Environmental Tobacco Smoke Avoidance Among Pregnant African-American Nonsmokers

Background

Environmental tobacco smoke (ETS) exposure during pregnancy contributes to adverse infant health outcomes. Limited previous research has focused on identifying correlates of ETS avoidance. This study sought to identify proximal and more distal correlates of ETS avoidance early in pregnancy among African-American women.

Methods

From a sample of low-income, black women (n=1044) recruited in six urban, prenatal care clinics (July 2001–October 2003), cotinine-confirmed nonsmokers with partners, household/family members, or friends who smoked (n=450) were identified and divided into two groups: any past-7-day ETS exposure and cotinine-confirmed ETS avoidance. Bivariate and multivariate logistic regression analyses identified factors associated with ETS avoidance. Data were initially analyzed in 2004. Final models were reviewed and revised in 2007 and 2008.

Results

Twenty-seven percent of pregnant nonsmokers were confirmed as ETS avoiders. In multivariate logistic regression analysis, the odds of ETS avoidance were increased among women who reported household smoking bans (OR=2.96; 95% CI=1.83, 4.77; p<0.0001), that the father wanted the baby (OR=2.70; CI=1.26, 5.76; p=0.01), and that no/few family members/friends smoked (OR=3.15; 95% CI=1.58, 6.29; p<0.001). The odds were decreased among women who had a current partner (OR=0.42; 95% CI=0.23, 0.76; p<0.01), reported any intimate partner violence during pregnancy (OR=0.43; 95% CI=0.19, 0.95; p<0.05), and reported little social support to prevent ETS exposure (OR=0.50; 95% CI=0.30, 0.85; p=0.01). Parity, emotional coping strategies, substance use during pregnancy, partner/household member smoking status, and self-confidence in avoiding ETS were significant in bivariate, but not multivariate analyses.

Conclusions

Social contextual factors were the strongest determinants of ETS avoidance during pregnancy. Results highlight the importance of prenatal screening to identify pregnant nonsmokers at risk, encouraging household smoking bans, gaining support from significant others, and fully understanding the interpersonal context of a woman's pregnancy before providing behavioral counseling and advice to prevent ETS exposure.

Introduction

Adverse effects of tobacco smoke exposure during pregnancy are dose-dependent for active¹ and passive smoking.2, 3 Adverse events associated with smoking include intrauterine growth retardation, small-for-gestational-age, preterm birth, stillbirth, spontaneous abortion, placenta previa, abruptio placenta, and bleeding.4, 5, 6 Low birthweight, intrauterine growth, preterm birth,2, 6, 7 vaginal bleeding,⁸ and fetal death² have been associated with environmental tobacco smoke (ETS) exposure. Nonwhites experience more adverse effects, particularly low birth weight and prematurity, than do whites from smoking9, 10, 11, 12 and ETS exposure.⁶ African-American nonsmokers13, 14 and smokers,¹⁵ irrespective of pregnancy, have consistently higher cotinine levels than whites or Hispanics, despite comparable ETS exposure levels or numbers of cigarettes smoked¹⁵; metabolize cotinine more slowly16, 17, 18; have a longer cotinine half-life¹⁹; and are more likely to smoke mentholated cigarettes,16, 20, 21 which increases cotinine and carbon monoxide levels,²² increases cotinine half-life,¹⁹ and influences nicotine metabolism and clearance.²³

Little is known about the prevalence or correlates of ETS exposure among pregnant nonsmokers. It has been reported that 21% of nonsmokers with singleton pregnancies had ETS exposure during pregnancy.⁷ In another study,²⁴ 28% of nonsmokers receiving prenatal care reported ETS exposure either at home or at work. In the Yale Pregnancy Outcome Study, 52% of nonsmokers had detectable levels of urinary cotinine.²⁵ Among low-income pregnant women in Minnesota, 12% of nonsmokers reported daily ETS exposure of less than 4 hours.²⁶

Correlates of ETS exposure among pregnant nonsmokers include being single²⁷; being black²⁷; having a lower education level and decreased knowledge of ETS exposure risks27, 28, 29; lower self-efficacy²⁹; a husband, partner, or household member(s) who smokes27, 28, 30; and no household smoking bans.²⁹ None of these studies focused specifically on African-American women who are clearly at increased risk, and although these ETS exposure–specific factors are important targets for behavioral counseling interventions, there may be other psychosocial or social contextual factors31, 32 that influence a woman's ability to limit ETS exposure during pregnancy.

This study examines correlates of ETS avoidance in a population of African-American pregnant women. The hypothesis was that proximal variables to ETS exposure, such as identified household smokers, the presence of household smoking bans, confidence in preventing ETS exposure, perceived harm to exposed infants, and support for reducing exposure would be most predictive. An attempt was also made in this study to identify other, more distal correlates (e.g., individual, social, and contextual factors) that may be useful to consider in designing interventions intended to promote ETS avoidance.