A recent study found that exposure to lithium among older adults was linked to a decreased risk of developing dementia and its subtypes, Alzheimer disease (AD) and vascular dementia (VD).
The retrospective cohort study, conducted by researchers from the University of Cambridge and the Cambridgeshire and Peterborough NHS Foundation Trust, aimed to identify preventive interventions that could help delay the onset of dementia, as dementia is the leading cause of disability and death among older adults in Western populations. Lithium has been suggested as a treatment option, but little research has investigated this possibility at the population level. To assess the role of lithium, the investigators collected data from the electronic clinical records of 548 patients who had been exposed to lithium and 29,070 patients who had not been exposed to lithium between January 1, 2005, and December 31, 2019. Among the participants, 40.2% were male, and the mean age was 73.9 years, with all patients being at least 50 years old at baseline. In the lithium-exposed group, 9.7% of patients received a diagnosis of dementia, including 6.8% with AD and 2.6% with VD. In the group that had not been exposed to lithium, 11.2%, or 3244, received a diagnosis of dementia, including 2276 with AD and 698 with VD. The investigators used Cox proportional hazard models to analyze the data, finding that lithium exposure was associated with a decreased incidence of dementia, AD, and VD, and in both short-term (≤1-year) and long-term (>5-year) exposure durations. Although no significant changes were identified in immediate durations, the longer the duration of lithium exposure, the lower the risk of developing dementia.1
The study’s main limitation, according to the investigators, was that 73% of patients in the lithium-exposed group had been diagnosed with mania/bipolar affective disorder (BPAD), which itself is a considerable risk factor for dementia. Although this might be expected to cause an increase in dementia in the lithium-exposed group, the investigators found the opposite. They suggested that, given the specific nature of the lithium-exposed group in this study, researchers should be cautious in extending the findings of this study to the general population.1
“Our findings support the possibility that lithium treatment could decrease the risk of developing dementia and supports the need for further randomized controlled trials (RCTs) to test the efficacy of lithium as a disease-modifying drug in dementia,” the investigators concluded.
1. Chen S, Underwood BR, Jones PB, et al. Association between lithium use and the incidence of dementia and its subtypes: a retrospective cohort study. PLOS Medicine; 2022.