The changing epidemiology of non-valvular atrial fibrillation: the role of novel risk factors

The growing ‘epidemic’ of atrial fibrillation (AF), with its associated morbidity and mortality, intersects with a number of risk factors including ageing and other conditions including thromboembolism, stroke, congestive heart failure, hypertension, and also perhaps metabolic syndrome and systemic inflammation. Currently in the USA, ∼2.3 million people are diagnosed with AF and, on the basis of the US census, this number is expected to rise to 3.3 million by 2020 and to 5.6 million by 2050. This may even be a substantial underestimate: recent data from Rochester, MN, USA suggest that there has been an almost three-fold increase in the prevalence of AF over the last three decades, after adjustment for age. The explanations for this phenomenon are likely multifactorial, and the socio-economic implications considerable. Ongoing efforts towards understanding AF are driven, in part, by the concept that the primary causal factors of AF in most patients may be the consequence of a systemic condition of reduced vascular compliance, atherosclerosis, obesity, and inflammation. Such epidemiological investigations must be undertaken in association with studies aimed at defining the structural and electrical phenotypes and molecular genetics of AF, which may provide additional insights into their potential interactions with age and environmental factors.