Some 6,820 Salt Lake County residents will be among the more than 1.2 million citizens nationwide contacted next month as part of the third and final follow-up in the largest cancer-prevention study ever conducted by the American Cancer Society.

The study, called Cancer Prevention Study II, was initiated in 1982 and has had follow-ups in 1984 and 1986. Many of the findings from those follow-ups have been published, including a report on changing smoking habits among Americans and the relationship of personal weight to cancer occurrences.This final follow-up is expected to provide sufficient data for the society to establish credible mortality figures for various forms of cancer. An analysis of many other suspected cancer risk factors will also be made, and the results of those studies will be published later.

Among the items researchers will be studying are American eating habits, with a focus on the consumption of those foods thought to pose lower cancer risks. The researchers will also evaluate the public's use of drug and vitamin products and the effects of occupational exposures.

The first cancer-prevention study was conducted from 1959 through 1965 with an extension of the study through 1972. That study identified many factors related to the development of cancer and other diseases.