Smoking ups risk of abdominal aortic aneurysm
Smoking appears to increase the risk of abdominal aortic aneurysm, particularly among current smokers, reports a recent meta-analysis. The risk appears to taper with a lower number of cigarette sticks smoked per day.
A total of 23 studies were eligible for inclusion in the analysis, most of which (n=20 studies) were of current smokers (n=8,901 smokers). Fifteen studies included 7,824 former smokers, while 18 studies involved 8,448 ever smokers.
Compared with never smokers, current smokers were significantly more likely to develop abdominal aortic aneurysm (relative risk [RR], 4.87; 95 percent CI, 3.93–6.02). There was significant heterogeneity among the studies (p<0.0001).
Similar risk elevations were observed for former smokers (RR, 2.10; 1.76–2.50) and ever smokers (RR, 3.28; 2.60–4.15), though of lower magnitudes. In both cases, heterogeneity among studies were likewise significant (p<0.0001). No evidence of publication bias was reported for all three analyses, according to Egger’s test.
A pooled analysis of seven studies showed that every 10-stick increment in daily use was associated with a significant increase in the associated risk (RR, 1.87; 1.45–2.40). The correlation was significantly nonlinear (p<0.0001), such that use of 15–20 sticks per day was associated with the strongest increase in risk, while use beyond 20 sticks had no further effect.
A similar effect was observed for the number of pack-years: Each 10-pack-year increment was associated with a significant rise in the risk of abdominal aortic aneurysms (RR, 1.78; 1.54–2.06).