Background Previous secondhand smoke (SHS) reduction interventions have provided only delayed feedback on reported smoking behaviour, such as coaching, or presenting results from child cotinine assays or air particle counters.
Design This SHS reduction trial assigned families at random to brief coaching and continuous real-time feedback (intervention) or measurement-only (control) groups.
Participants We enrolled 298 families with a resident tobacco smoker and a child under age 14.
Intervention We installed air particle monitors in all homes. For the intervention homes, immediate light and sound feedback was contingent on elevated indoor particle levels, and up to four coaching sessions used prompts and praise contingent on smoking outdoors. Mean intervention duration was 64 days.
Measures The primary outcome was ‘particle events’ (PEs) which were patterns of air particle concentrations indicative of the occurrence of particle-generating behaviours such as smoking cigarettes or burning candles. Other measures included indoor air nicotine concentrations and participant reports of particle-generating behaviour.
Results PEs were significantly correlated with air nicotine levels (r=0.60) and reported indoor cigarette smoking (r=0.51). Interrupted time-series analyses showed an immediate intervention effect, with reduced PEs the day following intervention initiation. The trajectory of daily PEs over the intervention period declined significantly faster in intervention homes than in control homes. Pretest to post-test, air nicotine levels, cigarette smoking and e-cigarette use decreased more in intervention homes than in control homes.
Conclusions Results suggest that real-time particle feedback and coaching contingencies reduced PEs generated by cigarette smoking and other sources.
Trial registration number NCT01634334; Post-results.
- Secondhand smoke
- Harm Reduction
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Contributors MFH, NEK, SCH, JB and PJEQ drafted the concept and design, aided in data interpretation, and assisted with drafting the manuscript, on which NEK and SCH served as equally contributing senior authors. BN, JB and SL handled data acquisition/management, conducted data analyses and helped draft the manuscript. VB conducted data analyses and helped draft the manuscript. MCB-D devised study protocols. MCB-D (during the first two years of the study) and SO (during the final two years of the study) coordinated field and office work, maintained operational fidelity and edited the manuscript. EJB edited the manuscript, providing pivotal feedback on content. WMO provided medical implications for future use of this type of technology, and edited the manuscript. DC performed laboratory analyses of air nicotine and urine cotinine samples. GEM edited the manuscript and contributed to the initial and final analytical models and their interpretation. RR provided leadership for the DSMB for the study, edited the manuscript and provided advice regarding the next steps in this line of research. CJ and JM provided access to and aided with recruitment of families in the Navy who qualified for the study, and confirmed possible future uses in the medical services provided by the Navy. MFH is guarantor. All authors approved the submitted manuscript.
Funding Research reported in this publication was supported by Grant Number R01HL103684 awarded to MFH and the SDSU Research Foundation (SDSURF) from the National Heart, Lung, and Blood Institute of the National Institutes of Health. JB was funded in part by a training grant provided by the National Institutes of Health (T32HL079891-11). MCB-D was funded in part by a Transdisciplinary Training for Predoctoral Behavioral Scientists, Ruth L. Kirschstein National Research Service Award (NRSA) Institutional Training Grant (T32), awarded to MFH at San Diego State University by the National Institute of General Medical Sciences, National Institutes of Health (T32 GM084896). Research reported in this publication was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under award number RO1HL103684.
Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health, SDSU, the SDSURF or other agencies. The views expressed reflect the results of research conducted by the authors and do not necessarily reflect the official policy or position of the Department of the Navy, the Department of Defense, or the U.S. Government.
Competing interests None declared.
Ethics approval The Institutional Review Board at San Diego State University approved the procedures for this study (IRB Study Number 770080) in October, 2011. There was no racial or gender bias in the selection of study participants.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement After de-identification, data will be made available to applicants who agree to use the data only for scientific purposes. Availability of the data and contact information for interested applicants will be posted on our website (http://www.cbeachsdsu.org).
Patient consent for publication Not required.