Trust but verify…the importance of multimethod and biomarker assessments of prenatal substance exposures

The paper by Micalizzi et al., “Insights into the validity of concurrent and retrospective maternal report of infant smoke exposure using biomarker-based validation,” is a timely reminder of the complexities of reliably assessing children’s exposure to tobacco in order to determine developmental sequelae and inform public health warnings and responses.The study capitalizes on a unique longitudinal data set derived from two sources over a 17-year period. The study found systematic bias in mothers’ recall of infant exposure, depending on whether they acknowledged or denied it. The findings highlight the need for prospective and bioverified studies of children’s exposure to ETS as well as to other substances that may harm children’s development, particularly where stigma and social undesirability, as well as degradation of memory, may influence maternal reporting. Methodological issues in developmental neurotoxicology studies are considered, including confounding factors of polysubstance use, environmental chemicals, biomarker characteristics, socioeconomic status and assessment timing, frequency and amount. Implications of the present study are important for several clinical and methodological reasons. Both biomarkers and survey reports or interview assessments are critical to increasing the accuracy of understanding the occurrence of and the thresholds for prenatal and postnatal impacts of substances such as ETS.