We evaluated the reproducibility of data on intake frequency of 33 food items, beverage intake frequency of 3 items, drinking and smoking habits, and past history of 10 diseases obtained from a self-administered questionnaire. The survey subjects consisted of 263 aged 39 to 79 years individuals in the general population. After about one year interval these subjects consecutively participated in two surveys and were unintentionally requested to answer to the same questionnaire. The means of percent exact agreements for 33 food items were 48.4% in all, 42.7% in males and 49.4% in females. The means of their percent agreements within one category difference were 85.4% in all, 83.3% in males and 85.8% in females. The reproducibility of beverage intake frequency was the highest in green tea, followed in order by black tea and coffee. The percent exact agreements were 85.4 % in males and 81.8 % in females for drinking habit, 87.5 % in males and 99.0% in females for smoking habit, and 93.7% in males and 97.2% in females for past history.The reproducibility of the self-administered questionnaire was the highest in past history, followed in order by smoking habit, drinking habit and dietary habit. The values of reproducibility were higher in females than in males except for drinking habit. Although reduction of categories was needed to improve the reproducibility, the obtained values from the self-administered questionnaire were sufficiently high for epidemiological studies. J Epidemiol, 1997; 7:61-69.
A cross-sectional survey on 1462 residents aged 55 years and over was conducted in an urban Japanese community to describe the factors influencing the people's desire to be institutionalized in later life. Multiple logistic regression analyses were performed to identify the variables associated with the desire for a nursing home placement. Men unsatisfied with their family bonds were more likely to desire placement in a nursing home. Younger women living alone or dissatisfied with their health status demonstrated a greater desire to be institutionalized. Among the elderly aged 70 years old and over, those who were dissatisfied with their family bonds or disabled in going outdoors were more likely to desire to live in a welfare facility. Gender, housing and financial characteristics were not significant factors for the desire to be institutionalized. Numerous factors were similar with actual predictors of nursing home placement; however, the elderly advancing in age were more concerned to remain at home. The present findings suggest that, aside from physical and mental disability, the family-related issue is the most important factor prompting the desire for institutionalization. J Epidemiol, 1997 ; 7 : 77-83.
Family history serves as the most important risk factor in prevention of coronary heart disease from youth. Prevalent methods of assessing family history, however, have serious drawbacks : a sudden rise of risk when a family member develops the disease; insufficient control for age among family members. We propose a simple quantitative method overcoming such drawbacks. Data on family history were obtained by questionnaires sent to 2, 393 male high school students and their cholesterol levels were measured. Family risk from each family member was calculated by (30 / Risk age)4, where the risk age was age at onset expressed by decade; if absent, it was replaced by present age or age at death. A mean score in a family served as the family risk. A total of 1, 584 students and 17, 127 family members were analyzed. The proposed method yielded a statistically significant association (Odds ratio=1.60; 95% confidence interval: 1.15-2.25) between the family risk (above or below the median) and the student's atherogenic index (above or below the 90th percentile) calculated from cholesterols. This association was stronger than those by conventional methods. The proposed method may be useful in prevention activities and its efficiency needs to be confirmed in other studies. J Epidemiol, 1997 ; 7 : 85-92.
The objective of this study is to compare the influence on delays in the tuberculosis casefinding process according to the types of medical facilities initially visited. The subjects include 107 patients 16 years and older who were diagnosed with bacteriologically confirmed pulmonary tuberculosis at nine tuberculosis specialized facilities in Ulaanbaatar, Mongolia from May 1995 to March 1996. Patients were interviewed about their demographic and socioeconomic factors and their medical records were reviewed for measuring delays. Fifty-five patients initially consulted general physicians and the remaining 52 patients initially visited other types of facilities including tuberculosis specialized facilities. Patients who initially consulted general physicians had shorter patient's delays and longer doctor's delays than those who had visited other facilities first. Since the reduction of patient's delay outweighs the extension of doctor's delay among patients who initially consulted general physicians, their total delay was shorter than that of patients who visited other facilities first. The beneficial influence of consulting general physicians first on the total delay was observed after adjusting for patient's age, sex, residence area, family income and family history of tuberculosis. This finding indicates that general physicians play an important role in improving the passive case-finding process in Mongolia. J Epidemiol, 1997; 7 : 93-98.
To disclose the association between smoking habits and lung cancer in Okinawa, Japan, we analyzed the data from a case-control study conducted from 1988 to 1991. The analysis, based on 333 cases and 666 age-, sexand residence-matched population controls, provided the following major findings. (a) The odds ratios (ORs) for current smokers relative to nonsmokers were much greater for squamous cell carcinoma than for adenocarcinoma. The OR was 9.82 for squamous cell carcinoma and 2.18 for adenocarcinoma in males, 28.2 and 1.14, correspondingly, in females. (b) Males who quitted smoking for 20 years or more demonstrated no elevated lung cancer risk. (c) Among male current smokers, the more the number of cigarettes smoked per day, the higher the lung cancer risk for both cell types, but particularly for squamous cell carcinoma. In contrast, deep smoke inhalation significantly increased the risk for adenocarcinoma in particular. (d) Okinawan brand cigarettes were more strongly associated with the risk, compared with other brand ones. This finding might partly explain the higher frequency of lung cancer in males with the relatively lower smoking rate in Okinawa. J Epidemiol, 1997 ; 7 : 99-105.
To examine whether the association between smoking and nasophayngeal cancer varies according to age at starting smoking and age at diagnosis of the disease, we compared 113 men with nasopharyngeal cancer diagnosed between 31 and 59 years old who lived within eight cancer registry areas to 1, 910 controls selected by random-digit telephone dialing. Compared to smoking which began at the age of 22 years or older, the risk estimates were 0.4 (95% confidence interval (CI) 0.2-0.9) and 0.8 (95%Cl 0.4-1.5) for smoking begun at the ages of 18-21 and 17 years or younger, when adjusted for pack-years smoked and other potential confounders (p for trend > 0.8). In contrast, the risk estimates adjusted for age at starting smoking and other variables were 1.3 (95%CI 0.7-2.6), 1.9(95%Cl 0.9-4.0) and 3.0(95%Cl 1.4-6.2) for 15-29.9, 30- 44.9 and 45 or over, relative to 15 or less pack-years smoked (p for trend < 0.005). The analyses were repeated for subgroups in terms of age at diagnosis. The relative risks of ever-smoking and the dose-effect relation between pack-years and the risk of the disease were not significantly different between men whose cancer was diagnosed at the age 49 or younger and those whose tumor was diagnosed between the ages 50 and 59. This study suggests that the magnitude of the risk for nasopharyngeal cancer may not vary significantly with the age at which smoking begins, and age at which the disease is diagnosed. J Epidemiol, 1997 ; 7 : 107-111.