The Research Group ATS-RF2 of the Italian National Research Council (Medicina Preventive CNR, II Clinica Medica, Università di Bari, 70124 Bari, Italy). Distribution of some risk factors for atheroscierosis in nine Italian population samples. Am J Epidemiol 1981; 338–46. Nine population samples of randomly chosen men and women aged 20–59 years in eight regions of Italy, for a total of 6699 Individuals (overall participation, 62%), were examined to determine the mean levels and distribution of some risk factors of atherosclerosis. Large differences between areas were shown to exist, with decreasing mean levels of serum cholesterol and blood pressure observed from north to south and to the Islands of Sicily and Sardinia. Decreases in the same geographic direction, confined to women, were found in the prevalence of smokers and in the number of cigarettes smoked per day, while an opposite but less clear trend was suggested for men. No evident geographic trend was demonstrated for serum triglyceride which, however, exhibited large Inter-area differences. A regular increase with increasing age has been observed for serum cholesterol, triglyceride and blood pressure, but not for smoking. The overall age-standardized mean levels for the factors considered in this preliminary report are as follows: cholesterol—men 211 mg/di, women 205 mg/di; triglyceride—men 133 mg/di, women 99 mg/di; systolic blood pressure—men 132 mmHg, women 131 mmHg; diastolic; blood pressure—men 65 mmHg, women 83 mmHg; prevalence of smokers—men 55%, women 26%; cigarettes per day among smokers—men 19, women 11; cigarettes per day in the whole population—men 10, women 3. Although such samples are not necessarily representative, since they depend, among other things, on participation rates, the regional differences observed here tend to run parallel to the regional differences of official death rates for coronary disease.