Original Article
Professional occupation and the number of teeth retained among older adults aged 50 and above Avraham Zini, Chen Lewit and Yuval Vered Department of Community Dentistry, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem, Israel
doi: 10.1111/ger.12152 Professional occupation and the number of teeth retained among older adults aged 50 and above Objective: To examine the association between occupational characteristics and number of natural teeth retained among older adults aged 50 and above. Background: Despite the integral part of the professional occupation of a person’s time, few studies have examined the effect of the occupational environment on one’s oral health. Material and methods: Self-administered questionnaires were randomly distributed among 280 participants, who had at least one professional occupation over a period of 10 years or more. Data from the questionnaire were collected concerning variables related to professional occupation and the selfreported number of natural teeth retained. The data were analysed using a logistic regression analysis with stepwise-backward selection. Results: Significant risk factors for the number of natural teeth being ≤25 were age (p < 0.001), years of education (p = 0.019) and a hospital/commercial environment of work (p = 0.021). The odds ratio for the number of natural teeth ≤25 increased with each year by 1.109, decreased with each additional year of education by 0.881, and was 2.693 folds higher for individuals working in a hospital/commercial environment compared to those in an office environment. Conclusions: These findings suggest the importance of operating community-based oral health programmes for these occupational risk groups. The results from this study also implicate the need for further studies of this subject to find the underlying reasons for these occupational environmental risks. Keywords: occupation, tooth loss, adults, oral health, number of teeth. Accepted 15 August 2014
Introduction Over the years, there has been a considerable increase in life expectancy, causing an increase in the elders’ population worldwide. Therefore, the concept of enhancing oral health related quality of life among elders is becoming more significant1. Recent studies have found a significant increase in the average number of teeth retained per person, and a radical decline in the incidence of complete edentulism among these population2. The World Health Organization (WHO) aimed a goal for the year of 2020 to increase the average number of teeth, and the proportion of individuals aged 65–75, who have a functional dentition3. The percentage of complete edentulism among elders (aged 65 years and above) in Israel is 52%, 260
a higher percentage compared to most western countries4,5. Predictors for tooth loss have been studied. Pathogenic factors such as caries and periodontal disease were found to have highly significant in prediction of tooth loss2, yet, socio-behavioural factors were found to be equally significant for prediction of complete edentulism2,6. Functional independence as a predictor for complete edentulism, while elders living in nursing homes showed a higher percentage of complete edentulism in comparison with independent elders7,8. Low socio-economic status and low level of education were also found to be risk factors for rheumatoid arthritis, which, in turn, is associated with higher percentages of complete edentulism9–11. Complex interactions exist between the different predicting factors that differ between populations. Gender
© 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
Professional occupation and the number of teeth
was found to be significantly related to complete edentulism, while women have higher rates of complete edentulism as compared to men12–14. Smoking, which has a high correlation with low socio-economic status9, was found as a risk factor for tooth loss by 10–30%. Cognitive function and intelligence among younger ages were found to affect the survival of dentition in older ages7,8. Occupational class was found as a predictor for complete edentulism at the ages of 70 and above8. Psychological effects by mental stress and negative events throughout life cause a rapid development of caries, or acute gum diseases such as acute necrotizing ulcerative gingivitis6. The influence of occupational stress on dental health was found to be multisystematic and include gastrointestinal effects, respiratory effects, musculoskeletal effects and mental health effects. Certain effects on employee’s periodontal health were associated with work-related mental demand, psychological stress factors by work load and unexpected tasks or personal conflicts6. Tooth loss have extensive impacts on the individual, both mentally and physically1,7,8,12,15–17. A review article that surveyed these implications found that complete edentulism causes low self-esteem, a low quality of life, and can predict mortality in older ages by its association with cardiovascular morbidity, hypertension and physical constraints7. A prospective study found an association between periodontal diseases and tooth loss with cancer in later stages in life16. It was found that there is a relationship between complete edentulism and poor overall health, poor nutrition, physical disability and low self-esteem8. In addition, oral health might affect daily routine, such as trouble sleeping, enjoying food, being able to smile during social events and staying at home more than usual. These effects were higher with increasing age1. Family time, work time and leisure time are the 3 major components in a person’s cycle of time6. It has been shown that time with the family has the greatest influence on life satisfaction, and accordingly on oral health6. In Israel, males work an average of 43 weekly hours18, whereas in France, for example, the number of weekly hours cannot exceed 35 h, by law19. Despite the integral part of the professional occupation of a person’s time, only few studies have examined the effect of the occupational environment on one’s oral health6. The objective of this study was to examine the association between occupational characteristics and number of natural teeth retained among older adults aged 50 and above.
261
Subjects and methods This study is a cross-sectional study. Self-administered questionnaires were randomly once distributed among a sample of 500 participants aged 50 years and above, throughout different areas in the state of Israel, both urban and rural strata. Approval for the study was received from the Board of Ethics in the Hebrew University of Jerusalem, and the participants were asked to sign an informed consent before filling out the questionnaires. Two inclusion criteria were administered: Age – 50 years and above – and professional seniority of at least 10 years in the same profession. An evidence-based method for the number of teeth retained was obtained by self-report after an enclosed instruction, to get an accurate data20–23. The participants were dichotomised by the median for statistical analysis purpose; participants with 25 natural teeth or less, as compared with participants who had more than 25 natural teeth as the dependent variable. The independent variables for this study were age, gender, years of education, occupational status (currently working vs. unemployed, regardless of retirement), retirement, self-employment, previous occupations, number of years spent in each occupation, immediate occupational environment (home, industrial/outdoors, hospital/commercial, school/grade school/university or office), occupational stress (in a subjective visual scale of 1–10 on which the participants were asked to grade themselves), level of income (low/average/high – as stated by the participant itself, without further detailing), working in shifts, regular meals, position at work (measures similarly to the occupational stress level – on a scale of 1–10), hours of work per day and number of work days per week. Occupations were later categorised into three different groups, after being defined as accurately as possibly by the participants: a blue-collar group (included occupations requiring manual labour); a whitecollar group (included occupations requiring office-work but little or no official professional training such as clerks, marketing workers, administrative workers); and a group of liberal professions that require formal training and labour unions (medicine, dentistry, veterinary, law practice, accounting, pharmacy, engineering, psychology, architecture, science, social work, education, libertarianism and nursing). The statistical analysis included Pearson’s chisquare test, independent t-test and analysis of variance (ANOVA) using SPSS 19.0 statistical software
© 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
262
A. Zini et al.
(IBM Corp. IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.). A conceptual multiple multilevel logistic regression stepwise-backward selection was performed. At the first step of analysis (1st model), sociodemographic variables were included (education as a proxy to socio-economic position). At the next stage (2nd model), all occupational variables were entered into the equation. Statistical level of significance was set as p < 0.05.
Results From 500 questionnaires randomly distributed, 283 questionnaires were eventually collected, indicating a response rate of 56.3% after one distribution. Of the 283 questionnaires collected, 3 were excluded due to lack of compatibility (working less than 10 years in all occupations). The mean age of the participants was 61.25 9.12 (ages ranged from 50 to 93 years). The majority of the sample (60%) were female, and 68.9% of were pre-retired (not yet retired) while 31.1% were already retired (officially, but might have still be working part-time or voluntarily, as measured by their current occupational status). The average number of natural teeth in this sample was 21.47, with a median of 25, determining the dichotomisation for statistical analysis. Figure 1 demonstrates the distribution of number of natural teeth by occupational environment and occupational group. The higher percentages of more than 25 teeth were found among school, grade school or university occupational environment, and among liberal professions group. Table 1 represents the association between categorical variables and the number of natural teeth. Occupational status of ‘currently unemployed’ was with significantly higher percentages of par-
ticipants with 25 natural teeth or less as compared to the ‘currently working’ group (p = 0.044). A higher percentage of participants with 25 teeth or less were among retired (p = 0.011), ‘blue-collar group’ (78.8%), followed by the ‘white-collar group’ (56.9%), (p < 0.001), and ‘home’ or ‘industrial/open grounds’ groups (90% and 72.1%, respectively; p < 0.001). It should be noted that the group of participants who were working at home was fairly small, including only 10 participants. No significant differences were found by gender, working in shifts, being selfemployed, eating regular meals and level of income. The results of the ANOVA analysis of the association between continuous variables and the number of natural teeth retained are shown in table 2. The only variables that showed an association to the number of natural teeth were age and years of education. Among the participants with 25 natural teeth or less, the average age was significantly higher than among the non-wearing dentures participants (63.98 10.25 vs. 58.23 6.21, respectively; p < 0.001). The mean years of education was significantly lower in the 25 or less natural teeth group as compared to the over 25 natural teeth group (14.36 3.34 vs. 15.83 2.70, respectively; p < 0.001). Figure 2 shows the number of natural teeth according to statistically significant differences in independent categorical variables (occupational status, retirement, occupational group and environment of work) based on the ANOVA and t-test analysis. In the ‘currently working’ group, the average number of teeth was higher than in the ‘currently unemployed’ group (22.62 vs. 18.92, respectively, p = 0.002). The ‘pre-retired’ group had a higher average number of teeth as compared to the ‘retired’ group (22.77 vs. 18.6,
Figure 1 Distribution of participants according to the number of natural teeth (%) in relation to occupational environment and occupational group. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
Professional occupation and the number of teeth
Table 1 Distribution of participants according to number of natural teeth (%) by gender, occupational status, retirement, occupation, occupational environment, shifts, regular meals and level of income (n = 280).
Gender Men Women Employment Currently working Currently unemployed Retired No Yes Occupational classifications Blue collar White collar Liberal professions Occupational environment Industrial/ outdoors Hospital/ commercial School/grade school/university Home Office Independency at work Employee Self-employed Shifts or hourly Working in shifts Working regular hours Regular meals Irregular Regular Income Below average Average Above average
263
≤25 natural teeth, %
>25 natural teeth, %
54.5 54.2
45.5 45.8
0.961
50.3
49.7
0.044*
63.2
36.8
49.2 65.5
50.8 34.5
78.8 56.9 40.7
21.2 43.1 59.3
25 natural teeth teeth Mean
SDa
Mean
SDa
pb
Age (years) 63.98 10.25 58.03 6.21
Professional occupation and the number of teeth retained among older adults aged 50 and above Avraham Zini, Chen Lewit and Yuval Vered Department of Community Dentistry, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem, Israel
doi: 10.1111/ger.12152 Professional occupation and the number of teeth retained among older adults aged 50 and above Objective: To examine the association between occupational characteristics and number of natural teeth retained among older adults aged 50 and above. Background: Despite the integral part of the professional occupation of a person’s time, few studies have examined the effect of the occupational environment on one’s oral health. Material and methods: Self-administered questionnaires were randomly distributed among 280 participants, who had at least one professional occupation over a period of 10 years or more. Data from the questionnaire were collected concerning variables related to professional occupation and the selfreported number of natural teeth retained. The data were analysed using a logistic regression analysis with stepwise-backward selection. Results: Significant risk factors for the number of natural teeth being ≤25 were age (p < 0.001), years of education (p = 0.019) and a hospital/commercial environment of work (p = 0.021). The odds ratio for the number of natural teeth ≤25 increased with each year by 1.109, decreased with each additional year of education by 0.881, and was 2.693 folds higher for individuals working in a hospital/commercial environment compared to those in an office environment. Conclusions: These findings suggest the importance of operating community-based oral health programmes for these occupational risk groups. The results from this study also implicate the need for further studies of this subject to find the underlying reasons for these occupational environmental risks. Keywords: occupation, tooth loss, adults, oral health, number of teeth. Accepted 15 August 2014
Introduction Over the years, there has been a considerable increase in life expectancy, causing an increase in the elders’ population worldwide. Therefore, the concept of enhancing oral health related quality of life among elders is becoming more significant1. Recent studies have found a significant increase in the average number of teeth retained per person, and a radical decline in the incidence of complete edentulism among these population2. The World Health Organization (WHO) aimed a goal for the year of 2020 to increase the average number of teeth, and the proportion of individuals aged 65–75, who have a functional dentition3. The percentage of complete edentulism among elders (aged 65 years and above) in Israel is 52%, 260
a higher percentage compared to most western countries4,5. Predictors for tooth loss have been studied. Pathogenic factors such as caries and periodontal disease were found to have highly significant in prediction of tooth loss2, yet, socio-behavioural factors were found to be equally significant for prediction of complete edentulism2,6. Functional independence as a predictor for complete edentulism, while elders living in nursing homes showed a higher percentage of complete edentulism in comparison with independent elders7,8. Low socio-economic status and low level of education were also found to be risk factors for rheumatoid arthritis, which, in turn, is associated with higher percentages of complete edentulism9–11. Complex interactions exist between the different predicting factors that differ between populations. Gender
© 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
Professional occupation and the number of teeth
was found to be significantly related to complete edentulism, while women have higher rates of complete edentulism as compared to men12–14. Smoking, which has a high correlation with low socio-economic status9, was found as a risk factor for tooth loss by 10–30%. Cognitive function and intelligence among younger ages were found to affect the survival of dentition in older ages7,8. Occupational class was found as a predictor for complete edentulism at the ages of 70 and above8. Psychological effects by mental stress and negative events throughout life cause a rapid development of caries, or acute gum diseases such as acute necrotizing ulcerative gingivitis6. The influence of occupational stress on dental health was found to be multisystematic and include gastrointestinal effects, respiratory effects, musculoskeletal effects and mental health effects. Certain effects on employee’s periodontal health were associated with work-related mental demand, psychological stress factors by work load and unexpected tasks or personal conflicts6. Tooth loss have extensive impacts on the individual, both mentally and physically1,7,8,12,15–17. A review article that surveyed these implications found that complete edentulism causes low self-esteem, a low quality of life, and can predict mortality in older ages by its association with cardiovascular morbidity, hypertension and physical constraints7. A prospective study found an association between periodontal diseases and tooth loss with cancer in later stages in life16. It was found that there is a relationship between complete edentulism and poor overall health, poor nutrition, physical disability and low self-esteem8. In addition, oral health might affect daily routine, such as trouble sleeping, enjoying food, being able to smile during social events and staying at home more than usual. These effects were higher with increasing age1. Family time, work time and leisure time are the 3 major components in a person’s cycle of time6. It has been shown that time with the family has the greatest influence on life satisfaction, and accordingly on oral health6. In Israel, males work an average of 43 weekly hours18, whereas in France, for example, the number of weekly hours cannot exceed 35 h, by law19. Despite the integral part of the professional occupation of a person’s time, only few studies have examined the effect of the occupational environment on one’s oral health6. The objective of this study was to examine the association between occupational characteristics and number of natural teeth retained among older adults aged 50 and above.
261
Subjects and methods This study is a cross-sectional study. Self-administered questionnaires were randomly once distributed among a sample of 500 participants aged 50 years and above, throughout different areas in the state of Israel, both urban and rural strata. Approval for the study was received from the Board of Ethics in the Hebrew University of Jerusalem, and the participants were asked to sign an informed consent before filling out the questionnaires. Two inclusion criteria were administered: Age – 50 years and above – and professional seniority of at least 10 years in the same profession. An evidence-based method for the number of teeth retained was obtained by self-report after an enclosed instruction, to get an accurate data20–23. The participants were dichotomised by the median for statistical analysis purpose; participants with 25 natural teeth or less, as compared with participants who had more than 25 natural teeth as the dependent variable. The independent variables for this study were age, gender, years of education, occupational status (currently working vs. unemployed, regardless of retirement), retirement, self-employment, previous occupations, number of years spent in each occupation, immediate occupational environment (home, industrial/outdoors, hospital/commercial, school/grade school/university or office), occupational stress (in a subjective visual scale of 1–10 on which the participants were asked to grade themselves), level of income (low/average/high – as stated by the participant itself, without further detailing), working in shifts, regular meals, position at work (measures similarly to the occupational stress level – on a scale of 1–10), hours of work per day and number of work days per week. Occupations were later categorised into three different groups, after being defined as accurately as possibly by the participants: a blue-collar group (included occupations requiring manual labour); a whitecollar group (included occupations requiring office-work but little or no official professional training such as clerks, marketing workers, administrative workers); and a group of liberal professions that require formal training and labour unions (medicine, dentistry, veterinary, law practice, accounting, pharmacy, engineering, psychology, architecture, science, social work, education, libertarianism and nursing). The statistical analysis included Pearson’s chisquare test, independent t-test and analysis of variance (ANOVA) using SPSS 19.0 statistical software
© 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
262
A. Zini et al.
(IBM Corp. IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.). A conceptual multiple multilevel logistic regression stepwise-backward selection was performed. At the first step of analysis (1st model), sociodemographic variables were included (education as a proxy to socio-economic position). At the next stage (2nd model), all occupational variables were entered into the equation. Statistical level of significance was set as p < 0.05.
Results From 500 questionnaires randomly distributed, 283 questionnaires were eventually collected, indicating a response rate of 56.3% after one distribution. Of the 283 questionnaires collected, 3 were excluded due to lack of compatibility (working less than 10 years in all occupations). The mean age of the participants was 61.25 9.12 (ages ranged from 50 to 93 years). The majority of the sample (60%) were female, and 68.9% of were pre-retired (not yet retired) while 31.1% were already retired (officially, but might have still be working part-time or voluntarily, as measured by their current occupational status). The average number of natural teeth in this sample was 21.47, with a median of 25, determining the dichotomisation for statistical analysis. Figure 1 demonstrates the distribution of number of natural teeth by occupational environment and occupational group. The higher percentages of more than 25 teeth were found among school, grade school or university occupational environment, and among liberal professions group. Table 1 represents the association between categorical variables and the number of natural teeth. Occupational status of ‘currently unemployed’ was with significantly higher percentages of par-
ticipants with 25 natural teeth or less as compared to the ‘currently working’ group (p = 0.044). A higher percentage of participants with 25 teeth or less were among retired (p = 0.011), ‘blue-collar group’ (78.8%), followed by the ‘white-collar group’ (56.9%), (p < 0.001), and ‘home’ or ‘industrial/open grounds’ groups (90% and 72.1%, respectively; p < 0.001). It should be noted that the group of participants who were working at home was fairly small, including only 10 participants. No significant differences were found by gender, working in shifts, being selfemployed, eating regular meals and level of income. The results of the ANOVA analysis of the association between continuous variables and the number of natural teeth retained are shown in table 2. The only variables that showed an association to the number of natural teeth were age and years of education. Among the participants with 25 natural teeth or less, the average age was significantly higher than among the non-wearing dentures participants (63.98 10.25 vs. 58.23 6.21, respectively; p < 0.001). The mean years of education was significantly lower in the 25 or less natural teeth group as compared to the over 25 natural teeth group (14.36 3.34 vs. 15.83 2.70, respectively; p < 0.001). Figure 2 shows the number of natural teeth according to statistically significant differences in independent categorical variables (occupational status, retirement, occupational group and environment of work) based on the ANOVA and t-test analysis. In the ‘currently working’ group, the average number of teeth was higher than in the ‘currently unemployed’ group (22.62 vs. 18.92, respectively, p = 0.002). The ‘pre-retired’ group had a higher average number of teeth as compared to the ‘retired’ group (22.77 vs. 18.6,
Figure 1 Distribution of participants according to the number of natural teeth (%) in relation to occupational environment and occupational group. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd, Gerodontology 2016; 33: 260–267
Professional occupation and the number of teeth
Table 1 Distribution of participants according to number of natural teeth (%) by gender, occupational status, retirement, occupation, occupational environment, shifts, regular meals and level of income (n = 280).
Gender Men Women Employment Currently working Currently unemployed Retired No Yes Occupational classifications Blue collar White collar Liberal professions Occupational environment Industrial/ outdoors Hospital/ commercial School/grade school/university Home Office Independency at work Employee Self-employed Shifts or hourly Working in shifts Working regular hours Regular meals Irregular Regular Income Below average Average Above average
263
≤25 natural teeth, %
>25 natural teeth, %
54.5 54.2
45.5 45.8
0.961
50.3
49.7
0.044*
63.2
36.8
49.2 65.5
50.8 34.5
78.8 56.9 40.7
21.2 43.1 59.3
25 natural teeth teeth Mean
SDa
Mean
SDa
pb
Age (years) 63.98 10.25 58.03 6.21
