No Associations Between Glucosamine Supplementation and Dementia or Parkinson's Disease: Findings From a Large Prospective Cohort Study.

Background: We investigated the associations between habitual use of glucosamine and incident dementia and Parkinson's disease in a population-based cohort.

Methods: Using the UK Biobank data, we included around 0.29 million middle- to old-aged participants free of dementia or Parkinson's disease at baseline. Glucosamine supplementation was measured by questionnaire at baseline. Some participants additionally answered 1-5 rounds of 24-hour dietary recalls afterwards, particularly 112 243 participants (for dementia) and 112 084 (for Parkinson's disease). Incident cases of dementia and Parkinson's disease were identified through linkage to health administrative data sets. We examined the associations of glucosamine supplementation with incident dementia and Parkinson's disease using Cox proportional-hazards regression models with adjustment for various covariates.

Results: During the study period (median follow-up: 9.1-10.9 years), 4 404 and 1 637 participants developed dementia and Parkinson's disease, respectively. Glucosamine intake was not associated with incident dementia or Parkinson's disease. In fully adjusted models, the hazard ratios associated with glucosamine intake were 1.06 [95% confidence interval (CI): 0.99, 1.14] for dementia and 0.97(95% CI: 0.86, 1.09) for Parkinson's disease. In the subsample, similar results were found as the frequency of reported glucosamine use over multiple dietary surveys was associated with neither of the 2 conditions.

Conclusions: Habitual supplementation of glucosamine was not associated with incident dementia or Parkinson's disease.