People who work long hours may have an increased risk of cardiovascular disease (CVD), a new study is reporting.

For this study, the researchers examined health and employment data on 1,926 adults taken from the Panel Study of Income Dynamics. The participants were employed for at least 10 years and did not have any heart problems at the start of the study. Overall, 43 percent of the participants had been diagnosed by a physician with at least one CVD, which included angina, heart failure or coronary heart disease, heart attack, high blood pressure (hypertension) or stroke.

The researchers were able to find an association between the number of work hours and risk of a CVD event over at least 10 years of employment in full-time employees only.

"We found that the risk of CVD increased as the average weekly working hours increased," wrote the research team headed by Sadie H. Conway at the University of Texas Health Sciences Center at Houston. 

The researchers reported that in general, for every additional hour of work recorded per week, risk of having a CVD increased by one percent. For employees with weekly work hours that were increasing from 30 to 40, risk of CVD increased steadily. For people who worked 40 to 45 hours per week, however, CVD risk started to decline.

The researchers noted that the 40-to-45-hours-per-week window might be the most ideal in regards to heart health since people who worked more than that had the greatest risk of heart disease. The researchers calculated that 55-hour work weeks were associated with a 16 percent increased risk of CVD while 60-hour work weeks were tied to a 35 percent increased risk of CVD.

"This study provides specific evidence on long work hours and an increase [in] the risk of CVD, thereby providing a foundation for CVD prevention efforts focused on work schedule practices, which may reduce the risk of CVD for millions of working Americans," Conway said.

The study authors stressed the need to improve work conditions in order to reduce risk of heart problems, especially since CVD is the leading cause of death within the nation. They added that if prevention measures for CVD are not developed and enforced, prevalence could pass 40 percent by 2030.

The Centers for Disease Control and Prevention (CDC) reported that in 2013, 611,105 deaths could be attributed to heart disease.

The study was published in the Journal of Occupational and Environmental Medicine.