Youth daily exposure to tobacco outlets and cigarette smoking behaviors: does exposure within activity space matter?

To examine whether daily exposure to tobacco outlets within activity spaces is associated with cigarette smoking and with the number of cigarettes smoked by youth that day.

The study used geographic ecological momentary assessment (GEMA) data that combined daily surveys with ecological momentary assessment of global positioning systems (GPS) using geographic information systems (GIS) to allow for real-time data collection of participants' environments and behaviors.

Eight mid-sized California (USA) city areas.

The analytical sample included 1065 days, which were clustered within 100 smoker and non-smoker participants (aged 16-20 years, 60% female).

Any cigarette smoking and number of cigarettes smoked on a given day, the number of tobacco outlets within 100 m of activity space polylines each day, the number of minutes participants spent within 100 m of tobacco outlets each day and demographic characteristics (age, sex, race/ethnicity and perceived socio-economic status).

Controlling for demographic characteristics, the findings of multi-level mixed effects logistic models were inconclusive, whether or not the number of tobacco outlets within 100 m of youths' activity space polylines or the number of minutes spent within 100 m of tobacco outlets were associated with whether the participant smoked cigarettes on a given day [odds ratio (OR) = 1.05, P = 0.24; OR = 0.99, P = 0.81, respectively]. However, in multi-level zero-inflated negative binomial models, the risk of smoking an additional cigarette on a given day increased with each additional tobacco outlet [incidence rate ratio (IRR) = 1.04, P < 0.05] and each additional minute spent within 100 m of tobacco outlets (IRR = 1.01, P < 0.001) each day.

Among young people in urban California, differences in day-to-day exposure to tobacco outlets within activity spaces does not seem to be significantly associated with whether a person smokes a cigarette on a given day, but higher exposure to tobacco outlets appears to be positively associated with the number of cigarettes smoked on that day.