Spanish researchers investigate the relationship between bone density and degree of intestinal damage caused by celiac disease.
Past research has shown that people with celiac disease are at a higher risk than the general population of losing bone mineral density (BMD) and developing osteoporosis, but debate still surrounds the need for bone density screening to be done on the newly diagnosed. To help fill this gap of knowledge, researchers from Spain set out to determine those risk factors associated with osteoporosis by studying 40 newly diagnosed people ranging from 18 to 67 years old.
Among their study population, the Spanish researchers observed that the degree of bone mass loss in the lumbar spine (the lower back) is directly related to the amount of intestinal damage observed at the time of diagnosis. When looking at the BMD of the hip bones of the study participants in correlation with intestinal damage, similar findings were observed, but the researchers noted the data “did not reach statistical significance.”
To determine the participants’ intestinal damage, researchers performed biopsies in the duodenum (the first part of the small intestine) and then rated them based on the Marsh scale. The Marsh scale categorizes the level of intestinal damage seen in people with celiac disease:
Marsh I: There is no villous atrophy and the epithelial cells are infiltrated by lymphocytes. Little malabsorption occurs. Most patients do not have celiac disease.
Marsh II: The number of lymphocytes increase and hyperplastic (enlarged) crypts surrounding the villi appear.
Marsh III: There is an increased number of lymphocytes and hyperplastic crypts
There are three subsets of Marsh III:
Stage IIIa: Partial villous atrophy
Stage IIIb: Subtotal villous atrophy
Stage IIIc: Total villous atrophy
Further, the researchers noted that 45% of patients in the study showed low BMD at the time of diagnosis at either or both the hip and the lumbar spine. Adult patients diagnosed with Marsh III exhibited an increased risk of bone fracture that was 3.5 times greater than those with Marsh I and Marsh II.
Overall, this study found that 18.8% of patients with Marsh I and II presented some degree of low BMD at either the hip or lumbar spine, while 70% of patients with some level of Marsh III were found to have a loss in BMD. As a result, the authors conclude that: “the stage of duodenal mucosal injury following Marsh’s classification was the most important factor in determining low BMD.”
To explain why low BMD occurs in celiac disease, the study identifies two potential causes for this increased risk. One recently proposed possibility is that low bone density can be caused by chronic intestinal inflammation. The researchers believe, however, that malabsorption and malnutrition due to intestinal damage is most likely the cause, especially in adults. While a gluten-free diet typically helps people to recover BMD, adults reach their peak bone density between 20-30 years old. Those diagnosed later in life may experience difficulties with low BMD despite adopting the gluten-free diet.
As mentioned above, many researchers have debated the need for bone density scans at the time of celiac diagnosis. Some believe the tests should be performed either immediately following diagnosis or within one year of maintaining a gluten-free diet. Others believe the moderate risk of bone fracture does not warrant the need for bone scans. The researchers in this study suggest bone scans should be performed in adult patients who fulfill one of the following three criteria: are above the peak age for bone density, exhibit villous atrophy (i.e. Marsh III), or present with symptoms or lab tests indicative of malabsorption/ malnutrition.
The full study can be found in the US National Library of Medicine on the National Institutes of Health website.
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