A matched cohort study using data from a large primary care record database in the U.K. has shown that atopic dermatitis raises the risk of subsequent fracture, with severity of the skin condition correlating with level of risk.
Published online ahead of print in The Journal of Allergy and Clinical Immunology (Nov. 19, 2019), the study identified 526,808 adults with atopic eczema and 2,569,030 people without atopic eczema, and matched individuals with eczema to up to five individuals without the condition. Primary care data was cross-referenced with hospital admission records. Investigators then estimated hazard ratios (HRs) comparing risk of major osteoporotic (hip, pelvis, spine, wrist, and proximal humerus) fractures individually and any fracture in those with and without atopic eczema.
Senior author Professor Sinéad Langan from the London School of Hygiene & Tropical Medicine, London, U.K., said in a press release: “Previous research has shown associations between atopic eczema and osteoporosis, a condition that weakens bones and makes them more likely to break, and between atopic eczema and fracture. However, this is the first evidence that eczema precedes fractures and that fracture risk increases with more severe eczema.”
The investigators found that risk of any fracture was as much as 13% higher in people with atopic eczema compared to people without. In particular, individuals with severe atopic eczema had a dramatically increased risk of fracture: 50% more hip fractures, 66% more pelvis fractures, and more than twice the risk of spine fractures.
Researchers did emphasize that the overall risk of fractures remains low. They estimated that in a sample of 100,000 individuals with eczema, there would be 164 more individuals who would experience a fracture, compared to a population of 100,00 age- and sex-matched individuals without the skin condition. The authors note that the results are of public health importance due to how common eczema is and the morbidity and mortality associated with fractures.
The increased risk of fracture was present even after adjusting for use of oral corticosteroids.
Professor Langan said: “Although the overall risk is low, the substantial increase in the risk of spine, hip and pelvic fractures seen in those with severe atopic eczema is particularly concerning, given the serious health issues associated with these fractures. Atopic eczema is currently not considered a risk factor for fracture. Our results suggest that bone density screening guidelines should consider including individuals with more severe atopic eczema in order to prevent fractures, improve long-term quality of life, and reduce fracture-related healthcare costs.
“Future work should focus on determining the possible biological mechanisms linking atopic eczema to lowered bone density, and whether targeted screening and intervention would benefit individuals with atopic eczema.”
Some limitations to the study identified by the authors include the possibility that there may be other reasons that could explain why people with atopic eczema may be more likely to break bones. Examples suggested include that people with eczema may have daily allergies, make dietary changes (some believe that certain foods trigger eczema flares) or avoid exercise (as sweating may increase the itch associated with their atopic eczema), any of which could make them more prone to fractures.