BACKGROUND: The life expectancy is an important measure for describing health status among population. Several studies from the United States and Europe showed the harm of smoking by describing the life expectancies with different smoking status. No such study is examined in Japan, the country with the world's highest life expectancy irrespective of high smoking rate among men. METHODS: The abridged life table method was applied to calculate the life expectancies of men and women among different smoking status from age 40 until age 85. Age-specific mortality rates stratified by different smoking status were obtained from follow-up data from random sample in Japanese population (NIPPON DATA80). RESULTS: Proportion of current smokers was 62.9% in men and 8.8% in women at the baseline survey in 1980. The life expectancies of 40-year-old never smokers, ex-smokers and current smokers were 42.1, 40.4, and 38.6 years in men and 45.6, 45.9, and 43.4 years in women. The life expectancy of 40-year-old men who smoked less than one pack per day was 39.0 and was longer than that of those who smoked one or two packs (38.8) and more than two packs (38.1). CONCLUSION: Life expectancy decreased gradually as the grade of smoking increased in the Japanese population. J Epidemiol 2007; 17: 31-37.
BACKGROUND: Relationships between consumption of dairy products and death from various types of cancer are largely unknown. METHODS: Between April 1992 and July 1995, a baseline survey was conducted for 11,349 residents in 12 communities in Japan, which included collection of demographic data and a self-administered food-frequency questionnaire inquiring about three dairy products: milk, butter and yogurt. The subjects were followed prospectively until 2002. Causes of death were identified using death certificates. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for each dairy product were calculated using Cox's proportional hazard models. RESULTS: Among eight common cancers, only deaths from hematopoietic neoplasm (n=14) were significantly associated with consumption of butter (HR=5.11, 95% CI: 1.40-18.62), though they exhibited a nearly-significant association with milk consumption (HR=3.17, 95% CI: 0.99-10.17), independent of age and sex. Consumption of milk and butter was significantly associated with non-lymphoma deaths (n=9) when adjusted for age and sex (HR=9.86, 95% CI: 1.23-79.19 for milk; and HR=10.04, 95% CI: 2.39-42.18 for butter). CONCLUSION: The frequencies of butter consumption, and probably that of milk, were correlated with death from hematopoietic neoplasm, particularly from non-lymphomas. J Epidemiol 2007; 17: 38-44.
BACKGROUND: The transtheoretical model (TTM) of health behavior change is one of the most promising approaches for health professionals to help individuals change their behaviors. Few studies have assessed calcium intake using the model on Asian women. This study aims at clarifying characteristics of each behavioral stage among Japanese women and providing clues to increase calcium intake to prevent osteoporosis. METHODS: A cross-sectional survey was conducted from September through November, 2005 using self-administered questionnaires. A total of 226 participants in an osteoporosis screening program were invited to take part in the study, and 150 women were enrolled. RESULTS: Adjusted means of total dietary calcium were positively significantly associated with successive stages (p<0.001). The proportion of calcium intake from plants and fish was higher in the precontemplation, contemplation, and preparation stages compared with the action and maintenance stages (p=0.038). Concomitantly, the plants and fish food group contributed 46.7% of total dietary calcium, while 32.4% was derived from milk and dairy food, and 20.9% from other foods. The correlation coefficient (95% confidence interval) between the proportion of calcium obtained from plants and fish and the proportion of fat energy was -0.22 (-0.37, -0.06). CONCLUSIONS: The proportion of calcium intake from plants and fish was higher among women in the lower stages compared with higher stages. Given the higher prevalence of lactose intolerance, it would seem plausible to recommend lower-stage women be educated and encouraged to derive more calcium from plants and fish diets as a means to prevent osteoporosis. J Epidemiol 2007; 17: 45-53.
BACKGROUND: Accurately evaluating a risk of chronic obstructive pulmonary disease (COPD) requires a large-scale longitudinal study using a standard criterion for diagnosing COPD. There have been only a few such follow-up studies in Europe and no reports in Asia. We estimated the incidence rate and incidence rate ratio (IRR) of age and smoking for COPD in a Japanese population using the diagnosis criterion of the Global Initiative for Chronic Obstructive Lung Disease guidelines. METHODS: Subjects were 17,106 participants aged 25-74 years during health check-ups including spirometry from April 1997 through March 2005 in Japan. Total follow-up of participants were 47,652 person-years in males and 25,224 person-years in females. The IRR of age and smoking was estimated using Cox proportional hazard models with both variables. RESULTS: We identified 466 incidence cases of COPD. The incidence rate per 100 person-years was 0.81 (95% confidence interval [CI], 0.73-0.89) in males and 0.31 (0.24-0.38) in females, and significantly increased with age in both sexes. The incidence rate for current smokers was significantly higher than that for male non-smokers but not significantly for females. Among males, the IRR for current smokers with Brinkman Index < 400, 400-799, and 800+ was 1.2 (0.8-1.9), 2.7 (1.9-3.8), and 4.6 (3.3-6.5), respectively. CONCLUSION: These results indicated that the COPD risk gradually increased with aging, and that there was a dose-response relationship between smoking and COPD risk. J Epidemiol 2007; 17: 54-60.
BACKGROUND: Evidence is still insufficient regarding the effects of Power Rehabilitation (PR) on physical performance and higher-level functional capacity of community-dwelling frail elderly people. METHODS: This nonrandomized controlled interventional trial consisted of 46 community-dwelling elderly individuals with light levels of long-term care needs. They were allocated to the intervention (I-group, n = 24) and control (C-group, n = 22) groups. Of them, 32 persons (17 in the I-group; 15 in the C-group) (median age, 77 years; sex, 28% male) completed the study. The I-group subjects underwent PR twice a week for 12 weeks. The outcomes were physical performance (muscle strength, balance, flexibility, and mobility) and higher-level functional capacity as evaluated by the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) and the level of long-term care need as certified by the public long-term care insurance. RESULTS: The I-group demonstrated a significant improvement in the measured value of the timed up-and-go test (median change, a decrease of 4.4 seconds versus a decrease of 0.2 seconds, p = 0.033) and the timed 10-meter walk (a decrease of 3.0 seconds versus an increase of 0.2 seconds, p = 0.007) in comparison with the C-group. No significant change was observed in the TMIG-IC scores or in the level of long-term care need in the I-group. CONCLUSION: PR improved mobility of community-dwelling frail elderly people; however, such improvement did not translate into higher-level functional capacity. Our findings demonstrate the difficulty in transferring the positive effects associated with PR into an improvement in higher-level functional capacity. J Epidemiol 2007; 17: 61- 67.