Here's a link to: PubMed - U.S. National Library of Medicine National Instutes of Health. (Much more reliable than the OP link.)
Eating habits and appetite control in the ... [Int Psychogeriatr. 2003] - PubMed - NCBI
Notice in the body of the article (abstract) the phrase "Anorexia nervosa" is never used. Instead, the single term "Anorexia" is used. Webster's definition of Anorexia: 1. loss of appetite and inability to eat. 2. Anorexia Nervosa
Yes, the definition includes Anorexia Nervosa, but the PubMed article NEVER mentions Anorexia Nervosa in describing the appetite problems of the elderly. They use the single term "Anorexia" to simply mean, "loss of appetite and inability to eat," for the various reasons given in the article.