Associations between data for male lung cancer and female breast cancer within five countries.

Mainly on the basis of associations noted between international rates of male lung cancer and female breast cancer, passive smoking has been suggested recently as a major risk factor for female breast cancer. In this report, the authors describe the associations between data for female breast cancer and male lung cancer within five countries. For one country (Scotland) the authors examined the mortality rates of these cancers over time, and their relationship to trends for tobacco consumption. The correlations between female breast cancer and male lung cancer were significantly positive in Italy, USSR, and West Germany, weakly positive in Canada, absent in Scotland, and significantly negative in England and Wales. In Scotland, the mortality rates of these cancers over time were significantly correlated. There was a clear relationship between male lung cancer and tobacco consumption, but only a weak relationship between female breast cancer and tobacco consumption.