Each year, approximately one in 25 adults will experience a swallowing problem in the United States (Bhattacharyya, 2014). Dysphagia cuts across so many diseases and age groups, its true prevalence in adult populations is not fully known and is often underestimated.
A number of epidemiologic reports indicate that the prevalence of dysphagia is more common among older individuals (Barczi, Sullivan, & Robbins, 2000; Bhattacharyya, 2014; Bloem et al., 1990; Cabré et al., 2014; Roden & Altman, 2013; Sura, Madhavan, Carnaby, & Crary, 2012). Conservative estimates suggest that dysphagia may be as high as 22% in adults over 50 years of age (Lindgren & Janzon, 1991; National Foundation of Swallowing Disorders, n.d.; Tibbling & Gustafsson, 1991); as high as 30% in elderly populations receiving inpatient medical treatment (Layne, Losinski, Zenner, & Ament, 1989); up to 68% for residents in long-term care settings (National Institute on Deafness and Other Communication Disorders [NIDCD], n.d.; Steele, Greenwood, Ens, Robertson, & Seidman-Carlson, 1997); and 13%–38% among elderly individuals who are living independently (Kawashima, Motohashi, & Fujishima, 2004; Serra-Prat et al., 2011). Additional studies suggest that elderly populations have an increased risk for the development of dysphagia-related complications such as pulmonary aspiration (Altman, Yu, & Schaefer, 2010; Marik, 2001; Schmidt, Holas, Halvorson, & Reding, 1994; Tracy et al., 1989). A report by the Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare Research and Quality [AHRQ]) estimates that approximately one third of patients with dysphagia develop pneumonia and that 60,000 individuals die each year from such complications (AHCPR, 1999).
Various neurological diseases are known to be associated with dysphagia. The exact epidemiological numbers by condition or disease also remain poorly defined. This, in part, is due to the concomitant medical conditions being reported and the timing and type of diagnostic procedures being used to identify swallowing disorders across neurological populations. For example, a systematic review by Martino and colleagues (2005) found that the incidence of dysphagia in stroke populations was as low as 37% when identified using cursory screening procedures and as high as 78% when identified using instrumental assessments. A later study by Falsetti and colleagues (2009) found that dysphagia occurs in over one third of patients admitted to stroke rehabilitation units. Further studies suggest that dysphagia occurs in 29%–64% of stroke patients (Barer, 1989; Flowers, Silver, Fang, Rochon, & Martino, 2013; Gordon, Hewer, & Wade, 1987; Mann, Hankey, & Cameron, 1999).
Additional systematic reviews and studies have reported variable estimates of dysphagia in other acquired and progressive neurogenic populations as well as other medical conditions. Alagiakrishnan, Bhanji, and Kurian (2013) reported prevalence ranges of dysphagia in dementia patients from 13% to 57%, whereas Kalf, de Swart, Bloem, and Munneke (2011) reported prevalence ranges from 35% to 82% for individuals with Parkinson's disease. A study by Coates and Bakheit (1997) suggests that dysphagia is as high as 90% in individuals diagnosed with Parkinson's disease or amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). Other neurogenic populations with dysphagia include individuals with multiple sclerosis (24%–34%; Calcagno, Ruoppolo, Grasso, De Vincentiis, & Paolucci, 2002; De Pauw, Dejaeger, D'Hooghe, & Carton, 2002; Roden & Altman, 2013) and traumatic brain injury (38%–65%; Terre & Mearin, 2009).
There are also other conditions known to have the consequence of dysphagia. A study by Garcia-Peris and colleagues (2007) found that 50% of patients with head and neck cancer experience oropharyngeal dysphagia, with these numbers increasing after chemoradiation treatment. The overall prevalence of dysphagia associated with gastroesophageal reflux disease (GERD) is approximately 14% (Mold et al., 1991; Spechler, 1999), and the frequency of dysphagia ranged from 3% to 64% following endotracheal intubation (Skoretz, Flowers, & Martino, 2010) and from 5% to 8% for adults with intellectual disabilities (Chadwick, Jolliffe, Goldbart, & Burton, 2006).