A certain habit may be associated with a reduced risk of alzheimer's disease, although the specifics of the habit and its effects are unclear. Some reports suggest that the habit could lower the risk by as much as 37% or 39%, while others imply that it may actually increase the risk. The nature of the habit is also inconsistent across reports, with some describing it as related to smelling farts or producing "rotten egg gas", while others do not provide a clear description.