But you may be less likely if you follow the gluten-free diet for other reasons
By Amy Ratner, Beyond Celiac Medical and Science News Analyst
People with celiac disease are no more likely to be depressed or have sleep difficulty than the general population, a new study based on a large national health survey has found.
Meanwhile, those who follow the gluten-free diet but have not been diagnosed with celiac disease were less likely to be depressed than controls, the study published in the European Journal of Gastroenterology and Hepatologyshowed.
“We found that both diagnosed and undiagnosed celiac disease participants had similar odds of depression compared to controls,” the study authors wrote.
Researchers from Columbia University and the Mayo Clinic reviewed data on more than 22,000 participants in the 2009-2014 National Health and Nutrition Examination Survey, which collects nationally representative physical examination and laboratory data from more than 5,000 participants every year.
They found 76 cases of celiac disease, 21 of whom were diagnosed and 52 who were not but had positive celiac disease blood tests. Another 213 did not have celiac disease, but reported that they were on the gluten-free diet, mostly as a result of their own decision to follow it.
The existence of depression or sleep disorders was determined by answers participants gave to several questionnaires, including one that asked about use of prescription drugs to treat depression.
Depression not inherent
Depression was found in 8.1 percent of participants with diagnosed celiac disease compared to 8.2 percent of controls. In those who were undiagnosed but had blood test results that showed celiac disease, depression was reported by 2.3 percent. However, that number did not hold up when researchers adjusted for a number of variables, including age and sex, and they concluded “the lower odds of depression in undiagnosed celiac disease was no longer statistically significant.” Still, the study suggests that depression is not prominent feature of undiagnosed and untreated celiac disease, the authors wrote.
The study results suggest that depression, whether someone is on the gluten-free diet or not, may not be an inherent functional change that accompanies celiac disease. Study authors said depression that does exist may stem from the fact a person with celiac disease is struggling with symptoms, the chronic nature of the disease, the burden of being on the gluten-free diet or other related medical conditions.
Some previous studies have shown a link between celiac disease and increased depression, while others have refuted those findings. Some link diagnosis and adoption of the gluten-free diet to the end of depression, while others report depression even in treated celiac disease.
Depression is often considered one of the symptoms of celiac disease, and some patients anecdotally report feeling depressed prior to diagnosis, with improvement on the gluten-free diet. Others says they are more depressed after diagnosis because of the limitations of the diet, including social isolation. The new study notes these inconsistencies, and the authors say one of the strengths of their work is use of a large U.S. population with an unbiased sampling method. However, they note that the small number of celiac disease patients in the sample might have caused the prevalence of depression to be underestimated.
But a larger study could also potentially show a decreased risk of depression, according to Benjamin Lebwohl, M.D., assistant professor of medicine and epidemiology at the Celiac Disease Center at Columbia University and one of the study authors, “We are certainly not seeing a trend towards an increased risk, which is reassuring,” Lebwohl said.
Why lower risk
For those on the gluten-free diet without a diagnosis, the rate of depression was 2.9 percent, which is less than half the rate reported by controls and those with celiac disease. The study says it is possible that gluten-free diet adherence contributed to lower odds of depression, but pointed out this is unlikely because the diagnosed group also followed the diet and did not show lower odds than the general population.
Lebwohl said it’s unclear why those on the gluten-free diet who don’t have celiac disease had a lower risk of depression.
“It could be that there is a modest protective effect of this diet with regard to depression, but that in those with celiac disease it is counterbalanced by the burden of the diet,” he said. “It’s also notable that subjects with celiac disease did not have higher rates of depression or sleep disturbance than the general population. This does not, in my opinion, diminish the difficulty of living with the condition or its diet, rather it underscores that depression is common in the general population as well. Celiac disease or not, depression is potentially serious and treatable.”
The study was the first to investigate sleep problems among a population with celiac disease in the United States, according to the authors. “We found no association between celiac disease and insomnia,” they wrote.
Despite not suffering from higher rates of major depression, both diagnosed and undiagnosed celiac disease participants reported higher rates of physical, mental and emotional limitations compared to the general population. “This suggests that although they may not fulfill the criteria for a diagnosis of depression, they still may have a significant treatment burden or difficulties coping with symptoms,” the study notes.
The authors said more research is needed to measure the presence of psychiatric conditions in patients with celiac disease and non-celiac gluten sensitivity before and after treatment with the gluten-free diet to explore the role of gluten in depression.