Swedish study finds about one more death in 100 over ten years
By Amy Ratner, Medical and Science News Analyst
People who have celiac disease have a slightly higher mortality risk than the those who don’t, a large Swedish study has found.
Over a ten year period, 9.7 people out of 100 people with celiac disease died from all causes compared to 8.6 out of 100 people who did not have celiac disease, according to the study.
|Mortality rate: the measure of the frequency of occurrence of death in a defined population during a specified interval.|
The study was based on nearly 50,000 Swedish celiac disease patients diagnosed between 1969 and 2017 and was done by researchers from the Columbia University Celiac Disease Center and the Karolinska Institute in Stockholm.
Benjamin Lebwohl, MD, director of clinical research at the Columbia celiac center and lead study author, called the slightly increased mortality rate a “small signal” that is found even when different groups of people with celiac disease are singled out. For example, it was found in young people; in those diagnosed most recently in the study – between 2010 and 2017, and in siblings who have celiac disease compared to those don’t.
However, no increase in mortality risk was seen when the 25 percent of celiac disease patients who had persistent damage to the villi were compared to those who had intestinal healing.
Previous studies have shown that even after diagnosis, celiac disease was associated with increased mortality, usually attributed to associated cancers, other autoimmune conditions, type 1 diabetes and more frequent fractures.
In the new study, investigators set out to see if celiac disease in the modern era, with increased diagnosis and greater ease in following the gluten-free diet due to increased availability of gluten-free food, is leading to a milder form of the condition as measured by mortality rates.
The database includes all patients in Sweden diagnosed with celiac disease and then follows them for an average of about 12 years. Its extent and duration enabled researchers to track patients from “cradle to grave,” according to Lebwohl. He said this kind of all-encompassing long-term study would not be possible in the United States, where there is no similar database.
“It is a small signal, but it is a signal,” Lebwohl said of the study’s findings on mortality risk. The reason celiac disease is associated with the small increased risk of death is unknown, the study authors wrote.
|Hazard ratio: likelihood of an event occurring in one group of people compared to another group of people over time
Absolute risk: the likelihood of an event occurring under specific conditions.
Many headlines and stories about the study focused on a 21 percent increased hazard ratio for celiac disease patients, but Lebwohl emphasized that the absolute risk, which was about 1 more person in 100 over 10 years is more practical. “We know that the great majority of people with celiac disease live long and healthy lives,” he said.
Researchers singled out data on a group of celiac disease patients with siblings who did not have the condition because their shared genes and similar early environments enabled researchers to control for factors that are usually difficult to regulate In this group they still found a slight increase in mortality, suggesting that risk can be traced to celiac disease and not some other measure.
The specific measure of mortality in those diagnosed between 2010 and 2017 is significant because it demonstrates that improved diagnosis rates in the United States and Europe has not been accompanied by a “substantial dilution of risk,” the study authors wrote.
The lack of difference in mortality risk between those with damaged villi and those with healing is “reassuring news” for many celiac disease patients who have ongoing intestinal injury, according to Lebwohl.
“If someone starts a gluten-free diet and fails to heal and has damage due to inadvertent gluten exposure, it’s not a big enough problem with life expectancy to show a signal,” Lebwohl explained. The mortality risk is diminished after diagnosis and the institution of the gluten-free diet but remained modestly elevated in the long term, study says.
Among the causes of death, patients with celiac disease were at slightly increased risk of cardiovascular disease death, cancer and respiratory disease. The study counted nearly 6,600 deaths, which the authors said may be the largest number in an investigation of mortality risk in celiac disease.
The study also found that the overall mortality risk was largest in the first year after diagnosis but persisted beyond 10 years after diagnosis. Additionally, the risk was greater in those diagnosed between 18 and 39 compared to those diagnosed at 40 and older. Those diagnosed as young adults may suffer the effects of celiac disease longer than those diagnosed as older adults, who may also have a clinically milder case that did not cause sufficient symptoms to lead to diagnosis until later in life, the study says.
But the main takeaway of the study, Lebwohl noted, is that celiac disease is serious and impacts life expectancy, though the degree of impact is not large. “It’s there and it’s measurable, but for individuals, after the gluten-free diet, they do very well.”
You can read more about the study here.