Assessing tobacco smoke exposure in pregnancy from self-report, urinary cotinine and NNAL: a validation study using the New Hampshire Birth Cohort Study

Abstract

ObjectivesAccurate assessment of tobacco smoke exposure is key to evaluate its effects. We sought to validate and establish cut-offs for self-reported smoking and secondhand smoke (SHS) exposure during pregnancy using urinary cotinine and 4-(methylnitrosamino)-1-(-3-pyridyl)-1-butanol (NNAL) in a large contemporary prospective study from the USA, with lower smoking prevalence than has previously been evaluated.DesignProspective birth cohort.SettingPregnancy clinics in New Hampshire and Vermont, USA.Participants1396 women enrolled in the New Hampshire Birth Cohort Study with self-reported smoking, urinary cotinine, NNAL and pregnancy outcomes.Primary and secondary outcome measuresCut-offs for urinary cotinine and NNAL concentrations were estimated from logistic regression models using Youden’s method to predict SHS and active smoking. Cotinine and NNAL were each used as the exposure in separate multifactorial models for pregnancy outcomes.ResultsSelf-reported maternal smoking was: 72% non-smokers, 5.7% ex-smokers, 6.4% SHS exposure, 6.2% currently smoked, 10% unreported. Cotinine and NNAL levels were low and highly intercorrelated (r=0.91). Geometric mean cotinine, NNAL were 0.99 ng/mL, 0.05 pmol/mL, respectively. Cotinine cut-offs for SHS, current smoking were 1.2 ng/mL and 1.8 ng/mL (area under curve (AUC) 95% CI: 0.52 (0.47 to 0.57), 0.90 (0.85 to 0.94)). NNAL cut-off for current smoking was 0.09 pmol/mL (AUC=0.82 (95% CI 0.77 to 0.87)). Using cotinine and NNAL cut-offs combined gave similar AUC to cotinine alone, 0.87 (95% CI 0.82 to 0.91). Cotinine and NNAL gave almost identical effect estimates when modelling pregnancy outcomes.ConclusionsIn this population, we observed high concordance between self-complete questionnaire smoking data and urinary cotinine and NNAL. With respect to biomarkers, either cotinine or NNAL can be used as a measure of tobacco smoke exposure overall but only cotinine can be used to detect SHS.

Nicotine or marijuana vaping exposure during pregnancy and altered immune responses in offspring

“…It is important to acknowledge that a discussion on the measurement of metabolites or adducts of carcinogenic substances would be helpful, since some of these compounds require metabolic activation to exert adverse effects. Some birth cohort studies, even with low smoking prevalence, have shown that urinary biomarker values and self-reported smoking can be used to assess passive exposures [ 44 ] . Interestingly, one birth cohort study observed an association between offspring DNA methylation and metabolites of cigarette smoke (except for nicotine) [ 45 ] .…”

“…Both nicotine and cannabis vapes contain complex mixtures of chemicals, and such complexity increases with thermal degradation chemistry [42] . The study by Li et al underscores the need for further research on individual components to gain a thorough understanding of aerosol composition from using various vaping devices while accounting for individual user settings [43] .…”

Bridging Differences in Cohort Analyses of the Relationship between Secondhand Smoke Exposure during Pregnancy and Birth Weight: The Transportability Framework in the ECHO Program

“…We limited eligible cohorts to those with at least 1,000 participants with complete exposure and outcome information (after excluding participants with self-reported active maternal smoking during pregnancy) to maximize the power for the cohort-specific target parameter estimation. This approach resulted in the following five cohorts contributing data for this study: the Healthy Start Study 18 , 19 with participants recruited in Denver, Colorado, between 2009 and 2014 (herein referred to as Cohort 1); the Pregnancy Environment and Lifestyle Study (PETALS) 20 with participants recruited in Northern California between 2013 and 2018 (herein referred to as Cohort 2); the Wayne County Health Environment Allergy and Asthma Longitudinal Study 21 with participants recruited in Wayne County, Michigan, between 2002 and 2007 (herein referred to as Cohort 3); the New Hampshire Birth Cohort Study 22 , 23 with participants recruited in New Hampshire between 2008 and 2022 (herein referred to as Cohort 4); and the NYU Children’s Health and Environment Study (NYU CHES) 24 with participants recruited in New York City, New York, between 2015 and 2022 (herein referred to as Cohort 5). Additional information for each cohort is detailed in Table S1.…”

“…Urine samples were collected at various stages during pregnancy according to individual study protocols ( wk of gestation for Cohort 1, between 24 and 28 wk of gestation for Cohort 4, and at , 18–25, and wk of gestation for a total of three samples in Cohort 5). 19 , 23 , 24 A binary cotinine-based definition of exposure considered participants with measurements above the lower level of quantification as exposed, whereas levels above were considered a conservative cutoff consistent with active smoking and were not included. 25 Because Cohort 5 had multiple measurements per participant, any given participant was considered exposed if any sample was above the lower level of quantification.…”

Malpresentation and autism spectrum disorder in the study to explore early development: Methodological challenges and considerations

“…For example, maternal smoking was self-reported 3-5 years after pregnancy and therefore subject to recall bias, while use of questionnaire data alone may lead to slight underestimates in the true prevalence of smoking and potentially distort the results. 9 Furthermore, as alluded to by the authors, the subgroup analysis by delivery mode should be interpreted cautiously. While the results may indicate an effect modification between malpresentation and vaginal delivery, the mode of delivery is a potential mediator, which makes the interpretation difficult.…”