Tuesday, 16 August 2011

HSP Prevalence

OK, so, in my internet trawl so far I have found several references to the prevalence of HSP in the general population. Some of these prevalence's have been referenced to studies and papers which provide further details. I've managed to find downloads for four different papers which give prevalence for HSP, and these papers all contain summaries to previous prevalence papers. This post combines all these papers together and tries to estimate the prevalence of HSP. I have found some further papers which have not been referenced in any of these four studies, but I'm going to leave those for inclusion in a further post.

So, the four papers I found in full are:
Erichsen et al, Norway, 2009: http://brain.oxfordjournals.org/content/132/6/1577.full.pdf
Monagle et al, Ireland, 2002: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1737699/pdf/v072p00043.pdf
Coutinho et al, Portugal, 1999: http://archneur.ama-assn.org/cgi/content/full/56/8/943
Polp et al, Spain 1991: http://brain.oxfordjournals.org/content/114/2/855.abstract?ijkey=c0472af598cf8de455d3b4f7839277c2f74d87be&keytype2=tf_ipsecsha (this sometimes asked for payment, but other times didn't)

From this, I get an overall list of the following studies into the prevalence of HSP:

Location1st AuthorYearCasesPopulationPrevalence per 100,000
Denmark (Zealand)Werderlin19752311790002
W. NorwaySkre19803172500012.1
Italy (Reggio Emilia)Lucci198244123241
Italy (Torino)Brignolio19863123279961.3
Spain (Cantabria)Polo1991495100009.6
Italy (Molise)Filla199293352112.7
Italy (Valle d'Aosta)Leone199551152704.3

This shows some interesting things to me. Generally these studies all relate to separate geographic areas, apart from there being two Norway and two Portugal, so, I will exclude the earlier and smaller studies from each of these countries to avoid double counting.

The main outliers in the data sets are the studies from Japan and Guam, with the Japan study having by far the largest overall population. On the whole the other studies give broadly the same results, and (apart from Libya) relate to European populations. This gives opportunities for combining data sets:

All studies excluding Skre 1980 and Silva 19976171402926690.44
All studies excluding Skre 1980 and Silva 1997 and Japan508172926692.94
All European studies excluding Skre 1980 and Silva 1997495169857552.91

Some while ago I read Guns Germs and Steel (http://www.amazon.co.uk/Guns-Germs-Steel-history-everybody/dp/0099302780 - a very interesting read) and this leads me to think that conditions would have different prevalence's in different parts of the world. So, I'll concentrate my analysis on the area where the main proportion of studies have been done - Europe. I would suggest that the overall prevalence of HSP in the European population is about 3 per 100,000 population, but noting that several of the papers indicated they thought their studies presented an underestimate.

Perhaps with further analysis I'll be able to draw out some further thoughts...

I was able to find an abstract for all of the papers listed except the Lucci paper of 1982, which appears to be strangely elusive. I would welcome contact from anyone who has a full copy of these papers (or links to other locations) to add to my collection! For completeness, links to abstracts for the other papers follow:

Guam, Chen, 1968: http://archneur.ama-assn.org/cgi/content/summary/19/6/573
Denmark, Werderlin, 1975: http://onlinelibrary.wiley.com/doi/10.1111/ane.1986.73.issue-S106/issuetoc
Norway, Skre, 1980: http://onlinelibrary.wiley.com/doi/10.1111/j.1399-0004.1974.tb00647.x/abstract
Libya, Sridharen, 1985: http://brain.oxfordjournals.org/content/108/4/831.abstract
Italy, Brignolio, 1986: http://www.springerlink.com/content/39x4u4351261153v/
Japan, Hirayama, 1989: http://www.ncbi.nlm.nih.gov/pubmed/8059595
Italy, Filla, 1992: http://www.ncbi.nlm.nih.gov/pubmed/1512613
Italy, Leone, 1995: http://www.ncbi.nlm.nih.gov/pubmed/7793232
Portugal, Silva, 1997: http://www.jclinepi.com/article/S0895-4356(97)00202-3/abstract

The missing reference:
Italy, Lucci, 1982: Lucci B, Motti L, Guidetti D, Zucco R. Indagine epidemiologica descritiva delle eredoatassie nella provincia di Reggio-Emilia. In: Atti del III Convegno Nazionale di Neuroepidemiologia. 1982;p. 169–174