For years we have been hearing that exposure to tobacco smoke is bad, being it from fresh exhaled smoke, coming from smouldering cigarettes or lingering around in enclosed spaces for some time now. These different instances of smoke around us lead to short or long term exposure to thousands of pollutants, some 70 of them, very dangerous, being potent carcinogens. The European Environment Agency, supports the evidence that tobacco smoking in the indoor environment has always been the most important and significant contributor to a poor indoor air quality.
Nicotine is well known to be the primary component of tobacco smoke, sticking to anything in any environment. In the indoor environment, the ageing secondhand smoke, under lack of ventilation and specific chemical conditions, very easily forms 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK is the most potent and important lung carcinogen from tobacco smoke. When someone inhales nicotine, the body converts it to cotinine (COT) and trans-3′-hydroxycotinine (3HC). At the same time one cannot avoid exposure to NNK, that the body will convert it to another very potent carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL).
Given the potency of both NNK and NNAL, most of the research around the world, to date, focused on adult smokers and non-smokers. Only four studies addressed to some extent the exposure of children/adolescents to these carcinogens. Young children tend to flush these carcinogens from their body slowly compared to adults.
Why this happens is partially understood, however, the implications of a longer exposure to NNAL at such a young age and their effects in their adulthood are largely unknown.
Dr Noel Aquilina from the Department of Chemistry was the principal investigator in a study, the fifth of its kind in the world, looking into the exposure of Maltese school children (aged 9-11) to secondhand smoke and a potent tobacco-specific carcinogen through the use of several biomarkers. This study was co-authored by Professor Stephen Montefort and Dr Peter Fsadni from the Department of Medicine, Faculty of Medicine and Surgery who led the Maltese group in the project SINPHONIE. The aim of SINPHONIE was to gather data on how to improve indoor air quality in schools.
One important tool was to collect information by a questionnaire to further understand how air quality at schools influences respiratory effects. Questions were also asked about exposure of school children to secondhand smoke at home. For this purpose, the SINPHONIE team collected urine samples from school children from five public schools in Malta. The samples collected to study biomarkers of secondhand smoke were stored for several years.
The Thirdhand Smoke Research Consortium led by Professor Neal L. Benowitz from the University of California in San Francisco, who is a world leader on understanding the chemistry advances, the dynamics and health effects of secondhand and thirdhand smoke. Co-author Dr Peyton Jacob III had optimised the analytical method of a new biomarker associated with a potent tobacco-specific carcinogen. In collaboration with Dr Aquilina, an affiliate researcher within this consortium, the team at UCSF analysed the urine samples collected in Malta. Findings from this study were published in an internationally peer-reviewed journal of significant importance in the area of exposure to pollutants, Environmental Research. School children from the project SINPHONIE had three biomarkers (COT, 3HC, NNAL) extracted from their urine samples. These biomarkers could verify the level of exposure to second hand smoke at home reported in questionnaires filled by their parents.
The highlights of the findings showed that although 72.4% of the parents reported no exposure to tobacco smoke of their children at home, 95.4% of the children were exposed to nicotine whilst 98.3% were to NNK.
As almost all children were exposed to tobacco smoke, as indicated by the detection of the biomarkers, the exposure does not occur only at home, but certainly also in transit (by walking or in cars) or during other social activities where adults smoke in the presence of children. Children who were clinically diagnosed as asthmatic and exposed to smoking, had double metabolite levels of non-asthmatics. Modelling of the factors influencing the metabolite levels were mainly the school and house locations and smoking frequency at home. Some geographic and socioeconomic differences might explain the overall higher exposure at home.
Confirmed that children take longer to flush NNAL from their body. For the World No Tobacco Day 2021, the WHO’s motto was Commit to Quit. Is the above mentioned information enough for a New Year’s resolution and donating a special health gift, especially to our children?
Research on the effects of Thirdhand Smoke (when the cigarette smoke is not visible anymore) on young children, especially in smoking homes, and the implications on their health as they grow up is in its infancy. There is a long way to go to unravel the understanding of how a mixture of carcinogenic compounds affects the health of non-smokers and how the cancer risk changes according to the carcinogenicity of the mixture.
