Association between shift rotation and 30-year Framingham risk of cardiovascular disease among male workers in a medium-sized manufacturing factory

Rotating shift work is associated with an increased risk of cardiovascular disease (CVD). This study compared the CVD risk score in 129 male line workers aged 22–49 years on different shifts in a medium-sized metal production factory from 2017 to 2020. We classified workers into four groups: permanent day shift, weekly rotation involving five consecutive nights, weekly rotation involving 3–4 consecutive nights, and monthly rotation involving two consecutive nights. We used the Framingham Risk Score to estimate the 30-yr risks of general and hard CVD (CVD risk estimates). We investigated the differences in CVD risk estimates between different groups using linear mixed models. The average 30-yr Framingham CVD risk estimates of each group ranged from 17.5% to 31.2% for general CVD and from 10.5% to 20.5% for hard CVD. Workers on weekly rotations involving 3–5 consecutive nights had 5%–10% significantly higher CVD risk estimates than workers on the permanent day shift. Workers on weekly rotations also had 6%–8% higher BMI-based CVD risk estimates than those on the monthly rotation involving two consecutive nights. While 24-h shift rotations are unavoidable, our findings underscored the potential CVD risk among workers on weekly rotations involving more consecutive nights.