Environmental tobacco smoke and children: assessment of exposure and health effects

To assess prospectively 1) concentrations of metals and progesterone in placental tissue related to cigarette smoking; 2) the effect of parental smoking on the susceptibility to colds in preadolescent children during winter months. The first study comprised healthy parturients with median age 28 years, 29 non-smokers and 27 women who smoked during pregnancy and/or within one year before last pregnancy. Placentas were collected after delivery at term and metals (by atomic absorption spectrometry) and placental progesterone (by specific radioimmunoassay) were analysed. A comparative study in 337 school children, second graders, was undertaken in central urban and suburban area. Information on children and families and on parental smoking was collected. During the six-month period incidence of acute respiratory diseases was followed-up. In placentas of smoking vs. non-smoking women a twofold increase in cadmium concentration, a decrease in iron and a half of progesterone concentration as a biomarker of effect of tobacco smoke exposure were found. Nearly 59 percent of Croatian children live in the household with at least one smoker. The incidence of colds in children was 25%. The study demonstrates an exposure-response relationship between the parental smoking and the reporting rates for doctor-diagnosed upper respiratory illness; in children exposed to both parents' smoke odds ratio was 2.03 and in children from the family with one smoker odds ratio was 1.65. Results support the established association of tobacco smoke exposure with increased placental cadmium concentration, and concomitant reduction of placental progesterone is a new evidence on health risk for mother and foetus. The higher risk of frequent colds in children related to environmental tobacco smoke is a relevant public health problem.