Prevalence is the proportion of a group of individuals having a health condition at a given point in time. In our review, prevalence is expressed as the number of cases of traumatic SCI per million in a given year. Table 6 presents the prevalence of traumatic SCI by geographic area.
There are 12 studies that provided estimates of prevalence of traumatic SCI varying from 50 to 1,298 cases per million worldwide. There are regional differences of traumatic SCI across the globe, but generally, the trend is towards increasing prevalence over the last decades.
In Canada, the estimated prevalence of SCI is 1,298 per million, the highest of any prevalence estimate to date. In different regions within the United States, the estimated prevalence varied from 50 to 906 individuals with traumatic SCI per million. In Sweden and Finland, the prevalence of traumatic SCI was estimated to be 227 and 280 individuals per million, respectively. Based on data from India, the prevalence of traumatic SCI was reported to be 236 cases per million (Razdan et al. 1994), while in Australia, O’Connor (2005) documented a prevalence of 681 individuals with traumatic SCI per million. In more recent studies, Correa et al. (2011) documented 112 cases per million in Chile, and Hagen et al. (2010) reported 35.1 to 41.9 cases per 100,000 in Norway. Knutsdottir et al. (2012) estimated the prevalence in Iceland to be 526 per million.
In one study reporting the prevalence of SCI at two or more time points from the United States, the results indicate an increasing prevalence of traumatic SCI. Griffin et al. (1985b) reported an increase in the prevalence of traumatic SCI in Olmsted County (Minnesota, USA) from 197 to 473 cases per million population between the 1950s and 1980s.