Secondhand Smoke Exposure Reduction After NICU Discharge: Results of a Randomized Trial

Secondhand Smoke Exposure Reduction After NICU Discharge: Results of a Randomized Trial Susan W. Blaakman, PhD, APRN; Belinda Borrelli, PhD; Elise N. Wiesenthal, BA, BSN; Maria Fagnano, MPH; Paul J. Tremblay, BSN; Timothy P. Stevens, MD, MPH; Jill S. Halterman, MD, MPH From the Department of General Pediatrics (Dr Blaakman, Ms Wiesenthal, Ms Fagnano, Mr Tremblay, and Dr Halterman), Department of Neonatology (Dr Stevens), University of Rochester School of Medicine and Dentistry, University of Rochester School of Nursing (Dr Blaakman), Rochester, NY; and Department of Psychiatry and Human Behavior, Brown University, and the Miriam Hospital, Centers for Behavioral and Preventive Medicine, Providence, RI (Dr Borrelli) The authors declare that they have no conflict of interest. Address correspondence to Susan W. Blaakman, PhD, APRN, University of Rochester School of Nursing, 601 Elmwood Ave, Box SON, Rochester, NY 14642 (e-mail: [email protected]). Received for publication December 8, 2014; accepted May 4, 2015.

ABSTRACT OBJECTIVE: Premature infants are at high risk for respiratory disease, and secondhand smoke (SHS) exposure further increases their risk for developing respiratory illness and asthma. Yet, SHS exposure remains problematic in this vulnerable population. Our objective was to evaluate the effects of brief asthma education plus motivational interviewing counseling on reducing SHS exposure and improving respiratory outcomes in premature infants compared to asthma education alone. METHODS: Caregivers and their infants #32 weeks’ gestational age were enrolled after discharge from a neonatal intensive care unit in Rochester, New York, from 2007 to 2011. Participants (N ¼ 165, 61% Medicaid insurance, 35% Black, 19% Hispanic, 59% male) were stratified by infant SHS exposure and randomly assigned to treatment or comparison groups. RESULTS: Caregivers in the treatment group reported significantly more home smoking bans (96% vs 84%, P ¼ .03) and reduced infant contact with smokers after the intervention

(40% vs 58%, P ¼ .03), but these differences did not persist long term. At study end (8 months after neonatal intensive care unit discharge), treatment group infants showed significantly greater reduction in salivary cotinine versus comparison (1.32 ng/mL vs 1.08 ng/mL, P ¼ .04), but no significant differences in other clinical outcomes. CONCLUSIONS: A community-based intervention incorporating motivational interviewing and asthma education may be helpful in reducing SHS exposure of premature infants in the short term. Further efforts are needed to support sustained protections for this high-risk group and ultimately, prevent acute and chronic respiratory morbidity. Strategies for successfully engaging families during this stressful period warrant attention.

KEYWORDS: motivational interviewing; neonatology; premature infants; respiratory illness; secondhand smoke ACADEMIC PEDIATRICS 2015;15:605–612

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likelihood that an infant will develop wheezing.1,7 For premature infants, prenatal SHS exposure compounds problems related to respiratory health during infancy.2,7 Additionally, postnatal SHS exposure among premature infants is a predictor of increased respiratory morbidity, asthma,1,8 and worsened asthma morbidity8 throughout childhood. One study found that SHS exposure in the first 3 months of life resulted in increased incidence of hospitalization for respiratory infection from birth to 8 years of age.9 While the harms of prenatal and postnatal smoke exposure are well known, SHS exposure in this population remains a troubling public health issue.1,8 Many caregivers find it difficult to quit smoking during pregnancy, and of those who are able to quit, as many as half relapse within 6 months.10 Additionally, caregivers who do not smoke, or who quit in either the prenatal or postnatal period can face challenges maintaining a smoke-free environment for their child, particularly if these efforts are not supported by family or other household members. In our previous

Motivating caregivers to reduce secondhand smoke exposure by enforcing smoking bans and reducing contact with smokers may significantly decrease salivary cotinine levels in premature infants. Intervention programs utilizing motivational interviewing and brief asthma education may benefit this high-risk population.

PRETERM INFANTS HAVE a significantly increased risk for developing respiratory illnesses throughout childhood.1–3 Babies born prematurely suffer more often from bronchopulmonary dysplasia and respiratory syncytial virus bronchiolitis,4 both often requiring hospitalization. Preterm infants also experience a higher prevalence of chronic respiratory illness in later childhood, particularly exercise-induced bronchospasm and asthma.3,5,6 Early life secondhand smoke (SHS) exposure is also clearly associated with increased prevalence of breathing problems in infancy, and substantially increases the ACADEMIC PEDIATRICS Copyright ª 2015 by Academic Pediatric Association

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study, almost half (41%) of the premature infants we enrolled were SHS exposed at home, and over two-thirds (67%) experienced respiratory symptoms.11 Motivational interviewing (MI) is an approach used to assist caregivers’ efforts to quit smoking and/or reduce smoke exposure of children in their care.12–16 MI is a person-centered counseling strategy that incorporates multiple communication strategies and treatment techniques to explore and resolve ambivalence regarding behavior change. By skillfully employing empathy, open-ended questions, and reflective listening, MI counselors identify gaps between an individual’s behavior and his/her values, goals and actions to build motivation and confidence for change.17 MI’s influence has been tested with respect to many health behaviors with varied findings,18–20 but evidence regarding changing caregiver smoking and SHS control behaviors has shown promise.13–16,21–24 Meta-analyses and systematic reviews generally indicate that MI specifically targeting smoking cessation is effective, usually when delivered in longer (>20 minutes), repeated sessions.20,25 Findings have been less clear when caregiver reduction of child SHS exposure is the primary focus, but of the studies critically examined, those using MI in clinical settings were mostly effective.26–28 In an early trial, Emmons and colleagues15 randomized low income families with young children to either a motivational intervention that included feedback using household nicotine and exhaled carbon monoxide measures or self-help. Results indicated that participants who received MI had significant reductions in objectively measured SHS versus self-help at a 6-month follow-up. Borrelli et al16 also conducted a randomized trial to compare MI (including carbon monoxide and SHS feedback) to a social cognitive theorybased treatment that provided equivalent contact time and relevant content, without MI. Participants were Latino caregivers who smoked and had a child with asthma. Intent-to-treat analyses revealed that 20.5% of MI participants were abstinent at 2-month follow-up versus 9.1% in the comparison condition, reinforcing MI’s usefulness for low income and ethnically diverse families. Our study aim was to evaluate the effectiveness of MI on reducing SHS exposure for another vulnerable population, premature infants. We hypothesized that premature infants of caregivers who participated in a community-based, asthma education plus MI smoke reduction program would be more likely to live in smoke-free homes and have less respiratory illness as compared to those whose caregivers received asthma education alone.

METHODS PARTICIPANTS We enrolled infants born at #32 weeks’ gestational age, along with their caregivers, into a randomized controlled trial within 6 weeks of their discharge from the neonatal intensive care unit (NICU) at Golisano Children’s Hospital in Rochester, New York. Families were recruited in-person in the NICU or over the phone after discharge from March

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2007 to May 2011; 165 infants were enrolled. Exclusion criteria included caregiver age <16 years, infants with serious medical comorbidities that could interfere with the assessment of respiratory outcomes (eg, diaphragmatic hernia, pulmonary hypoplasia, congenital heart disease), non-English-speaking caregivers, no access to a working telephone, and residence greater than 30 miles from the NICU. In situations of multiple eligible children (eg, twins), we enrolled 1 infant per family based on caregiver preference. Subject characteristics are provided in Table 1. We assessed 337 families for eligibility. Fifty screened ineligible, and of the remaining 287 eligible families, 122 did not participate. Initial home visits were scheduled at the time of eligibility screening, and 165 infants and their caregivers were randomized (participation rate ¼ 58%; Figure). Study protocols were approved by the University of Rochester Institutional Review Board. ASSESSMENTS At baseline, all participants received a 60-minute initial in-home assessment to obtain written informed consent and survey data pertaining to demographic information, family health history, past infant respiratory illness, and parentreported infant exposure to SHS. We collected a saliva sample from each infant to analyze salivary cotinine as a proxy measure of SHS exposure.29 A brief (5 to 10 minutes) asthma education session focusing on the mechanisms and symptoms of asthma, identification of triggers, and ways to reduce exposure to asthma triggers, including SHS, was provided to each family during this visit before randomization. All families were given printed educational resources, and time was allotted for questions and discussion. Participating caregivers were also contacted by phone 5 and 8 months after discharge from the NICU to complete 10- to 20-minute follow-up surveys. Caregivers were asked about infant SHS exposure and the smoking status of previously identified smokers in the home. Data about infant respiratory symptoms and health care utilization were also collected. Assessments were completed by study team members blinded to the infants’ randomization category. A brief home visit at study end was used to collect a final infant saliva sample for cotinine analysis. RANDOMIZATION AND INTERVENTION Ending the baseline visit, families were randomly assigned to either the treatment or comparison condition using a concealed envelope system. Randomization was stratified by caregiver-reported routine infant SHS exposure, which was determined if the infant slept $1 night per week in a home with a smoker. A permuted block design assured an equal balance of infants in each group over time. Caregivers randomly assigned to the comparison group received only the brief asthma education session described, at the baseline visit. Caregivers randomized to the intervention group additionally received counseling from 1 of 2 research nurses [PJT, SWB] who were trained in MI and actively supervised by an expert in the field [BB]. These sessions provided smoking

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Table 1. Baseline Demographics and Infant Smoke Exposure Characteristic Infants Male Gestation age, wk Gestation age <28 wk Birth weight, g Age at discharge, d Cesarean delivery Race White Black Other Ethnicity: Hispanic Insurance: Medicaid Family history of asthma Caregiver Caregiver: Mother Age <30 y Marital status: single Education: less than high school Depressed Caregiver smoked 100 cigarettes in lifetime Smoke exposure Mother smoked during pregnancy Caregiver smoked a puff in the past 30 days Infant has routine contact with a smoker

Total (N ¼ 165)

Treatment (n ¼ 83)

Comparison (n ¼ 82)

98 (59) 28.4  2.5 73 (45) 1180  418 64.5  35.7 94 (58)

49 (59) 28.7  2.4 33 (41) 1197  412 64.7  36.5 44 (54)

49 (60) 28.1  2.5 40 (49) 1163  426 64.3  35.2 50 (62)

71 (43) 58 (35) 36 (22) 32 (19) 100 (61) 80 (49)

35 (42) 33 (40) 15 (18) 13 (16) 49 (59) 35 (44)

36 (44) 25 (30) 21 (26) 19 (23) 51 (62) 44 (54)

161 (98) 88 (53) 97 (59) 44 (27) 13 (8) 62 (38)

81 (98) 44 (53) 47 (57) 26 (31) 7 (8) 31 (37)

80 (98) 44 (54) 50 (61) 18 (22) 6 (7) 31 (38)

29 (18) 42 (26) 95 (58)

14 (17) 19 (23) 49 (59)

15 (18) 23 (28) 45 (56)

Results reported as n (%) or mean  SD; all P > .5.

cessation or relapse prevention counseling for willing caregivers who were current or former smokers, while exploring and reinforcing SHS exposure control efforts for all. Education about the risks of smoking and SHS exposure and about the potential benefits of change was provided using the MI technique of elicit-provide-elicit.17 Information about resources (eg, smokers’ quit line, pharmacotherapy options) and cotinine feedback was provided in this manner also. Consistent with the principles of MI, all intervention components were delivered nonjudgmentally, emphasizing caregiver values and choice. Caregivers who reported no infant exposure to SHS received a single 10- to 15-minute counseling phone call 2 to 3 weeks after baseline to provide cotinine feedback and reinforce SHS control practices. Caregivers reporting infant SHS exposure or who identified smokers living in the home, received a 30- to 45-minute home MI counseling session 1 week after baseline, followed by two 15- to 20minute counseling phone calls occurring at 2 weeks and 2 months after baseline. Cotinine feedback was provided during the first MI phone call. TREATMENT FIDELITY Counselors were 2 registered nurses who received extensive training from an MI-certified trainer. Training occurred over 2 full days and included didactics, role-plays, demonstrations, and videos. Skill acquisition was assessed via role playing, simulated study encounters, and supervised practice with pilot participants. Nurses used a treatment manual to ensure standardization. All counseling sessions were audiotaped. Over 20% of the counseling sessions were reviewed for reliable MI adherence to the treatment protocol. Counselors met weekly with the trainer to review active

cases and were provided additional booster trainings as needed (ie, 1 or 2 times per year). PRIMARY OUTCOME MEASURES The primary outcome for this study was postintervention infant exposure to SHS. This was determined utilizing caregiver-reported data from the survey that occurred closest to completion of the intervention (the 5-month survey). Because infant salivary cotinine samples were not collected at this time, samples obtained at the study end (8 months after NICU discharge) were used as an objective measure of infant SHS exposure. Survey data from this time point are also reported. SMOKING BANS Smoking bans were evaluated on the basis of caregiver report. We asked caregivers to choose the best option regarding smoking in their home/car. For example, 1) Smoking is allowed in any room in the home; 2) Smoking is limited to part of the house where child rarely goes; or 3) There is no smoking at all. If caregivers reported there was no smoking at all, we asked them to identify any exceptions to that rule.30 A home ban was considered in place when the caregiver reported no smoking in the home with no exceptions. The definition of a car ban was met if the caregiver reported no smoking in the car with no exceptions, which included caregivers without a car. Caregivers with both a home ban and a car ban were considered to have a total smoking ban. ROUTINE INFANT CONTACT WITH SMOKERS We asked caregivers to identify the number of people who smoked cigarettes, cigars or pipes and had routine

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Figure. CONSORT enrollment diagram.

contact (infant sleeping $1 night per week where a smoker resided) with their child. We dichotomized the responses to identify participants with no routine contact with smokers or any routine contact with a smoker. SALIVARY COTININE Salivary cotinine, a biomarker of nicotine, was used as an objective measure of smoke exposure.29 Using absorbent swabs, we collected saliva samples from all infants at baseline and at 8-month follow-up to measure infant cotinine levels. Following standard protocols, swabs were maintained and sent to Salimetric Labs for analysis by enzyme-linked immunosorbent assay with a lower detection limit of 0.15 ng/mL. SECONDARY OUTCOME MEASURES Postintervention secondary outcomes were determined by caregiver-reported data collected at the 5-month survey using instruments tested in previous work.31 Variables included caregiver confidence and motivation to quit

smoking, infant respiratory symptoms, and infant health care utilization and were measured as follows. These surveys were repeated at study end. CAREGIVER CONFIDENCE AND MOTIVATION TO QUIT Caregivers who smoked were asked to separately rate their confidence and their motivation to quit smoking on a scale from 1 to 10 (1 ¼ not at all; 10 ¼ extremely), so that higher scores reflected greater confidence or motivation to quit, respectively. We compared mean scores between groups. INFANT RESPIRATORY SYMPTOMS AND HEALTH CARE UTILIZATION Infant respiratory symptoms were assessed by asking caregivers to quantify in the past 2 weeks: the number of days with wheeze/cough, the number of nights awakened due to wheeze/cough, the number of days having taken rescue medication, and the number of symptom-free days (24 hours with no respiratory symptoms).32 We also

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assessed the number of visits to a primary care provider, emergency department, or hospitalizations for wheezing or breathing problems since the prior survey. COVARIATES Covariates for planned analyses included demographic information (infant race/ethnicity, Medicaid insurance, caregiver age, caregiver education, and caregiver marital status) as well as pertinent health factors (infant gestational age, infant birth weight, infant age at discharge, delivery type, family history of asthma and caregiver postnatal depression33). STATISTICAL ANALYSIS Analyses were completed using Predictive Analytics SoftWare (PASW) 18.0 and 20.0 (IBM, Armonk, NY). We used both parametric and nonparametric tests, depending on distribution of data, to compare outcomes between groups. Bivariate statistics explored relationships among baseline demographic variables, smoking bans, routine contact with a smoker, very low cotinine, and health care utilization measures. Mann-Whitney tests compared independent group means for nonparametric variables including salivary cotinine levels, salivary cotinine changes, caregiver motivation and confidence to quit smoking, and infant respiratory symptoms. Multivariate logistic or linear regression analyses, respectively, were used to analyze dichotomous or continuous primary outcomes, controlling for infant gender, ethnicity, race, and Medicaid insurance, as well as caregiver age, education level, and marital status. Covariates (eg, infant gestational age, birth weight, age at discharge) that did not contribute to the regression models were not retained in final analyses. A 2-sided alpha of <.05 was considered statistically significant. We used a natural log transformation for analysis of cotinine and cotinine change over time to account for abnormal distribution of data. Zero values were converted to 0.01 to avoid exclusion of data. We considered raw data and also truncated data with values >15 ng/mL (to 15 ng/ mL) for analysis. This cutoff was based on previous research that associated cotinine in this range with active smoking, which is not applicable in this population.34 For clarity, actual cotinine means are reported in Table 2 with P values obtained from the transformed (log cotinine)

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comparisons. Table 3 shows the ranges of raw cotinine data.

RESULTS We collected postintervention survey information for 144 caregivers (87%) and saliva samples from 132 infants (80%). Participating premature infants were 59% male, 35% Black, 19% Hispanic, and 61% used Medicaid as their primary insurer at enrollment; 45% of infants were born <28 weeks’ gestational age, and 58% were delivered via cesarean section. Caregivers were mostly mothers of enrolled infants (98%), single (59%) and <30 years (53%); 27% did not finish high school. At enrollment, 26% of caregivers reported smoking “even a puff” of cigarettes, cigars or pipes in the last 30 days, and 58% reported that their infant had routine contact with at least one smoker. There were no significant differences between groups when comparing demographics or SHS exposure at baseline (Table 1). Table 2 shows the postintervention infant SHS exposure outcomes. Five months after discharge from the NICU, caregivers in the treatment group were significantly more likely to report a home smoking ban than the comparison group (96% vs 84%, P ¼ .03). Caregivers receiving the intervention were also significantly less likely to report routine infant contact with a smoker (40% vs 58%, P ¼ .03). Differences in reported home bans (92% vs 83%, P ¼ .14) and routine infant contact with smokers (44% vs 53%, P ¼ .33) between the treatment and comparison groups were no longer significant at study end. We did not observe a difference in car smoking bans or total smoking bans between groups at any time. Eight months after NICU discharge, infants in the intervention group had lower salivary cotinine measurements and a significantly greater decrease in salivary cotinine since baseline than infants in the comparison group. Treatment group infants also trended toward having cotinine measurements in the “very low” (<0.5 ng/mL) range (52% vs 35%, P ¼ .08) (Tables 2 and 3). Regression analyses results are not reported because they did not yield more meaningful data, even when retaining covariates that significantly contributed to the models (infant race, ethnicity, and Medicaid status; caregiver age, education, and marital status). Overall, very few caregivers quit smoking, which did not differ between groups after intervention (Table 4) or at

Table 2. Postintervention Infant Smoke Exposure Characteristic

Treatment (n ¼ 68)

Comparison (n ¼ 76)

P

Home smoking ban Car smoking ban Total smoking ban (home and car) Routine contact with a smoker Salivary cotinine level, ng/mL* Cotinine change from baseline, ng/mL*,† Very low cotinine (<0.5 ng/mL)

65 (96) 62 (91) 60 (88) 27 (40) 2.15 ± 3.78 1.32 ± 4.28 33 (52)

64 (84) 65 (86) 58 (76) 44 (58) 2.43 ± 3.08 1.08 ± 2.67 24 (35)

.03 .32 .08 .03 .04 .04 .08

Results reported as n (%) or mean  SD. Bold indicates statistical significance. *Cotinine true values reported; P values reported from analysis of log transformation. †Mann-Whitney test.

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Table 3. Baseline and Postintervention Raw Cotinine Values Characteristic*

Total, n (%)

Treatment, n (%)

Comparison, n (%)

Baseline cotinine Very low Low Moderate High Final cotinine Very low Low Moderate High

n ¼ 163 25 (15) 54 (33) 48 (30) 36 (22) n ¼ 132 57 (43) 33 (25) 21 (16) 21 (16)

n ¼ 82 10 (12) 26 (32) 29 (35) 17 (21)a n ¼ 64 33 (52) 14 (22) 8 (13) 9 (14)c

n ¼ 81 15 (19) 28 (35) 19 (23) 19 (23)b n ¼ 68 24 (35) 19 (28) 13 (19) 12 (18)d

*Cotinine ranges are as follows: very low, 0.15 to <0.5 ng/mL; low, 0.5 to <2.0 ng/mL; moderate, 2.0 to <4.5 ng/mL; and high, 4.5 ng/ mL to highest (a100.49, b33.63, c25.04, and d27.37).

study end. Of the 29 total primary caregivers who reported smoking 5 months after NICU discharge, caregivers in the intervention group reported significantly higher confidence to quit than smoking caregivers in the comparison group (mean ¼ 8.6 vs 6.73, P ¼ .02) at the 5-month survey, but not at study end (mean ¼ 7.38 vs 6.12, P ¼ .21). Caregiver motivation to quit was not significantly different between groups at any time. After the intervention, we asked all caregivers about infant breathing problems in the past 2 weeks and health care utilization since the last survey. Caregivers in both groups reported infants experiencing many symptoms across categories (Table 5), which is common given the respiratory vulnerabilities in this population. There were no significant differences between the intervention and comparison group in daytime symptoms, nighttime awakening due to wheeze or cough, days requiring rescue medication use, or symptom-free days. We did not observe differences between groups in doctor’s visits, emergency department visits, or hospital visits due to wheeze. These findings remained consistent at study end.

DISCUSSION Our intervention had a positive impact on short-term infant SHS exposure when compared to brief asthma education alone. MI counseling along with asthma education close to the time of NICU discharge was associated with reduced caregiver-reported SHS exposure. At the follow-up survey 5 months after NICU discharge, significantly fewer infants in the intervention group had routine contact with smokers. We also found a higher prevalence of home smoking bans and total smoking bans reported

by caregivers in the intervention group versus the comparison group at this time. Additionally, infants in the intervention group had significantly lower salivary cotinine levels at study end compared to infants in the comparison group. The reduction in infant cotinine also was significantly greater in the intervention group than the comparison group from baseline to final assessments, objectively indicating decreased SHS exposure over time. We were unable to observe differences in caregiver smoking behaviors. Smoking caregivers in the intervention group reported significantly higher confidence to quit compared to smoking caregivers in the comparison group at the postintervention survey. However, there were no group differences in caregivers’ motivation to quit smoking throughout the study, and confidence to quit was no longer significantly different at study completion. This was not entirely unexpected, as the SHS reduction intervention occurred early in the study period and was not intensively focused on smoking cessation as is necessary to substantially affect long term smoking abstinence.35 It is also worth noting that only 66% (n ¼ 55) of the 83 caregivers randomized to the treatment group received the full MI intervention of 1 home visit and 2 counseling phone calls. About half (49%) of caregivers with SHS exposed infants (often due to the caregiver smoking) completed the full intervention, while almost all (94%) of caregivers whose infants were not SHS exposed completed the entire program. Yet, the improvements found in reported smoking bans and in infant salivary cotinine were aligned with the objectives of our study and indicate that brief MI counseling in conjunction with asthma education can benefit these premature infants. Despite a reduction in smoke exposure, we found no difference in respiratory symptoms or health care utilization for wheezing between groups. In part, this may be because while SHS exposure was decreased overall, many infants remained exposed to smoke. Furthermore, respiratory illness in this high-risk population is related to multiple factors, including bronchopulmonary dysplasia, respiratory syncytial virus infection, and other respiratory infections that we did not directly target.7 Additional efforts to prevent respiratory illness in this population are needed. This study has limitations. The enrollment period was lengthy (4.25 years), which may have influenced intervention fidelity over time, although our nurse interventionists remained consistent, and safeguards (eg, ongoing supervision) were enacted. Group differences could be due to contact time differences. Additionally, our participation rate

Table 4. Postintervention Caregiver Motivation and Confidence to Quit Smoking Characteristic

Total (N ¼ 144)

Treatment (n ¼ 68)

Comparison (n ¼ 76)

P

Caregiver smokes Caregiver quit Caregiver motivation to quit* Caregiver confidence to quit*

29 (20) 5 (4) 6.88  2.22 7.48 ± 1.90

12 (18) 3 (5) 6.10  2.28 8.60 ± 1.58

17 (22) 2 (3) 7.40  2.10 6.73 ± 1.75

.51 1.00 .13 .02

Results reported as n (%) or mean  SD. Bold indicates statistical significance. *Mann-Whitney test.

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Table 5. Postintervention Infant Respiratory Symptoms and Health Care Utilization Characteristic

Total (N ¼ 144)

Treatment (n ¼ 68)

Comparison (n ¼ 76)

P

Days with wheeze/cough/short of breath in past 2 weeks* Nights awakened due to wheeze/cough in past 2 weeks* Days with need for rescue medication use in past 2 weeks* Symptom-free days in past 2 weeks* 1 or more doctor’s visit due to wheeze since last survey 1 or more emergency department visit due to wheeze since last survey 1 or more hospital visit due to wheeze since last survey

2.89  4.59 0.80  2.54 1.04  3.38 10.8  5.0 38 (26) 22 (15) 10 (7)

2.65  4.29 0.94  3.05 1.04  3.39 10.9  4.9 15 (22) 9 (13) 4 (6)

3.11  4.85 0.67  1.98 1.04  3.40 10.7  4.0 23 (30) 13 (17) 6 (8)

.77 .92 .82 .69 .34 .64 .75

Results reported as n (%) or mean  SD. *Mann-Whitney test.

was relatively low. Families with infants admitted to the NICU at large, research university medical centers such as ours are routinely offered participation in multiple studies throughout each phase of care and, understandably, sometimes decline. We did not systematically collect reasons for every declination. Anecdotally, many families who declined cited disinterest (feeling their child was not smoke-exposed and the study was not applicable) or inability to commit to the program (fearing they would be overwhelmed after NICU discharge or due to participating in other studies). We did enroll both smokeexposed and non-smoke-exposed infants. We chose this approach to reach infants without reported SHS exposure at baseline, but who could face such exposure very early in life (eg, daycare providers, public areas). However, this may have reduced our power to detect program effects for the highest-risk infants. We also did not assess for the effects of multi-unit housing on smoke-exposure or of social desirability on caregiver-reported measures. Lastly, because nicotine metabolism has not been studied extensively in premature infants, meaningful cut points for salivary cotinine, as an objective measure of SHS exposure, are not well defined in this population.35 This study also has strengths. Our stratification and randomization strategies assured equal distribution of smoke-exposed and nonexposed participants, and allowed us to assess potential program benefits using a broad community-based approach. Additionally, few programs have been effective at reducing SHS exposure in this highly vulnerable population. This study demonstrated, through both subjective (caregiver report) and objective (infant salivary cotinine) measures, the effectiveness of a community-based intervention in achieving this goal. In conclusion, our findings of reductions in infant salivary cotinine and in caregiver-reported SHS exposure suggest that intervention programs incorporating MI counseling and brief asthma education around the time of NICU discharge may be helpful at reducing SHS exposure in this high-risk population. Empowering caregivers to reduce SHS exposure by enforcing smoking bans and reducing routine contact with smokers can significantly decrease salivary cotinine levels in premature infants. Further efforts are needed to implement successful smoking cessation interventions for caregivers of these infants and to better understand the relationship of SHS exposure on clinical outcomes in this period.

ACKNOWLEDGMENTS This work was funded by a grant from the Halcyon Hill Foundation (Halterman, PI), which had no involvement in the submission of this manuscript for publication.

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