Geographic distribution of mortality from systemic lupus erythematosus

BackgroundSystemic lupus erythematous (SLE) shares many common epidemiologic features with other autoimmune diseases or diseases associated with an underlying Epstein-Barr virus (EBV) infection. It was hypothesized that the geographic variation of mortality from SLE would reveal a similar pattern as Hodgkin lymphoma (HL), multiple sclerosis (MS), Crohn's disease (CD), and ulcerative colitis (UC).MethodsUsing the vital statistics of 21 countries from 1951-2022, overall and age-specific death rates from the 5 diseases were calculated for each individual country. The death rates of different countries were compared using linear regression analysis.ResultsWhereas other autoimmune diseases or diseases associated with an underlying EBV infection, such as HL, MS, CD, and UC, showed remarkably similar geographic variations, the geographic distribution of SLE did not fit this overall pattern. High death rates from SLE were not clearly associated with developing versus developed countries, northern versus southern latitude, or any specific continent. However, similar geographic distributions of SLE were consistently found among consecutive age groups, ranging from 0-4 to 85+ years.ConclusionsThe similarities in the geographic distributions of death rates from HL, MS, CD, and UC suggest that these 4 diseases share a set of one or more common environmental risk factors. Other environmental risk factors besides EBV infection must contribute to the varying occurrence of SLE across the globe. These risk factors start exerting their influence at a very young age of less than 5 years.