The first analysis to test this prediction was that of Kloog et al." from lsrael. They combined into regres- sion models breast cancer incidence in 147 commu- nities with satellite data on nocturnal illumination from the same communities, as well as information per ira income, population density, birth rate and ethnic makeup. They also modelled lung cancer incidence as a 'negative control' as a test of the spe- cificity of their method Nocturnal community Jight level was significantly associated with breast Cancer incideneer and the model, the highest LAN intensity community had a 73% higherineaans I than the lowest. was n association of LAN and lung cancer incidence This result is a necessary but not sufficient condition for causality.