On the Epidemiology of Multiple Sclerosis in the Middle East and North Africa

mating pooled measures because of heterogeneity of studies’. This poor old clinician had difficulty interpreting such pooled measures and believed it was far preferable simply to look at the data. Included here is a table 1 , which I constructed (from their tables 1 and 2) that summarizes to me their major epidemiologic findings. Prevalence day was presumably in the last of the cited study years. Half the surveys were, understandably perhaps, from Iran. In that country, Sherlock Holmes’ dog that did nothing in the nighttime is relevant: two of its three largest cities were cited: Tehran and Isfahan/Esfahan; the third city, Mashhad, was not cited presumably because there was little MS found there. Mashhad is in the far northeastern corner of the country, near Turkmenistan. Please see the map ( fig. 1 ). Six of the surveys for Iran were from Isfahan with the earliest conducted in 2004–2005 showing the lowest prevalence rate of 36 per 100,000; this increased thereafter to 86 and 73 in 2003–2013 and 2003–2010, respectively. Incidence rates of 9 per 100,000 in these two Isfahan studies suggest an even higher prevalence in the future. Rates in Tehran clearly increased markedly over time: from the authors’ Complementary table 4, the change was from 60 cases in 8.8 million population in 1989 to 763 in 13.4 million in 2006. Much of the marked population growth in Tehran was attributed to immigrants, presumably those Professor Sahraian and his colleagues from Tehran, Iran, have presented a unique summation of the developing evolution of the epidemiology of multiple sclerosis (MS) in a region of growing importance, and a region about which most of us have little awareness [1] (Neuroepidemiology in press). The trend of the prevalence of MS with a high frequency in the north and with a low frequency in the south has long disappeared from Europe and has been reducing in the Americas as well. Citing recent scattered reports suggesting that regions of the Middle East and North Africa, situated largely between the 15th and 25th parallels of latitude, may also be joining in this trend of increasing MS, they have analyzed all relevant publications that appeared between January 1, 1985 and August 1, 2014; 52 such reports were included in their analysis. Results were presented in several dense tables that I found difficult to absorb, including one (table 3) titled ‘meta-analysis of the pooled estimates for prevalence, mean age at disease onset, and female proportion of patients’. The first of these cited a pooled estimate of prevalence of 51.52 per 100,000 population (LL 36.10, UL 66.95), 4,835.85 heterogeneity statistic, and I-squared of 99.8%; this last figure, which with these other measures I had to look up, I think means that almost all the variance in the meta-analysis was attributable to study heterogeneity. ‘A moment-based random model was used for estiPublished online: June 16, 2015