Abstract
BACKGROUND: Smoking is the strongest modifiable risk factor for the development of abdominal aortic aneurysm (AAA). This study aims to confirm whether smoking is a stronger risk factor in women than men and identify contributory reasons, including inflammation, for any sex-specific difference observed.
METHODS: Systematic review and meta-analysis, conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. Data sources were Medline, Embase, and Cochrane Central Register of Controlled Trials. Population-based studies reporting the risk of AAA, adjusted for age and cardiovascular risk factors, for women versus men, were included. These were complemented by data from UK Biobank, which also were assessed for sex-specific effects of smoking on incident atherosclerotic cardiovascular disease.
RESULTS: Meta-analysis of 6 studies (including UK Biobank, 2001-2024) showed that the relative risk ratio of current versus never smokers for incident AAA in women versus men was 1.78 (95% CI, 1.32-2.38). In the UK Biobank cohort, the sex-specific relative risks of current smoking risks were higher for AAA than for atherosclerotic cardiovascular disease; hazard ratio, 1.74 and 1.29, respectively: analysis by cigarettes per day echoed these findings, but pack-year history had lesser association. The proportionately lower AAA incidence rate in exsmokers (versus current smokers) was more marked in women. Sex-specific risks of current smoking for incident AAA were not significantly modified by CRP (C-reactive protein), white blood cell count, or other inflammatory markers.
CONCLUSIONS: The relative risk of developing AAA by current smokers is almost twice as high in women versus men, but no strong association with inflammation was observed. Other reasons, including smoking intensity, must be sought.
REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD2024586609.