Shift work a risk factor for aortic aneurysm

People who work shifts, especially those with unhealthy lifestyle, face a heightened risk of aortic aneurysm (AA), according to new research.

Analysis of data on more than 200,000 participants from the UK Biobank showed that working outside the conventional daytime hours of 9:00 am to 5:00 pm was associated with a 26-percent increase in the risk of AA (hazard ratio [HR], 1.26, confidence interval [CI], 1.06–1.47; p=0.007). [J Am Heart Assoc 2025;doi:10.1161/JAHA.124.040481]

The risk further increased to 28 percent among participants who often or always worked shifts compared with those who never worked shifts (HR, 1.28, 95 percent CI, 1.04–1.58; p=0.018). Conversely, the risk was not significantly elevated for participants who sometimes worked shifts (HR, 1.21, 95 percent CI, 0.97–1.51; p=0.083) and for those required to work night shifts as part of their shift work (HR, 0.88, 95 percent CI, 0.66–1.16; p=0.359). 

The toll of unhealthy lifestyle

When lifestyle behaviours were examined, unhealthy lifestyle showed a dose‐dependent association with the risk of AA, which heightened as the cumulative healthy lifestyle scores increased. This association was particularly pronounced among shift workers than among nonshift workers. For instance, the risk of AA was more than twofold higher among shift workers with 4 to 5 unhealthy lifestyle factors relative to nonshift workers with 0 or 1 unhealthy lifestyle factor (HR, 2.26, 95 percent CI, 1.63–3.14).

However, mediation analysis showed that the cumulative unhealthy lifestyle score accounted for only 2.2 percent (95 percent CI, 0.4–11.3) of the association between shift work and AA. Smoking had the greatest mediating effect among the factors examined, explaining 6.7 percent (95 percent CI, 2.4–38.4) of the association.

How shift work may increase the risk of AA remains unclear but may be potentially related to a disruption in the circadian rhythm. This disruption, according to the investigators, can activate the sympathetic nervous system, enhancing myocardial contractility and thereby increasing cardiovascular load.

Additionally, while the study highlighted the cumulative effect of unhealthy lifestyle behaviours on the risk of AA, especially among shift workers, the fact that unhealthy lifestyle scores accounted for only a small proportion of the mediation suggests that the adverse effects of shift work may be influenced by multiple other factors, such as socioeconomic status and access to social resources, the investigators pointed out.

“Although promoting healthier lifestyles is important, our findings indicate that additional interventions, beyond lifestyle changes alone, are necessary to reduce AA risk effectively,” they added.

The analysis included 213,971 employed or self‐employed participants (mean age 52.5 years, 50.2 percent male, 94.9 percent White) from the UK Biobank, of which 34,883 (16.3 percent) reported engaging in shift work. Shift workers were more likely to be men, have lower education levels, and be smokers, and perform heavy physical labour at work compared with nonshift workers.

The investigators acknowledged that the study was limited by its observational nature, the lack of detailed information on the size of AAs, and the inclusion of mostly White participants.

“Further research is warranted to evaluate [the] generalizability [of the findings] across different ethnic populations,” they said.