The clinical profile of MS in Australia: a comparison between medium- and high-frequency prevalence zones.

Recent epidemiologic studies of multiple sclerosis (MS) in Australia defined the State of Queensland as a medium-frequency zone and the more southerly placed cities of Perth, Newcastle, and Hobart as high-frequency zones. Clinical profiles in the patient populations of both frequency zones were remarkably similar in most respects to each other and to MS populations in the northern hemisphere. However, male patients in Queensland differed from their counterparts in the three cities by showing a greater tendency to develop a progressive disease course and, hence, more disability. The explanation for these observations is uncertain; we speculate that the hotter climate in Queensland may be relevant.