Tobacco and Public Health - TCSC Indonesia

300
PASSIVE SMOKING AND HEALTH
ranging from 1.2 to 2.6 for those exposed compared with those nonexposed. These
studies are too limited to support any conclusions.
Postnatal health effects. Secondhand smoke exposure due to maternal or paternal
smoking may lead to postnatal health effects, including increased risk for SIDS,
reduced physical development, decrements in cognition and behavior, and increased
risk for childhood cancers. For cognition and behavior, evidence is limited and
is not considered in this review. There is more extensive information available on
maternal smoking during pregnancy and subsequent neurocognitive development
(US Department of Health and Human Services 2001; US Department of Health and
Human Services & Centers for Disease Control and Prevention 2003).
SIDS. SIDS refers to the unexpected death of a seemingly healthy infant while asleep.
Although maternal smoking during pregnancy has been causally associated with SIDS,
these studies measured maternal smoking after pregnancy, along with paternal smoking
and household smoking generally. In the WHO consultation, the evidence on passive
smoking (i.e. postbirth) and SIDS was considered to be inconclusive, although
there was some indication of increased risk (WHO 1999). Since most women who
smoke during pregnancy continue to do so after delivery, researchers cannot separate
the effects of exposure from maternal smoking before and after delivery and the
evidence on paternal smoking, constituting exposure to secondhand smoke alone,
is inconclusive.
Cancers. Secondhand smoke exposure has been evaluated as a risk factor for the major
childhood cancers. The evidence is limited and does not yet support conclusions about
the causal nature of the observed associations. In the meta-analysis conducted for the
WHO consultation (Boffetta et al. 2000), the pooled estimate of the relative risk for any
childhood cancer associated with maternal smoking was 1.11 (95 per cent confidence
interval (CI): 1.00, 1.23) and that for leukemia was 1.14 (95 per cent CI: 0.97, 1.33).
Lower respiratory tract illnesses in childhood. Lower respiratory tract illnesses are
extremely common during childhood. Studies of involuntary smoking and lower
respiratory illnesses in childhood, including the more severe episodes of bronchitis
and pneumonia, provided some of the earliest evidence on adverse effects of secondhand
smoke (Colley et al. 1974; Harlap and Davies 1974). Presumably, this association represents
an increase in the frequency or in the severity of illnesses that are infectious in
etiology and not a direct response of the lung to the toxic components of secondhand
smoke. Effects of exposure to tobacco smoke in utero on the airways may also play
a role in the effect of postnatal exposure on risk for lower respiratory illnesses. Infants
of mothers who smoke during pregnancy have evidence of damage to their airways
during gestation on lung function testing shortly after birth, and this damage may
increase the likelihood of having a more severe infection (Samet and Wang 2000). The
evidence indicates that the airways of the exposed infants are functionally narrowed
and have a higher degree of nonspecific responsiveness.