Public Health and Clinical Training
The Prevalence and Effects of Environmental Tobacco Smoke Exposure Among Inner-City Children: Lessons for Pediatric Residents
Kum-Nji, Phillip MD, MPH; Meloy, Linda D. MD; Keyser-Marcus, Lori PhD
Dr. Kum-Nji is associate professor of pediatrics, epidemiology, and public health, Children’s Hospital of Richmond, and Virginia Commonwealth University School of Medicine, Richmond, Virginia.
Dr. Meloy is professor of pediatrics and director, Newborn Nursery, Children’s Hospital of Richmond, and Virginia Commonwealth University School of Medicine, Richmond, Virginia.
Dr. Keyser-Marcus is assistant professor, Department of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, Virginia.
Correspondence should be addressed to Dr. Kum-Nji, Children’s Hospital of Richmond, Virginia Commonwealth University School of Medicine, 1001 E. Marshall St., Box 980646, Richmond, VA 23298; telephone: (804) 828-0099; fax: (804) 828-6301; e-mail: email@example.com.
Purpose: To determine the prevalence of environmental tobacco smoke (ETS) exposure, to explore the relationship between ETS exposure and the use of health services, and to examine the degree to which pediatric residents document ETS exposure status and counsel parents.
Method: In 2006, the authors recruited dyads of children (0–12 years old) and their mothers from an inner-city pediatric group practice clinic. Mothers completed a survey, and the authors searched the children’s medical charts. The authors compared ETS-exposed children with nonexposed children using chi-square, t test, and ANOVA analyses. They also ran logistic regression analyses to examine the relationship between the use of health services and selected child and maternal variables.
Results: More than 60% (142/232) of children were exposed to ETS, and more than 69% (99/142) of those children had a mother who smoked. ETS exposure significantly predicted the overall number of sick visits, even after controlling for sociodemographic confounders (odds ratio = 7.44; 95% confidence internal = 1.21–44.55). About 80% (187/232) of mothers reported that their child’s pediatrician had counseled them on the dangers of ETS exposure. Less than half (105/232) of the children’s charts included their ETS exposure status.
Conclusions: Although pediatric residents often counsel parents on the dangers of ETS exposure, educators should teach residents to regard ETS exposure status as a fifth vital sign. By screening for and documenting ETS exposure status, residents can identify at-risk children and parents, who could benefit from counseling.
Environmental tobacco smoke (ETS) exposure is one of the most important preventable health hazards in our community today. It has been associated with asthma,1–5 various upper and lower respiratory tract infections,2,6–11 and serious bacterial infections, such as sepsis and meningitis.12,13 Researchers also have linked ETS exposure to sudden infant death syndrome,14–16 childhood cancers,17–19 and growth delay, including cognitive and developmental problems such as attention problems and hyperactivity.20–25
Despite the overwhelming evidence of the harmful effects of ETS exposure on children, a significant percentage of young children still are exposed in their homes.26–32 Pediatricians are in a unique position to inform parents of the risks associated with ETS exposure during well and sick visits. Unfortunately, physician-initiated screening, documentation, and counseling are often not done during each visit, as groups such as the American Academy of Pediatrics (AAP) have recommended.33–35 Physicians often cite time constraints and a lack of training as reasons for inconsistent documentation and counseling.36 We have little information on how often pediatric residents routinely inquire about and document the smoking status of members of their patients’ households. We also have insufficient information on how often pediatric residents counsel parents on the dangers of ETS exposure in the home and in public places.35,36
The goal of our study was to examine the frequency with which pediatric residents document ETS exposure and provide counseling to parents in an inner-city resident pediatric group practice (PGP). We hypothesized that (1) pediatric residents infrequently (<25% of the time) document ETS exposure, and (2) less than 50% of parents would confirm being counseled on the dangers of ETS exposure by their child’s pediatrician. We also conducted additional analyses examining the relationship between a child’s ETS exposure status and his or her use of health services.
We conducted our study at an inner-city, university-based PGP clinic in Richmond, Virginia. Here, pediatric residents treat about 15,000 children under the age of 20 annually (about 20,000 visits) under the supervision of attending physicians. The ratio of faculty to residents is about 1:3. Approximately 85% of patients are black, 10% Hispanic, and 5% white. Almost 100% of patients lack private insurance, and most are on Medicaid (95%) or self-pay (~5%).
Study design and sample selection
Between January 1 and December 31, 2006, we enrolled 232 children who regularly attended the PGP clinic throughout the year and were present on the clinic days when we were present. To be eligible, a child had to be (1) a current patient of the clinic (between 0 and 12 years of age), (2) accompanied by a legal parent or legal guardian who was able to provide written informed consent, and (3) not already enrolled in our study and not have a sibling who was already enrolled. We screened parents before enrolling each child to ensure that they had not previously completed a survey for either the child present that day or a sibling. By doing so, we avoided the recruitment of more than one child from the same family. We included only children under the age of 12 to avoid including older children who could themselves be smokers. Although our enrollment period spanned 12 months, children under the age of 1 were also eligible. We obtained ethical approval from the Virginia Commonwealth University institutional review board prior to study implementation.
We developed a brief written survey consisting of four questions, which we pilot-tested with 10 parents to see whether it elicited the appropriate responses. Questions in the survey included the smoking status of the mother and other family members, regardless of whether they smoked in the house or car or only outside the home. The survey did not ask for the number of cigarettes that they smoked. The survey also included questions about the parents’ last encounter with their child’s pediatrician and whether they were informed of the consequences of ETS exposure and/or advised against exposing their children to smoking in the home. We did not ask about the specific methods that pediatricians used to counsel the parents.
We reviewed the participating children’s medical charts and abstracted the following information: (1) documentation of ETS exposure by a pediatrician, (2) sociodemographic variables for the child (daycare, exposure to ETS, age, gender, number of other young children in the home, birth weight, and immunization status) and the mother (age, breastfeeding [yes/no], and race), and (3) the frequency and reasons or diagnosis for sick clinic visits, emergency room (ER) visits, and hospitalizations during a 12-month period.
We compared ETS-exposed children with nonexposed children in a series of analyses, using SPSS version 19.0 software (Chicago, Illinois).37 First, we compared sociodemographic variables using t tests for continuous variables and chi-square comparisons for categorical variables. We defined a child as exposed to ETS if any member of the household smoked, regardless both of whether family members smoked in the house or car or only outside the home and of the number of cigarettes they smoked per day. Next, we used chi-square comparisons to examine the relationship between maternal and child characteristics and chart documentation of the child’s ETS exposure status. We again used chi-square comparisons to examine the same child and maternal characteristics and their relationship to the parent reporting that a pediatric resident provided ETS counseling. Then, we used t tests to compare ETS-exposed children and nonexposed children on the number of both sick visit types and specific illnesses. Further, we used ANOVA tests to examine the relationships between ETS exposure intensity and the number of sick visits. We used the number of smokers in the household as a proxy for exposure intensity to determine whether a relationship existed between ETS exposure and the use of health services. We categorized exposure intensity as 0 = no smokers, 1 = one smoker, and 2 = two or more smokers.
Finally, to determine the unique variance attributed to ETS exposure on the number of sick visits, we built four logistic regression models, in which ETS exposure (yes/no) and eight other variables (maternal age, child age, birth weight, number of children at home, child gender, daycare, breastfeeding history, and immunization status as defined by the AAP) were all forced into each of the full main effect models. We did not include race because over 80% of our sample were black. We considered P < .05 to be significant.
Characteristics of the study population
Almost two-thirds of the children in our sample were exposed to ETS in their homes (142/232; 61.2%). Overall, the mean maternal age was 24 years old (standard deviation [SD] = 6.96), and the mean child age was 30 months old (SD = 28.01). With regard to race, children were predominantly black (203/232; 87.5%); only 7% (16/232) were white. See Table 1 for a complete summary of the sociodemographic characteristics of the children and their mothers in our sample.
Our analyses on selected sociodemographic characteristics revealed comparability between the ETS-exposed children and the nonexposed children with regard to both maternal characteristics and child characteristics. The only exception was breastfeeding: ETS-exposed children were significantly more likely to not have been breastfed. This finding is not surprising because researchers have noted a negative correlation between breastfeeding and maternal smoking.38
Prevalence and sources of ETS exposure
Of the 232 children in our sample, 142 (61.2%) lived in a household with at least one smoker. Of those children, 31 (21.8%) lived in a household where their mother was the only smoker, 43 (30.3%) lived in a household where another family member (not the mother) was identified as the smoker, and 68 (47.9%) lived in a household where two or more smokers were identified (the mother and another family member). Thus, of the 232 children in our sample, only 90 (38.8%) were from smoke-free homes, whereas 99 (42.7%) had a mother who smoked.
Association of ETS exposure on common illnesses
Of the 10 common illnesses that we examined, ETS exposure was significantly associated with 5 (asthma, viral upper respiratory infection [URI], acute otitis media [AOM], allergic rhinitis, and gastroenteritis). Further, we noted a marginal association (P = .054) with conjunctivitis (see Table 2). In our secondary analysis of the 174 children over the age of 12 months, we still noted significant differences for asthma (t = −2.98, df = 139, P = .003), URI (t = −2.16, df = 166, P = .032), AOM (t = −2.12, df = 167, P = .036), allergic rhinitis (t = −2.01, df = 164, P = .046), and gastroenteritis (t = −2.40, df = 161, P = .004). However, conjunctivitis was no longer significant.
In our analyses of the relationships between ETS exposure and common illnesses (see Table 3), we noted significant linear relationships between the number of smokers in the household and the number of cases of reactive airway disease (RAD)/asthma (F [2, 221] = 4.11, P = .018), URI (F [2, 221] = 3.65, P = .028), and gastroenteritis (F [2, 214] = 6.13, P = .003). Our post hoc pairwise comparisons revealed differences in the relationships between children with no smokers and children with two or more smokers in the household for both asthma and URI. However, children with one smoker in the household experienced a significantly higher mean number of sick visits related to gastroenteritis than children with no smokers and children with two or more smokers in the household. Subsequently, a cumulative dose effect did not seem to be present for our sample. Again, we ran a secondary analysis of children over the age of 12 months to determine whether between-group differences remained. We still noted significant relationships with regard to ETS exposure and both RAD/asthma (F [2, 166] = 4.08, P = .019) and gastroenteritis (F [2, 161] = 7.63, P = .001). However, we only noted a trend for URI (P = .056).
Association of ETS exposure on the use of health services
Over 90% (216/232) of the children in our sample had one or more sick visits. About 30% (69/232) had at least one ER visit, and only 10% (23/232) had one or more hospitalizations. The results of our t tests (see Table 3) revealed that ETS exposure was strongly associated with an increased number of sick visits, with ETS-exposed children averaging 5.89 clinic visits and nonexposed children averaging 4.01 (t = −3.17, df = 205, P = .002). We noted the same relationship with regard to ER visits, with ETS-exposed children averaging more ER visits (mean [M] = 0.37) than nonexposed children (M = 0.16) (t = −3.26, df = 209.6, P < .001). However, ETS exposure was not associated with the number of hospitalizations (t = −1.20, df = 206.4, P = .233). When we included all sick visits as one variable (clinic visits + ER visits + hospitalizations), ETS exposure was strongly associated with the use of health services (t = −3.36, df = 202, P < .001), with ETS-exposed children having a greater number of sick visits (M = 6.55) than nonexposed children (M = 4.32). Further, these relationships remained significant when we restricted our analysis to children over the age of 12 months.
The results of our ANOVA tests confirmed the relationships between the number of smokers in the household and the number of sick visits. Our post hoc pairwise comparisons revealed differences between children with no smokers and children with either one smoker or two or more smokers in the household. We noted these differences for all of our analyses. However, the tests of trend were not significant because we did not note differences between children with one smoker and children with two or more smokers in the household. Rather, it was an all-or-none response (see Table 4). These findings remained consistent when we restricted our analyses to children over the age of 12 months.
Our logistic regression analyses (see Table 5) revealed that ETS exposure was the only predictor that uniquely contributed to variance in sick visits in three of the four models that we tested: all sick visits (odds ratio [OR] = 7.34, confidence interval [CI] = 1.21–44.55, P = .030), clinic sick visits (OR = 8.38, CI = 1.48–47.58, P = .016), and ER visits (OR = 2.44, CI = 1.02–5.84, P = .045). ETS exposure, however, did not predict the number of hospitalizations (P = .241). When we restricted our logistic regression analyses to children over the age of 12 months, ETS exposure continued to be the sole predictor of all sick visits and clinic sick visits. However, ETS exposure no longer contributed to variance in ER visits.
Screening, counseling, and documentation of ETS exposure
Overall, the majority of parents (187/232; 80.6%) reported that their child’s pediatric resident discussed the dangers to their child of ETS exposure. However, only 45% (105/232) of the participating children’s medical charts had documented evidence of their ETS exposure status.
Documentation of ETS exposure was more likely for children whose mothers smoked than for children whose mothers did not smoke (P = .004). Counseling, however, was similar for both groups. Documentation of ETS exposure also was more likely for children under the age of 24 months than for children over the age of 24 months (P < .001). In addition, mothers of children under the age of 24 months were more likely to be counseled than mothers of children over the age of 24 months (P < .001). Interestingly, documentation of ETS exposure and counseling were both less likely among children attending daycare than among children not attending daycare. Surprisingly, children with a history of asthma and other allergic episodes, or recurrent URIs, were as likely as children without such a history to have their ETS exposure documented and to have received counseling. Also noteworthy, mothers with children who had recurrent AOM (defined as three or more episodes in one year) were less likely to be counseled than those whose children had fewer AOM infections (P = .018).
Findings from our study demonstrate the continued importance of examining ETS exposure among inner-city children. Almost two-thirds (61%) of the children in our sample were exposed to ETS, which is consistent with national trends. Studies suggest that ETS exposure rates may be between 40% and 80% in some population subgroups in the United States.39–45 In 2000, the Surgeon General’s report on Healthy People 2010 recommended that ETS exposure rates among children be reduced from a baseline of 27% to 10% by 2010.46 Although pediatric residents screen and counsel a relatively high percentage of parents on the dangers of ETS exposure (81% according to the mothers in our study), documentation of such screenings and counseling is sporadic.
Our finding that more than 80% of mothers reported being counseled on the dangers of ETS exposure is rather surprising because we expected a much lower percentage. This finding likely suggests that about 80% of the mothers had been counseled sometime in the past on the dangers of ETS exposure. However, repeated screening and counseling during every well and sick visit is recommended as an effective way to reduce ETS exposure among young children.35,36
Before counseling can begin, documenting the smoking status of all family members is crucial because it enables the health care provider to appropriately focus on the techniques that can reduce that child’s specific ETS exposure. For example, parents may think that the harmful effects of smoking will not endanger their children if smoking takes place outside the house, in a different room, or even in the car. In one study, 15% of parents said that there were no smokers in their household, but subsequent home visits revealed that the children were actually exposed to smokers.40 In another study, 30% of self-reported nonsmokers were actually smokers, as indicated by biomarker measurements.41 Parents may not realize that even brief periods of exposure to smoking or the presence of ash trays in the home can be injurious to their children’s health.
In our PGP clinic, we noticed that parents’ answers to questions about smoking in the home often conflicted. For example, when we ask, “Does anyone smoke in the home?” parents may answer “No” even when household members do smoke. On the other hand, when we rephrase the question as “Are there any family members who are smokers?” the answer will often be “Yes, but not in the house.” Documenting the number of smokers in a household is important because it indicates to health care providers the intensity of a child’s ETS exposure,47–49 as parents often grossly underestimate how many cigarettes they or other family members smoke per day.
Our findings demonstrated a positive relationship between ETS exposure and the use of health services, both by type of visit (e.g., ER or clinic visit) and by type of disease. We expected these findings because ETS exposure has been associated with an increase in the frequency and severity of the symptoms of asthma and various respiratory infections.1–11 Our finding of the association of ETS exposure on acute gastroenteritis, however, was surprising. This association, though biologically plausible because of the known toxic and immunologic effect of nicotine on the epithelial cells lining the gastrointestinal tract, has been reported only in one small study50 and warrants further exploration.
Studies on the effect of ETS exposure on the use of health services are few and often provide conflicting results. For instance, McBride and colleagues29 found no difference in the use of health services between ETS-exposed children and nonexposed children. They also found that ETS-exposed children had fewer preventive visits than nonexposed children. These findings are similar to those of Vogt.26 In another study, however, Jacobs-van der Bruggen and colleagues27 found that ETS-exposed children used health services less often than nonexposed children, after controlling for various confounders. Finally, Maziak and colleagues31 showed that ETS exposure increased the number of ER visits and hospitalizations among children with asthma symptoms. One explanation for these differences is that smokers may ignore their children’s symptoms, whereas nonsmokers will seek medical attention for their children.27 We believe that this explanation is only part of the answer. It is more likely that, in most of these studies, the researchers only looked at the smoking status of the mother, failing to account for the smoking status of the other family members in the household. By doing so, they misclassified the ETS exposure status of the children in their sample, skewing their results.
Our study included only children under the age of 12 to avoid including older children who could themselves be smokers. Studies that found no association between ETS exposure and the use of health services included children from a wider range of ages (often those between 0 and 18 years). This range is too broad because we believe that the effects of ETS exposure on the use of health services are much more severe among children under the age of 5. Indeed, researchers who limited their sample to children under the age of 5 often demonstrated a positive correlation between ETS exposure and the use of health services. In this respect, our findings are similar to those of a recent study, which showed that ETS exposure was highly predictive of the number of physician sick contacts, even after controlling for various confounders.51 Our findings are also similar to those of Lam and colleagues,52 who demonstrated that ETS-exposed children under the age of 18 months used outpatient and hospital services more frequently than nonexposed children. In a similar study, Stoddard and Miller53 noted that children under the age of 18 months were more likely to be treated for asthma symptoms if they were exposed to smokers at home than if they were not exposed.
Our study has a few limitations. First, both the small sample size and the fact that we used a convenience sample of the parents and children who were present on the clinic days when we were present threaten the internal and external validity of our study. Demographically speaking, however, the children in our sample were comparable to the larger population of children served by the clinic. Second, we collected parent data retrospectively, not prospectively, thus inviting error due to recall bias. Finally, biological confirmation of smoking was not possible, which may have led to the underreporting of smoking in the household. However, by using the number of smokers in the household rather than the number of cigarettes smoked per day, we hope to have reduced the threat of underreporting.
Despite these limitations, our findings build on the existing literature by confirming previous findings regarding the high percentage of children who are exposed to ETS. Our findings also underscore the need for residency training programs, often located in areas serving predominantly indigent populations with a high percentage of ETS exposure, to adopt standardized practices for teaching trainees to document ETS exposure status in children. The training of medical students and residents presents a unique opportunity to teach the benefits of consistently screening children and counseling parents on the consequences of ETS exposure. Because physicians in the workforce often cite a lack of time and training as reasons for not screening children and counseling parents, we suggest teaching trainees to use a 30- to 60-second technique (dubbed the 3 As) during every patient encounter. This technique includes the following steps: (1) Ask if there are any smokers in the home, regardless of whether they smoke only outside or not, (2) advise the parents or caregivers to stop smoking and/or avoid exposing their children to ETS because of the dangers of such exposure both in and outside the home, and (3) arrange for a follow-up visit and refer the parents to a smoking cessation program. Residents should document children’s ETS exposure status as they do vital signs during every patient encounter, which will help trigger the above-mentioned counseling program. Finally, residency programs should measure residents’ documentation and counseling practices to provide evidence of the teaching interventions that are effective.
Our findings demonstrate that a significant percentage of children who attend an inner-city PGP clinic were exposed to ETS. We also found that pediatric residents appear to screen and counsel parents on the dangers of ETS exposure, although this practice is not accurately and consistently documented during all clinic visits. We recommend that training programs teach residents to regard ETS exposure status as a fifth vital sign, and, as such, residents should document it during all visits. We also recommend that educators develop innovative programs to assist pediatricians in both better identifying children who are at risk for ETS exposure and more effectively intervening with families to reduce children’s exposure to ETS.
Acknowledgments: The authors acknowledge Bill Moskowitz, MD, and David Friedman, MD, MPH, both of the Children’s Hospital of Richmond, Richmond, Virginia, who read and edited an earlier version of this report and made useful comments. They also thank Emmanuel Anum, MB ChB, PhD, of the Department of Biostatistics and Epidemiology, SUNY Downstate, Brooklyn, New York, for his contribution during the data analysis. Finally, they thank all the pediatric residents and nursing staff who were instrumental in bringing this study to fruition.
Other disclosures: None.
Ethical approval: The authors obtained ethical approval from the Virginia Commonwealth University institutional review board.
Previous presentations: The authors presented an earlier version of this report at the 2007 Pediatric Academic Societies’ Annual Meeting in Toronto, Ontario, Canada.
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