Exposure to tobacco smoke and validation of smoking status during pregnancy in the MIREC study
- DOI
- Language of the publication
- English
- Date
- 2018-01-03
- Type
- Article
- Author(s)
- Arbuckle, Tye E.
- Liang, Chun Lei
- Fisher, Mandy
- Caron, Nicolas J.
- Fraser, William D.
- the MIREC Study Group
- Publisher
- Springer Nature
Abstract
Given that prenatal exposure to tobacco smoke can lead to increased risks of adverse health effects, having valid measures of exposure is important. In a Canadian cohort (n = 2000), maternal and infant biospecimens were analysed for cotinine. Sensitivity and specificity of self-reported active smoking status were estimated. Regression modelling was used to identify potential predictors of maternal and infant plasma cotinine in non-smoking women. During the first trimester, 60.6% of the women reported never smoking, 27.3% were former smokers, 6.1% had quit when they found out they were pregnant, 5.8% were smokers and 42% of the non-smokers reported exposure to secondhand smoke (SHS). Low detection of tobacco biomarkers in meconium limited its ability to identify exposure to SHS. The sensitivity and specificity for self-reported smoking during the 1st trimester were 85.37 and 99.45%, respectively. The lowest sensitivity was found in participants with the highest level of education and income, oldest women and those born outside Canada. Non-smoking women living in an apartment had 1.7 times higher odds of detectable plasma cotinine than those living in a single home after adjusting for other variables. Our results suggest that while self-reports are fairly accurate, they may be less so in populations with higher socio-economic status. This investigation underscores the need to consider the participant socio-economic characteristics and dwelling type when using questionnaires to estimate active and passive tobacco exposure.
Plain language summary
Health Canada helps to protect the health of Canadians by assessing and managing the health risks associated with exposure to environmental contaminants. Limited information is available on exposure to tobacco smoke in Canadian pregnant women. As prenatal exposure to tobacco smoke can lead to increased risks of adverse health effects for the infant, it is important to have valid measures of exposure. In the Maternal-Infant Research on Environmental Chemicals (MIREC) Study of 2,000 pregnant women from 10 cities across Canada, women were asked about their smoking habits and exposure to second-hand smoke. Their blood and that from the infant’s umbilical cord were analysed for cotinine, a metabolite of nicotine. During the first trimester, 61% of the women reported never smoking and 4.5% reported daily smoking. Smokers were more likely to be younger, less educated, and have a lower household income. There was good (85%) agreement between the woman’s report of her exposure to tobacco and the cotinine levels in her blood. Non-smoking women living in an apartment had 1.7 times higher odds of cotinine being measured in their blood than those living in a single detached home, even after considering other variables. Dwelling type was not significantly associated with cotinine levels in the umbilical cord of non-smoking women. Although smoking prevalence was low in this population, it was higher in those women with a lower socio-economic status. The study results suggest that self-reports are fairly accurate; however, it is important to evaluate how true self-reported tobacco exposure is, as it may vary by population. This study was conducted in collaboration with the Centre de toxicologie du Québec, the Centre de recherche du Centre hospitalier universitaire de Sherbrooke, and the Sainte Justine University Hospital Research Center. The results of this paper will be used to inform future research, and provide Canadians with information so they can make healthier choices, lead healthier lives, and build a healthier society.
Subject
- Health,
- Health and safety