Relationship Between the Level of Activities of Daily Living and Chronic Medical Conditions Among the Elderly

The purpose of this study is to observe the disease-disability association through a crosssectional study. Between 1994 and 1995, we conducted a questionnaire survey in 5 towns in Japan. Among the items included in the questionnaire, 5 related to ADL (bathing, feeding, dressing/undressing, toileting, and going out socially) were treated as purpose variables; and 5 related to the history of medical treatment received over the past year (diabetes, heart disease, cerebrovascular disease, neuralgia, and bone fractures) were used as explanatory variables. Multiple logistic models were applied to observe the relationship. The history of medical treatment for cerebrovascular disease greatly and unavoidably affects disability related to ADL. Bone fractures, diabetes, and heart diseases contributed to specific ADL disabilities. J Epidemiol, 1998 ; 8 : 272-277.

Aging of the Japanese population has progressed rapidly: the number of senior citizens 65 years and older exceeded 14% of the total population in 1995.It is expected to exceed 17% in 2000 and 20% in 2010.It is vital that community attention be directed not only to chronic medical conditions but also to disability related to ADL.This will foster suitable public policies to be implemented to counteract the emerging problems so that a healthier and more vital aged society can be created.
Disabilities related to activities of daily living (ADL), especially those caused by various diseases, adversely affect one's mental state, e.g., isolation-related depression and decline in self-respect.Moreover, exaggerated decubitus ulcers, a decline in muscle strength, contracture, and risk of injuries due to falling 'become more prevalent as the degree of disabilities progresses.Thus the prevention and alleviation of disabilities related to ADL are very important.Some authors refer to preventing chronic conditions which lead to functional limitation in the elderly 2, 3.4) as the key to healthy aging and the level of ADL as the indicator of the status of the elderly 5,6).Some chronic medical conditions, such as cerebrovascular disease, diabetes, and bone fractures adversely affect the level of ADL.However, the relationship between a disease and the proportion of old persons with ADL-related disabilities have not been well defined.We conducted a survey on typical problems related to aging in 5 towns in Japan to observe the relationship between some chronic medical conditions and the proportion of the elderly with disabilities.

Subjects
In 1994 and 1995, we conducted a survey, using questionnaires in 5 towns in Japan.We retrieved responses from 7,303 inhabitants aged 60 years or older.The total population of this age in these towns was 17,485 in 1995.

Data collection
Among the items in the questionnaire, 5 were related to ADL (bathing, feeding, dressing/undressing, toileting, and going out socially).These were rated as 0 (independent) or 1 (requires help).Questions on medical history related to 5 outstanding adult diseases (diabetes, heart disease, cerebrovascular disease, neuralgia, and bone fractures) were included.Each respondent was asked to rate them as follows: 0, have not experienced; or 1, have experienced in the past year.The results were adjusted for age.
All data were collected together with the common questionnaire forms at mass screening health examinations conducted in 4 towns out of 5 between 1994 and 1995.In remained Minamikawachi town, the same questionnaires were mailed to subject's home, and also collected by mail.

Analyses
We prepared contingency tables for both males and females, dependent on the change in the level of the 5 types of daily activity and on medical history related to the 5 disease entities over the past year.Chi-square tests were conducted on the data.
The disabilities related to the 5 types of ADL were treated as purpose variables for men and women.Medical treatment given for the 5 disease entities over the pastyear was treated as explanatory variables.Age was included in all models as a potential confounding factor.Analyses based on multiple logistic models for each of the purpose variables were conduct-ed to assess the independent effects of the explanatory variables.Odds ratios of histories of medical treatment over the past year in relation to the level of disability were calculated.We used the statistic package "SAS System for Windows" for the analysis of all data.

RESULTS
Figure 1 shows the geographical location of the 5 Japanese Towns.They are Yakumo town in Hokkaido Area, Asahi town, Minamikawachi town, Kisuki town in Honshu Area, and Hisayama town in Kyushu Area.
Table 1 shows backgrounds of the 5 towns.All of the five towns are small and located in rulal areas.
Table 2 shows the age and sex distribution for 7,303 subjects classified by town.The total sample consisted of 2,943 males (average age, 71.3) and 4,360 females (average age, 71.9).
Table 3 shows the proportions of elders with at least one ADL disability classified by town.They were 7.0% in males and 8.4% in females.Few subjects in Kisuki and Hisayama had ADL disabilities.
Table 4 shows the proportion of persons with a history of medical treatment and ADL-related disabilities.The incidence of a history of medical treatment for heart diseases was highest in both males (10.9%) and females (11.2%).Treatment of bone fractures was lowest in males (2.2%) and for cerebrovascular diseases, lowest among females (1.2%).The proportion of ADL-related disabilities manifested most frequently in going out socially among both males (6.4%) and females (7.8%); and least in feeding behavior among both males   (1.4%) and females (1.1%).
Table 5 shows the proportions of elders with each chronic medical condition according to age grade.Heart disease had the largest number through all age grades both in males and females.
Table 6 shows the proportion of disabilities related to the 5 items of ADL according to the history of medical treatment.
The proportion of ADL-related disabilities was generally higher when a history of medical treatment was reported by both males and females.When the history of medical treatment for cerebrovascular disease was recorded, the incidence of the disability rose in all 5 items of ADL.
Table 7 shows odds ratios for the history of medical treatment for 5 disease conditions against ADL-related disabilities.
Table 6.The proportions(%) of ADL-related disabilities according to each chronic medical condition.
Table 7. Odds ratios for chronic medical conditions against ADL-related disabilities.
(95% confidence intervals in parenthesis) We used all disabilities as explanatory valiables according to each medical condition on the head of the files as purpose valiables .
With the existence of cerebrovascular disease, ADL-related disabilities were uniformly outstanding in both males and females.The odds ratios for cerebrovascular disease among males were higher than among females in bathing, feeding, dressing/undressing and toileting, but not in going out socially (value, 13.47).This finding indicated that men with a history of cerebrovascular disease have a risk 13.47 times greater than men without a history of cerebrovascular disease to lose their ability to go out socially.The odds ratio (18.36) for females was higher in relation to going out socially.
In relation to diabetes, statistically significant reductions were noted in bathing and toileting for males and dressing/undressing, going out socialy, and feeding for females.Disabilities related to dressing/undressing among males and bathing and going out socially among females were significant in relation to bone fractures.For heart disease, no disabilities were significant among males; but among females, disabilities affecting all but one (feeding) item were significant.No disabilities were statistically significant in males and females in relation to neuralgia.

DISCUSSION
As a greater proportion of the population live to be very old, the public health impact of the burden of disease and disability, related utilization of medical care, and a need for supportive and long-term care have become an important issues 7) and effective countermeasures for the health and welfare of the aged become urgent.Therefore, the establishment of suitable countermeasures to slow the progression of disabilities and age-related physical deterioration is mandatory .It is also necessary that we investigate the chronic conditions that cause a functional decline in the elderly to improve the quality of their daily lives.Specific countermeasures will be required to improve the level of ADL for each chronic condition because the requisite care varies according to the disease even when the items of ADL to be rated are the same.The World Health Organization and others have proposed models to explain the functional consequences of diseases 8, 9, 10).Fried,et al. 11) hypothesized that a stage of preclinical disability exists with a varying degree of functional ability and that there is a need to employ compensatory strate-gies to prevent a greater risk of functional decline and the onset of disability.
The chronic conditions observed in the current study were diabetes, heart disease, cerebrovascular disease, neuralgia and bone fractures.In addition to these, chronic obstructive pulmonary disease, 12) infection, Parkinson's disease, visual impairment, 13) and many other conditions trigger a decline in the level of ADL.Social isolation, mental disorders, and poor compliance with medical treatment further contribute to the decline.These are not included in the targets of the present study; but they constitute potential subjects for future studies on the relationship between the level of ADL and chronic diseases or conditions.
Self-reports on the history of medical treatment during the past year were used as explanatory variables.It is possible that there may be individuals who were unaware of the existence of a particular disease and who neglected to report the treatment.They were included in the group with no history of medical treatment.However, some studies indicate that a self-report is often an accurate indicator of disease status for older persons 14,15) A number of risk factors for disability have been reported, including specific chronic diseases, health-related behavioral factors, and sociodemographic characteristics 2.
3.4, 16-20) Guralnik , et al.Reported that a previous heart attack, stroke, high blood pressure, diabetes, dyspnea, and exertional leg pain were associated with significant risk factors for a loss of mobility 3).In another report, they indicated that lower-extremity functions predicted the onset of disability 17).Verbrugge, et al. 4) reported that 7 chronic conditions, which included arthritis, visual impairment, hearing impairment, ischemic heart disease, chronic obstructive pulmonary disease, diabetes mellitus, and malignant neoplasms had an impact on US adults activity levels.However, there is a paucity of reports that refer to specific ADL-related disabilities that are affected by chronic conditions.
When compared to other diseases, the history of cerebrovascular disease contributed uniformly and greatly to a decline in the level of ADL.Some of ADL-related disabilities were significantly affected by bone fractures, diabetes, heart disease and specific ADL was affected both in males and females by each disease condition.The ADL items in which significant values were observed in chi-square tests but not when examined by using logistic model are going out socially in relation to a history of heart disease and neuralgia and bathing in relation to the history of bone fractures in males.The ADL items for which significant values were observed with logistic models but not in chi-square tests are toileting in relation to the history of diabetes in males.Confounding factors were adjusted by logistic model.
The odds ratios for cerebrovascular disease obtained from the logistic model for males were higher than those for females in relation to bathing, feeding, dressing/undressing and toileting; but the ratio for going out socially for females was as high as 18.36 (13.47 for males).As for the other 4 disease entities, none had a significant effect on going out socially for men, whereas diabetes, heart disease and bone fractures exerted significant effects on going out socially by women.
In Japan, efforts have recently been made to prevent a homebound state (not having outside social activities).In the future, it is anticipated that effective countermeasure will be implemented for aged women with chronic diseases (cerebrovascular disease in particular) to prevent them from becoming homebound and improving their ADL level.
When we focus on the disabilities related to ADL except for going out socially, men have higher odds ratios in relation to cerebrovascular disease.Support for family members becomes necessary in Japan when a man succumbs to a stroke because Japanese husbands are highly dependent on their wives in performing daily activities.
On the other hand, females are expected to be more independent than males in their activities because Japanese wives cannot depend on family members, especially husbands.This is so because husbands do not provide aid for daily activity.However, future research is necessary to ascertain whether the sequelae of cerebrovascular diseases are milder or the same criteria for determining disease severity is appropriate for women.
Clinical intervention can reduce the onset and progression of disabilities.
A number of studies have shown that intervention may improve characteristics such as physical strength, gait, and balance 21,21) On the other hand, when persons who suffer from ADL-related disabilities recover through rehabilitation, most regain physical functions in the order of feeding, moving, walking, toileting, dressing/undressing and personal hygiene 23).Therefore, functional recovery is facilitated if it starts with help in feeding when help is necessary for both feeding and dressing/undressing.Common rules might be applied to most of the elderly who have multiple ADL-related disabilities.
Primary prevention of disease is the ultimate method of averting disabilities.There is also a great need for designing careful countermeasures for ADL-relateddisabilities of the elderly caused by chronic conditions such as those described above.

Table 1 .
Backgrounds of the 5 towns.

Table 2 .
The age and sex distribution for the subjects classified by town.

Table 4 .
Frequencies and percentages of proportions of elders with each chronic medical condition and ADL-related disability.