Abstract
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.