Atrial fibrillation and the interaction with stroke in relation to white matter lesion volumes: A population‐based study in 70‐year‐olds

Background Atrial fibrillation (Afib) increases the risk of stroke and dementia. However, the mechanisms underlying the association between Afib and dementia in the absence of manifest stroke are not that well understood. The aim of this study is to investigate the association between Afib and white matter lesion (WML) volumes in a population‐based sample of 70‐year‐olds. Method Data were obtained from the Gothenburg H70 birth cohort studies (H70). In 2014, 1203 participants were examined (response rate: 72%) and a subsample (n=791) underwent structural MRI using a fluid‐attenuated inversion recovery (FLAIR) sequence. WML volumes were measured on FLAIR images using the Lesion Segmentation Tool (LST) and subsequently log transformed for further statistical analyses. Afib was diagnosed through self‐report, ECG, and hospital register. Stroke was diagnosed through self‐report, proxy‐report, hospital register, and large infarctions (>15mm) on brain‐MRI. Linear regression was used to analyze the association between Afib and WML volumes, while adjusting for potential confounders. Result After excluding individuals with neurodegenerative diseases, valvular heart diseases, and incorrect WML segmentation, 779 individuals remained for statistical analyses. Of these, 65 individuals (8.3%) had Afib. Individuals with a history of Afib had larger WML volumes than individuals without Afib after adjusting for total intracranial volume and sex. However, after additional adjustments for cardiovascular and metabolic diseases, smoking, alcohol risk‐consumption, education and stroke, this association was no longer seen (β 0.1 (95% CI ‐0.2‐0.3); p=0.697). A significant interaction was found between Afib and stroke (p