Thursday December 18 2014
Shift working can disrupt the rhythms of the body
"Higher rates of obesity and ill-health have been found in shift workers than the general population," BBC News reports.
These are the key findings of a survey into health trends among shift workers; defined as any working pattern outside of the normal fixed eight-hour working day (though start and finish times may vary).
According to the survey (The Health Survey for England 2013), shift workers were more likely to report general ill-health, have a higher body mass index (BMI) and increased incidence of chronic diseases such as diabetes.
The Health Survey for England 2013 also monitored other trends in the nation’s health, including people’s weight, smoking habits, fruit and vegetable consumption, and prescribing patterns for drugs (a story we covered earlier this month).
Who produced the data?
The report was produced by the Health & Social Care Information Centre (HSCIC), the official provider of national health and social care statistics. The HSCIC was set up by the government in April 2013. Its role is to provide information on a range of issues concerning health for use by commissioners, analysts and clinicians in driving patient services.
In the interests of transparency we should point out that the Behind the Headlines team, along with all NHS Choices staff, is employed by the HSCIC.
The HSCIC produces an annual Health Survey for England that monitors important aspects of the population’s health.
How was the data collected?
The data comes from interviews with a representative sample of the population. Participants aged 16 years and over who were in employment were asked whether they worked in shifts either "most of the time", "occasionally" or "never". Those who answered either "most of the time" or "occasionally" were then asked which type of shift work they were doing. Shift work was defined in the question as "work outside the hours of 7am to 7pm in your (main) job".
Participants were then grouped into shift workers (who reported that they did shift work "most of the time" or "occasionally") and non-shift workers.
Comparisons between shift workers and non-shift workers across a range of health and lifestyle factors were age-standardised, so that any differences in age profile are taken into account in the comparisons.
What were the key findings?
- Men were more likely than women to report that they did shift work (33% of men and 22% of women).
- Shift working was most prevalent in the 16-24 age group, and declined with age for both men and women. Almost half of men and over a third of women aged 16-24 did shift work compared with fewer than a third of men and a fifth of women aged 55 and over.
- The prevalence of shift work varied significantly by household income, being highest in the lowest two income quintiles (42-43% among men, 27-28% among women, compared with 21% and 19% respectively in the highest income quintile). Similarly, the proportion of men and women in shift work was highest in the most deprived quintile compared with the least deprived.
- Both men and women in shift work were more likely than non-shift workers to report fair or bad health.
- Shift workers were more likely than non-shift workers to have a limiting longstanding illness; they were also more likely to have more than one longstanding illness.
- Shift workers were more likely than non-shift workers to be obese. This is reflected in higher mean body mass index (BMI) measurements, higher proportions classified as obese, and greater proportions with a very high waist circumference.
- Men and women in shift work were more likely than non shift workers to have diabetes (10% of both men and women in shift work, compared with 9% and 7% respectively of those not working shifts).
- Current cigarette smoking prevalence was higher among shift workers than non-shift workers, with a larger difference among women than men. 28% of men in shift work currently smoked compared with 23% of men who did not do shift work. The equivalent figures for women were 26% and 15% respectively.
- The proportion of both men and women who drank alcohol in the last year was slightly smaller among shift workers (84% of men, 81% of women) than among those who did not work shifts (88% and 83% respectively).
- Daily fruit and vegetable consumption was lower among shift workers than non-shift workers. Men in shift work ate an average of 3.3 portions compared with 3.6 for non-shift workers. Among women the equivalent means were 3.6 and 3.8 respectively. Shift workers were also slightly less likely than non-shift workers to meet government recommendations of eating five or more portions per day.
Why do shift workers tend to be less healthy?
There are a number of potential underlying factors that may impact on health and wellbeing.
Firstly, shift working can disrupt what are known as circadian rhythms, the internal "body clock". This can disrupt the normal workings of a hormone called melatonin. This disruption can lead to poor sleep and chronic fatigue.
Persistent lack of good quality sleep has been linked to a range of chronic conditions such as obesity, depression, diabetes and heart disease.
While the body can slowly adapt to the changes in working patterns, many shift workers are on rotating shifts and suddenly switching from a night to day shift leads to further disruptions.
Rotating shift work can also disrupt the production of insulin, which may increase the risk of someone developing type 2 diabetes.
There is also the fact that shift workers tend to be on the lower end of the socioeconomic scale. And there is evidence that people on lower incomes have an increased tendency to smoke, drink excessive amounts of alcohol and eat a poor diet. There is also the stress and worry associated with trying to make ends meet.
What has previous research found?
There has a been a range of studies linking shift work to a number of different adverse outcomes; which we have looked at previously in Behind the Headlines. These include claims that:
The issue with all the studies is that due to the complex play of personal, environmental and socioeconomic factors, researchers were unable to prove a direct cause and effect link between shift work and the outcomes listed above; only an association.
Still, there seems to be a consensus that while shift work may not be actively dangerous, it is certainly not an ideal arrangement for healthy living.
So what can shift workers do?
Well, ideally, find another job. But that is often easier said than done. Most of us don’t have the luxury of quitting a job if the hours don’t suit us unless we have another job lined up.
That said, if you are unhappy with your current situation, it is worth spending a few hours every week signing up to job search sites. Along with commercial sites, the government also provides a service known as Universal Jobmatch.
The Health and Safety Executive also offers some useful and practical advice for people working shift work. This includes:
- take extra care if you drive to and from work as your concentration may be impaired; if possible it may be a better idea to use public transport
- identify a suitable sleep schedule of at least seven hours a day, you may find it useful to keep a diary to assess what sleep times suit you best
- try to create an environment that promotes good sleep, for example heavy curtains or an eye mask may help you sleep during the day
- making changes to your diet to improve both alertness and digestion; smaller healthy snacks during your shift may be a better idea than one big meal
- limit your use of stimulants such as caffeine or energy drinks as well as sedatives such as alcohol; while they may bring short-term benefit they are unlikely to be of help in the long term
- try to get regular exercise – at least 30 minutes per day
Read more Hints and tips for shift workers
Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.