Julián N Acosta1, Natalia Szejko1,2,3, Cameron P Both1, Kevin Vanent1, Rommell B Noche1, Thomas M Gill4, Charles C Matouk5, Kevin N Sheth1, Murat Gunel, Guido J Falcone1. 1. Division of Neurocritical Care and Emergency Neurology, Department of Neurology (J.N.A., N.S., C.P.B., K.V., R.B.N., K.N.S., G.J.F.), Yale School of Medicine, New Haven, CT. 2. Department of Neurology (N.S.), Medical University of Warsaw, Poland. 3. Department of Bioethics (N.S.), Medical University of Warsaw, Poland. 4. Department of Internal Medicine (T.M.G.), Yale School of Medicine, New Haven, CT. 5. Department of Neurosurgery (C.C.M.), Yale School of Medicine, New Haven, CT.
Abstract
BACKGROUND AND PURPOSE: Animal and observational studies indicate that smoking is a risk factor for aneurysm formation and rupture, leading to nontraumatic subarachnoid hemorrhage (SAH). However, a definitive causal relationship between smoking and the risk of SAH has not been established. Using Mendelian randomization (MR) analyses, we tested the hypothesis that smoking is causally linked to the risk of SAH. METHODS: We conducted a 1-sample MR study using data from the UK Biobank, a large cohort study that enrolled over 500 000 Britons aged 40 to 69 from 2006 to 2010. Participants of European descent were included. SAH cases were ascertained using a combination of self-reported, electronic medical record, and death registry data. As the instrument, we built a polygenic risk score using independent genetic variants known to associate (P<5×10-8) with smoking behavior. This polygenic risk score represents the genetic susceptibility to smoking initiation. The primary MR analysis utilized the ratio method. Secondary MR analyses included the inverse variance weighted and weighted median methods. RESULTS: A total of 408 609 study participants were evaluated (mean age, 57 [SD 8], female sex, 220 937 [54%]). Among these, 132 566 (32%) ever smoked regularly, and 904 (0.22%) had a SAH. Each additional SD of the smoking polygenic risk score was associated with 21% increased risk of smoking (odds ratio [OR], 1.21 [95% CI, 1.20-1.21]; P<0.001) and a 10% increased risk of SAH (OR, 1.10 [95% CI, 1.03-1.17]; P=0.006). In the primary MR analysis, genetic susceptibility to smoking was associated with a 63% increase in the risk of SAH (OR, 1.63 [95% CI, 1.15-2.31]; P=0.006). Secondary analyses using the inverse variance weighted method (OR, 1.57 [95% CI, 1.13-2.17]; P=0.007) and the weighted median method (OR, 1.74 [95% CI, 1.06-2.86]; P=0.03) yielded similar results. There was no significant pleiotropy (MR-Egger intercept P=0.39; MR Pleiotropy Residual Sum and Outlier global test P=0.69). CONCLUSIONS: These findings provide evidence for a causal link between smoking and the risk of SAH.
BACKGROUND AND PURPOSE: Animal and observational studies indicate that smoking is a risk factor for aneurysm formation and rupture, leading to nontraumatic subarachnoid hemorrhage (SAH). However, a definitive causal relationship between smoking and the risk of SAH has not been established. Using Mendelian randomization (MR) analyses, we tested the hypothesis that smoking is causally linked to the risk of SAH. METHODS: We conducted a 1-sample MR study using data from the UK Biobank, a large cohort study that enrolled over 500 000 Britons aged 40 to 69 from 2006 to 2010. Participants of European descent were included. SAH cases were ascertained using a combination of self-reported, electronic medical record, and death registry data. As the instrument, we built a polygenic risk score using independent genetic variants known to associate (P<5×10-8) with smoking behavior. This polygenic risk score represents the genetic susceptibility to smoking initiation. The primary MR analysis utilized the ratio method. Secondary MR analyses included the inverse variance weighted and weighted median methods. RESULTS: A total of 408 609 study participants were evaluated (mean age, 57 [SD 8], female sex, 220 937 [54%]). Among these, 132 566 (32%) ever smoked regularly, and 904 (0.22%) had a SAH. Each additional SD of the smoking polygenic risk score was associated with 21% increased risk of smoking (odds ratio [OR], 1.21 [95% CI, 1.20-1.21]; P<0.001) and a 10% increased risk of SAH (OR, 1.10 [95% CI, 1.03-1.17]; P=0.006). In the primary MR analysis, genetic susceptibility to smoking was associated with a 63% increase in the risk of SAH (OR, 1.63 [95% CI, 1.15-2.31]; P=0.006). Secondary analyses using the inverse variance weighted method (OR, 1.57 [95% CI, 1.13-2.17]; P=0.007) and the weighted median method (OR, 1.74 [95% CI, 1.06-2.86]; P=0.03) yielded similar results. There was no significant pleiotropy (MR-Egger intercept P=0.39; MR Pleiotropy Residual Sum and Outlier global test P=0.69). CONCLUSIONS: These findings provide evidence for a causal link between smoking and the risk of SAH.
Authors: Anil Can; Victor M Castro; Yildirim H Ozdemir; Sarajune Dagen; Sheng Yu; Dmitriy Dligach; Sean Finan; Vivian Gainer; Nancy A Shadick; Shawn Murphy; Tianxi Cai; Guergana Savova; Ruben Dammers; Scott T Weiss; Rose Du Journal: Neurology Date: 2017-08-30 Impact factor: 9.910
Authors: Nohra Chalouhi; Muhammad S Ali; Robert M Starke; Pascal M Jabbour; Stavropoula I Tjoumakaris; L Fernando Gonzalez; Robert H Rosenwasser; Walter J Koch; Aaron S Dumont Journal: Mediators Inflamm Date: 2012-12-13 Impact factor: 4.711
Authors: Clare Bycroft; Colin Freeman; Desislava Petkova; Gavin Band; Lloyd T Elliott; Kevin Sharp; Allan Motyer; Damjan Vukcevic; Olivier Delaneau; Jared O'Connell; Adrian Cortes; Samantha Welsh; Alan Young; Mark Effingham; Gil McVean; Stephen Leslie; Naomi Allen; Peter Donnelly; Jonathan Marchini Journal: Nature Date: 2018-10-10 Impact factor: 49.962