Nitrate in community water supplies and incidence of non-Hodgkin's lymphoma in Sardinia, Italy. (Short Report).

Studies of non-Hodgkin's lymphoma (NHL) evaluating risk associated with nitrate concentrations in community water supplies have found inconsistent results. (1-4) To further explore this hypothesis, we compared the NHL incidence in 1974-1993 with nitrate monitoring data from 1971-1994 available for 75% (282 of 376) of the communes (administrative units) in Sardinia, Italy.

METHODS

We selected the 153 communes with at least one nitrate measurement in 1993 or earlier (median: 5 measurements; range: 1-51) after excluding the six major urban areas. The population of these 153 communes ranged from 140 to 61 636 (median: 2459) and included a population of 703 000 (41% of the Sardinian population). There were a total of 3909 nitrate measurements. The nitrate ion was measured by spectrophotometry with the sodium salicilate method. For our primary analysis, we used the average nitrate concentration in 1993 as the exposure metric. Fifteen communes (23% of the study population), also had nitrate data in 1971-84. For these we also evaluated the median concentration in 1971-84. NHL incidence in 1974-1993 was determined by commune from the registries of all pathology and haematology …