Gut health and depression genetically entwined

Gut health and depression genetically entwined

The researchers have confirmed a link between depression and stomach ulcers, in the world's largest study of genetic factors in peptic ulcer disease. They have provided clues to how the gut and brain work together by studying health data from nearly half a million people.

The research supported a holistic approach to caring for patients with gastrointestinal diseases like peptic ulcers, which affect between five and 10 per cent of people at some time in their lives.

"As a medical student, I noticed how some patients' gastrointestinal symptoms improved after psychotherapy or psychiatry treatment," the senior author said.

"This study linking major depression with an increased risk of gastrointestinal disorders also explains the co-morbidity of the conditions."

Stress was thought to be the leading cause of peptic ulcer disease until it was linked to the bacteria H. pylori by Australian Nobel Prize winners Barry Marshall and Robin Warren.

The authors identify 8 independent and significant loci for peptic ulcer disease (PUD) at, or near, genes MUC1MUC6, FUT2PSCAABOCDX2, GAST and CCKBR. There are previously established roles in susceptibility to Helicobacter pylori infection, response to counteract infection-related damage, gastric acid secretion or gastrointestinal motility for these genes. Only two associations have been previously reported for duodenal ulcer, here replicated trans-ancestrally.

The results highlight the role of host genetic susceptibility to infection. Post-GWAS analyses for PUD, gastro-oesophageal reflux disease (GORD), irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) add insights into relationships between these gastrointestinal diseases and their relationships with depression, a commonly comorbid disorder.

The author said medication had since reduced the disease's prevalence, but the importance of other risk factors including lifestyle and psychological factors now needed to be re-emphasised.

"To identify why some people develop ulcers, we studied health data from 456,327 individuals from the UK Biobank and identified eight genetic variations associated with the risk of getting peptic ulcer disease," The senior author said.

"Six of the eight variations can be linked to why some people are more prone to H. pylori infection, which would make them more susceptible to peptic ulcer disease."

The senior author said an existing peptic ulcer treatment targets the gene linked to one of these genetic variations and so identification of other associated genes could offer opportunities to develop new treatments.