Further experimental and observational studies should be conducted to assess the effect of long-term and acute ETS exposure on cardiac function, blood pressure, and angina in nonsmokers.

Several other health outcomes have been studied that relate to the growth and health of children. For all postnatal outcomes, it is often not possible to differentiate the effect of in utero exposure to ETS from subsequent childhood exposures to ETS.

Nonsmoking pregnant women exposed to smoking spouses have been reported to produce babies of lower birthweight than nonsmoking women with nonsmoking spouses. Some studies have noted a dose-response relationship between the number of cigarettes smoked by fathers and birthweight of the offspring. Additional studies of intrauterine fetal growth retardation associated with ETS exposure of nonsmoking mothers need to be conducted with better assessments of the magnitude of ETS exposure.

Several studies have examined possible relationships between chronic exposure to ETS by children and parameters of growth and development. Growth is an especially difficult phenomenon to study since many factors—such as genetics, nutrition, social class, and ethnicity—play important roles. It is difficult to assign proportional causality to each factor. Moreover, height and weight ratios and other growth measures are not reliably obtained in standard pediatric surveys. A few studies have shown that children of smokers have reduced growth and development, and one study reported a dose-response relationship between reduced height and increasing numbers of cigarettes smoked in the home by either the mother or the father. Further work is needed to determine the nature of this association.

Otitis media is a common occurrence in young children. In several studies, parental smoking, along with several other risk factors, has been linked to increased risk of chronic ear infections in children. Further work is needed to determine whether the association is causal.