The impact of environmental tobacco smoke exposure on cardiorespiratory fitness in children: A pilot study

Abstract

Environmental tobacco smoke (ETS) in indoor air is a substantial risk factor for many health issues. Children are particularly susceptible to ETS with increased risk of asthma attacks, respiratory infections and sudden infant death syndrome. The health effects of ETS are well researched in adults, but few studies examine the impact on children’s cardiorespiratory fitness (CRF). CRF has been shown to be a useful biomarker for monitoring health effects which would normally be too subtle to identify at rest. In adults, ETS has been shown to reduce CRF, and children may be at greater risk due to high respiration rates and developing organs. This preliminary research tests the hypothesis that ETS has a detrimental impact on CRF in children. Twenty-five children (9-11 years) from one Merseyside primary school were recruited. ETS exposure was determined by parental surveys and coupled with children’s exhaled carbon monoxide concentration. CRF was determined using a VO2peak test, with lung function assessed using standard spirometry, and fractional exhaled nitric oxide (FeNO) provided an indication of lung inflammation. Initial results show that children exposed to ETS had statically lower CRF scores (p = 0.048) and were more likely to be classified as ‘unfit’ compared to children not exposed. A negative correlation was found between the number of cigarettes smoked at home and children’s CRF (r = -0.526, p = 0.008), suggesting a possible dose-response relationship. Spirometry and FeNO values were not statistically different between groups. Results indicate that ETS exposure is likely to be detrimental to children’s CRF. They highlight the need for further work, on a larger dataset that will allow more robust analysis with greater statistical power. To the author’s knowledge, this study is the first of its kind to use laboratory-based fitness measurements to explore associations between ETS and CRF in children.