Story adapted from The North American Menopause Society (NAMS)

It’s no secret that working non-traditional shifts can wreak havoc on lifestyle and sleep habits. Shift work has also been known to have a negative effect on workers’ health. A new study that used data from the Canadian Longitudinal Study on Aging (CLSA) suggests it also may delay the onset of natural menopause, possibly because of disruptions in circadian rhythms.

The research was published online in the journal Menopause.

Shift work has increased globally in recent years, with an estimated one in four Canadians working some type of non-traditional or alternating shifts.

Although shift work has become an economic necessity to keep up with the increased demand for goods and services, it is not without health risks, such as coronary events, peptic ulcers, Type 2 diabetes and cancer.

Although previous studies have shown the various adverse health effects of shift work on working adults, there has been little research on the effect of shift work on middle-aged and older adults.

This new study, based on secondary data analyses of nearly 3,700 premenopausal women enrolled in the CLSA, aimed to investigate the association between shift work exposure and variations in age at natural menopause in adult Canadian workers.

Based on study results, a significant relationship has been shown between rotating shifts and delayed onset of menopause. The researchers speculate that disruptive circadian rhythms may play a role, although further investigation is necessary.

“The workers who were ever exposed to shift work during their entire career were significantly associated with later onset of menopause,” said Durdana Khan, a PhD student in the Department of Kinesiology and Health Sciences at York University. “Specifically, women who worked as a rotating shift worker in current job or in longest job were more likely to delay onset of menopause.”

Age at natural menopause is a matter of concern for middle-aged and older women because both early or late menopause may be a significant risk marker for subsequent morbidity and mortality. Environmental factors such as smoking, parity, and socioeconomic status have previously been identified to be strongly associated with variations in age at natural menopause.

“This delaying effect of rotating shift work on age at natural menopause has not been reported before, therefore, to develop a more complete picture of the relationship between shift work and onset of menopause, additional studies will be needed to confirm the association as well as determine any physiological pathways that are influenced. Future studies should examine further details of shift work and how they relate to age at menopause, such as the type and direction of rotating shifts, the number of consecutive night shifts and the number of days off between shifts,” Khan said.