Plenty of headlines lately have warned about the risks of frequent and extensive periods of sitting. Here’s another risk to add to the list: a connection between sedentary behavior and pulmonary embolisms—blockage of the main artery of the lung—among women. The researchers followed 69,950 female nurses for 18 years, with the subjects completing biennial surveys on lifestyle habits, such as amount of time spent sitting. The scientists discovered that 49% of respondents sat between 11 and 40 hours per week and 22% sat for 41 hours or more. Throughout the intervention, there were 268 cases of pulmonary embolism among the women. After adjusting for other risk factors, such as smoking, it was determined that those who spent the greatest amount of time sitting had the most significant association with pulmonary embolism. According to the data, age wasn’t necessarily a risk factor; however, a positive association was drawn between pulmonary embolism and greater body mass index. “

Americans lead an increasingly inactive lifestyle, and this could partly explain the high prevalence of pulmonary embolism,” the study authors observed. “Public health campaigns that discourage physical inactivity among the general population could reduce the incidence of pulmonary embolism.”

The study was published July 4 in BMJ, the online edition of the British Medical Journal.