Seasonal blood pressure variation: implications for cardiovascular risk stratification.

Long-term blood pressure variations contribute to an increased risk of cardiovascular events during cold season, requiring personalized management of antihypertensive medications in a single patient, and can influence the results of clinical trials and epidemiological surveys in population studies. In addition to blood pressure values, which guide the stratification of cardiovascular risk, other cardiovascular risk factor levels also tend to be higher in the winter months and lower in the summer months. The resultant estimation of individual cardiovascular risk may thus vary depending on the season. At the patient level, only a low value in the winter should thus be considered a true measure of low cardiovascular risk, whereas low values measured in the summer do not indicate a low risk in the winter. Likewise, estimations of cardiovascular risk in population studies may vary according to the period of the year. Efforts should thus be directed at considering the potential influence of seasonal variations in establishing "normal" and "high-risk" assessment at both the patient and population levels, integrating such data into clinical practice.