A pilot study into erratic eating in shiftworking nurses and doctors raises questions about the health risks of shiftwork. FIONA CASSIE talks to researcher Anne Jaquiery.
Snacking on the run, eating ‘breakfast’ at tea time and dinner whenever you can grab the time.
What effect does erratic eating from day to day have on a shiftworking nurse’s metabolism? Does it put them more at risk of cardiovascular disease and type II diabetes?
Anne Jaquiery, a senior lecturer at the University of Auckland and a hospital paediatrician, doesn’t claim to have the answers, but she recently led a pilot study that opens up some interesting questions.
Prior to the study, her research had focused on maternal and child nutrition, including the impact of unpredictable eating patterns. Then she got to thinking about the impact of irregular eating patterns on hospital nurses who worked rotating shifts.
If the body’s normal responses to hunger signals were confused by not eating when your body was expecting a meal or eating when not hungry, how did the body metabolise and store that food?
Jaquiery says recent research indicates eating regularly is associated with a lower incidence of metabolic disease and a lower risk of cardiovascular disease or type II diabetes. Research also shows that shiftworkers on rotating shifts have a higher incidence of metabolic disease than non-shift workers, and shiftwork is associated with irregular eating habits.
She used summer studentship funding on a pilot study* looking at how variable and unpredictable eating patterns actually were of rotating shiftworkers in a regional hospital.
Did the number of meals and snacks – and the timing between them – differ whether they were on day shift, afternoon shift or night shift?
The hypothesis was that the mismatch of hunger signals and food intake would disrupt normal circadian rhythms and appetite regulating pathways. This, in turn, would affect the shiftworker’s metabolism in ways that promoted weight gain and the risk of metabolic syndrome.
16 nurses (all women) and 13 junior doctors (six men and seven women) volunteered to take part in the observational study. Each participant had their height, weight, waist measurement, and BMI (body mass index) recorded, filled in a brief questionnaire, and then kept a two-week food diary recording their meals and snacks both on and off shift.
The average age of the nurses was 43 years compared to 25–26 years for the junior doctors, and the nurses’ average length of time in shift work was 17.7 years, compared to just one to two years for the junior doctors.
The average BMI of the nurses was just over 30 (obese) compared with 22-24 for the much younger doctors. However, BMI was not directly related to age in the nurses, with some of the younger nurses having the higher BMIs and one of the oldest nurses being lean and athletic.
Jaquiery said overall the nurses’ BMI was higher than would generally be considered healthy, and she was sure that a contributing factor was likely to be rotating shifts. “I’m sure it doesn’t help”.
The study found that half of the nurses had variable numbers of meals depending on which shift they were working. The female junior doctors’ eating habits were even more variable, and in particular, they ate fewer meals and more snacks while on night shift.
What all the female participants had in common was they ate double the recommended daily intake of sugar, both when on shift and on their days off. The male doctors had higher than recommended salt intakes – possibly due to eating more hot savoury takeaways.
She says nurses and doctors know the ‘dos and don’ts’ of eating. But when busy, stressed, or in the middle of the night, good eating habits can go out the window.
Jaquiery says an ED nurse joked that her food diary would have been “lolly, lolly, chip, lolly, chip”.
“And that’s what some shifts are like – you are too busy to take a proper meal break and you eat what food is around.”
“For some people, that may not matter so much, but for people who already have genetic or environmental predisposition to metabolic disease or other risk factors, then I think that does matter,” says Jaquiery.
She believes the health sector also has some responsibility to mitigate the risk of metabolic disease for longterm shiftworkers like nurses. Particularly making it as easy as possible for shiftworking staff to make healthy eating choices.
“Because they are always going to need round-the-clock shiftworkers, we need to appreciate that this work is done at some personal cost”.
Jaquiery would like to see further research done into eating patterns on shift work involving a control group and a pilot of some simple intervention, perhaps preceded by a glucose tolerance test and followed by a form of intervention. The findings could help develop some simple evidence-based guidelines on healthy eating patterns for rotating shiftworkers.
For example, Jaquiery says one study participant came up to her several months later to report she had started eating breakfast and had lost six kilos.
She says early in her career she worked at a small provincial hospital that provided cold meat and salad for a sit-down ‘lunch’ in the middle of night shift. This may or may not have been good for the metabolism but it did mean healthy food was provided after hours rather than just a vending machine or dial-a-pizza.
So if any researchers are interested in picking up from where the pilot study ended, she is keen to hear from them. “I think it would be a great Masters or PhD study”. ?
Dr Clare Wall, University of Auckland also helped with the project and students Talya Postelnik and Vicki Alderson-Wallace carried out the study.