Important risk factors include inherited or
genetic susceptibility, lack of adequate home care, age, diet,
health history, and medications (Krasse and Brill, 1960,
Page and Schroeder, 1982, Genco et al., 1998, Gorrel, 1998, Harvey, 1998, Lund et al., 1999; Roudebush et al., 2005, and Logan, 2006).