Objective: In order to prevent ischemic heart disease in working adult males, we analyzed risk factors by age groups based on data from an eight-year follow-up study of male employees enrolled in the Denso Health Insurance Program.
Subjects and methods: Of the 27,945 male employees aged 30 to 55 enrolled in the program in 2003, the data of 19,742 (70.6%) who underwent regular health checkups were analyzed. Information obtained from health insurance claims for hospitalization and cause of death from discontinuation data were used to analyze risk factors for ischemic heart disease by age group. Hazard ratios and 95% confidence intervals were estimated from Cox proportional-hazards models.
Results: In males aged 30-39 years, a BMI of 25.0-27.5 was associated with a 2.21 higher risk of ischemic heart disease (95%CI: 1.01-4.84) than those not overweight (BMI of <25.0); LDL of 160 mg/dl or more was associated with a 3.85 higher risk (95%CI:1.62-9.14) than LDL of less than 120 mg/dl; and FPG of 160 mg/dl or more was associated with a 6.43 higher risk (95%CI: 1.02-40.63) than a FPG of less than 110 mg/dl. For males aged 40-55 years, higher LDL was a risk factor of ischemic heart disease (1.95 (95%CI: 1.28-2.98) and 1.97 (95%CI: 1.34-2.90) for LDL of more than 160 mg/dl and 140-159 mg/dl, respectively), compared to those with LDL of less than 120 mg/dl. In the same age group, compared to those unaffected, the risk of ischemic heart disease was 1.94 times higher (95%CI: 1.27-2.97) and 1.61 times higher (95%CI: 1.08-2.40) for those treated for hypertension and hyperlipidemia, respectively. Furthermore, compared to non-smokers, those smoking more than 20 cigarettes a day had 3.12 higher risk (95%CI: 1.21-8.06) and 1.81 higher risk (95%CI: 1.25-2.62) of ischemic heart disease in the 30-39 and 40-55 years age groups, respectively. Interaction effects with age group were not significant.
Discussion: In males aged 30-39 years having a high BMI, LDL, FPG, and smoking more than 20 cigarettes increased the risk of ischemic heart disease. For males aged 40-55 years taking medication for hypertension and hyperlipidemia increased the risk. To prevent ischemic heart disease during the prime of life, offering support for weight control and stopping smoking is necessary in younger age groups. Moreover, implementing a long-term risk management plan to prevent the onset of hypertension, diabetes, or hyperlipidemia is also important.