根据严格的诊断标准,[3]Hoek HW. Incidence, prevalence and mortality of anorexia nervosa and other eating disorders. Curr Opin Psychiatry. 2006 Jul;19(4):389-94.http://www.ncbi.nlm.nih.gov/pubmed/16721169?tool=bestpractice.com 西方国家大约 0.3% 的人群(0.5%-1% 大学年龄女性)患有此病。[4]Miller KK, Grinspoon SK, Ciampa J, et al. Medical findings in outpatients with anorexia nervosa. Arch Intern Med. 2005 Mar 14;165(5):561-6.http://www.ncbi.nlm.nih.gov/pubmed/15767533?tool=bestpractice.com 一项在几千户美国家庭的国家共患病调查估计,女性 AN 终生患病率为 0.9%,男性为 0.3%。[5]Hudson JI, Hiripi E, Pope HG Jr, et al. The prevalence and correlates of eating disorders in the National Comorbidity Survey Replication. Biol Psychiatry. 2007 Feb 1;61(3):348-58.http://www.ncbi.nlm.nih.gov/pubmed/16815322?tool=bestpractice.com 据估计每 10 名患者中有 3 名为男性,但是许多男性可能不会就诊寻求治疗;因此,在被诊断的患者中 90% 为女性。[6]Torpy JM, Burke AE, Glass RM. Anorexia nervosa. JAMA. 2006 Jun 14;295(22):2684.http://www.ncbi.nlm.nih.gov/pubmed/16772633?tool=bestpractice.com
一些报告指出,青春期前男孩的 AN 相对患病率很高,男女比例可达 1:4。[7]Bryan-Waugh R, Lask B. Childhood-onset eating disorders. In: Fairburn GC, Brownell KD, eds. Eating disorders and obesity: a comprehensive handbook. 2nd ed. New York: Guilford Press, 2002:210-4. 男性被确诊的可能性更低,这是因为怀疑度较低,因此实际的发病率可能高于通常报告的水平。[8]Andersen AE. Eating disorders in males. In: Fairburn CG, Brownell KD, eds. Eating disorders and obesity: a comprehensive handbook. 2nd ed. New York: Guilford Press, 2002:210-4.
青春期后期发病风险最高,40% 的新发病例集中在 15-19 岁的患者中。21 岁之后 AN 发病风险显著降低。[3]Hoek HW. Incidence, prevalence and mortality of anorexia nervosa and other eating disorders. Curr Opin Psychiatry. 2006 Jul;19(4):389-94.http://www.ncbi.nlm.nih.gov/pubmed/16721169?tool=bestpractice.com 只有三分之一的患者就诊求助。[9]Hoek HW, van Hoeken D. Review of the prevalence and incidence of eating disorders. Int J Eating Dis. 2003 Dec;34(4):383-96.http://www.ncbi.nlm.nih.gov/pubmed/14566926?tool=bestpractice.com 很难获得可靠的流行病学数据,但现有的最佳信息表明,AN 的发病率(每年新增病例数)在过去三十年中没有发生显著变化。[10]Smink FR, van Hoeken D, Donker GA, et al. Three decades of eating disorders in Dutch primary care: decreasing incidence of bulimia nervosa but not of anorexia nervosa. Psychol Med. 2016 Apr;46(6):1189-96.http://www.ncbi.nlm.nih.gov/pubmed/26671456?tool=bestpractice.com
与其他少数种族的女性相比,白人女性更可能被诊断为 AN。不论哪种人群,如果临床医师忽略关于进食、体重变化既往史和相关认知的特定问题,则可能无法发现病例。此外,患者可能未透露疾病症状。虽然节食行为不会直接导致大多数人患 AN(因为大多数节食的人不会出现 AN),但是这种疾病发生在崇尚追求身体纤瘦的环境下。
AN 在西方国家更普遍,其研究也更深入。[11]Steiner H, Kwan W, Shaffer TG, et al. Risk and protective factors for juvenile eating disorders. Eur Child Adolesc Psychiatry. 2003;12(suppl 1):I38-46.http://www.ncbi.nlm.nih.gov/pubmed/12567214?tool=bestpractice.com[12]Nagel KL, Jones KH. Sociological factors in the development of eating disorders. Adolescence. 1992 Spring;27(105):107-13.http://www.ncbi.nlm.nih.gov/pubmed/1539487?tool=bestpractice.com 跨文化研究认为,进食障碍发病率增加与接触西方媒体和理念有关,[13]Becker AE. Television, disordered eating, and young women in Fiji: negotiating body image and identity during rapid social change. Cult Med Psychiatry. 2004 Dec;28(4):533-59.http://www.ncbi.nlm.nih.gov/pubmed/15847053?tool=bestpractice.com 有证据表明,在非西方国家,这种可能增加进食障碍风险的看法正在增加。[14]Tao ZL. Epidemiological risk factor study concerning abnormal attitudes toward eating and adverse dieting behaviours among 12- to 25-years-old Chinese students. Eur Eat Disord Rev. 2010 Nov-Dec;18(6):507-14.http://www.ncbi.nlm.nih.gov/pubmed/20593481?tool=bestpractice.com