Corrigendum

John F. Kurtzke. Epidemiology in multiple sclerosis: a pilgrim’s progress. Brain 2013: 136; 2904–17; doi:10.1093/brain/awt220.

The author wishes to call attention to and correct erroneous statements on: (i) distribution of multiple sclerosis in Denmark; (ii) legend for Fig. 7; and (iii) column heading for Table 2. Corrections for (i) and (ii) are cited in italics within the published texts.

(i) On p. 2908, the rest of the paragraph following ‘Two surveys of successive generations in Denmark were carried out by Gram (1934) and Hyllested (1956).’ should read:

‘Prevalence rates were 45 per 100 000 in 1933 and 74 per 100 000 age 0–15 versus 1921 population for the latter series. Distributions by county (Amt) in each provided evidence of a single concentration or focus of contiguous high frequency counties … .[T]he early survey … which was based on all patients receiving national disability compensation for this disease from 1921–1933 was very highly correlated with the childhood distributions of Hyllested (Fig. 7A) and in both the highest rates extended from Thisted (#17) on the Atlantic coast eastward down across the Jutland peninsula and on to the island counties of Svendborg (#9) and Odense (#10).

There was a clear spread or diffusion by the time of onset in the later study (Fig. 7B), which was based on personal review of all cases in Denmark, but with a strong correlation between the two distributions.’

(ii) ‘Figure 7 Distribution of multiple sclerosis by county (Amt) in Denmark, expressed as significance levels for rates at/above the respective national mean age specific prevalence rates per 100 000 population from the 1949 prevalence series of Hyllested (1956). (A) cases age 0–15 versus 1921 population age 5–24; (B) cases at onset (1938) versus 1940 population age 25–44. Counties significantly high above mean (χ²_a > 4.0) are solid black; high of dubious significance (χ²_a 2.0–4.0) are cross-hatched; insignificantly at/above mean (χ²_a < 2.0) are diagonal-lined. From Kurtzke, Acta Neurol Scand 1967; 43: 293–98.’

(iii) Table 2 Relative risk of multiple sclerosis in US veterans, heading for last data column should read: ‘Gulf War Era 1990–2007’. The author regrets these errors. The remainder of the presentation has been checked and is accurate as published.