Incubation period of coronary heart disease.

Serum cholesterol concentrations and blood pressure were measured during 1958-64 among men aged 40-59 who took part in the Seven Countries Study. In the present study these measurements were related to the national mortality from coronary heart disease in the periods 1959-61, 1964-6, 1969-71, and 1974-6. The correlations increased with time (r = +0.86, 0.90, 0.93, and 0.96 respectively for serum cholesterol concentration and r = +0.48, 0.56, 0.57, and 0.64 for systolic blood pressure), suggesting that the "incubation period" between exposure to major coronary risk factors and the maximum effects on mortality may be 10 years or more.