Women who work night shifts at a greater risk of dying from heart disease than those who work 9 to 5, according to researchers. In one of the largest studies of its kind, doctors found those who worked rotating night shifts for five or more years were at increased risk of death from diseases of the heart or blood vessels. Those working 15 or more years of rotating night shift work were at increased risk of dying from lung cancer. In 2007, the World Health Organisation classified night shift work as a probable carcinogen (cause of cancer) due to the way it disrupts a person’s body clock. For the current study, the researchers used data from the Nurses’ Health Study, which began in 1976 and involved 121,700 U.S. female nurses aged 30-55 who have been followed up with questionnaires every two years. Rotating shift work was defined as working at least three nights per month in addition to days or evenings in that month. The study found that death from all causes was 11 per cent higher for women who worked more than five years. Death from cardiovascular disease was 19 per cent higher for this group. For lung cancer, there was a 25 per cent higher risk in those who worked night shifts for more than 15 years. Professor Eva Schernhammer, of Harvard Medical School and the Brigham Women’s Hospital in Boston, said the study ‘is one of the largest prospective cohort studies worldwide with a high proportion of rotating night shift workers and long follow-up time’. ‘These results add to prior evidence of a potentially detrimental relation of rotating night shift work and health and longevity,’ she added. The research was published in the American Journal of Preventive Medicine. Health Survey for England data released in December showed that 30 per cent of shift workers are obese, compared with 24 per cent of men and 23 per cent of women who worked normal hours. Additionally, 40 per cent of male and 45 per cent of female shift workers had long-standing health conditions such as back pain compared with 36 per cent and 39 per cent of the rest of the population. Source
