Antiphospholipid Antibodies and the Risk of Stroke in Urban and Rural Tanzania

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 Dares-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.

Neurosyphilis in Africa: A systematic review

“…A case-control study of stroke conducted in Tanzania between 2003–2006 enrolled 158 stroke cases and 369 age- and sex- matched controls[ 42 ]. Serology for syphilis was performed using an IgG ELISA ( Treponema pallidum IgG ELISA; IBL international GmbH, Hamburg, Germany).…”

Clinical Relevance of Isolated Lupus Anticoagulant Positivity in Patients with Thrombotic Antiphospholipid Syndrome

“…Data from 158 stroke cases and 369 controls indicated that LAC is a strong risk factor for stroke, especially in young and middle-aged individuals. On the contrary, the presence of other aPLs showed very low association with increased risk for stroke 16 .…”

The Lupus Anticoagulant Paradox

“…62 Data obtained from large population-based case-control studies and prospective cohort studies among aPL carriers support the prothrombotic properties of isolated LA. 3,17,34,61 Prospective data indicate that thrombotic complications occur three-to fourfold more often in these patients than is expected in people of the same age. 3,61 The Lupus Anticoagulant Paradox…”

“…27 The association between antiprothrombin antibodies and thrombosis is currently unclear: Several studies report an association with thrombosis, [28][29][30][31][32] which is contradicted by others. 17,28,33,34 There are several possible reasons for this discrepancy, including differences in study design, patient population, control group, and method used to detect the antiprothrombin antibodies (and thus, probable heterogeneity in antiprothrombin antibodies themselves). While some studies focused on venous thromboembolism, others investigated arterial thrombosis, which likely represent two different pathophysiologic mechanisms, with differences in the involved cell type, fluid shear stress, and the contribution of the coagulation system to thrombus formation.…”