Seasonal variation in thoracic vessel calcifications: Evidence from a chest computed tomography study

Background: Cardiovascular disease incidence and mortality exhibit a winter peak and a summer trough, a fact that could have radiological manifestations. Purpose: To identify possible seasonal trends in the occurrence of thoracic vessel calcifications. Material and Methods: 505 male construction workers (aged 39-80 years) were each imaged once with chest spiral computed tomography (CT) during a 2-year period. Based on visual assessment of calcified plaques (0=no, 1=slight, 2=moderate, 3=extensive calcification), sum scores of atherosclerosis in coronary arteries, in the thoracic aorta, in the pre-cervical artery bases, and overall were constructed. The scores were regressed on the annual rank number of the CT day. Results: By using the cubic regression model, seasonal variation in calcified plaques in coronary arteries (P=0.003), in pre-cervical artery origins (P=0.015), and in the overall sum score (P=0.004) was observed. The peak occurred in January-February and the nadir in August. Depending on the model, about 2-3% of the variation in atherosclerotic calcifications could be explained by the season of imaging. Conclusion: The observed seasonal trend in calcifications parallels with mortality reports. Seasonal variations should be considered in atherosclerosis treatment studies. Confirmatory studies using modern imaging technology are needed in different countries and geographical locations, preferably with repeat imaging of the same individuals.