Bone mineral density, osteopenia, osteoporosis, and fracture risk in patients with atopic dermatitis: a systematic review and meta-analysis

Background: The relationship between atopic dermatitis (AD) and abnormal bone metabolism remains unclear. We performed a systematic review and meta-analysis to determine whether patients with AD were associated with increased risks of low bone mineral density (BMD), osteopenia, osteoporosis, and related fractures. Methods: We searched PubMed, Embase, and the Cochrane Library through December 2019 to identify studies that investigated the association between AD and abnormal bone metabolism (including BMD, osteopenia, osteoporosis, and related fractures). The predefined primary outcome was related fractures; secondary outcomes included osteoporosis, osteopenia, and BMD. We calculated the summary odds ratios (ORs) and 95% confidence intervals (CIs) using a random-effects model. Results: Ten studies were included in this systematic review. In children and adolescents, four studies investigated the association between AD and BMD; three studies indicated that children and adolescents with AD were associated with an increased risk of low BMD; one study found similar BMD between AD and control groups. In adults, three studies assessed the risk of fracture and were included in the meta-analysis, comprising 562,405 AD patients among 3,171,268 participants. Adults with AD were associated with an increased risk of fracture (OR 1.13; 95% CI, 1.05-1.22; P=0.001). Three studies investigated the association between AD and osteoporosis, which suggested that patients with AD were associated with an increased risk of osteoporosis (OR 1.95; 95% CI, 1.18-3.23; P=0.009). Further, patients with AD were associated with increased risks of osteopenia (OR 1.90; 95% CI, 1.51-2.38; P<0.001) and low BMD at the femur and spine. Conclusions: Patients with AD were associated with increased risks of low BMD, osteopenia, osteoporosis, and related fractures. Both clinical studies and basic research are needed to clarify the mechanisms of association between AD and abnormal bone metabolism.