Smoking socio-economic inequalities in school-aged teenagers from six European Cities: the role of social network: Vincent Lorant Free

Background

In Europe, smoking accounts for a large share of health socio-economic inequalities. As smoking initiation occurs around 13 years old, it is likely that social ties at school play an important role in it. The SILNE study is an international social network survey achieved in 6 European Cities (Namur, Tampere, Hannover, Latina, Amersfoort, Coimbra) to study how social ties at school explain smoking inequalities. We test two hypotheses: (1) smoking socio-economic inequalities result from peer exposure to smoking at school, and (2)the contribution of such peer exposure to smoking depends on the school context.

Methods

A social network survey was carried out in 2013 in six medium size European Cities In each city, 6 to 8 schools were selected and all adolescents from two grades (14-16 years old) were invited to participate to a social network survey. Each adolescent had to nominate up to 5 of his best friends. 11,015 adolescents from 50 schools were recruited (participation rate = 77%). Peer exposure was measured by the number of smokers in the 1st, 2nd and 3rd-degrees separations friends. We examined the school context on three issues: magnitude of the peer-smoking clustering (using clustering Moran’I coefficient), the school traking (vocational versus non-vocational) and tobacco control policies enforcement (low enforcement vs high enforcement).

Results

Nineteen percent of the adolescent were regular smoker. On most socio-economic status (SES) measurements, the higher the SES, the lower the adolescent was exposed to friends' smoking. Socio-economic inequalities in smoking was explained by this network exposure to smoking. At the school-level, we found strong evidence that smoking prevalence and peer-effect vary greatly across schools: higher SES schools display lower smoking prevalence and more social clustering of smokers compared with low SES schools (F ≥ 11.6; p < 0.001).

Conclusions

Despite smoking bans, there is strong evidence that smoking inequalties remain an issue at school in Europe: smoking still spreads through peer influence, and expose more schools hosting more low SES teenagers.

Key messages

• Smoking is a major contributor to health inequalities.

• School and social network are major drivers of smoking inequalities.