People with a close family member who has celiac disease face the highest risk, with about 1 in 20 first-degree relatives eventually developing the condition themselves. But family history is just one piece of the picture. Your genes, sex, existing health conditions, and even certain childhood infections all influence how likely you are to develop celiac disease.
Genetics: The Required Starting Point
Celiac disease cannot develop without a specific genetic setup. Nearly 99% of people with celiac disease carry one or both of two gene variants known as HLA-DQ2 and HLA-DQ8. These genes control how your immune system reads proteins, and when gluten enters the picture, they can trigger an immune response that damages the small intestine.
Here’s the catch: carrying these genes is common. Roughly 40% of the general population has HLA-DQ2, HLA-DQ8, or both, yet only a small fraction of them ever develop celiac disease. So these genes are necessary but not sufficient on their own. Think of them as a loaded gun that still needs a trigger. If you don’t carry either gene variant, your chance of developing celiac disease is essentially zero, which makes genetic testing useful for ruling the condition out.
Family History Raises Risk Sharply
Having a parent, sibling, or child with celiac disease puts you in the highest-risk group. Studies of first-degree relatives consistently find a celiac prevalence of at least 4.8%, roughly five to ten times the rate in the general population. Siblings appear to be affected more often than parents, though anyone sharing that close genetic link should be aware of the possibility. Among relatives of celiac patients, about 90% carry the relevant gene variants, compared to roughly 55% of unrelated people.
Second-degree relatives (aunts, uncles, grandparents, cousins) also face elevated risk, though the numbers drop compared to immediate family. If celiac disease runs in your family at all, the odds that you carry the genetic predisposition are considerably higher than average.
Women Are Diagnosed More Often
Celiac disease is diagnosed in women roughly twice as often as in men, with some studies reporting ratios as high as 10 to 1 depending on the population. In a large cohort study spanning 25 years, 65% of diagnosed patients were female, and women were diagnosed about four years earlier on average than men.
Whether this reflects a true biological difference or a pattern of women seeking medical care sooner remains an open question. Hormonal factors and differences in immune system activity between sexes may play a role, but it’s also possible that men with celiac disease are simply underdiagnosed. Either way, the practical takeaway is that women with suggestive symptoms or a family history should have celiac disease on their radar.
People With Type 1 Diabetes
Type 1 diabetes and celiac disease share genetic roots, and the overlap is striking. About 8% of people with type 1 diabetes also have celiac disease, with individual studies reporting rates anywhere from 3% to 16%. That’s roughly eight to sixteen times the general population rate. The connection is strong enough that many pediatric diabetes guidelines recommend routine celiac screening, especially in children. Celiac disease in this group often presents with few or no digestive symptoms, which means it can go undetected for years without deliberate testing.
People With Autoimmune Thyroid Disease
Autoimmune thyroid conditions, particularly Hashimoto’s thyroiditis, also cluster with celiac disease. In one cross-sectional study, 9.3% of patients with autoimmune thyroid disease tested positive for celiac antibodies. A Dutch study found that 15% of Hashimoto’s patients were positive on at least one celiac screening test. These rates are high enough that some clinicians screen thyroid patients for celiac disease as a matter of course, though the practice isn’t universal.
People With Down Syndrome
Children with Down syndrome develop celiac disease at roughly 5 to 7% rates, far above the general population. A longitudinal birth cohort study found that 6.7% of children with Down syndrome had confirmed celiac disease. The American Academy of Pediatrics estimates the rate at about 5% and recommends screening. Turner syndrome and Williams syndrome are also associated with elevated celiac risk, though the data for these conditions is less extensive.
Certain Ethnic and Geographic Groups
Celiac disease was once considered a European condition, but that picture has changed significantly. The global seroprevalence (based on blood antibody testing) is about 1.4%, while the rate confirmed by intestinal biopsy sits around 0.7%. Europe and Oceania have the highest confirmed rates at 0.8%, while South America has the lowest at 0.4%.
Some genetically isolated populations show dramatically higher rates. The Saharawi people of Western Sahara have the world’s highest known celiac prevalence at 5.6%. Southern Brazilian Mennonites come in second, with a seroprevalence of 3.5% (about 1 in 29 people) and a biopsy-confirmed rate of 1.3%. These populations share limited genetic diversity, which concentrates the HLA gene variants that predispose to celiac disease. Populations of Northern European descent generally carry these genes at higher rates, which partly explains why celiac disease appears more common in those regions.
Viral Infections as a Trigger
In people who already carry the genetic predisposition, certain viral infections during early childhood may be the event that actually sets celiac disease in motion. Reoviruses have the strongest direct evidence. Researchers showed that a specific strain of reovirus, an otherwise harmless gut virus, could break the immune system’s tolerance to gluten in genetically susceptible mice. The virus essentially reprograms the immune response so that gluten, which should be ignored as a harmless food protein, gets flagged as a threat.
Enteroviruses, rotaviruses, and influenza viruses have also been linked to celiac onset. A study tracking stool samples from children at genetic risk found that those who developed celiac antibodies had higher rates of parechovirus infections beforehand, particularly when combined with enterovirus. A separate prospective study of nearly 2,000 genetically susceptible children found that frequent rotavirus infections appeared to increase celiac risk. These findings help explain why two people with identical genetic risk can have different outcomes: one encounters the wrong virus at the wrong time, and the other doesn’t.
Unexplained Iron Deficiency as a Clue
Iron-deficiency anemia that doesn’t respond to supplements or doesn’t have an obvious cause is one of the most common ways celiac disease reveals itself, sometimes as the only symptom. In studies of patients with unexplained iron deficiency, about 4% turned out to have undiagnosed celiac disease. The damaged intestinal lining in celiac disease prevents proper iron absorption, so persistent anemia, especially in someone with any of the risk factors above, is worth investigating further. This is particularly relevant because many people with celiac disease don’t have the classic digestive symptoms like diarrhea or bloating, and anemia may be the first and only red flag.