Why do the elderly change into the patients who seldom go to dental clinics ?
- the General Remarks in terms of Macro-Analyses -
Toru Takiguchi D.D.S.,Ph.D
Director, Dental Health Division, Health Policy Bureau, Ministry of Health, Labor and Welfare
DCurrent health care statuses and national challenges on prolonging of healthy life expectancy
1) Life expectancy and healthy life expectancy in Japan
According to the survey by WHO1) in 1999 on ranking of each countryÕs peopleÕs life expectancy in the world, Japan is number one both male and female out of 191 countries in terms of having the longest average life expectancy and healthy life expectancy . WHO defines "healthy life" as follows:
"healthy life means a full range of functional capacity at each life stage, from infancy through old age, allowing one the ability to enter into satisfying relationships with others, to work, and to play".
Especially, it is very important recognition that the elderÕs healthy lives are lost easily by diseases, injuries, or dementia.
2) The population of the elderly in now and future in Japan
According to the National Survey (Figure 1) by MHLW (Ministry of Health,Labour and Welfare), the population of the elderly in Japan reached absolutely 20 % in 2001, and it is estimated that the rate hereafter will increases rapidly and reach to about 35% in 2050. On the other hand, the visiting rate for medical hospitals or clinics in the elderly is 2.5 times higher in case of outpatients, and 6 times higher in case of inpatients than younger people respectively. This is the main cause that total medical care expenses in Japan increase almost 1 trillion yen year by year.
3) Diseases Trend in Japan
Figure 2 shows the changes in mortality rate2) in Japan from 1930s. Serious infectious diseases such as cholera, dysentery, and typhoid fever spread out until about five decades ago. However, after 1950s breakthrough of sanitary, nutritional and medical conditions resulted in sharp reduction of mortality rate. On the other hand, the rates of Lifestyle-Related Diseases (previous name is Adult Diseases) such as diabetes, cancer, and circulatory diseases are all but unchangeable. These diseases often deprive people, in particular the elderly, of their healthy life.
4) National challenges on prolonging of healthy life expectancy
Because of reasons mentioned above, MHLW proposed "Healthy Japan 213)" based on the new concept of Lifestyle-Related Diseases in March 2000. "Healthy Japan 21" campaign emphasizes the Primary prevention of Lifestyle-Related Diseases as follows:
@cancer, Acerebral apoplexy and heart disease, Bdiabetes, Cmental diseases and Ddental diseases. In addition, lifestyle related behaviors which should be improved to overcome these diseases are as follows:
a) Nutrition, b) exercise moderately, c) smoking, and d) alcohol
5) National challenges on prolonging of tooth life expectancy
The 8020 Campaign3) is a well-known national oral health campaign that was proposed by the Dental Health Division , Ministry of Health, Labour and Welfare in 1989. The concept of the 8020 Campaign is to ensure that all citizens can enjoy a healthy diet throughout their life through the prevention of tooth loss results in masticatory dysfunction.
To crystallize happy old life, 8020 Campaign is an unique national campaign which means the keeping of the chewing ability until 80 years old and over . The relationship between Healthy Japan 21 Campaign and the 8020 Campaign is interactive complementary relationship.
Fortunately, the Health@Promotion@Law which includes Healthy Japan 21 and the 8020 Campaign will enforce on April 1,2003. This low will pave the way for all 47 prefectures and about 3,000 and over municipalities to make the individual health care schemes based on Healthy Japan 21 Campaign include 8020 Campaign.
DComparison new medical patients rate with new dental patients rate by age
1) Pattern of new medical patients rates
Figure 3 shows the changes of the new medical patients rates by each age group in 1982 and 1996,Japan4). In Figure 3, X-axis means age group, and Y-axis means number of new medical patients per 100,000 populations. Blue line and red line mean data in 1982 and 1996 respectively. Patterns of distributions by age groups show "U-shaped" patterns both in1982 and in1996. The rates fall down to bottom in young adult and thereafter they increase sharply depend on age.
2) Pattern of new dental outpatients rate
Figure 4 shows the changes of number of new dental patients rates by each age group in 1982 and 1996,Japan4). Patterns of distributions by age groups show "reverse W-shaped " patterns both in1982 and in1996. The rates temporarily fall down from 5-9 aged group to 10-14 aged group, and they rise depend on age until 45-49 aged group in case of 1982, until 65-69 aged group in case of 1996 respectively. However, after 55-59 aged group in 1982, after 70-74 aged group in 1996, both rates sharply drop down depend on age. Oral conditions of the elderly are apparently worse than younger people because affects of tooth loss are accumulated by age. Therefore, it is extremely strange that the new dental patients rates steeply drop down in the elderly stage.
3) Two hypotheses Two hypotheses that can explain why the elderly seldom go to dental clinics are as follows: Why do the elderly seldom go to dental clinics?
Hypothesis 1: It is because those general conditions of the elderly generally become poor by age.
Hypothesis 2: It is because that remaining teeth of the elderly generally significantly decrease, namely teeth suffering from serious caries or periodontal diseases notably reduce. In other word, it is because those elder of edentulous or those of wearing of full dentures significantly increase.
4) The verification of Hypothesis 1 because of general conditions?
Figure 6 shows the changes of new patients rates per 100,000 populations by each kind of disease and each age group (45 years old and over) in 1996, Japan5)
Common logarithmic transform was applied to Y-axis in order to compare easily the changes of each disease not in terms of absolute vales but rates. For example, in Y-axis, absolute difference between 100 and 1,000 is 900, and absolute difference between 1,000 and 10,000 is 9,000. However, in terms of logarithmic measures, 1,000/100 is equivalent to 10,000/1,000, and then both intervals can be compared as same 10 in visible. In figure 6, pattern of dental diseases outpatients make an interest contrast with those of eye diseases outpatients.
To try more accurate comparison, only two diseases were extracted in Figure 7. In case of eye diseases outpatients, the rates steeply increase until 75-79 years old and do not notably decrease before 85 years old. Spreading of cataract or glaucoma by age causes the sharp increase of eye outpatients. On the other hand, the rates of dental diseases outpatients reach a plateau until 55-64 years old and sharply decrease from 75-79 years old in spite of serious tooth loss. The two curves intersect at 75-79 old ages. It is strongly suggested that general conditions of the elderly before 85 years old are generally good enough to go to clinics.
Therefore, it is indicated that drop down of new dental outpatientÕs rates before 85 years old is caused not by general conditions but other special proper reasons on dental diseases and treatment.
5) The verification of Hypothesis 2 because of dental conditions?
Figure 8 shows changes of mean remaining teeth by 5 years age group in Japan.
The source is "Report on the Survey of Dental Diseases (1975-1999)6)" by MHLW. Remaining teeth of Japanese people from 45 years old increase apparently by dental examination year. It is strongly suggested that the improvements of oral statuses contribute to the changes of dental patientÕs visiting rates. However, the relationship between improvement of remaining teeth (Figure 4) and dental patientÕs visiting rates (Figure 8) is not so simple. Because, it seems that the increase of remaining teeth in young and middle adult ages results in the decrease of visiting dental clinics caused by the reduction of serious caries or periodontal diseases. On the contrary, dental caries are never healed in natural, and serious periodontal diseases are not cured easily, therefore, two dental diseases are advanced and accumulated by age. Eventually, the rates of visiting dental clinics rise because of serious caries or periodontal diseases in the elderly. Douglass CW and et al. proposed the "more teeth, more disease" theory7) in 1990, and confirmed it using cross-sectional data of elders aged 70 years and older in 19968). The theory indicates that "more teeth" decreases dental demands in young adults stages but increase them in middle and elder stages, and eventually net total dental demands increase ("more disease"). The results of their studies are coincidence with this study (Figure 4). However, it is not clear whether net total dental demands increase or not in Japan because basic conditions of nine background factors (e.g. diagnostic services, preventive services, changes of dental treatment method) referred by Douglass CW7) are different between US and Japan. In any case, it is necessary to make more accurate studies of the relationship between improvement of remaining teeth and dental patientÕs visiting rates through all humanÕs life in Japan.
Figure 9 shows relationships between changes of new patients ratio and distributions of persons who wear three types of prostheses (Bridges, PD; partial dentures and FD; full dentures) by each age group9). New patients ratios raise until 65-69 aged group, but fall down from 70-74 aged group same as Figure 4. On the other hand, the wearing rates of three types of prostheses are widely different from each other. In case of bridges and partial dentures, the rates fall down from 60-64 aged group, 70-74 aged group, respectively. On the contrary, in case of full dentures, the line shows a significant linear increase from 45-49 aged group. Differences of patterns among three types of prostheses in the elderly can be explained by only one cause. That is the significant reduction of remaining teeth in the elderly (Figure 8). Therefore, it is suggested that drop down of the dental clinics visiting rates in the elderly is strongly connected with extensive tooth loss, especially with edentulous.
6) Conclusion
Which is reliable Hypothesis 1 or 2?
Through discussions 4) and 5) mentioned above, it became clear that Hypothesis 2 was probably main cause of reduction for the dental visiting rates in the elderly.
In addition, this conclusion is supported by DouglassÕs the "more teeth, more disease" theory in 1990. Generally speaking, macro-analyses sometimes has some basic risks derived from differences of subjects of each investigation. Therefore, further more studies on this theme are needed to confirm the relationship between dental conditions and new dental visiting rates by using individual cohort data in the elderly.
References
1)Mathers CD et al., Healthy life expectancy in 191 countries, Lancet, 357(9269): 1685-1691,1999.
2)Ministry of Health, Labour and Welfare,Japan(1990). Vital Statsistics,37:48-55.Tokyo, Ministry of Health, Labour and Welfare,Japan.
3) Takiguchi T, Oral health in Japan Šapproaches for the eldery.Proceeding of a WHO international symposium Kobe,Japan,10 Nov.2001.
4) Takiguchi T, Countermeasures against dental caries under the Health Insurance system in Japan, Dental Outlook,Vol 99( 5), 1116-1121,2002.
5) Wada K, Ogura M, Takiguchi T, Why do the visiting rates of dental clinics fall down in the elderly ?, The Nippon Dental Review, Vol 62(1), 170-174,2002.
6) Ministry of Health, Labour and Welfare Japan. Report on the survey of Dental Diseases (1981,1987,1993,1999) Dental Health Division, Health Policy Bureau,Minstry of Health, Labour and Welfare Japan.
7) Douglass CW, Furino A. Balancing dental service requirements and supplies;the epidemiological and demographic evidence. J Am Dent Assoc;121:587-5921,1990.
8)Joshi A, Douglass CW, et al., Consequences of Success:Do More Teeth Translate into More Disease and Utilization?. J Public Health Dent Assoc;56(4):190-197,1996.
9) Miyatake K, Takiguchi T et al., Reforming the evaluation of dental prosthetic skills regarding the future of the dental insurance system. Japanese Journal of Health Economics and Policy, 5:31-47,1998.