Mika Kivimäki (University College, London, UK & University of Helsinki, Finland): Effect of stress on health, disease and ageing
The WHO Global Action Plan for the Prevention and Control of Non-Communicable Diseases targets established risk factors, including physical inactivity, tobacco use, heavy alcohol consumption, unhealthy diets, overweight, and raised blood pressure. However, a number of new risk factors have been proposed. In this keynote, the most recent evidence for stress as a risk and prognostic factor for chronic diseases is reviewed. To cover the multiple roles of stress in disease pathology, the review is organized according to the disease process, from the development of subclinical disease and the acute triggering of clinical disorder to progression of the disease. In prospective cohort studies, stress has been linked to increased risk of diabetes, coronary heart disease, stroke and depressive disorders, but no robust associations with site-specific cancers, all cancers combined, chronic obstructive pulmonary disease, asthma, Crohn’s disease or ulcerative colitis have been observed. Over the last 5-10 years, pooling of multiple datasets into mega studies has accelerated progress in research on stress. These studies suggest that severe stressful experiences in childhood, such as physical abuse and household substance abuse, can substantially damage mental and physical health. By contrast, adulthood stress might be an important risk factor in specific groups only. For example, stress is a trigger for cardiovascular events in persons who already have a high atherosclerotic plaque burden. Adulthood stress may also affect prognosis and outcome in those with pre-existing diabetes, cardiovascular or cerebrovascular disease. Mechanistic studies in real-life settings have corroborated earlier laboratory-based observations on stress-related pathophysiological changes that underlie triggering, such as lowered arrhythmic threshold and increased sympathetic activation with related increases in blood pressure, as well as pro-inflammatory and procoagulant responses. In some clinical guidelines, stress is already acknowledged as a target for prevention for vulnerable groups of people. However, few scalable, evidence-based interventions are currently available.