Letters RESEARCH LETTER

Association Between Opioid Use and Atrial Fibrillation: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study It has been estimated that more than 4.3 million adults in the United States are taking opioids regularly in any given week.1 Opioid receptors are downregulated in animal models of atrial fibrillation (AF).2 However, to our knowledge, the association between opioid use and AF has not been examined in

population-based studies. We examined the cross-sectional association between prescription opioid use and AF using data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.3 Methods | Details of the REGARDS study and its design have been published.3 Briefly, between January 25, 2003, and October 30, 2007, a total of 30 239 participants were recruited using postal mailings and telephone calls from across the United States. Demographic information, medical histories,

Table 1. Characteristics of REGARDS Study Participants No. (%) Opioid Use (n = 1887)

Characteristic

No Opioid Use (n = 22 745)

P Valuea

Demographic Variables Age, mean (SD), y

64 (9.4)

65 (9.4)

.048

Male sex

656 (34.8)

10 673 (46.9)