Elsevier

Archives of Gerontology and Geriatrics

Volume 70, May–June 2017, Pages 209-213
Archives of Gerontology and Geriatrics

Relationship between chewing ability and cognitive impairment in the rural elderly

https://doi.org/10.1016/j.archger.2017.02.006Get rights and content

Highlights

  • We visited the house of elderly living in rural area and assessed cognitive impairment using the Mini-Mental State Examination for Dementia Screening (MMSE-DS), activities of daily living, nutritional status, and chewing ability.

  • Chewing ability was assessed objectively using gum that changed color based on chewing performance.

  • Our result showed that poor chewing ability is associated with cognitive impairment or dementia in the elderly living in rural area.

  • We assessed cognitive impairment, activities of daily living, nutritional status, and chewing ability of rural elderly.

Abstract

Objective

Relationship between masticatory function and cognitive impairment had been suggested but still understudied. We investigated the association between chewing ability and cognitive impairment among the elderly living in a rural region.

Methods

A total of 295 elderly individuals aged ≥70 years in a rural city of Korea participated in a cross-sectional study. Trained nurses conducted interviews and assessed chewing ability using gum that changed color based on chewing performance. Cognitive impairment was assessed using the Mini-Mental State Examination for Dementia Screening (MMSE-DS) of Korean vesrsion. Socio-demographic characteristics, activities of daily living (ADL), Mini-Nutritional Assessment (MNA) were also assessed using questionnaires as potential confounders.

Results

The mean age of the participants was 81.4 (ranged 70–102) years and 67.8% of them were female. Participants with low chewing ability were significantly older, dependent, and had lower MNA and MMSE-DS scores. The elderly with middle or low chewing ability had significantly higher risk for having cognitive impairment than those with higher chewing ability.

Conclusion

Our findings suggest that poor chewing ability is associated with cognitive impairment or dementia in the elderly living in rural area.

Introduction

Cognitive impairment or dementia is a common cause of disability and decreased quality of life in the elderly (Ferri et al., 2006). Therefore, prevention and treatment of cognitive impairment are becoming increasingly important given the aging population.

Age, sex, genetic and vascular factors have been reported to be associated with cognitive impairment (Beck, Benson, Scheibel, Spar, & Rubenstein, 1982; Carlo et al., 2000). Moreover, some studies have reported a relationship between oral health and cognitive impairment (Ghezzi & Ship, 2000).

In 1997, Kato et al. were the first to describe a relationship between tooth loss and spatial memory deficits in senile rats; rats without molar teeth consuming a soft diet showed worse behavioral performance than rats with molar teeth consuming a solid diet. In an epidemiological study, Stein, Desrosiers, Donegan, Yepes, and Kryscio (2007) suggested that having no or very few teeth might be a risk factor for dementia in later life. In addition, Kimura et al. (2013) reported that low chewing ability was associated with lower cognitive functioning.

In contrast, some studies have reported that loss of teeth or chewing ability was not associated with cognitive impairment (Chen, Shuman, Hodges, Gatewood, & Xu, 2010; Onyper, Carr, Farrar, & Floyd, 2011). In 2014, Teixeira et al. indicated that studies regarding a relationship between loss of teeth or masticatory deficiency and cognitive impairment are necessary, because loss of teeth and masticatory deficiency are very closely related. Because the objective assessment of chewing ability is relatively more difficult than counting the number of lost teeth, we are aware of only a few studies regarding the relationship between chewing ability and cognitive impairment. Therefore, we aimed to assess the relationship between chewing ability and cognitive impairment by objectively assessing chewing ability using color-changing gum.

Section snippets

Study participants

A total of 295 participants were recruited from elderly registered at the public health center of a rural city of Korea. Trained nurses performed oral examinations and interviewed participants and caregivers at the participants’ homes. Participants were included based on the following criteria: (1) agreed to enroll in this study by themselves or caregivers, (2) complied with the questionnaires, and (3) whose caregivers could help the examiner if necessary. Those who were not able to communicate

Results

Socio-demographic characteristics, geriatric, and cognitive function, as measured using IADL, PADL, MNA, and MMSE-DS, are shown in Table 1 in addition to the comparison of chewing ability. The mean age of all of the participants was 81.4 (70–102) years, and most of the participants were women (67.8%), lived alone (62.0%), and were being treated for a disease (83.4%). Most participants had independent PADL (79.0%), and approximately half of the participants had independent IADL (58.6%).

Discussion

In this study, we analyzed the relationship between chewing ability and cognitive impairment among rural Korean elderly. The level of chewing ability was significantly associated with cognitive function. Participants who had lower chewing ability were more likely to have lower cognitive function. To our knowledge, this is the first study showing an association between chewing ability only measured by color-changing gum that is even simple approach as an objective proxy measure for mastication

Conclusions

This study demonstrated that there was a possibility that the risk of having cognitive impairment increased among the elderly living in a rural region with lower chewing ability. Therefore it was worth more researching on the association between oral health and cognitive impairment.

Conflict of interest statement

The authors declare that there are no conflicts of interest.

Author contributions

I and E-K Kim designed this study and drafted and wrote the original manuscript, SK Lee and Y-S Jung collected data, HC Kim and H-K Lee performed data analyses and interpreted data, M Tanaka, K Hirotsu, and A Amano provided critical comments on the original manuscript and contributed to development of the final draft.

Acknowledgments

This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2014S1A3A2044496). This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2016R1D1A3B03934825).

References (31)

  • K. Watanabe et al.

    The molarless condition in aged SAMP8 mice attenuates hippocampal Fos induction linked to water maze performance

    Behavioural Brain Research

    (2002)
  • T. Yamamoto et al.

    Effects of soft-diet feeding on synaptic density in the hippocampus and parietal cortex of senescence-accelerated mice

    Brain Research

    (2001)
  • H. Aoki et al.

    Cell proliferation in the dentate gyrus of rat hippocampus is inhibited by soft diet feeding

    Gerontology

    (2005)
  • J.C. Beck et al.

    Dementia in the elderly: The silent epidemic

    Annals of Internal Medicine

    (1982)
  • A. Carlo et al.

    Cognitive impairment without dementia in older people: Prevalence, vascular risk factors, impact on disability. The Italian Longitudinal Study on Aging

    Journal of the American Geriatrics Society

    (2000)
  • Cited by (43)

    • Associations of general health conditions with masticatory performance and maximum bite force in older adults: A systematic review of cross-sectional studies

      2022, Journal of Dentistry
      Citation Excerpt :

      Besides, the association between anorexia and MP remained significant after adjusting for confounding factors [9,33]. Regarding reporting history of systemic disease, MP was not significantly reduced in people who reported a history of systemic disease [34–36], but it was significantly reduced in patients who reported history of treated diseases [37]. MBF was not significantly changed during Parkinson's disease progression [38].

    • Effects of oral exercise on tongue pressure in Taiwanese older adults in community day care centers

      2022, Journal of Dental Sciences
      Citation Excerpt :

      Without proper swallowing function, an individual may be forced to alter their diet, thereby limiting their intake of essential nutrients and increasing their risk of malnutrition.3,4 In addition, impaired chewing function may be associated with cognitive impairment, dementia, and aspiration pneumonia.5–7 Three methods are used for evaluating swallowing dysfunction: trial swallows, videofluoroscopic swallowing studies, and tongue pressure measurement.

    • Association between regional brain volume and masticatory performance differed in cognitively impaired and non-impaired older people

      2020, Experimental Gerontology
      Citation Excerpt :

      Therefore, the role of the specific prefrontal functions in oromotor performance (e.g., attentional deployment during chewing) would require further clarification. Poorer MP was found in elderly people with worse cognitive abilities (Campos et al., 2017; Kim et al., 2017; Weijenberg et al., 2015). The underlying mechanisms have remained unclear.

    View all citing articles on Scopus
    View full text