AN ECOLOGICAL STUDY OF DIET AND LUNG-CANCER IN THE SOUTH-PACIFIC

Incidence rates of lung cancer have been markedly lower for Fiji than for other South Pacific countries, despite similar rates of smoking. W e conducted population-based surveys in several island nations of the South Pacific (Cook islands, Fiji, Tahiti and New Caledonia) and used data from Caucasian, Japanese, Hawaiian, Filipino and Chinese controls in a case-control study of lung cancer in Hawaii to investigate the r ole of diet in explaining differences in lung cancer incidence among 2 0 ethnic-sex groups. In a stepwise linear regression of lung cancer ra tes on smoking, diet and other variables, smoking, as expected, explai ned the majority (61%) of the variability in incidence. However, sever al dietary components also explained significant portions of the varia nce. Lutein intake explained 14% and vitamin E intake, cholesterol int ake and height explained 5-7% each of the remaining variance in incide nce. Associations with lutein and vitamin E were inverse, whereas thos e with cholesterol and height were direct. Dietary beta-carotene intak e was not associated with lung cancer incidence. These ecological data provide evidence for a protective effect of lutein against lung cance r. A protective effect of dietary vitamin E and a risk-enhancing effec t of dietary cholesterol are also suggested. (C) 1995 Wiley-Liss, Inc.