There may be differences in how they metabolize nicotine, which would influence smoking behaviors such as the depth and frequency of inhalation of tobacco smoke. There could be genetic factors on how they metabolize tobacco smoke.

The differences were more pronounced at lower levels of smoking, but all of these differences were highly statistically significant. At much higher levels of smoking, these racial and ethnic differences were modest, suggesting some type of saturation level of the carcinogenic effect.

We observed quite striking differences. This suggests there are racial and ethnic differences in the smoking-related risk of lung cancer.

The factors that explain these differences we don't know about.

But when you're talking about smoking, the message doesn't change; it stays the same. Elimination of smoking will reduce lung cancer incidence.

The Multiethnic Cohort offers clues in understanding the racial and ethnic differences in cancer incident rates.