Lifestyle risk factors for atrial fibrillation in Ireland

Atrial fibrillation (AF) is the most common sustained arrhythmia. The prevalence of AF is age dependent, affecting up to 17% of over 80 s.1 The population is ageing, and it is estimated that the number of patients with AF in Europe will grow to almost 18 million by 2060.2 In Ireland, the number of adults aged over 65 years is increasing by 3–4% annually, which will increase the number of new cases of AF each year.3 The AF epidemic will have a significant impact on health services due to the increased morbidity and mortality associated with this condition.1 The prevention and early detection of AF are therefore key factors in reducing the economic and societal burden of this arrhythmia. Multiple studies suggest an association between AF and lifestyle risk factors, especially excessive alcohol consumption.4–6 Ireland as a society has a reputation for excessive and harmful alcohol consumption. In 2016, alcohol consumption in Ireland was approximately 10.9 litres of pure alcohol per person per year almost 2 litres over the Organisation for Economic Co-operation and Development average.7 There is also evidence suggesting that smoking may be associated with the increased incidence of AF.4,5Almost 20% of Irish people are current smokers, with a higher prevalence of smoking among men (20.9%) versus women (15.5%).8 To our knowledge, no study has yet examined how drinking and smoking patterns in Ireland may affect the prevalence of AF in older adults. We therefore examined whether alcohol consumption and smoking are predictors of AF in older adults in Ireland. Analysis of a large, prospective, multicentre observational study was carried out to evaluate the impact of lifestyle risk factors on the prevalence of AF in an older population in rural communities in the west of Ireland. The study has been described in detail previously.9 In brief, 37 general practice surgeries were recruited in counties Sligo, Galway and Leitrim in the west of Ireland. Opportunistic screening for AF was carried out in patients 65 years of age or older between January 2014 and June 2014. Ethics approval for this study was obtained from the Irish College of General Practitioners research ethics committee. Screening was performed by way of a pulse check and AF was subsequently confirmed by a 12-lead electrocardiogram (ECG). A binary variable representing all cases of AF was recorded, as well as a binary variable representing all new cases of AF – that is those without a previous diagnosis of AF. Demographic and clinical characteristics were recorded including age, sex, smoking status and average weekly alcohol intake. Alcohol consumption was categorised into three groups according to the amount of alcohol consumed during a typical week; no alcohol, 0–14 units, 14–21 units and 21 units or more of alcohol per week. A binary variable was created for smoking status, categorising into those who reported never smoking, and those who reported currently smoking or smoking in the previous 10 years. Statistical analysis was carried out using STATA 14 (Stata Corporation). Multivariable logistic regression was used to assess whether characteristics including age, sex, smoking status and weekly alcohol consumption were associated with increased odds of AF and of new AF. A total of 7262 patients was screened for AF and their smoking status and alcohol consumption were recorded. Of those screened, 794 (10.9%) had AF on ECG, of whom 55 (0.76%) had a new diagnosis of AF. Multivariable logistic regression was used to assess factors associated with AF. This analysis included age, sex, smoking status and alcohol consumption. The results are displayed in Table 1. AF was associated with increased age (odds ratio (OR) 1.08, 95% confidence interval (CI) 1.07, 1.09; P < 0.001), male sex (OR 1.80, 95% CI 1.53, 2.12; P < 0.001) and drinking 21 or more units of alcohol per week (OR 1.75, 95% CI 1.11, 2.74; P = 0.015). Subsequent analysis of incident cases of AF was performed. The results of multivariable logistic regression with new AF are also displayed in Table 1. New cases of AF were associated with increased age (OR 1.04, 95% CI 1.01, 1.08; P = 0.025). Association between demographic and lifestyles risk factors and AF. All AF: all patients who were identified with atrial fibrillation; New AF: patients who received a new diagnosis of atrial fibrillation; OR: odds ratio; CI: confidence interval. P value < 0.05. Association between demographic and lifestyles risk factors and AF. All AF: all patients who were identified with atrial fibrillation; New AF: patients who received a new diagnosis of atrial fibrillation; OR: odds ratio; CI: confidence interval. P value < 0.05. The concept of AF as a preventable disease has been explored in the recent literature. Although obesity and hypertension appear to have the strongest association with the development of AF, there is evidence that excessive alcohol consumption and smoking are also implicated. It appears that there is a linear relationship between alcohol consumption and the risk of AF.4,–6 Furthermore, there are data to suggest that the avoidance of obesity, low levels of alcohol consumption and non-smoking reduce the risk of AF.5 In addition, adequate control of blood pressure may further reduce the incidence of new-onset AF.6 This paper has shown that age, male sex and excessive alcohol intake were associated with AF in Ireland. This is consistent with international evidence; however, it is particularly important in the Irish context. A significant proportion of the older population in our study engaged in unhealthy behaviours. Over 13% of women and 7% of men were moderate to heavy drinkers. Culturally, Ireland is a society with unhealthy alcohol consumption habits, with an estimated 1.35 million adults in Ireland who drink in a harmful manner.10 This study highlights the need for focused public health programmes and interventions to reduce harmful drinking in Ireland, particularly in older adults. Increasing awareness of the association of harmful drinking and AF and the devastating effects of stroke as a result will aid in preventing the ongoing AF epidemic. A limitation of the current study includes that, while the population of individuals screened for AF in this study was large, a relatively small number of new cases of AF were diagnosed. This may explain the lack of a statistically significant association between alcohol consumption and new cases of AF, despite a significant association between alcohol consumption and existing cases. The association between AF and alcohol is well established; however, to the authors’ knowledge this is the first paper examining this question in a rural Irish population. In summary, this study highlights the importance of lifestyle risk factors in the prevention of AF. Strategies to reduce alcohol consumption as part of a healthy lifestyle are likely to have an impact on the prevalence of AF in Ireland.