BACKGROUND: Echocardiographically detected left ventricular(LV) hypertrophy is a risk factor for cardiovascular morbidity and mortality. A better understanding of the determinants of LV mass may aid in strategies directed toward the promary and secondary prevention of LV hypertrophy and its consequences. Previous studies have reported that male gender, arterial blood pressure(BP), obesity, age, aortic valvular stenosis, dietary sodium, endocrine factors, and physical activity are positively correlated with LV mass. Of these determinants male gender, hypertension, and obesity are well known but age and blood pressure in healthy adults are controversial. To assess the determinants of LV mass, the relation of 2-dimensional(2D) echocardiographically determined LV mass to body mass inedx(BMI), age, sex, casual BP, and 24 hour ambulatory blood pressure(ABP : systolic, diastolic, and mean BP of 24 hour, day-time, and night-time) was examined in healthy adults. METHODS: The study population consisted of 200 healthy adults who were normotensive, nonobese, and had no evidence of cardiovascular disease(range in age from 20 to 69 years, five decades, 20 men and 20 women per each decade). LV mass was derived from area length method measurements obtained by 2D echocardiography and corrected for height. ABP monitoring was performend over 24 hour(divided into day-time(6am-10pm) and night-time(10pm-6am)periods) with 30 minute inervals. RESULTS: 1) BMI was significantly and independently related to LV mass corrected for height (p<0.001, partial R2=0.31 in men and 0.43 in women). An increase of BMI by 1 kg/m2increased LV mass corrected for height by 1.9g/m in men and 2.0g/m in women. 2) Age was significantly and independently related to LV mass corrected for height(p<0.001, partial R2=0.15 in men and 0.17 in women). The increments of Lv mass corrected for height per decade were 2.1 g/m in men and 3.4 g/m in women. 3) Gender was significantly and independently related to LV mass corrected for height(p<0.001, partial R2=0.12), which was greater in men than in women by 6.34g/m. 4) Casual Bp and 24 hour ABP were not significantly associated with LV mass corrected for height in total population and women, and 24 hour systolic BP was significantly related to LV mass corrected for height only in men(p<0.001) with weak partial R2(0.05). CONCLUSION: BMI, age, and male gender were statistically significant and independent correlates of LV mass corrected for height(p<0.001). Maintenance of ideal body weight and normal BP, weight reduction in obese persons and BP control inhypertensive patients may contribute to the primary and secondary prevention of LV hypertrophy and its sequalae.