Aphthous stomatitis caused by a reduction in numbers of CD4+ T cells may be implicated in RAS-type ulceration in HIV infection. The thickness of the mucosa may be an important factor in aphthous stomatitis. Usually, ulcers form on the thinner, non-keratinizing mucosal surfaces in the mouth. Factors which decrease the thickness of the mucosa increase the frequency of occurrence, and factors which increase the thickness of the mucosa correlate with decreased ulceration. The nutritional deficiencies associated with aphthous stomatitis (Vitamin B12, folate, and iron) can all cause a decrease in the thickness of the oral mucosa (atrophy). Local trauma is also associated
Anthroposophic medicine part it complements conventional medicine, and in part it substitutes for it. In 2008, Ernst wrote that it was being promoted as an "extension to conventional medicine". Ernst writes that Steiner used imagination and insight as a basis for his ideas, drawing mystical knowledge from the occult Akashic Records, a work which is supposedly situated on the astral plane, and which Steiner said was accessible to him via his intuitive powers. On this basis, Steiner proposed "associations between four postulated dimensions of the human body (physical body, etheric body, astral body, and ego), plants, minerals, and the cosmos". Steiner also