Validation of a simple tool to assess risk of waterpipe tobacco smoking among sixth and seventh graders in Lebanon.

Waterpipe tobacco smoking (WTS) is highly prevalent in the Eastern Mediterranean region. While studies have identified socio-demographic factors differentiating smokers from non-smokers, validated tools predicting WTS are lacking. Over 1000 (n = 1164) sixth and seventh grade students in Lebanon were randomly assigned to a prediction model group and validation model group. In the prediction model group, backward stepwise logistic regression enabled the identification of socio-demographic and psychosocial factors associated with ever and current WTS. This formed risk scores which were tested on the validation model group. The risk score for current WTS was out of four and included reduced religiosity, cigarette use and the perception that WTS was associated with a good time. The risk score for ever WTS was out of seven and included an additional two variables: increased age and the belief that WTS did not cause oral cancer. In the validation model group, the model displayed moderate discrimination [area under the curve: 0.77 (current), 0.68 (ever)], excellent goodness-of-fit (P > 0.05 for both) and optimal sensitivity and specificity of 80.1 and 58.4% (current), and 39.5 and 94.4%, (ever), respectively. WTS use can be predicted using simple validated tools. These can direct health promotion and legislative interventions.