Posted on 17 October 2022
Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.
Why is this research important: Our guts are linked to other aspects of our health in ways we are still piecing together. As they break down food, the bacteria in our guts produce chemicals that can have far-reaching health effects. The composition of the gut microbiome also has an effect on food transit time. Previous studies suggest that the frequency of bowel movements may predict the onset of age-related diseases outside of the gut. For example, constipation appears to predict the onset of Parkinson’s disease. Improving our understanding of such relationships could help us predict a person’s risk of a given disease, and may also help us better understand what causes it.
What did the researchers do: In this study, researchers looked at data from the China Kadoorie Biobank. They looked at 487,198 participants aged 30-79 who had no previous diagnosis of cancer, heart disease or stroke at the start of the study. Participants were asked roughly how often they experienced bowel movements, with the options being less than three times a week; once every 2-3 days; once a day; more than once a day. They were then followed up for an average period of 10 years to see if there was any association between bowel movement frequency and risk of various diseases, including heart diseases and type II diabetes.
Key takeaway(s) from this research: When compared to 1 bowel movement every 1-3 days, and after adjusting for factors like age, having 2+ bowel movements a day was associated with a significant increase in risk of ischaemic heart disease, heart failure, chronic obstructive pulmonary disease, type 2 diabetes mellitus and chronic kidney disease. The largest increases were for heart failure and chronic obstructive pulmonary disease, with a 33% and 28% increased risk respectively. However, having fewer than three bowel movements a week was also associated with negative health outcomes, with significant increases in the risk of ischaemic heart disease, major coronary events, ischaemic stroke and chronic kidney disease.
This study isn’t the first of its kind, but it is the first to investigate as wide a range of diseases, and has the advantage of a large sample size representing both urban and rural regions of China. As this was an observational study, it’s not clear why this relationship between bowel movement frequency and disease exists. Some of the most obvious explanations include poor diet, physical inactivity and obesity, which could all affect both gut function and disease risk. However, controlling for such factors didn’t have much of an effect on the strength of the relationship in most cases. There were a few confounders the researchers couldn’t control for, such as total calorie intake and use of certain drugs, which could have contributed to the apparent associations.
More research is needed to determine exactly why these relationships exist, which could help us better understand the role of the gut in human disease. In the meantime, should doctors adopt bowel movement frequency as method of estimating disease risk? At the very least, perhaps people with an abnormal frequency of bowel movements should consider themselves more at risk of future health conditions.
Bowel movement frequency and risks of major vascular and non-vascular diseases: a population-based cohort study among Chinese adults: http://dx.doi.org/10.1136/bmjopen-2019-031028