Strikingly Low Prevalence of Atrial Fibrillation in Elderly Tanzanians

OBJECTIVES: To determine the prevalence of atrial fibrillation (AF) in individuals aged 70 and older in a rural African community. DESIGN: Community-based cross-sectional survey. SETTING: A demographic surveillance site (DSS) within the rural Hai district of northern Tanzania. PARTICIPANTS: Approximately one-quarter (N = 2,232) of the population aged 70 and older of the DSS. MEASUREMENTS: Participants were screened for AF using 12-lead electrocardiography; demographic and 1-year mortality data were collected; and functional status, body mass index, and blood pressure were recorded. The sex-specific prevalence of AF in each 5-year age band was determined. RESULTS: Fifteen of 2,232 participants (12 women, 3 men) had AF, giving a crude prevalence rate of 0.67% (95% confidence interval (CI) = 0.33-1.01) and an age-adjusted prevalence of 0.64% (95% CI = 0.31-0.97). Prevalence was 0.96% (95% CI = 0.42-1.49) in women and 0.31% (95% CI = -0.04 to 1.24) in men. Prevalence increased with age, from 0.46% (95% CI = 0.01-0.90) in those aged 70-74-1.30% (95% CI = 0.17-2.42) in those aged 85 and older. One-year mortality was 50% in women and 66.6% in men. CONCLUSIONS: This is the first published community-based AF prevalence study from sub-Saharan Africa. The prevalence rate of AF is strikingly lower than in other elderly populations studied, yet the 1-year mortality rate was exceedingly high.