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Medicine (Baltimore). 2015 May;94(17):e785. doi: 10.1097/MD.0000000000000785.

Hemoglobin a1c levels and the risk of cardiovascular disease in people without known diabetes: a population-based cohort study in Japan.

Author information

1
From the Departments of Diabetes Research, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan (AG, MN, MG, MK); Department of Public Health, Tokyo Women's Medical University, Tokyo, Japan (AG); Departments of Clinical Research (YM) and Epidemiology and Prevention (KK, AN, TM), National Center for Global Health and Medicine, Tokyo, Japan; Department of Internal Medicine, Mitsui Memorial Hospital, Tokyo, Japan (AI); Division of Diabetes and Metabolism, Iwate Medical University School of Medicine, Iwate, Japan (YT); Department of Health Promotion, National Institute of Public Health, Saitama, Japan (SO); Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan (KY); Department of Public Health, Fujita Health University, Aichi, Japan (HY); Department of Basic Nursing and Health Science, Ehime University Graduate School of Medicine, Ehime, Japan (IS); Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, Osaka, Japan (YK); Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan (NS, ST); AXA Department of Health and Human Security (MI) and Diabetes and Metabolic Diseases (TK), Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Public Health, Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, Osaka, Japan (HI).

Abstract

High hemoglobin A1c (HbA1c) levels are strongly associated with an increased risk of cardiovascular disease (CVD) in people with and without diabetes. However, information regarding the relationship between low HbA1c levels and the risk of CVD among people without known diabetes is limited. The aim of this large-scale, prospective, population-based cohort study was to clarify the association between HbA1c levels and CVD risk among people without known diabetes.We followed-up 10,980 men and 18,079 women (46-80 years old and free of CVD and cancer at baseline) in the Japan Public Health Center-based Prospective Study. Using Cox models, we estimated the hazard ratios for CVD risk with adjustments for age, sex, geographic areas, body mass index, smoking status, sports and physical exercise, alcohol intake, systolic blood pressure, non-high-density lipoprotein cholesterol, and high-density lipoprotein cholesterol.During the median follow-up of 9.4 years, 935 CVD events (770 strokes and 165 coronary heart diseases) occurred. We observed a nonlinear association between HbA1c levels and CVD risk in participants without known diabetes. Compared with HbA1c levels of 5.0 to 5.4% (31-36 mmol/mol), the hazard ratios for CVD in participants without known diabetes were 1.50 (95% confidence interval: 1.15-1.95), 1.01 (0.85-1.20), 1.04 (0.82-1.32), and 1.77 (1.32-2.38) for HbA1c levels of <5.0% (<31 mmol/mol), 5.5 to 5.9% (37-41 mmol/mol), 6.0 to 6.4% (42-47 mmol/mol), and ≥6.5% (≥48 mmol/mol), respectively (P value for nonlinear trend: <0.001). In addition, the hazard ratio for CVD was 1.81 (1.43-2.29) in patients with known diabetes compared with participants with HbA1c levels of 5.0 to 5.4% and without known diabetes. This nonlinear relation persisted after excluding people with kidney dysfunction, liver dysfunction, anemia, body mass index <18.5 kg/m, or early events within 3 years of follow-up (P value for nonlinear trend: <0.01 for all tests).In conclusion, both low and high levels of HbA1c were associated with a higher risk of CVD in a Japanese general population without known diabetes.

PMID:
25929925
PMCID:
PMC4603057
DOI:
10.1097/MD.0000000000000785
[Indexed for MEDLINE]
Free PMC Article

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