Follow-up and Mortality Profiles in the Miyagi Cohort Study

BACKGROUND: Findings from a large-scale population-based prospective cohort would lead us to better understanding of the relationship between lifestyle and health, thus better provision of strategies for disease prevention and health promotion. METHODS: We conducted a baseline survey with two self-administered questionnaires regarding lifestyle and personality on the residents aged 40 to 64 years in 14 municipalities of Miyagi Prefecture, Japan, during June through August, 1990. Out of the eligible 51,925 residents, 47,605 (91.7%) responded to the lifestyle questionnaire and formed the cohort under study. We then have been following up the subjects for mortality, migration, and incidence of cancer. RESULTS: During the follow-up from June 1990 through March 2001, 2,536 subjects (5.3%) died and 2,166 subjects (4.5%) emigrated. The distribution of the causes of death among the study subjects was quite consistent with the national average. CONCLUSIONS: In this cohort study, both the participation rate and the follow-up rate are satisfactorily high. We expect this Miyagi Cohort Study to provide the society with evidence for health promotion and disease prevention.

grants, we obtained no information regarding a new address. Therefore, the emigrants were lost to follow-up at the time of emigration.
We calculated the mortality rate among the study subjects for all causes, cancer, heart disease, and cerebrovascular disease, respectively. Mortality rate was calculated as the number of decedents divided by the number of person-years of follow-up. In classifying causes of death, we defined cancer as ICD-9 Codes from 140 through 208; heart disease as ICD-9 Codes from 393 through 398 and those from 410 through 429; and cerebrovascular disease as ICD-9 Codes from 430 through 438. Table 2 indicates the number of decedents and emigrants by sex and five-year age group. Out of 47,605 cohort subjects, 2,536 subjects (5.3%) died and 2,166 subjects (4.5%) emigrated. The death rates increased with age, and were larger in men than in women. Table 3 indicates the person-years of follow-up, the number of decedents and mortality for all causes, cancer, heart disease, cerebrovascular disease, respectively, by sex and five-year age group. For both men and women, the most common cause of death was cancer (n=1,132), occupying 43.6% of all deaths in men and Tsuji I, et al. and incidence of cancer.
In this article, we would report follow-up status and mortality profile in this cohort study between June 1990 and March 2001.
In order to follow up the subjects for migration and mortality, we established the Follow-up Committee. The Committee was consisted of Miyagi Cancer Society; Community Health Division of all 14 municipalities; Department of Health and Welfare, Miyagi Prefectural Government; and Division of Epidemiology, Tohoku University Graduate School of Medicine. The Committee periodically reviewed the Residential Registration Record of each municipality. It is generally accepted that this registration system in Japan is accurate and reliable because this is the basis for tax, pension, and human services provided by the municipalities. So far, the Committee reviewed the Record five times (Table 1).
With this review, we identified the subjects who either died or emigrated during observation. For both decedents and emigrants, we recorded the date of death/emigration. For decedents, we investigated cause of death by reviewing the death certificates of the subjects at Public Health Centers of the study area. The underlying cause of death was coded according to International Classification of Diseases, the Ninth Revision (ICD-9). 3 For emi- In this article, we reported the method of following-up the cohort subjects and the number of decedents and emigrants during the follow-up from June 1990 through March 2001 in the Miyagi Cohort Study. Although we stopped following the emigrants at the time when they moved, the emigration rate was as low as 4.5%. We have documented 2,536 deaths, which seemed to be large enough for us to analyze the association between the healthrelated lifestyle and the risk for mortality. With this dataset, we would examine and report the effect of lifestyle such as smoking, alcohol drinking, body mass index, physical activity, and so forth in this Supplement.
We would further continue to follow up the cohort subjects, and we expect this Miyagi Cohort Study to provide the society with evidence for health promotion and disease prevention.
46.1% in women. Deaths from heart disease (n=358) occupied 15.2% in men and 11.9% in women. Deaths from cerebrovascular disease (n=307) occupied 11.1% in men and 14.3% in women. The distribution of the causes of death among the study subjects was quite consistent with the national average. In 1995, among the decedents aged 40 to 64 years in Japan, cancer occupied 40.1% in men and 48.2% in women, heart disease occupied 12.3% in men and 9.3% in women, and cerebrovascular disease occupied 10.3% in men and 11.2% in women. 4 Table 4 indicates the number of decedents and mortality for varying sites of cancer by sex and five-year age. In men, the most common cause of cancer deaths was stomach (n=150; 20.2% of all cancer deaths), followed by lung (n=138; 18.6%), colorectum (n=81; 10.9%), and liver (n=74; 10.0%). In women, stomach (n=55; 14.1%) was the most common, followed by colorectum (n=49; 12.6%), breast (n=46; 11.8%), and pancreas (n=45; 11.5%).

Men
Person