Impact of social marginalization on oral health-related quality of life in older adults

Abstract The aim of this study was to determine the association between oral health-related quality of life (OHRQoL) and social marginalization in people aged 60 years and older enrolled in social security in Mexico. A cross-sectional and analytical study was carried out in older adults. To assess the OHRQoL, the OHIP-14 instrument was applied, and the degree of social marginalization and sociodemographic characteristics were analyzed. Measures of central tendency and dispersion, simple frequencies and proportions were estimated. Student’s t-test was used for comparison of means, and prevalence ratio (PR) and logistic regression were used to assess associations, all with a significance value of 0.05 and 95% confidence intervals. Perceived OHRQoL in the population measured through the OHIP-14 reached an average value of 9.84 ± 8.91, with the highest value in the dimension of physical pain (2.06 ± 1.91). Perceived treatment need was higher among people with social marginality (p = 0.011). The multivariate analysis shows that marginalized people have a lower OHRQoL. Socially marginalized older adults showed a low a better perception of OHRQoL, independent of demographic and clinical factors.


Introduction
The World Health Organization (WHO) recognizes that the burden of oral disease is particularly high in the poorest and most vulnerable populations in both developed and developing countries. 1dentulism and other oral pathologies are considered global public health problems because these pathologies manifest in pain, chewing problems, loss of function, and esthetic problems that impact the overall health and quality of life of individuals. 1,2Oral health is therefore an important predictor of subjective well-being later in life. 3cGrath and Bedi point out that better oral health is associated with higher dental care attendance.Additionally, a relationship has been observed between the number of functional natural teeth and quality of life in the elderly population 4

and socioeconomic c o n d it i o n s h ave b e e n s h ow n t o b e a s s o c i at e d w it h t h e
Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.
prevalence of edentulism among adults with the worst living conditions. 5,6lthough there is evidence of the relationship between socioeconomic conditions and oral health, 7,8 this field has not been systematically studied in Mexico.Therefore, the objective of the present study was to determine the association between oral health-related quality of life (OHRQoL) and social marginality in people aged 60 years and older who are covered by social security in Mexico.

Methodology
A cross-sectional analytical study was conducted on 370 adults aged 60 years and older who were assigned to a medical unit of the Mexican Institute of Social Security in Mexico City from January to December 2020.After authorization by the local research committee, written informed consent was requested from the participants and an oral examination was performed by a qualified dentist.
For calculating the minimum sample size, an expected proportion of 87% was considered, which has been previously reported by Bellamy and Moreno. 7he calculated sample size was 173 adults aged 60 years and older, and to account for a loss of 10%, the final sample size was 190 individuals.
Systematic sampling was performed and the sampling interval was calculated by dividing the number of eligible individuals in the sampling frame by the specific sample size (n): 52820/190 = 3.5.The first patient was chosen at random and from that point on, every 4th adult in the age group of interest who attended the medical unit during the study period was selected successively.
Tooth loss was identified as the absence or loss of a permanent tooth, either by its fall or its extraction, with the number of teeth present recorded, and the participant was classified as having a dysfunctional dentition when they had fewer than 20 teeth. 9he participants were asked about self-perceived need for treatment and use of dental prostheses.To determine the OHRQoL, the Oral Health Impact Profile 14 (OHIP-14) instrument was applied and functional limitation (difficulty in chewing), physical pain (tooth sensitivity), psychological discomfort, physical disability (changes in diet), psychological disability, social disability (avoidance of social interaction), and handicap were evaluated.Each dimension is made up of two questions and a higher score represents a lower OHRQoL.Variables such as age, sex, level of schooling, perceived need for oral treatment, use of prostheses, and history of diabetes and hypertension were also recorded.Educational level was considered low when people had secondary education or less.
Social marginality was classified according to the domicile of the participants classification reported by the Secretary of Inclusion and Social Welfare of Mexico City at the block level.Those living in areas of very low and low marginality were the group with the best social conditions and were classified as having no marginality, while the rest of the participants were considered as having social marginality. 10n exploratory data analysis was performed for the distribution of the study population; measures of central tendency and dispersion, simple frequencies, ratios, and proportions were estimated.Normality tests were performed for quantitative variables, and according to the type of distribution, Student's t-test and Levene's test for data with normal distribution or Mann-Whitney U test for data that did not have a normal distribution were applied to compare means.Mantel-Haenszel chi-square tests and odd ratio (OR) with 95% confidence intervals (95%CI) were calculated for categorical data.Finally, a multivariate analysis was performed using logistic regression, classifying the value of the OHIP-14 into two groups, taking the 50th percentile as the cutoff point and contrasting the variables according to the marginality condition.The data were analyzed with the SPSS version 25.

Results
A total of 370 adults were studied, of whom 155 (41.9%) were men and 215 (58.1%) were women.The average age was 73 years; no age differences were found between men and women (p = 0.43).Of the population studied, 74.6% had a low level of education, while 25 older adults were illiterate, representing 6.8% of the population studied.Among the comorbidities studied, 71.6% had hypertension and 147 (39.7%) had diabetes.People with marginalization accounted for 62.7% of the population studied.
The average number of teeth was 16.2 (standard deviation = 9.96), 98.6% of participants had at least one lost tooth and 15.1% were edentulous.The presence of a functional dentition, understood as the presence of 20 or more teeth, occurred in 53.5% of the people studied and 56.8% reported using some type of dental prosthesis.A total of 52.4% of the persons interviewed reported perceived need for treatment.
Regarding the presence of functional dentition, no statistically sig nificant differences were found between men and women.People living with hypertension were 39% more likely to have dysfunctional dentition than those without hypertension; this association was not statistically significant (95%CI = 0.88-2.19).
Those living with diabete s were 22% more likely to have dysfunctional dentition than non-diabetics (95%CI = 0.80-1.85).The analysis by level of schooling was not associated with the presence of functional dentition (95%CI = 0.80-2.04)(Table 1).
The dimension of the OHIP-14 with the highest value was physical pain followed by psychological discomfort, functional limitation, physical disability, psychological disability, and social disability; the lowest value was for the handicap dimension (Table 2).No differences were found in total OHIP-14 score according to the functionality of dentition.The results for the analysis of OHIP-14 dimensions according to dental functionality are shown in Table 2.
The items "Have you ever felt pain in your mouth?" and "Are you worried about problems in your mouth?" had a greater impact among those who are socially marginalized compared to those who are not marginalized.The inability to perform daily activities due to problems with teeth, mouth or dentition was approximately twice as high among marginalized people (p = 0.011) (Table 3).Table 4 shows the distribution of the sample and the bivariate analysis of the OHIP-14 score by social marginalization according to the variables studied.A significant association was found between the OHIP-14 score and the perception of the need for treatment among people with social marginalization (p < 0.001).
Multivariate analysis shows that marginalized people have a lower OHRQoL for the variables analyzed in this study (Table 5).

Discussion
In Mexico, it has been reported that 86.7% of adults over 50 years of age who are beneficiaries of the Mexican Institute of Social Security (IMSS) have some dental loss, 7 but in our study we found a higher percentage (98.6%)with loss of at least one tooth.The percentage of edentulous persons was higher than the 2.7% reported by the Ministry of Health at the national level. 11he percentage of participants with functional dentition was lower than the 89.9% reported in a Mexican population. 12This is relevant given that tooth loss is related to the perception of a lower quality of life and has a negative impact on social relationships due to the lack of teeth. 13t has been demonstrated that people with poorer social conditions and living in a disadvantage territory present greater dental loss in comparison with those who have a better economic and territorial situation.The socially disadvantaged population may present the combination of various chronic diseases, have more severe oral diseases, and the lack of possibility of dental rehabilitation. 13lthough oral esthetics have less impact in the elderly, which limits the perception for treatment need and search for care, 14 there is a greater utilization of dental care in older adults with higher economic status and schooling compared to the rest of the population. 15This is congruent with the results obtained, showing that people without social marginalization indicated a greater perception of the need for dental treatment, while this may indicates a process of naturalization of dental loss and a poorer quality of oral life among the more socially disadvantaged.
It has been reported that subjects with diabetes and cardiovascular disease exhibit greater tooth loss and periodontal disease than subjects without those conditions, while hypertension may be a risk indicator for tooth loss. 2,16,179][20][21] Despite this, in our study, we did not find an association between these diseases and OHRQoL, even when social marginality was present.
The main limitation of this study is its crosssectional design and that it presents a problem of temporal ambiguity that therefore does not allow causal relationships to be established.

Conclusions
The OHIP-14 is a widely used assessment tool to measure the impact of oral problems in the lives of older adults.Based on OHRQoL outcomes, prevention and care actions can be proposed, since oral diseases start by a change in oral conditions, such as the alteration of the supporting tissues of teeth that can lead to tooth loss, which in turn results in a certain degree of functional limitation and disability.These actions will allow the promotion of healthy aging, especially among marginalized groups, and to avoid considering poor oral health as a natural phenomenon of the aging process.

Table 1 .
Characteristics of the population according to functional dentition.

Table 2 .
Distribution of OHIP-14 scores by domain and type of dental functionality.

Table 3 .
Comparison of OHIP-14 scores for all domains by social marginalization.

Table 4 .
Sample distribution and bivariate analysis of OHIP-14 score by social marginalization.

Table 5 .
Logistic regression analysis of low OHIP-14 scores in the presence of social marginalization.