Adult smokeless tobacco use and age of onset.

To determine if an earlier age of onset is associated with greater levels of adult smokeless tobacco (SLT) use and to evaluate if this relationship differs by SLT type, 345 current adult SLT users were interviewed to obtain the age at first onset and current frequency of SLT use. The results indicated that more than twice as many SLT users began during adulthood than during preadolescence. Although preadolescent onset was associated with greater chewing tobacco use than adolescent onset, the greatest levels of both chewing tobacco and snuff use were associated with adult onset, suggesting an increased need for SLT prevention programs for young adults.