Influence of siblings on student smoking patterns

Questionnaires on the smoking habits of school children, their parents, and their siblings were completed by 6,810 students (91%) in the public high school system of Newton, Massachusetts. Smokers tend to come from larger families than do nonsmokers. The larger sibship size results from smokers having more older siblings rather than more younger siblings. Frequency of smoking is much higher among children who are members of families in which there is an older sibling who smokes than among children of families where there are older siblings who do not smoke or where there are no older siblings. The risk of smoking to the index child does not vary with the sex of the older sibling to whom he is exposed. Older siblings who do not themselves smoke exert a slight deterrent effect on student smoking. These findings, together with earlier reports of the influence of parental smoking habits on the smoking patterns of children, are consistent with general concepts of the motivation of American (and perhaps all) teen-agers. They raise questions as to the advisability of health-education campaigns directed exclusively at children.