It has been suggested that lithium may have neuroprotective abilities, but it is not clear whether lithium reduces the risk of dementia.
To investigate whether continued treatment with lithium reduces the risk of dementia in a nationwide study.
An observational cohort study with linkage of registers of all patients prescribed lithium and diagnosed as having dementia in Denmark from January 1, 1995, through December 31, 2005.
We identified all patients treated with lithium in Denmark within community psychiatry, private specialist, and general practices and a random sample of 30% of the general population. Subjects A total of 16,238 persons who purchased lithium at least once and 1,487,177 persons from the general population who did not purchase lithium. Main Outcome Measure Diagnosis of dementia or Alzheimer disease during inpatient or outpatient hospital care.
Persons who purchased lithium at least once had an increased rate of dementia compared with persons not exposed to lithium (relative risk, 1.47; 95% confidence interval, 1.22-1.76). For persons who continued to take lithium, the rate of dementia decreased to the same level as the rate for the general population. The rate of dementia decreased early after the consumption of lithium tablets corresponding to 1 prescription (typically 100 tablets) and stayed at a low level, although with a slight increase according to the number of subsequent prescriptions. The association between the number of prescriptions for lithium and dementia was unique and different from the association between the number of prescriptions for anticonvulsants and dementia. All findings were replicated in subanalyses with Alzheimer disease as the outcome.
Continued lithium treatment was associated with reduction of the rate of dementia to the same level as that for the general population. Methodological reasons for this finding cannot be excluded, owing to the nonrandomized nature of data.
there are no previous studies linking repeated heat exposure of sauna and the risk of memory diseases. We aimed to investigate whether frequency of sauna bathing is associated with risk of dementia and Alzheimer's disease.
prospective population-based study.
the frequency of sauna bathing was assessed at baseline in the Kuopio Ischaemic Heart Disease population-based prospective cohort study of 2,315 apparently healthy men aged 42-60 years at baseline, with baseline examinations conducted between 1984 and 1989. Hazard ratios (HRs) with 95% confidence intervals (CIs) for dementia and Alzheimer's disease were ascertained using Cox-regression modelling with adjustment for potential confounders.
during a median follow-up of 20.7 (interquartile range 18.1-22.6) years, a total of 204 and 123 diagnosed cases of dementia and Alzheimer's disease were respectively recorded. In analysis adjusted for age, alcohol consumption, body mass index, systolic blood pressure, smoking status, Type 2 diabetes, previous myocardial infarction, resting heart rate and serum low-density lipoprotein cholesterol, compared with men with only 1 sauna bathing session per week, the HR for dementia was 0.78 (95% CI: 0.57-1.06) for 2-3 sauna bathing sessions per week and 0.34 (95% CI: 0.16-0.71) for 4-7 sauna bathing sessions per week. The corresponding HRs for Alzheimer's disease were 0.80 (95% CI: 0.53-1.20) and 0.35 (95% CI: 0.14-0.90).
in this male population, moderate to high frequency of sauna bathing was associated with lowered risks of dementia and Alzheimer's disease. Further studies are warranted to establish the potential mechanisms linking sauna bathing and memory diseases.