Of the total 981 parents who were enrolled in 10 PROS control practices, 817 reported having a car. The majority (70%) of the parents were in the age group 25 to 44 years, 77% were females, mostly mothers (98% vs 2% legal guardians), and 68% were non-Hispanic whites. Many parents (42%) had only a high school degree, and 16% had completed college. Most of the children (60%) were covered by Medicaid ().
Parent Characteristics (N = 817)
Of the 817 parents who reported having a car, 795 answered questions about their car smoking policy. Of these 795 parents, 73% reported that someone had smoked in their car in the past 3 months (). Fewer than 1 in 3 parents (29%) reported having a smoke-free car policy, and only 24% reported having a strictly enforced smoke-free car policy, which is less than one-half the parents who reported having a strictly enforced smoke-free home policy (57%). There was some geographic variability in the number of parents reporting strictly enforced smoke-free car policies across the 8 states. It ranged from 16% in Virginia (mean of 3 practices) to 39% in Connecticut; the other states were as follows: Tennessee, 17%; Missouri, 23%; New Mexico, 24%; Pennsylvania, 28%; South Carolina, 31%; and Alaska, 33%. Eighty-two percent of parents who reported having a strictly enforced smoke-free car policy also reported having a strictly enforced smoke-free home policy. However, the majority (66%) of those with a smoke-free home policy do not have a strictly enforced smoke-free car policy. Almost 1 in 5 parents who had a smoke-free car policy reported that it was violated in the past 3 months. Of the 562 parents who did not report having a smoke-free car policy, 48% reported that smoking occurred with children present in the car.
Parental Smoking Behavior in Cars and Pediatrician Assistance (N = 795)
Approximately one-fifth of all enrolled parents reported being asked by a pediatric health care provider about their smoking status (). Only 14% of smoking parents reported being asked if they had a smoke-free car, and even fewer (12%) reported being advised to have a smoke-free car policy by a pediatric health care provider. Of those who smoked with children present in the car, only 5% were counseled about having a smoke-free car. Of those who were advised to have a smoke-free car policy, 54% identified the reason for the visit as a routine well-child visit and 34% as a sick visit.
Bivariate analysis () showed that having a child <1 year old and smoking fewer cigarettes per day were associated with having a strictly enforced smoke-free car policy. Having another smoker at home was associated with a lower likelihood of having a strictly enforced smoke-free car policy. We did not find any association between parent’s age, race and ethnicity, education, and intention to quit smoking with having a strictly enforced smoke-free car policy. In the multivariable logistic regression model (), we confirmed that factors associated with greater likelihood of having a strictly enforced smoke-free car policy were having a child <1 year old versus ≥1 year (OR: 1.64 [95% CI: 1.14–2.34]) and parents smoking ≤10 cigarettes per day versus >10 cigarettes per day (OR: 3.59 [95% CI: 2.45–5.26]). Having another smoker in the home versus not having another smoker at home was associated with a lower likelihood of having a strictly enforced smoke-free car policy (OR: 0.56 [95% CI: 0.35–0.89]). The model fit was acceptable with a C statistic of 0.70.
Strictly Enforced Smoke-Free Car Policy by Parent and Child Characteristics (N = 795)
Multivariable Logistic Regression Showing Odds of Having a Strictly Enforced Smoke-Free Car Policy (N = 793)
In the exploratory analyses, we arrived at a final model after considering all possible interactions between the 4 parent demographic variables (age, gender, race, and education) and the 3 significant predictors of car policy (child’s age, number of cigarettes smoked per day by the parent, and having another smoker at home). Parent gender and education interacted with child’s age: parents of children aged <1 year were more likely to have strict smoke-free car policies if they were female (OR: 3.00 [95% CI: 1.22–7.38], P = .016) or college educated (OR: 2.42 [95% CI: 1.21–4.83], P = .013). Strict smoke-free car policies were more common when parents were both light smokers (smoked ≤10 cigarettes per day) and college educated (OR: 2.88 [95% CI: 1.24–6.66], P = .013). No other interactions were statistically significant. The model fit was acceptable with a C statistic of 0.71.