Background

There is evidence that children's decisions to smoke are influenced by family and friends.

Objectives

To assess the effectiveness of interventions to help family members to strengthen non‐smoking attitudes and promote non‐smoking by children and other family members.

Search methods

We searched 14 electronic bibliographic databases, including the Cochrane Tobacco Addiction Group specialized register, MEDLINE, EMBASE, PsycINFO and CINAHL. We also searched unpublished material, and the reference lists of key articles. We performed both free‐text Internet searches and targeted searches of appropriate web sites, and we hand‐searched key journals not available electronically. We also consulted authors and experts in the field. The most recent search was performed in November 2007.

Selection criteria

Randomized controlled trials (RCTs) of interventions with children (aged 5‐12) or adolescents (aged 13‐18) and family members to deter the use of tobacco. The primary outcome was the effect of the intervention on the smoking status of children who reported no use of tobacco at baseline. Included trials had to report outcomes measured at least six months from the start of the intervention.

Data collection and analysis

We reviewed all potentially relevant citations and retrieved the full text to determine whether the study was an RCT and matched our inclusion criteria. Two authors independently extracted study data and assessed them for methodological quality. The studies were too limited in number and quality to undertake a formal meta‐analysis, and we present a narrative synthesis.

Main results

We identified 22 RCTs of family interventions to prevent smoking. We identified six RCTs in Category 1 (minimal risk of bias on all counts); ten in Category 2 (a risk of bias in one or more areas); and six in Category 3 (risks of bias in design and execution such that reliable conclusions cannot be drawn from the study).

Considering the sixteen Category 1 and 2 studies together: (1) four of the nine that tested a family intervention against a control group had significant positive effects, but one showed significant negative effects; (2) one of the five RCTs that tested a family intervention against a school intervention had significant positive effects; (3) none of the seven that compared the incremental effects of a family plus a school programme to a school programme alone had significant positive effects; (4) the one RCT that tested a family tobacco intervention against a family non‐tobacco safety intervention showed no effects; and (5) the trial that used general risk reduction interventions found the group which received the parent and teen interventions had less smoking than the one that received only the teen intervention, and in the trial of CD‐ROMs to reduce alcohol use, both groups which received the alcohol reduction intervention had less smoking than the control. In neither trial was there a tobacco intervention, but tobacco outcomes were measured.

For the included trials the amount of implementer training and the fidelity of implementation are related to positive outcomes, but the number of sessions is not.

Authors' conclusions

Some well‐executed RCTs show family interventions may prevent adolescent smoking, but RCTs which were less well executed had mostly neutral or negative results. There is thus a need for well‐designed and executed RCTs in this area.