Teenage smoking behavior influenced by friends’ and parents’ smoking habits

April 12, 2013

New research from the Keck School of Medicine of USC highlights opportunities for smoking intervention programs

LOS ANGELES — The company you keep in junior high school may have more
influence on your smoking behavior than your high school friends,
according to newly published research from the University of Southern
California (USC).

The study, which appears in the April 12 issue of the Journal of Adolescent Health,
identifies how friends’ and parental influence on cigarette smoking
changes from junior high to high school.

The research indicates that intervention targets to counteract friends’
influence may have more of an effect in junior high than in high
school, and that parents remain influential on smoking behavior through
high school, indicating another possible intervention target, the
researchers said.

“Based on social developmental model research, we thought friends would
have more influence on cigarette use during high school than junior
high school,” said first author Yue Liao, M.P.H., a doctoral student in the department of preventive
medicine’s Institute for Health Promotion and Disease Prevention
Research (IPR) at the Keck School of Medicine of USC. “But what we found was friends have
greater influence during junior high school than high school. We think
the reason may be that friends’ cigarette use behavior may have a
stronger influence on youth who start smoking at a younger age. During
high school, cigarette use might represent the maintenance of behavior
rather than a result of peer influence.”

Researchers analyzed the first seven waves of longitudinal data from
1,001 adolescents who participated in the Midwestern Prevention Project
(MPP), a community-based substance abuse prevention program. Mary Ann Pentz,
Ph.D., professor of preventive medicine and director of the Institute
for Health Promotion and Disease Promotion, is the primary investigator
of that trial, and a co-author of the current study. MPP is the longest
running substance use prevention, randomized controlled trial in the
U.S.,; its multi-component community-based program is listed on several
national registries for evidence-based substance use prevention. The
full trial followed adolescents from age 11 to adulthood, specifically
age 37. Participants were first observed in the seventh grade — during
junior high school — and then again after six months, and then
annually through the 12th grade, during high school. Students were
asked to indicate the number of close friends and parents, or two
important adults, who smoked cigarettes. They were also asked how many
cigarettes they had smoked in the last month. The effects of friends’
and parents’ cigarette use on self-use were assessed from early to late
adolescence in order to identify changes in trends and magnitude.

Results confirmed that overall, both friends’ and parental cigarette
use had significant effects on adolescents’ cigarette use during both
junior high school and high school. However, while friends’
influence was generally higher in junior high school than in high
school, parental influence remained relatively stable between these two
periods, with a decreasing trend from 10th to 12th grade. This finding
confirms previous research that suggests social units, such as school
or community, may exert more influence on youth behavior than parents
in high school.

The researchers also observed gender differences in friends’ and
parental influence. Friends’ influence on cigarette smoking was greater
for girls than boys during ninth and 10th grade. However, there was an
increasing trend in friends’ influence from ninth to 11th among boys
whereas friends and parents had less influence on girls from 10th to
12th grade.

“Boys tend to foster friendship by engaging in shared behaviors,
whereas girls are more focused on emotional sharing. So, it is possible
that boys are adopting their friends’ risky behaviors, like smoking, as
the groups grow together over time,” Liao said.

The observations from this study present opportunities for intervention
and may help to guide the implementation of adolescent smoking
prevention programs, Liao said.

“We observed a big dip in friends’ effect on smoking behavior from
eighth to ninth grade. Thus, the first year of high school represents
an opportunity for interventions to counteract peer influence and to
continue to target parents as their behavior remains influential
through the end of high school,” Liao said. “In addition, teaching
students refusal skills during junior high school could be effective in
decreasing cigarette use at the beginning of high school. Programs
could also promote positive parenting skills to protect children from
deviant peer influence.”

Liao suggests future research on sibling effects for a more complete
picture of familial influence. The current study assessed sibling
behavior only during junior high school.

Other USC co-authors include Zhaoqing Huang, M.D., M.A, a doctoral
student in the department of preventive medicine, Institute for Health
Promotion and Disease Prevention Research; Jimi Huh, Ph.D., assistant
professor of research for the Institute for Health Promotion and
Disease Prevention Research; and Chih-Ping Chou, Ph.D., professor of
preventive medicine.

Funding for the research came from the National Institutes of Health
(grant number R01-DA-027226, Chou, PI).

Liao, Y., Zhaoqing, H., Huh, J., Pentz, M.A., Chou, C.P. (2013) Changes
in friends’ and parental influences on cigarette smoking from early
through late adolescence. Journal of
Adolescent Health
. Published online April 12, 2013.

Contact: Leslie Ridgeway at (323) 442-2823 or lridgewa@usc.edu;
Molly Rugg (323) 442-2548 or mrugg@usc.edu