A nationwide cohort study of educational background and major causes of death among the elderly population in Japan Yoshihisa Fujino, M.D., Ph.D. a, * , Akiko Tamakoshi, M.D., Ph.D. b , Hiroyasu Iso, M.D., Ph.D. c , Yutaka Inaba, M.D., Ph.D. d , Tatsuhiko Kubo, M.D. a , Reiko Ide, D.D.S., Ph.D. a , Ai Ikeda, M.S.W., M.P.H. c , Takesumi Yoshimura, M.D., M.P.H., Ph.D. a for the JACC study group 1 a Department of Clinical Epidemiology, Institute of Industrial Ecological Science, University of Occupational and Environmental Health, Kitakyushu, Japan b Department of Preventive Medicine/Biostatistics and Medical Decision Making, Field of Social Life Science, Program in Health and Community Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan c Department of Public Health Medicine, Institute of Community Medicine, University of Tsukuba, Tsukuba, Japan d Department of Epidemiology and Environmental Health, Juntendo University School of Medicine, Tokyo, Japan Available online 21 August 2004 Abstract Background. This prospective cohort study examined the association between educational level and major causes of death in Japan. Method . A baseline survey was conducted between 1988 and 1990 among 110,792 inhabitants of 45 areas aged 40–79 years. Follow-up surveys were conducted annually and causes of death were identified from death certificates. The analysis was restricted to 16,715 men and 23,284 women. Results . During the follow-up period (377,139 person-years), 6628 deaths were recorded. Individuals with low levels of education had an increased overall risk of death [relative risk (RR) = 1.16, 95% confidence interval (CI): 1.08, 1.25, in men; RR = 1.26, 95% CI: 1.14, 1.39, in women], cancers (RR = 1.17, 95% CI: 1.04, 1.32, in men; RR = 1.10, 95% CI: 0.93, 1.30, in women), and death from external causes (RR = 1.81, 95% CI: 1.29. 2.54, in men; RR = 1.78, 95% CI: 1.18, 2.70, in women). Ischemic heart disease risk was marginally reduced in men with low levels of education (RR = 0.77, 95% CI: 0.58, 1.01). Conclusions . These results show that health inequalities exist in Japan, even though wealth inequalities are relatively low. Social and political initiatives will be needed to correct these inequities between different socioeconomic statuses. D 2004 The Institute For Cancer Prevention and Elsevier Inc. All rights reserved. Keywords: Japan; Prospective study; Education; Socioeconomic determinants of health; Mortality; Cancer; Coronary heart disease; External death Introduction Socioeconomic status is commonly used as a proxy for environmental and lifestyle factors that relate to health status [1]. This approach initially attempted to identify biological causal relationships between environmental factors, lifestyle factors, and diseases. However, socio- economic status has recently been recognized as a determi- nant of health, which is of relevance to the design of prevention strategies and health policies. Occupation, income, and education are often used as indices of socio- economic status. However, previous reports have consis- tently shown that members of the higher socioeconomic group have better health status, regardless of the values of these indices [2–5]. 0091-7435/$ - see front matter D 2004 The Institute For Cancer Prevention and Elsevier Inc. All rights reserved. doi:10.1016/j.ypmed.2004.07.002 * Corresponding author. Department of Clinical Epidemiology, Insti- tute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishiku, Kitakyushu 807- 8555, Japan. Fax: +81 93 603 0158. E-mail address: zenq@med.uoeh-u.ac.jp (Y. Fujino). 1 See acknowledgments for the investigators (name and affiliation) involved in the JACC Study. Preventive Medicine 40 (2005) 444 – 451 www.elsevier.com/locate/ypmed