Mediterranean Diet is Associated with Reduced Risk of Abdominal Aortic Aneurysm in Smokers: Results of Two Prospective Cohort Studies

Abstract

Objective: Smoking is a strong risk factor for the development of abdominal aortic aneurysm (AAA). It was hypothesised that a Mediterranean diet via its anti-oxidative properties would decrease the risk of AAA, particularly among smokers.

Methods: The study population included the Cohort of Swedish Men (45 072 men) and the Swedish Mammography Cohort (36 632 women), aged 45 - 83 years at baseline. A modified Mediterranean Diet (mMED) score, including eight food groups, was calculated based on a food frequency questionnaire. Cox proportional hazard models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).

Results: During 17.5 years of follow up (1 427 841 person-years), 1 781 AAA cases (1 496 in men, 285 in women; 1 497 non-ruptured, 284 ruptured) were ascertained via Swedish registers. The mMED score was inversely associated with AAA incidence in men (per each one point increment in mMED score HR 0.96, 95% CI 0.93 - 1.00) and in women (HR 0.83, 95% CI 0.77 - 0.90), for non-ruptured (HR 0.95, 95% CI 0.92 - 0.99; in men with infrarenal aortic diameter ≥ 30 mm HR 0.90, 95% CI 0.81 - 1.00) and for ruptured AAA (HR 0.81, 95% CI 0.70 - 0.93). In current and ex-smokers with low (< 20) and moderate (20 - 39.9) pack-years of smoking, a statistically significant inverse association was observed. HRs for each one point increment in the mMED score in current smokers were 0.83 (95% CI 0.75 - 0.91) and 0.90 (95% CI 0.84 - 0.97), respectively; in ex-smokers 0.89 (95% CI 0.81 - 0.97) and 0.93 (95% CI 0.85 - 1.01), respectively. No association was observed among current or ex-smokers with ≥ 40 pack-years; HRs 1.02 (95% CI 0.91 - 1.13) and 0.95 (95% CI 0.83 - 1.10), respectively.

Conclusion: Adherence to the Mediterranean diet was associated with a reduced AAA risk in current and ex-smokers with low pack-years of smoking.

Keywords: Abdominal aortic aneurysm; Dietary pattern; Mediterranean diet; Prospective study; Smoking status.