Ecological investigations on arsenic dietary intake and endemic chronic poisoning in man: dose-response curve.

The city of Antofagasta (northern Chile), is an area of endemic chronic arsenic poisoning due to arsenic-polluted drinking water. In order to explore the possibility of a dose-response relationship, a dietary survey was carried out in 1972 in that city for measuring the daily fluid intake in the various age groups. The sample (N = 220) included 13 males and 13 females in each age group, except the 81-90 year-old group with 6 males and 6 females. A linear relationship was found between arsenic dose (mg/kg body weight/day) and age for males being P less than 0.001 (slope) and r = -0.6712; and for females P less than 0.001 (slope) and r = 0.6667. Age-specific prevalence rates per 100,000 population (both sexes combined) for chronic arsenic poisoning in Antofagasta Commune for the 1968-71 period, were plotted against mean arsenic doses (mg/kg body weight/day) by age group. A dose-response curve was computed, being F = 83.19, d.f. = 1,7 and P less than 0.01 (slope). The correlation coefficient was + 0.9604.