"care for kids is care for future"

Passive Smoking & Children

Clinical and Experimental Forums

- Summary of the Meeting -

An international academic symposium held on August 24-25th, 1998, at the Medical School of Essen University, Germany, was devoted to clinical and experimental studies on toxicologic / paediatric aspects of involuntary exposure to tobacco smoke. The main organizer of the symposium was Professor Ed Nelson, head of the toxicology group at the Institute of Hygiene & Occupational Medicine of the Medical School. Over one hundred participants from Canada, China, England, Estonia, France, Germany, Hong Kong, Holland, Ireland, Norway, Poland, Scotland and USA presented scientific data on health hazards of cigarette smoke during the early infancy and childhood.

The meeting began with an invited critical-review-study by Sasco and Vainio from International Agency for Research on Cancer (IARC, Lyon) who evaluated the 50 internationally published epidemiologic studies on prenatal exposure to passive smoking, maternal active smoking, and postnatal exposure to environmental tobacco smoke (ETS), and enhanced incidence of childhood cancer. Based on the results, tumors most often found associated with maternal smoking in pregnancy or ETS exposure are childhood brain tumors and leukemia/lymphoma. According to IARC, recommendations should aim at fully protecting fetuses, newborns and infants from tobacco smoke.

Whereas the scientists from Estonia and Hong Kong presented data on the prevalence of passive smoking among school children in their countries, several European colleagues emphasized on higher incidence of respiratory diseases among passive smoking children, particularly among those with allergies or asthma. Köhler et al. (Magdeburg) compared the intensity of respiratory illness of infants and older children with the parental reports about the extend of daily cigarette smoke exposure of their kids. To access intensities of the exposure, cotinine and trans-3´-hydroxycotinine (nicotine metabolites) were analyzed in the urine of kids. Their shocking results indicate that parents of infants with serious respiratory diseases either lie or knowingly report underestimated exposure of their kids to cigarette smoke. This study was based on physical examination of 295 children aged from 2 weeks to 11 years. Almost similar disappointing results concerning the parental reports about their own smoking behavior at home were seen in Hong Kong, as presented by Chan et al.

To investigate whether advising parents of asthmatic children to either stop or reduce smoking in order to enhance the life qualities of their kids is beneficial, Irvine and colleagues (Scotland) selected 501 families at random. Cotinine was determined in sputum of kids before and after the intervention. Parents were contacted several times and intensively advised for a year. Comparing the cotinine levels determined at the end of that intervention with those collected prior to study, there was no significant difference indicating non-effectiveness of giving advice to parents. A few parents even enhanced the exposure level, whereas others ignored the professional advice.

Luck et al. (Berlin) performed a follow-up study on 307 children aged 1-5 years and found a significant reduction in total exposure of kids after entering the kindergarten. They also found that the maximum concentration of cotinine in urine was seen at the age of 1. The most common respiratory symptoms seen among school children in Hong Kong where families included at least one smoker, found Lam et al., were coughing, phlegm , wheezing and permanent irritation of nasal epithelium.

Dybing and Sanner (Oslo) summarized international literature evidencing associations between childhood passive exposure to tobacco smoke and enhanced incidences of bronchitis, bronchiolitis, pneumonia, middle ear infections, and meningococcal disease. Sudden infant death syndrome (SIDS) also seems to be associated with paternal smoking, but the link is found to be stronger if the mother smokes too. The association between passive smoking and respiratory infections and allergies could be further evidenced through laboratory studies of Fan et al. (Illinois) who found reduction in critical function of macrophages in defense mechanism following exposure to cigarette's sidestream smoke. According to Kulig et al. (Berlin), pre- and postnatal exposure to tobacco smoke enhances specific serum IgE and thus leads to a significant increase in food allergies.

Through a population-based study on 3178 Dutch twin pairs, Orlebeke and Koole (Amsterdam) demonstrated that although maternal smoking increases the prevalence of strabismus, paternal smoking does not clearly seem to have the same effect but still requires further investigations.

Several scientists considered different biological samples suitable for prediction of passive exposure of children to tobacco smoke. Whereas Nuesslein et al. (Bochum) recommended testing meconium for cotinine in early infancy, Klein et al. (Toronto) demonstrated effectiveness of testing hair samples and Phillips et al. (Yorkshire) showed efficiency of saliva from older kids for such a routine testing.

In contrast to international findings regarding developmental toxicity of passive smoking, Hanke et al. (Poland) could find a "weak" association between maternal passive smoking during gravidity and small-for-gestation of newborns. They, however, honestly criticized their own methodical shortcomings during the investigation. Another Polish scientist, Florek, talked about acute respiratory distress syndrome in kids associated with maternal smoke inhalation during gestation, and about influences of smoke on fertility in experimental animals. Experimental studies of Gairola et al. (Lexington) following pre- and postnatal exposure of rat pups to cigarette's sidestream smoke have demonstrated that although sidestream smoke has a minimal effect on developing rat pulmonary surfactant, it induces biochemical changes in the lung.

Although there is no more scientific doubt that maternal active smoking during pregnancy can cause malformations at various degrees of magnitude, there has been no indication before that maternal passive smoking, i.e. paternal smoking during pregnancy of wives, can also lead to teratogenic effects. A long-term study at the laboratory of Nelson (Essen) showed that maternal passive exposure to the sidestream smoke of one cigarette results in about 40% reduction in birthweight and dimensions of rat pups. Furthermore, an ossification retardation could be observed in skeleton of most in utero exposed animals. Microscopically, hyperplasia of bronchial muscles, proliferation of bile duct cells, immature glomeruli of kidney, epithelhypoplasia of stomach, and hypoplasia of intestinal villi were common among newborns of passively exposed mothers. These data lead to a new evidence that passive smoking during pregnancy can indeed induce various hidden malformations and thus consequences of passive smoking upon pregnancy are not limited to only a reduced birthweight.

The last session of the symposium was devoted to an open discussion panel. Five invited key scientists along with enthusiastic audience and several journalists continued discussions aiming at prophylactic strategies and how to keep parents, physicians, kindergarten and school teachers, as well as allied health professionals informed about the actual health hazards of passive smoking during infancy and childhood.

The 1999 spring issue of the international journal "Human & Experimental Toxicology" (Vol. 18, issue 4) covers full manuscripts of most lectures presented at this meeting (in English language only).

Abstract book (in English only) can be obtained from the author by fax (see below); you'll be charged for copy & postage.

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