New research involving more than 266,000 UK adults indicates that working permanent night shifts can disrupt the body’s circadian rhythm, alter gut function, and elevate the risk of irritable bowel syndrome (IBS). This significant finding may influence how shift work and digestive health are perceived.
The study, published in Frontiers in Public Health, establishes a link between night shift work and an increased risk of IBS. Irritable bowel syndrome, a gastrointestinal disorder, is characterised by abdominal pain, bloating, and irregular bowel habits. The disorder’s global prevalence ranges from 0.2% to 7.6%, with variations depending on geographical and demographic factors. Chronic symptoms of IBS can severely impact quality of life and productivity.
The body’s circadian system — its internal clock — regulates daily physiological changes. Disruptions in this system, common among night or rotating shift workers, can lead to metabolic disorders. Previous research has already associated shift work with higher risks of diabetes, obesity, and cardiovascular diseases. Against this backdrop, researchers from Jiaotong University, China, conducted a comprehensive study to explore the correlation between night shift work and IBS risk among UK shift workers.
The study analysed data from 266,605 participants in the UK Biobank, focusing on shift work patterns and IBS incidence. Excluding those with prior IBS, coeliac disease, or gluten sensitivity, the study identified 5,218 new IBS cases over nine years. The analysis, accounting for age, gender, and other factors, found a notable risk increase for permanent night shift workers, especially those with a body mass index over 25.
The research suggests that circadian rhythm disruption may lead to gut microbiota imbalance, impaired gastrointestinal motility, and increased inflammation — all potential IBS triggers. Night shift patterns are known to suppress melatonin, a hormone crucial for sleep and gut health. Although melatonin supplementation was not tested, previous studies indicate it may alleviate IBS symptoms.
Notably, the risk was more pronounced in overweight or obese individuals, possibly due to obesity-related factors like altered gut microbiota and systemic inflammation. While the study’s observational nature limits its ability to establish causality, it underscores the potential benefits of avoiding night shifts for those at risk of IBS.
Further research is required to confirm causality and explore underlying mechanisms. The study’s findings primarily apply to European-descended UK Biobank participants, potentially limiting broader applicability. Nonetheless, this extensive study suggests that maintaining a regular circadian rhythm could benefit those susceptible to IBS.
