APOL1 Risk Variants Associate With the Prevalence of Stroke in African American Current and Past Smokers

Area of Science:

• Genetics
• Epidemiology
• Cardiovascular Disease

Background:

• African American smokers exhibit a 2.5-fold higher stroke risk compared to non-smokers.
• Approximately 50% of African Americans carry 1 or 2 APOL1 gene variants (G1 and G2), which are rare in other populations.
• While APOL1 variants are linked to stroke, their role in tobacco-related stroke remains unclear.

Purpose of the Study:

• To investigate if APOL1 risk variants modify the association between tobacco smoking and stroke prevalence in African Americans.
• To determine the differential impact of smoking on stroke risk based on APOL1 genotype.

Main Methods:

• A cross-sectional study involving 513 African American adults.
• Assessment of APOL1 variants, smoking status (ever vs. never smokers), and stroke history using DNA, plasma, and questionnaires.
• Logistic regression models to analyze the association between smoking and stroke, stratified by APOL1 carrier status.

Main Results:

• The study found a significant interaction between APOL1 genotype and smoking status regarding stroke prevalence (P=0.014).
• Among APOL1 risk variant carriers, ever smokers had a 2.46-fold increased odds of stroke compared to never smokers.
• No significant association between smoking and stroke was observed in non-carriers of APOL1 risk variants.

Conclusions:

• African Americans who smoke and carry APOL1 G1 and/or G2 risk variants may have increased susceptibility to stroke.
• APOL1 risk variants appear to potentiate the stroke risk associated with tobacco use in this population.