There are a number of known CHD risk factors, such as smoking, poor diet, lack of physical activity, and elevated body mass index.
“However, even after controlling for these risk factors, we still saw an increased risk of CHD associated with rotating shift work,” lead author Celine Vetter of the US Brigham and Women’s Hospital said in a statement.
The researchers examined the association between rotating night shift work and CHD, using data from the long-running Nurses’ Health Study I and II, which has followed 240,000 female nurses over a 24-year period.
About 189,000 nurses, who reported their lifetime exposure to rotating night shift work, defined as working at least three night shifts per month in addition to morning and evening shifts, were included in the analysis.
These women also reported on their coronary health, indicating whether they had an angiogram that confirmed CHD-related chest pain, a heart attack, or cardiovascular procedures such as angioplasty, coronary artery bypass graft surgery or stents.
In the case of a self-reported heart attack, or death, information was confirmed by medical records and death certificates to ensure that the event was related to CHD.Their analysis indicated that increasing years of rotating night shift work was associated with “a statistically significant but small absolute increase” in CHD risk.