Longitudinal patterns of tobacco smoking from childhood to middle age.

This study described the development of tobacco smoking of subjects between ages 12 and 36 using prospectively collected self-reports of 212 Swedish men and women born in the 1950s. Smoking habits were studied in terms of stability, longitudinal patterns of smoking, and the relation between age of initiation and later smoking. Findings showed that light smoking (up to 6 cigarettes/day) did not remain stable after adolescence. Typical development patterns from age 15 to age 36 included staying a nonsmoker; smoking intensely (>10 cigarettes/day) and continuing into adulthood; smoking less intensely for some periods; or smoking intensely and quitting before age 36. Differences in age at smoking initiation were related to later habitual smoking only when participants reported initiation had occurred after age 12.