Antiphospholipid antibodies and the risk of stroke in urban and rural Tanzania a community-based case–control study

Document Type

Article

Department

Internal Medicine (East Africa); Imaging and Diagnostic Radiology (East Africa)

Abstract

Background and Purpose, The burden of stroke is high in sub-Saharan Africa, and improved knowledge of risk factors is needed. Antiphospholipid antibodies are a common acquired stroke risk factor in young individuals. Antiphospholipid antibodies may be induced by infectious diseases. Sub-Saharan Africa has a high infectious burden, and we analyzed the contribution of antiphospholipid antibodies to the risk of stroke in an incident population from rural and urban Tanzania.

Methods, Stroke cases and age- and sex-matched community-acquired controls from the rural Hai district and urban Dar-es-Salaam areas of Tanzania were recruited in a wider study of stroke incidence between June 2003 and June 2006. Lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein I, and antiphosphatidylserine/prothrombin antibodies were determined in stored plasma, as well as IgG antibodies against Treponema pallidum.

Results, Data from 158 stroke cases and 369 controls were analyzed. Thirty cases (19%) and 4 controls (1%) had a lupus anticoagulant (odds ratio, 20.8; 95% confidence interval, 7.2–60.5). Anticardiolipin IgG was the only other antiphospholipid antibody subtype associated with increased stroke risk (odds ratio, 2.1; 95% confidence interval, 1.0–4.3), but this association disappeared when corrected for IgG antibodies against Treponema pallidum results. The prevalence of anti-β2-glycoprotein I IgG antibodies in the Tanzanian healthy population was high when Dutch cutoff values were applied (67%), whereas presence of anti-β2-glycoprotein I IgM was associated with a reduced stroke risk (odds ratio 0.3; 95% confidence interval, 0.1–1.1).

Conclusions, The presence of lupus anticoagulant is a strong, and to date unrecognized, risk factor for stroke in Tanzania, especially in young and middle-aged individuals.

Publication (Name of Journal)

Background and Purpose, The burden of stroke is high in sub-Saharan Africa, and improved knowledge of risk factors is needed. Antiphospholipid antibodies are a common acquired stroke risk factor in young individuals. Antiphospholipid antibodies may be induced by infectious diseases. Sub-Saharan Africa has a high infectious burden, and we analyzed the contribution of antiphospholipid antibodies to the risk of stroke in an incident population from rural and urban Tanzania. Methods, Stroke cases and age- and sex-matched community-acquired controls from the rural Hai district and urban Dar-es-Salaam areas of Tanzania were recruited in a wider study of stroke incidence between June 2003 and June 2006. Lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein I, and antiphosphatidylserine/prothrombin antibodies were determined in stored plasma, as well as IgG antibodies against Treponema pallidum. Results, Data from 158 stroke cases and 369 controls were analyzed. Thirty cases (19%) and 4 controls (1%) had a lupus anticoagulant (odds ratio, 20.8; 95% confidence interval, 7.2–60.5). Anticardiolipin IgG was the only other antiphospholipid antibody subtype associated with increased stroke risk (odds ratio, 2.1; 95% confidence interval, 1.0–4.3), but this association disappeared when corrected for IgG antibodies against Treponema pallidum results. The prevalence of anti-β2-glycoprotein I IgG antibodies in the Tanzanian healthy population was high when Dutch cutoff values were applied (67%), whereas presence of anti-β2-glycoprotein I IgM was associated with a reduced stroke risk (odds ratio 0.3; 95% confidence interval, 0.1–1.1). Conclusions, The presence of lupus anticoagulant is a strong, and to date unrecognized, risk factor for stroke in Tanzania, especially in young and middle-aged individuals.

DOI

https://doi.org/10.1161/STROKEAHA.116.013760

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