Environmental exposure to tremolite and respiratory cancer in New Caledonia: A case-control study

A case-control study on respiratory cancers was conducted in New Caledonia (South Pacific), where a high incidence of malignant pleural mesothelioma h ad been observed. The disease pattern suggested an environmental exposure t o asbestos. The first results showed that, in some areas, tremolite asbesto s derived from local outcroppings was used as whitewash (locally named "po" ). All cases diagnosed between 1993 and 1995 (including 15 pleural mesothel iomas, 228 lung cancers, and 23 laryngeal cancers) and 305 controls were in cluded in the study. Detailed information on past or present use of the whi tewash, residential history, smoking, diet, and occupation was collected. T he risk of mesothelioma was strongly associated with the use of the whitewa sh (odds ratio (OR) = 40.9; 95% confidence interval (CI): 5.15, 325), All M elanesian cases had been exposed. Among Melanesian women, exposure to the w hitewash was associated with an increased risk of lung cancer (OR = 4.89; 9 5% CI: 1.13, 21.2), and smokers exposed to po had an approximately ninefold risk (OR = 9.26; 95% CI: 1.72, 49.7) compared with women who never smoked and had never used the whitewash, In contrast, no association was noted bet ween exposure to po and lung cancer risk among Melanesian men, probably bec ause of lower exposure levels. Among non-Melanesians, the numbers of expose d subjects were too small to assess the effect of exposure to po. There was no indication of elevated risks for the other cancer sites.