title: Cumulative impact of axial, structural, and repolarization ECG findings on long-term cardiovascular mortality among healthy individuals in Japan: National Integrated Project for Prospective Observation of Non-Communicable Disease and its Trends in the Aged, 1980 and 1990.
abstract: OBJECTIVE
  Various cohort studies have shown a close association between long-term cardiovascular disease (CVD) outcomes and individual electrocardiographic (ECG) abnormalities such as axial, structural, and repolarization changes. The combined effect of these ECG abnormalities, each assumed to be benign, has not been thoroughly investigated.
  
  
  RESULTS
  Community-dwelling Japanese residents from the National Integrated Project for Perspective Observation of Non-Communicable Disease and its Trends in the Aged, 1980-2004 and 1990-2005 (NIPPON DATA80 and 90), were included in this study. Baseline ECG findings were classified using the Minnesota Code and categorized into axial (left axis deviation, clockwise rotation), structural (left ventricular hypertrophy, atrial enlargement), and repolarization (minor and major ST-T changes) abnormalities. The hazard ratios of the cumulative impacts of ECG findings on long-term CVD death were estimated by stratified Cox proportional hazard models, including adjustments for cohort strata. In all, 16,816 participants were evaluated. The average age was 51.2 ± 13.5 years; 42.7% participants were male. The duration of follow up was 300,924 person-years (mean 17.9 ± 5.8 years); there were 1218 CVD deaths during that time. Overall, 4203 participants (25.0%) had one or more categorical ECG abnormalities: 3648 (21.7%) had a single abnormality, and 555 (3.3%) had two or more. The risk of CVD mortality increased as the number of abnormalities accumulated (single abnormality HR 1.29, 95% CI 1.13-1.48; ≥2 abnormalities HR 2.10, 95% CI 1.73-2.53).
  
  
  CONCLUSIONS
  Individual ECG abnormalities had an additive effect in predicting CVD outcome risk in our large-scale cohort study.
authors.affiliation: Keio University School of Medicine, Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Inohara
authors.affiliation: Keio University School of Medicine, Tokyo, Japan kohsaka@cpnet.med.keio.ac.jp.
authors.forename: Shun
authors.initials: S
authors.lastname: Kohsaka
authors.affiliation: Keio University School of Medicine, Tokyo, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Okamura
authors.affiliation: National Cerebral and Cardiovascular Center, Suita, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Kyoto Women's University, Kyoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Higashiyama
authors.affiliation: Osaka Kyoiku University, Kashiwara, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kadota
authors.affiliation: National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Nagako
authors.initials: N
authors.lastname: Okuda
authors.affiliation: Shiga University of Medical Science, Otsu, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Department of Hygiene and Public Health, Teikyo University School of Medicine, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.affiliation: Shiga University of Medical Science, Otsu, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Miura
authors.affiliation: First Institute for Health Promotion and Health Care, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Okayama
authors.affiliation: Shiga University of Medical Science, Otsu, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D044466:Asian People; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000208:ethnology / Q000401:mortality* / Q000503:physiopathology; D002423:Cause of Death; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
keywords: Cardiovascular outcomes; NIPPON DATA80; NIPPON DATA90; cohort study; electrocardiography