The rising popularity of domestic fridges during the 20th century may be responsible for a similar rise in Crohn's disease, say French scientists.
Some bacteria can thrive in the fridge
Their theory, published in the Lancet, is that bugs which grow in the fridge may play a role in the gut disorder.
Traces of these have been found in the bowel ulcers of Crohn's patients.
However, other experts point out there is no proof these cause the illness - and say fridges prevent dangerous food poisoning cases.
The unusual theory was suggested by doctors at hospitals in Paris, who noticed an interesting trend in cases of Crohn's during the last century.
Crohn's is much more common today than it was at the turn of the 20th century, and there is no obvious explanation for this.
But the researchers noticed that as the domestic fridge became a fixture in more and more homes from the 1940s onwards, the numbers of Crohn's cases rose as well.
In the US, where the fridge came into fashion earlier than in Europe, the rise in cases of the disease came earlier too.
Now approximately one in a thousand people in the UK has Crohn's, which causes inflammation of the lower gut, leading to severe cramps, diarrahoea, and, in the long term, the need for surgery to remove damaged sections of bowel.
The French theory centres on "psychrotrophic bacteria" - which, unlike most bugs, have the ability to carry on reproducing even at quite low temperatures.
Two in particular, Yersinia and Listeria, will grow in numbers even inside a fridge, although not sufficiently quickly to cause food poisoning.
There is other evidence Crohn's may be linked to some kind of immune system problem - many sufferers have a mutation in a gene linked to immunity.
In addition, say the researchers, studies of the contents of Crohn's disease "lesions" inside the gut found traces of Yersinia and Listeria.
This, they say, points to the possibility that some kind of inappropriate immune response to these bacteria may trigger or worsen Crohn's - and say that the role of the fridge in exposing consumers to larger concentrations of them could be historically important.
"We propose a specific candidate for the development of Crohn's disease: The refrigerator.
"By themselves, each line of evidence is quite convincing, but their association is even more persuasive."
However, the researchers conceded that the benefits of refrigeration both at home and in food production far outweighed the risk of Crohn's should their theory be proven true.
Only a theory
Dr Jeremy Sanderson, a consultant gastroenterologist at St Thomas' Hospital in London, and an adviser to the National Association for Crohn's and Colitis, said: "It is good to see that people are thinking about the link between Crohn's disease genetics and bacteria.
"However, this paper is just a hypothesis and there is no shortage of hypotheses in the hunt for the cause of Crohn's disease."
Professor Jonathon Rhodes, a researcher at the University of Liverpool, agreed, saying: "This is an interesting hypothesis but it is not backed by any new data.
"We would say that if this hypothesis is correct, we would expect to see better therapeutic responses to the antibiotics known to be effective against Yersinia and Listeria in people with Crohn's disease."
A spokesman for the Food Standards Agency stressed the importance of refrigeration in the fight against food poisoning - which can be fatal in the very young and old.
"If some foods are not kept refrigerated, harmful bacteria can grow and toxins form, causing food poisoning," said a spokesman.