Study finds no association between inflammatory disease and risk of Alzheimer's disease
USA: A recent study showed that patients in the Health and Retirement Study (HRS) with common immune-mediated inflammatory diseases (IMID) were not at an increased risk of Alzheimer's disease (AD) over a 6-year period.
The study was published in the journal BMC Rheumatology on 12 November 2021.
Immune-mediated inflammatory diseases are characterized by systemic inflammation that affects joints and healthy organ systems. Previous studies examining the association between individual IMIDs and the risk of Alzheimer's disease have produced mixed results. Michael J. Booth, University of Michigan, MI, USA, and colleagues, therefore, aimed to examine AD risk across a group of IMIDs in a large population-based sample of older adults.
The researchers draw data from the HRS on a national sample of US adults over age 50 and linked Medicare claims from 2006 to 2014. IMIDs include psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, and related conditions. They identified IMIDs from 2006 to 2009 Medicare claims using International Classification of Diseases (ICD9-CM) codes. IMIDs were identified from 2006 to 2009 Medicare claims using International Classification of Diseases (ICD9-CM) codes. The risk of AD was examined from 2009 to 2014.
Following were the study's key findings:
- One hundred seventy-one (6.02%) of the 2842 total HRS respondents with Medicare coverage and genetic data were classified with IMIDs.
- Over the subsequent 6 years, 9.36% of IMID patients developed AD compared to 8.57% of controls (unadjusted hazard ratio (HR): 1.09). Adjusted HR 1.27.
- Age (HR for 10-year increment 3.56), less than high school education (HR 1.70), and APOE-e4 (HR 2.61), were also statistically significant predictors of AD.
"Using a large sample of U.S. older adults, we found no difference in the risk of Alzheimer's disease associated with immune-mediated inflammatory diseases relative to the risk in a large sample drawn from the general US population," the authors concluded. "In subgroup analyses, we found no increased risk of AD associated with RA, PSA, and AS; however, we recommend cautious interpretation of disease-specific results due to small subgroup sizes."
"Our primary finding is that as a group, respondents with IMIDs had no increased risk of AD," they wrote.
Booth, M.J., Kobayashi, L.C., Janevic, M.R. et al. No increased risk of Alzheimer's disease among people with immune-mediated inflammatory diseases: findings from a longitudinal cohort study of U.S. older adults. BMC Rheumatol 5, 48 (2021). https://doi.org/10.1186/s41927-021-00219-x