Secondhand smoke exposure, smoking hygiene, and hospitalization in the first 18 months of life.

Background: Recognizing the suboptimal public health effects of a complete cessation strategy for parents and child caregivers who smoke, some researchers have called for a harm reduction approach; however, the evidence remains scanty and controversial.
Objective: To examine the effects of secondhand smoke and smoking hygiene on infant health and related health care costs during the first 18 months of life.
Methods: We conducted prospective follow-up on 8327 newborns during April and May of 1997 for 18 months in a population-based birth cohort of infants from Hong Kong, China.
Main Outcome Measures: Number of hospital admissions, adjusted odds ratios for ever hospitalization for each secondhand smoke exposure variable, and corresponding population attributable risks.
Results: Most secondhand smoke exposure came from fathers and other household contacts, whereas only 2.8% of mothers smoked postpartum. The odds ratio of ever hospitalization due to all illnesses combined for infants living in a household with any (maternal, paternal, or other) smoker who was smoking at least 3 m away from the infant, as reported by a parent, was 1.00 (95% confidence interval, 0.88-1.13) compared with those in a smoke-free household. The corresponding odds ratio for infants living with any smoker at home with poor smoking hygiene (<3 m away) was 1.28 (95% confidence interval, 1.07-1.52), which translated into 2.8% of all inpatient episodes in the first year of life, representing an additional 616 admissions.
Conclusions: Hospital admission was significantly more likely among infants exposed to secondhand smoke if it was accompanied by poor smoking hygiene. Harm reduction strategies should be rigorously adhered to when complete cessation is not possible.