Pharmacoepidemiology and the Australian regional prevalence of multiple sclerosis

Abstract

Background: Over some 50 years, field surveys have shown that the prevalence of multiple sclerosis (MS) increases with increasing distance from the equator in both the northern and the southern hemispheres. Such a latitudinal gradient has been found in field surveys of MS prevalence carried out at different times in various local regions of Australia. Objective: The objective of this paper is to use a pharmacoepidemiological approach to obtain whole of population estimates of the prevalence of MS in the various Australian states and territories from the use of MS disease-modifying drugs used to treat relapsing–remitting MS (RRMS). Methods: We analysed the dispensed use of subsidised RRMS drugs by jurisdiction. Results: In the 2005–2008 period, the calculated mean treated RRMS prevalence in Australia ranged from 7.5 per 100,000 in the far north to 53.2 per 100,000 in the extreme south and was linearly related to increasing southerly latitude. Public domain Australian data suggested that multiplying this prevalence by a factor of 2.2 (to account for untreated RRMS and other types of MS) may provide a measure of the prevalence of all varieties of the disease. Conclusion: These findings provide contemporary and more comprehensive evidence for the gradient of MS prevalence with latitude in Australia than has previously been available.

Multiple sclerosis disease modifying medicine utilisation in Australia

“…There was generally higher use of RRMS DMM in the more southerly Australian administrative areas than in the more northerly ones, consistent with the known higher prevalence of the disease with increasing distance from the equator in both hemispheres [16][17][18][19][20][21][22][23], the reasons for which remain unclear [24]. There was, however, an exception to this relationship in the relatively high use of RRMS DMM in the ACT, compared with their use in the surrounding state of NSW -a usage pattern driven by heavy prescribing of glatiramer acetate in the ACT.…”

T Regulatory Cell Subpopulations Associated with Recent Ultraviolet Radiation Exposure in a Skin Cancer Screening Cohort

“…In mouse studies, UVB-induced Treg cell activation in skin lasted for 2 wk after exposure and then later contributed to expansion of these cells in the peripheral blood (23). Some previous studies of UVR exposure and immune-related conditions have relied on self-report of sun exposures and ecologic measures, such as latitude, to estimate UVR exposure (27, 29, 30, 85). Other studies have demonstrated that Treg cell populations are altered with UVR exposure in a small cohort of patients presenting with autoimmune disorders (31, 34), including one such study that demonstrated that activated CD45RA − Treg cells are increased in psoriasis patients with recent UV exposure (32).…”

Seasonal variation of relapse rate in multiple sclerosis is latitude dependent

“…It is well recognized that the incidence and prevalence of multiple sclerosis (MS) varies significantly with geographical location: it is more common in northern parts of the northern hemisphere and southern parts of the southern hemisphere [1][2][3] . The reason for this latitudinal variation is as yet unknown.…”