A new study published today in The Lancet shows that people with “highly demanding” job or those with “little freedom” are more likely to have a heart attack. Specifically, they are 23% more likely to have a heart attack than those with less stressful jobs.

The study, led by Professor Mika Kivimäki from the University College London department of epidemiology and public health, looked at 13 European national cohort studies from Belgium, Denmark, Finland, France Netherlands, Sweden, and the U.K. since 1985. The nearly 200,000 people who participated in the studies were given questionnaires that assessed their job demands, workload, time-pressure demands, and freedom to make decisions at work.

“The overall population attributable risk (PAR) for CHD events was around 3.4 per cent, suggesting that if the association were causal, then job strain would account for a notable proportion of coronary heart disease (CHD) events in working populations,” said Kivimäki. “As such, reducing workplace stress might decrease disease incidence. However, this strategy would have a much smaller effect than tackling standard risk factors such as smoking (PAR 36%) and physical inactivity (PAR 12%).”

The 23% higher risk of heart attack the new study finds stays consistent regardless of gender, age, or socioeconomic status. According to the University College London, previous studies linking work stress and heart disease have been limited, inconsistent, and put into question by shortcomings such as publication bias and reverse causation bias.

“The pooling of published and unpublished studies allowed us to investigate the association between CHD and exposure to job strain – defined by high work demands and low decision control – with greater precision than has been previously possible,” said Kivimäki. “Our findings indicate that job strain is associated with a small, but consistent, increased risk of experiencing a first CHD event such as a heart attack.”