A new study found that the popular pain relievers known as nonsteroidal anti-inflammatory drugs, or Nsaids, may increase the risk for the most common type of irregular heartbeat, atrial fibrillation.

Dutch researchers followed 8,423 people, average age 69, with normal heart rhythm at the start of the study for an average of 13 years. Over the period, 857 developed atrial fibrillation.

Compared to those who never used Nsaids — which includes such drugs as ibuprofen and aspirin — current or recent use was associated with an 80 percent increased risk of atrial fibrillation. The study was published online in BMJ Open.

The scientists controlled for blood pressure, cholesterol, smoking and other cardiovascular risk factors, but the association persisted.

Still, they could not prove a causal relationship, and the reasons for the association remain unclear. One theory is that the drugs lead to increases in blood pressure and fluid retention, which can affect heart function.

The senior author, Dr. Bruno H. Stricker, a professor of pharmaco-epidemiology at Erasmus University Medical Center in Rotterdam, said these drugs have also been associated with the risk for coronary artery disease and heart attack.

“I would really strongly advise that older people be very careful with using these drugs,” he said. “They don’t do anything except relieve pain. Pain is a nuisance, but dying is a nuisance, too.”