Sedentary behaviour contributes to increased atrial fibrillation risk in older women

Longer total sitting time and prolonged sedentary bouts put women at risk of developing atrial fibrillation (AF), a study has found.

The study used data from the OPACH study and included 2,675 AF-free individuals (mean age 78.2 years, body mass index 28.1 kg/m²) who wore a triaxial accelerometer on a belt for 1 week and had subsequent Medicare follow‐up. On average, the participants were sedentary for 9.2 hours per day.

Over a median follow‐up of 3.8 years, 268 participants (10.0 percent) developed incident AF at a rate of 31 cases per 1,000 person‐years. There were 111 all‐cause deaths (4.1 percent) documented at a rate of 13 deaths per 1,000 person‐years. The cumulative incidence of AF was 12.1 percent at the end of follow‐up.

In multivariable Cox proportional hazards models, longer total sedentary time was linked to a greater risk of incident AF (quartile 4 vs 1: hazard ratio, 1.20, 95 percent confidence interval, 0.81–1.78; p=0.05 for trend). However, after further adjustment for physical function and self‐rated health, the association was no longer significant.

Both longer mean sedentary bout duration and more continuous sedentary periods (versus frequent breaks in sedentary time) also conferred higher risks of incident AF, but these associations were also attenuated after serial adjustment.

The findings suggest that associations between sedentary behaviour and incident AF may be attributable to other patient characteristics. More studies are needed to determine whether interventions that limit sedentary behaviour can reduce rates of AF in older women, as well as to evaluate the influence of sedentary behaviour on incident AF in other populations.