• autoimmune diseases
• epidemiology
• rheumatoid arthritis
• systemic lupus erythematosus

Autophagy is an intracellular pathway by which cells generate energy and metabolites by recycling their own non-essential, redundant or damaged components.1 Pathophysiological studies have demonstrated that the impairment of autophagy contributes to protein aggregate accumulation that occurs during Alzheimer’s disease and experiments have shown that autophagy inhibitors, such as chloroquine and hydroxychloroquine, block amyloid plaque degradation.1 2 Further, a recent case–control study found that patients with rheumatoid arthritis who used hydroxychloroquine were at increased risk of dementia.3 We investigated whether chronic exposure to chloroquine/hydroxychloroquine increases the risk of Alzheimer’s disease.

Data from The Health Improvement Network (THIN) were used (January 1990–December 2016). THIN is a UK primary care database on >12 million people. Participating general practitioners prospectively enter clinical information on individuals so that the database provides a longitudinal medical record for each individual. THIN is representative of the UK population. …