Objective: In Japan, high blood pressure (high BP), hyperlipidemia (HL), and high blood glucose (high Glu) are atherosclerotic risk factors for cardiovascular disease in not only obese, but also non-obese individuals. The present study examined the effects of obesity and atherosclerotic risk factors on the incidence of cerebrovascular disease (CVD) and ischemic heart disease (IHD).

Methods: We analyzed 35,026 individuals in the Osaka Municipal Employees' Mutual Aid Association (Mutual Aid Association) who periodically underwent specific health check-ups between 2014 and 2020 and did not have cardio-cerebrovascular diseases at baseline. Subjects were divided into two groups based on abdominal circumference and BMI: obese (abdominal circumference ≥85 cm in men and ≥90 cm in women or BMI ≥25 kg/m²) and non-obese. Atherosclerotic risk factors (the risk) were defined as high BP (Systolic BP (SBP) ≥130 mmHg or Diastolic BP (DBP) ≥85 mmHg), HL (Triglyceride ≥150 mg/dL or HDL cholesterol (HDL-C) <40 mg/dL), and high Glu (fasting blood glucose (Glu) ≥100 mg/dL or HbA1c (NGSP) ≥5.6%) according to the criteria of Specific Health Guidance in Japan. The risk was also examined in the non-obese group using the criteria of the Mutual Aid Association, which were set higher than those of Specific Health Guidance (SBP ≥140 mmHg or DBP ≥90 mmHg, Triglyceride ≥300 mg/dL or LDL-C ≥140 mg/dL, Glu ≥110 mg/dL or HbA1c (NGSP) ≥6.0%). An event history analysis (discrete time logit model) was performed to investigate the relationship between the incidence of cardiovascular disease (CVD and IHD) and atherosclerotic risk factors adjusted for age, sex, and years of follow-up, stratified by the obesity status.

Results: CVD and IHD occurred in 916 and 800 individuals, respectively. Regarding CVD in the non-obese group, a correlation with the risk was observed for both Specific Health Guidance (OR: 1.22, 95%CI: 1.01-1.48, p=0.038) and the Mutual Aid Association (OR: 1.67, 95%CI: 1.39-2.01, p<0.001). Similarly, for IHD, Specific Health Guidance (OR: 1.40, 95%CI: 1.13-1.74, p=0.002) and the Mutual Aid Association (OR: 1.38, 95%CI: 1.12-1.70, p=0.003) both correlated with the risk.

Conclusion: Even in the non-obese group, the presence of risk factors for atherosclerosis, not only meeting the criteria for the incidence of lifestyle-related diseases, but also at a level below that threshold, was associated with an increased risk of CVD and IHD. Therefore, the appropriate management of blood pressure, lipids, and blood glucose among not only obese, but also non-obese individuals is important for the prevention of cardiovascular diseases.