# Sex-specific association between atherogenic index of plasma and risk of newly diagnosed abdominal aortic aneurysm: a large population-based cohort study

## TL;DR

This study finds that a blood lipid measure called AIP is linked to a higher risk of developing abdominal aortic aneurysms, especially in men and female smokers.

## Contribution

This is the first study to investigate sex-specific associations between AIP and AAA risk in a large population.

## Key findings

- Higher AIP was associated with increased AAA risk in both males and females.
- AIP improved AAA prediction model discrimination in males and female smokers.
- Smoking modified the association in females, with risk only observed in ever-smokers.

## Abstract

Atherosclerosis of aortic wall has been suggested as a key pathological feature of abdominal aortic aneurysm (AAA). We conducted a first-ever prospective cohort study aiming at assessing the sex-specific association between atherogenic index of plasma (AIP) and risk of newly diagnosed AAA.

This study included 193,013 male and 226,785 female participants from the UK Biobank. AIP was calculated as a ratio of logarithmically transformed triglycerides to high-density lipoprotein-cholesterol. The outcome of interest was new AAA, identified by ICD-10 and OPCS-4 code, or by AAA-related death. All analyses were sex-stratified: Multivariable Cox proportional-hazard models were employed to assess the association between baseline AIP and AAA risk. Harrell’s c index was estimated to assess the value of AIP added to the discrimination of AAA prediction model.

Over an average follow-up of 15.3 years, 1931 (1.00%) new AAA cases were recorded in males and 424 (0.19%) in females. In the fully adjusted models, compared with the bottom AIP quintile, HRs (95% CI) of newly diagnosed AAA was 1.67 (1.41, 1.96) in males and 1.75 (1.22, 2.52) in females within the top quintile. Subgroup analysis found smoking status significantly modified the association in females, with association existing only in female ever-smokers. Adding AIP into prediction model comprising age, smoking, and CVD history significantly improved the discrimination in males and male high-risk subgroups and in female ever-smokers (p < 0.05).

This study highlights the potential of AIP as a biomarker for AAA and its utility in identifying high-risk individuals qualified for AAA screening.

The online version contains supplementary material available at 10.1186/s40001-025-02586-4.