Seasonal variations in cardiovascular disease

Key Points Seasonal variations across a broad range of populations and climates (but predominantly derived from the temperate climates of Europe) have been documented in all types of cardiovascular disease (CVD) Most studies report 'winter peaks' in CVD-related hospitalizations and mortality; event rates in winter are typically 10–20% greater than during 'summer troughs' CVD seasonality is probably caused by a complex interaction between the susceptibility of individuals and a range of environmental factors (including ambient temperature) CVD seasonality is most pronounced in individuals living in milder climates, who are least prepared for extreme weather variations A lag effect, potentially modulated by air pollution levels and concurrent influenza, has been documented after 'cold snaps' Potential exists to attenuate seasonality in CVD via multifaceted interventions that modulate exposure to various provocations to the cardiovascular system in high-risk individuals (those with established CVD) Cardiovascular disease (CVD) follows a seasonal pattern in many populations, often peaking after 'cold snaps'. In this Review, Stewart and colleagues identify the physiological and environmental factors that contribute to seasonality in nearly all forms of CVD, and describe the potential strategies that might attenuate peaks in cardiovascular events during cold and hot periods of the year. Cardiovascular disease (CVD) follows a seasonal pattern in many populations. Broadly defined winter peaks and clusters of all subtypes of CVD after 'cold snaps' are consistently described, with corollary peaks linked to heat waves. Individuals living in milder climates might be more vulnerable to seasonality. Although seasonal variation in CVD is largely driven by predictable changes in weather conditions, a complex interaction between ambient environmental conditions and the individual is evident. Behavioural and physiological responses to seasonal change modulate susceptibility to cardiovascular seasonality. The heterogeneity in environmental conditions and population dynamics across the globe means that a definitive study of this complex phenomenon is unlikely. However, given the size of the problem and a range of possible targets to reduce seasonal provocation of CVD in vulnerable individuals, scope exists for both greater recognition of the problem and application of multifaceted interventions to attenuate its effects. In this Review, we identify the physiological and enviro