The detrimental effects of environmental tobacco smoke (ETS) exposure on child health have been well documented and include chronic respiratory symptoms, asthma, decreased lung function, and middle ear disease 123. Infants and young children exposed to maternal smoke are at especially high risk due to the intensity and duration of the exposure 4. In the United States, nearly 40% of children reside in homes where adults smoke and ETS exposure is even more common among children living in poverty 567.

Voluntary household smoking restrictions, and especially complete home smoking bans, can substantially reduce child ETS exposure 89101112. Studies evaluating smoking restrictions have found that U.S. Hispanic households are as likely or more likely to ban smoking in the home and automobile than non-Hispanic White households, and significantly more likely to ban smoking than African American households 1314. Few studies have examined automobile smoking bans among racial/ethnic groups, though existing data suggest that the prevalence of car smoking bans among U.S. Hispanics (67%) is similar to Whites, but higher than among African Americans (55%) 13. To date no studies have examined the prevalence and degree of voluntary smoking restrictions or child ETS exposure among U.S.-born and Mexico-born Hispanics.

Hispanics are heterogeneous with respect to social and cultural characteristics as well as various health outcomes including tobacco use 1516. Smoking prevalence is a strong predictor of smoking bans, and recent data indicate substantial heterogeneity in smoking prevalence rates among U.S. Hispanic subgroups, particularly between English- and Spanish-speaking Hispanic women 17. These differences in smoking rates may also extend to differences in voluntary smoking restrictions among U.S. Hispanic subgroups.

This paper examines the prevalence of home and automobile smoking bans, as well as associations of mother's country of birth and smoking practices with home and automobile smoking bans and child ETS exposure, among U.S.- and Mexico-born Hispanics residing in the southwestern United States. This research provides new information to public health professionals for increasing the adoption of home and automobile smoking bans, and for reducing ETS exposure among Hispanic children.

Study data were collected as part of a survey of stressors, social supports, and smoking behaviors among Hispanic mothers of young children. The University of New Mexico Health Sciences Center's Human Research Review Committee approved the study protocol. During November 2003 through April 2004, study staff recruited survey participants from waiting rooms of a pediatric emergency room/urgent care clinic, a family practice and pediatric health care facility, and a Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) clinic, all located in southeast Albuquerque, New Mexico.

Clinic appointment logs and sign-in sheets were used to systematically screen women who presented for clinic services. Eligible study participants included U.S.-born or Mexico-born Hispanic mothers of children aged 2 through 12 years. During screening, women were asked, "Which of the following best describes your ethnicity?". Response options were Mexican, Mexican American, Spanish New Mexican, Other Hispanic, and non-Hispanic. Women who responded 'Other Hispanic' were eligible if they were born in the United States or Mexico. A total of 357 eligible Hispanic mothers were identified. Of these, 81 declined to participate and an additional seven interviews could not be completed for other reasons, resulting in a final sample size of 269 (144 U.S.-born; 125 Mexico-born) mothers. The overall response rate was 75.4% (70% for Spanish speakers and 81% for English speakers).

This study is the first to examine the prevalence and correlates of home and automobile smoking restrictions, and of child ETS exposure, among U.S.-born and Mexico-born Hispanics in the United States. We found that the adoption of complete home and automobile smoking bans were strongly associated with mother's country of birth after controlling for smoking behaviors and sociodemographic characteristics. In contrast with Mexico-born mothers, U.S.-born mothers in our sample had 6-fold greater odds of lacking a complete home smoking ban and 3-fold greater odds of lacking a complete automobile smoking ban. Given that complete smoking bans provide substantially greater protection from ETS exposure than partial bans, tobacco education programs designed to reduce child ETS exposure should consider maternal nativity an important parameter differentiating smoking restriction practices among U.S. Hispanics 20.

Young children's ETS exposure occurs primarily in homes and automobiles 21. The overall prevalence (86%) of home smoking bans observed in our sample of U.S.- and Mexico-born Hispanic mothers in Albuquerque, New Mexico is somewhat higher than findings from studies of California Hispanics (79.9%) 13. Only a few studies have reported on automobile smoking bans. Our observed prevalence (81%) of complete smoking bans for the family automobile was also higher than rates reported by Norman et al. among Hispanics (67%) and African Americans (55%) in California, and more than double the 38% reported by Kegler and Malcoe among rural low-income families of Native American and White young children in Oklahoma 1314. The higher rate of smoking bans observed in our study may reflect the presence of children in all study homes, as well as the lower smoking prevalence among U.S. Hispanic women in general and Mexico-born women in particular 111422232425. However, despite the higher prevalence of home and automobile smoking bans observed in our study, substantial opportunity for improvement remains, especially among smoking and U.S.-born Hispanic mothers.

Previous studies have demonstrated that smokers are less likely to ban home and automobile smoking 11121323. Our study confirms these findings in a clinic-based sample of Hispanic families with young children. We found that complete bans were present in 63% of smoking households, in contrast with 96% of nonsmoking households. Further, our multivariate analyses showed that U.S.-born mothers and homes with adult smoker(s) other than the mother had much greater odds of lacking complete home and automobile smoking bans. These latter findings suggest that interventions to increase smoke-free home environments for Hispanic children in the southwestern United States should focus on U.S.-born mothers in particular and utilize strategies that impact smoking practices of all household members 26.

An important tobacco control objective of Healthy People 2010 is to reduce the proportion of U.S. children who are regularly exposed to tobacco smoke in the home 27. We found that 36% of Hispanic children in our sample lived with a smoker. Our analyses further showed that complete smoking bans were associated with seven to 10-fold lower odds of room or automobile ETS exposure among Hispanic children. Several randomized controlled trials have demonstrated the effectiveness of parent counselling and coaching for decreasing children's reported ETS exposure, but only one has shown significant decreases in objective ETS exposure measures greater than those observed among controls 26282930. Notably, Hovell and colleagues showed that coaching is effective in reducing ETS exposure among Latino asthmatic children where the majority of mothers were nonsmokers and of Mexican descent 26. However, no trials have investigated the effectiveness of interventions for reducing home ETS exposure among children of U.S.-born Hispanics. Our multivariate findings, which showed that Hispanic children of U.S.-born mothers (compared with Mexico-born mothers) had three-fold increased odds of room ETS exposure, indicate that future trials should design and test ETS interventions targeting U.S.-born Hispanics with young children.

Our study is not without limitations. First, smoking restrictions and child ETS exposure were self-reported by the mother. Studies including biomarker and environmental measures of ETS have found that objective ETS exposure measures are somewhat higher than those based on self-reports 3132. However, we have no reason to believe that U.S.- compared with Mexico-born mothers would be more or less likely to incorrectly report their child's ETS exposure. Second, our study population was recruited from pediatric emergency/urgent care and primary care clinics that provide services to underserved populations, and not through a population-based sampling approach. To avoid selection bias, women presenting for clinic services were systematically screened for eligibility through use of appointment logs and sign-in sheets. Thus, our sample was generally representative of low-income, urban Hispanic women in the study area who utilize clinic services. Finally, we did not ask mothers if their child was exposed to ETS in their own home or family car, or whether they were exposed to ETS in other locations not under the control of parental smoking bans. Future studies may wish to include these questions to more fully evaluate the impact of personal smoking restriction policies on child ETS exposure.

The reduction of child ETS exposure is a national priority in the United States 27. This paper presents new findings of substantial differences between U.S.- and Mexico-born Hispanics in the prevalence of home and automobile smoking bans, and resulting child ETS exposure. As the Hispanic population of the United States grows, more women will belong to the high-risk U.S.-born group, and thus active smoking and ETS exposure will have a greater impact on the health of these women and their children. This trend could be especially significant among Mexican American women because they represent the largest and fastest growing segment of the Hispanic population in the United States 33. The involvement of health professionals in encouraging Hispanic parents to reduce ETS exposure in the home and automobile, and ideally, to opt for smoke-free environments, is an important public health approach to reducing ETS-related morbidity. Tobacco intervention messages targeted at reducing ETS exposure among Hispanic children should consider maternal nativity an important factor influencing home and automobile smoking restriction practices.

The author(s) declare that they have no competing interests.

MG and LHM conceived of and designed the study, oversaw study implementation, analysed and interpreted the data; and drafted and revised the manuscript. MCK contributed to development of study measures and critically revised the manuscript. JE was the data manager for the study, contributed to data analysis, and revised the manuscript. All authors read and approved the final manuscript.