A novel approach to assessing family history in the prevention of coronary heart disease.

Family history serves as the most important risk factor in prevention of coronary heart disease from youth. Prevalent methods of assessing family history, however, have serious drawbacks: a sudden rise of risk when a family member develops the disease; insufficient control for age among family members. We propose a simple quantitative method overcoming such drawbacks. Data on family history were obtained by questionnaires sent to 2,393 male high school students and their cholesterol levels were measured. Family risk from each family member was calculated by (30/Risk age)4, where the risk age was age at onset expressed by decade; if absent, it was replaced by present age or age at death. A mean score in a family served as the family risk. A total of 1,584 students and 17,127 family members were analyzed. The proposed method yielded a statistically significant association (Odds ratio = 1.60; 95% confidence interval: 1.15-2.25) between the family risk (above or below the median) and the student's atherogenic index (above or below the 90th percentile) calculated from cholesterols. This association was stronger than those by conventional methods. The proposed method may be useful in prevention activities and its efficiency needs to be confirmed in other studies.