24, 3.92) vs 2.87 (2.59, 3.15), p<0.01) and higher in the lowest income quintile areas than in the highest, whether rural (5.18 (4.24, 6.26) vs 3.29 (2.55, 4.17), p<0.0001) or urban (3.65 (2.97, 4.44) vs 2.24 (1.73, 2.87), p<0.01). The patterns of relationship between SES (rurality and income levels) and prevalence of NCBIH and PEP were similar to those between SES and DBIH. CONCLUSIONS Although only a descriptive study, the results suggest that policies for control of dog-bite injuries should be area-specific. Prevention efforts could perhaps be improved by focussing not only on families, but also on neighbourhood regions.