Perceived smoking prevalence was associated with smoking among primary school students in Hong Kong

Objectives:  To examine the relation of perceived peer smoking prevalence with smoking behavior and intention among primary students.

Methods:  In 2008, primary 4 to 6 students in 14 randomly selected schools completed an anonymous questionnaire.  Smoking status was categorized as current (at least <1 cig/week), former (smoked any numbers of cigarettes but not any more) and ever (current and former smoker) versus never.  Intention to smoke when grown up (yes versus no) was recorded.  Perceived peer smoking prevalence among all primary school students was classified as over-estimated (half) and grossly over-estimated (most/all) versus under/accurately estimated (none/some).  Data were weighted by census school grade distribution.  Logistic regression was used to calculate the odds ratios (ORs) for smoking behavior and intension adjusting for socio-demographic characteristics and taking into account clustering effect of schools.

Results:  Among 3995 never and 257 ever-smoker, 73.3% under-estimated or accurately estimated, 16.4% over-estimated and 10.3% grossly over-estimated the prevalence of peer smoking.  The adjusted current smoking ORs (95% CI) for over-estimation and gross overestimation were 1.30(0.42-4.08) and 5.56(1.88-16.4) (P for trend <0.001).  The corresponding ORs for former and ever smokers were 1.87(1.22-2.84), 5.81(4.41-7.65) and 1.80(1.26-2.58), 5.75(4.19-7.88), respectively, (all p for trend <0.01).  Over-estimation and gross over-estimation were positively associated with smoking intention (P<0.05).

Conclusions:  Over-estimating peer smoking prevalence was positively associated with smoking and intention to smoke in primary students.  Prospective studies are needed to examine the temporality of the association and trials are needed to investigate the effects of correcting perceived prevalence of smoking on smoking behaviours and intention.

Funding: The Hong Kong Council on Smoking and Health