Long-term shift work linked to decreased brain function, says study

A new study has claimed that long working hours or shift work like chronic jet lag disrupts the body's internal clock and is linked to range of health problems, such as ulcers, cardiovascular disease, metabolic syndrome, and some cancers.

The researchers tracked the cognitive abilities of more than 3000 people who were either working in a wide range of sectors or who had retired, at three time points: 1996, 2001and 2006.

Just under half (1484) of the sample, which was drawn from the patient lists of three occupational health doctors in three different regions in southern France, had worked shifts for at least 50 days of the year and participants were aged exactly 32, 42, 52 and 62 at the time of the first set of tests, which aimed to assess long and short term memory; processing speed and overall global cognitive abilities.

Around one in five of those in work i.e.18.5% and a similar proportion of those who had retired 17.9% had worked a shift pattern that rotated between mornings, afternoons, and nights.

The second set of analyses looked at the impact of working a rotating shift pattern and found that compared with those who had never worked this type of shift, those who had, and had done so for 10 or more years, had lower global cognitive and memory scores equivalent to 6.5 years of age related cognitive decline.

The results indicated that it was possible to regain cognitive abilities after stopping shift work, but that this took at least five years, processing speeds excepted.