Oral health effects on the nutritional status of elderly people

Summary Introduction The aim of the study was to establish the association between oral health and malnutrition in people over the age of 65. Material and Methods Cross-sectional study included 146 respondents residing in gerontology center, and 300 respondents who lived in their own homes or with their families. Nutritional status was evaluated using the Mini Nutritive Scale and standardized questionnaire. Dental status was evaluated by clinical examination using inspection method. The presence and absence of teeth was evaluated in each dental arch (third molars were not taken into consideration). Also, the presence of prosthetic restorations (total and partial dentures) was noticed without analyzing their adequacy and functionality. Self-assessment of health with categorical components assessed the overall health status. The research was conducted in 2018. Results Most of respondents who had malnutrition or were at risk of malnutrition had worse dental status; they were completely or partially edentulous. There was high statistically significant difference in dental status of the upper (χ2=47,797; p < 0,001) and lower jaw (χ2 = 66,680; p < 0,001). The number of lost teeth had an impact on self-assessment of general health (χ2 = 47,270; p < 0,001). Conclusion Oral health status in elderly people had significant influence on nutritional status.


INTRODUCTION
Nutritional status disorders and malnutrition usually occur as a result of changes in appetite, limited mobility, socioeconomic constraints, chronic illness, depression, cognitive impairment, multiple types of medication, frequent complications and hospitalizations [1]. According to Chen [2], malnutrition of elderly is defined as inadequate nutritional status or malnutrition, followed by inadequate food intake, loss of appetite, loss of body mass and decreased muscle mass. Numerous studies have shown that the prevalence of this problem increases with age so that after 65 years of life it is 15% to 85% (depending on the parameters used, as well as the place of residence) [3,4,5]. Oral health, as one of the indicators of general health status, has great significance in determining nutritional status in older people [6,7,8]. This population often has loss of large number of teeth or all teeth, presence of caries lesions and periodontally compromised teeth, xerostomia and oral pre-cancer. The loss of teeth significantly reduces masticatory efficiency that affects the choice of food and eating habits. Soft food rich in saturated fatty acids and cholesterol are more consumed then fiber-rich food. Inability to chew food due to loss of teeth, lack or inadequate dental restorations or dentures is often associated with difficult swallowing, malnutrition or serious risk of malnutrition [9]. Numerous prospective studies have shown that the most frequent problems in elderly is the problems of chewing (42%) and xerostomia (63%) [10,11]. Also, worse oral and nutritional status is observed in higher percentages in elderly people residing in gerontological centers [12,13,14].
Previous studies were mostly focused on the association of oral health with malnutrition in elderly residing in gerontological institutions [12,13,14], but there is very little information on the impact of oral health on general health and risk of malnutrition in elderly people living in the community. The aim of the study was to establish the association between oral health and malnutrition in people over 65 years of age.

Respondents
The cross-sectional study was carried out in the period from April to September 2018 among elderly people in four municipalities of Republika Srpska: East Sarajevo, Rogatica, Pale and Foca. The sample consisted of 446 respondents of both genders, divided into the two groups depending on their place of residence; 146 participants were from gerontology institutions while 300 respondents were community-based. Living in the community is defined as residing in your own or family home. Respondents in the community were selected using a register of patients older than 65 years of age in the family medicine services of local health centers. By software, every third person according to specific criteria was included in the study. If the selected person did not meet criteria for inclusion in the study, the following one would be included until certain number of respondents was reached. The criteria for inclusion in the study was: person was orientated in time, space and able to recognize faces, while criteria for excluding were bad general condition, disorientation, inability to establish cooperation, the presence of mental illness, dementia, malignant diseases and chronic renal insufficiency. All users of gerontology centers, East Sarajevo, Pale and Rogatica who fulfilled the inclusion criteria and signed the informed consent were included in the study.

Research Instruments
A standardized questionnaire was used to collect sociodemographic data on respondents in the study (gender, age of respondents, education, residence, income, social activity and integration, cohabitation, socializing, hobby, use of mobility aids). Dental status was evaluated by clinical examination, using inspection method. The presence of complete or partial edentulism (third molars were not taken into consideration) for each jaw was assessed. The presence of prosthetic restorations (complete and partial dentures) was assessed without analyzing their adequacy and functionality. General health was analyzed with one question: "For your age, what would you say in general, that your health is?" The answers offered were: "Excellent", "Good", "Medium Good", "Average", "Bad" and "Very Bad". Nutritional status was investigated using the Mini Nutritional Scale Short Version-MNA-SF, which included two steps: screening (MNA-SF1) and evaluation (MNA-SF2). The maximum total score for MNA was 30 points (> 23.50 and indicated adequate nutritional status, 17 -23.49 risk for malnutrition and <17 points indicates malnutrition) [15].

Statistical analysis
Data analysis was done using descriptive statistical analysis measures in SPSS packages 22 (SPSS IBM, Inc., Chicago, IL, United States). Results were presented as mean values ± SD for continuous variables and numbers / percentages for categorical variables. Differences were tested using Chi square test. As the level of statistical significance, usual value of p <0.05 was considered.

Ethical considerations
The study was approved by the Ethics Committee of the Faculty of Medicine in Foca, University of East Sarajevo, with the decision: 01-2-1. All respondents gave written informed consent. Data were presented in a way that it hides the identity of all participants.
According to self-evaluation of general health, only 1.6% of respondents had excellent health, 43.8% good health, 38.1% medium-well, 16.1% poor and 0.4% very poor. The highest number of respondents in gerontology institutions (93.2%) was either in malnutrition or at risk of malnutrition, as opposed to community respondents (40.8%). People with lower educational level (χ2=30,221; p <0,001) who stayed in geriatric institutions (χ 2 =126,224; p <0,001) used mobility aids (χ 2 =94,192; p < 0,001) and did not have hobby (χ2 = 68,155; p <0,001 ) had higher risk of malnutrition (Table 1). Table 2 shows the results of the overall nutritional status assessment in relation to dental status of respondents. It was found that respondents, who had malnutrition or were at risk of malnutrition, had poorer dental status. There was high statistically significant difference in dental status of upper (χ2 = 47,797; p <0,001) and lower jaw (χ2 = 66,680; p <0,001 ). Respondents who had poorer nutritional and dental status were considered to have poorer overall health status, while among respondents without risk of malnutrition, good health was observed (χ2=47,270; p <0,001) ( Table 3).

DISCUSSION
The study found link between oral health and nutritional status in elderly subjects. Study subjects with poorer dental status also had poorer nutritional status, ie. they were malnourished. Our results confirmed the results of previous studies [12,14]. Earlier it was believed that loss of teeth and edentulism is expected and normal result of aging. However, age, by itself, does not cause teeth loss. The most common causes of teeth loss are: periodontal disease, tooth decay, worsened general health condition of the patient [16,17]. Meta-analysis of results from about 1000 publications published in English in the last 20 years have shown negative impact of teeth loss on the quality of life, regardless of where studies were conducted or methodology used [16]. Today it is considered that changes in periodontium, loosening and loss of tooth in older age, are the consequence of cumulative effects of many risk factors during life. Aging cannot be considered the main risk factor for the occurrence and progression of periodontal diseases if some other factors are not present: decrease of the amount of saliva, poor oral hygiene, systemic illness, poor diet, some medications, mental state or social status of the person. Namely, periodontal disease is not specific for elderly people and diet is one of  the main factors contributing to the maintenance of good oral health [18]. In regards to socio-demographic characteristics of respondents, significant correlation was observed between gender, degree of education, cohabitation, as well as place of residence and assessment of oral and nutritional status. These results are in accordance with findings of other studies. Knowing the influence of oral clinical variables on self-assessment of health is of great importance for obtaining clearer insight into association with objectively and subjectively assessed mouth and tooth health [19]. Based on the results of our research it was found that the incidence of malnutrition was present in subjects with poorer dental status. Inadequate food also affects oral health [20], and poor oral health affects the choice of consumed food. Nutrition with no vitamins, minerals, proteins and low calories affect immune system and is associated with oral health, and especially dental diseases in older people [21]. The lack of appetite in elderly people is common, especially in individuals who suffer from anorexia, nausea, vomiting, or xerostomy caused by medications. Food intake has been further reduced in individuals with chronic diseases. The Swiss study conducted in hospitalized elderly was focused on the relationship between clinical parameters of malnutrition, serum albumin levels, and oral health indicators (dental status, oral hygiene, chewing function) [22]. Choosing the type of food largely depends on the ability to consume food with pleasure, and some food is refused due to inability to chew. The function of chewing in elderly can be called into question in the case of loss of teeth and inadequate dentures. Individuals living in institutions are more likely to have this problem and need help of appropriately trained staff [23].
The results obtained with MNA weight loss questionnaires were logical and expected. Previous research suggests connection between poor oral health and weight loss, where it is evident that tooth loss is a risk factor for body weight loss. Poor oral health may be related to systemic diseases in a bidirectional manner, and weakening the chewing ability and food consumption may affect nutrition [24]. Social relationships also play an important role since they are optimized for the benefit of elderly. Many authors [25] described a model of social relations that clearly point to the relationship between behavior and social behavior and their influence on the quality of life associated with oral health (OHRQOL). Petersen et al. [26] determined the life expectancy index for elderly people in a community in Denmark where they found close association between poor dental health and reduced life activity. In addition, indexes for measurement of health support in relation to inclusion in social activity (families, friends or neighbors) are registered. Numerous studies [27] have shown that isolated seniors have the poorest dental health status and rarely use health services. Results of our study showed that malnourished subjects differed significantly in terms of dental status than those who did not have malnutrition. Important risk factors for oral health are eating habits, as well as some bad habits. Inadequate nutrition habits were found in our research that contributed to the risk of malnutrition. Our research showed that great number of respondents took more than 3 drugs per day (74.4%), 53.4% did not consume meat, fish or chicken every day, 43.7% of respondents did not consume two or more portions of fruits and vegetables daily, while 49.3% of respondents consumed up to five cups of liquid per day. The results of the research suggested that 55.8% of respondents reduced food intake due to chewing problems and swallowing difficulties, and 34.3% of respondents believed that there was no adequate diet. Previous research has shown that older people usually consume sweets and snacks (63.0%), juices, sweet drinks and carbonated drinks (54.0%) every day, which is inadequate diet. Similar data have been published and other authors have confirmed consumption of inadequate food due to poor dental status [28].
Older people around the world have issues with healthcare, as access to dental services is limited, especially in rural areas. Health promotion programs dedicated to elderly are rare, therefore the evaluation of oral and nutritional status can provide important information that will lead to improved oral health promotion and health care of elderly.

CONCLUSION
Dental status in older people is associated with the risk of malnutrition. Socio-demographic characteristics and their own perception of health are important factors in assessing the effect of oral health on the nutritional status of elderly. Concerning that treatment of oral diseases is costly and requires high level of engagement of dental staff and resources, the prevention of oral diseases should focus also on nutrition. Establishing co-operation between a dentist and a family physician, family nurses as well as improving dental care of the elderly can play a significant role in preservation of dental health and malnutrition.
Authors declare that there are no conflicts of interest.