Yes, but per usual a study done with such small numbers, especially considering the self-reporting required for it, to not provide meaningful results.
Apple Cider Vinegar May not be healthy if splashed onto the teeth. Apple cider vinegar may be bad news for the stomach lining. Diluted with water and drinking while avoiding the teeth may be wise. Everyone that I know of who tried apple cider vinegar would up discontinueing the attempts. I think though that vinegar does clean window glass and will clean a person’s insides.