Prevalence of Candida albicans and non-albicans on the tongue dorsa of elderly people living in a post-disaster area: a cross-sectional survey

BACKGROUND Candida species are normal commensal organisms of the mouth. However, they can cause oral mucosal and severe systemic infections in persons with reduced immune function, which is common in the very elderly. In post-disaster areas, the number of elderly residents rapidly increases due to the outflow of younger generations. Hence, we examined the prevalence of Candida albicans and non-albicans in association with oral and systemic conditions, life style, medications, and living conditions. METHODS This study was performed in 2014. Participants of this study were 266 community dwellers aged 60 years or older in Otsuchi town, which was severely damaged by the Great East Japan Earthquake and Tsunami in 2011. Oral specimens were collected from tongue dorsa by swabbing. After 48 h incubation on CHROMagar™ medium, C. albicans and non-albicans were identified by the morphology and pigmentation of the colonies. Oral and systemic health check-ups were performed to assess the following: number of remaining teeth and periodontal status, oral hygiene, use of dentures, obesity, hypertension, hyperlipidemia, and hyperglycemia. A questionnaire addressed lifestyle, medications, and living conditions. Using the variables above, the relative factors involved in the colonization and the amounts of each type of Candida were determined. RESULTS C. albicans and non-albicans were detected in 142 (53.4%) and 63 (23.7%) participants, respectively. Multinomial logistic regression analyses revealed that the significant factors of colonization by C. albicans were "having decayed teeth" and "relocation from home". Factors related to non-albicans colonization were "age over 80 years", "number of remaining teeth", "use of dentures", and "obesity". On the contrary, none of the parameters were related to the amount of non-albicans in the carrier, and the amount of C. albicans was significantly associated with "number of teeth" and "hypertension". CONCLUSIONS Prevalence-related factors differed between C. albicans and non-albicans colonization. In addition, other than oral status, systemic and living conditions affected the prevalence of both C. albicans and non-albicans in elderly people living in a post-disaster area.