4.17 Health effects of secondhand smoke for infants and children

Last updated: March 2021
Suggested citation: Campbell MA, Winnall WR, Ford C, & Winstanley MH. 4.17 Health effects of secondhand smoke for infants and children. In Greenhalgh, EM, Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2021. Available from http://www.tobaccoinaustralia.org.au/chapter-4-secondhand/4-17-health-effects-of-secondhand-smoke-for-infants

 

This section summarises the research on the association between exposure to secondhand smoke and the childhood conditions of:

Worldwide, secondhand smoke causes significant morbidity and mortality.1 Children are particularly susceptible to the effects of secondhand smoke due to their higher breathing rates, greater lung surface area,2 and the developmental processes their bodies are undergoing.3 Infants and children are also generally unable to control their environment, and therefore cannot take steps to avoid exposure to secondhand smoke.2 A lower ability to detoxify cancer-causing chemicals from smoke may also make children more susceptible to the effects of secondhand smoke than adults.4

There are several possible routes by which the effects of tobacco smoke may compromise infant and child health. Before birth, there may be damage to sperm from paternal active smoking.3, 5-7 In utero maternal active smoking or maternal secondhand smoke exposure can also cause foetal harm.2, 3 The effects of smoking during pregnancy are discussed further in Section 3.7. Following birth, infants and children may be exposed to parental secondhand smoke in the home,3 to thirdhand smoke in household dust and indoor surfaces,8 and to bacterial or viral infections carried by a parent or carer who smokes.9-11 Both prenatal and postnatal tobacco exposure have been found to contribute to several health conditions.3, 12 Delineating the impact of each route of exposure in the causation of disease can sometimes be difficult, particularly for rare conditions. In many studies, the effects of maternal smoking are considered as a whole, rather than determining the individual effects of pre and post-natal maternal smoking.

Children are most likely to be exposed to secondhand smoke in the home. In Australia, larger household size, rural living, low socioeconomic status and a single-parent household are risk factors for home second-hand smoke exposure.13 Infant exposure to secondhand smoke in Australia (measured by urine cotinine levels) is associated with the smoking status of household members, absence of complete smoking bans in smoking households and having more than one smoker in the home.14 In Australia, the proportion of children who are exposed to secondhand smoke at home is falling—see Section 4.5.

The proportion of mothers who smoke during pregnancy is also falling in Australia. Between 2011 and 2017, the proportion of mothers who reported smoking during the first 20 weeks of pregnancy fell from 13% to 9.5%.15 See Section 1.10.1 for further details.

4.17.1 Infant death

Infant death is defined as the death of a child within the first year of life.15 Exposure to smoking in utero and following birth is associated with several of the major causes of death during infancy, including low birthweight, preterm delivery and sudden infant death syndrome (see Section 4.17.2).3, 12, 16-20 In US prenatal smoking has been associated with preterm-related infant deaths (adjusted OR 1.5) and SIDS deaths (adjusted OR of 2.7). This equated to 5.0% to 7.3% of preterm-related deaths and 23.2% to 33.6% of SIDS deaths attributed to prenatal smoking.21 A study from South-East Asia found that exposure to secondhand smoke increased the odds of under-five child mortality (OR of 1.25), particularly when both parents smoked (OR of 2.6).22 

4.17.2 Sudden infant death syndrome (SIDS)

Sudden infant death syndrome (SIDS) is defined as the sudden, unexpected death of an infant under one year of age, occurring during sleep, which remains unexplained after a thorough investigation including performance of a complete autopsy and review of the circumstances of death.23 SIDS is predicted to have a multifactorial cause. The triple risk hypothesis proposes that SIDS occurs when a vulnerable infant is at a critical but unstable developmental period in homeostatic control, and is exposed to an exogenous stressor. Exposure to secondhand smoke during development and after birth can make these infants vulnerable to exogenous stressors, such as sleeping in a prone position.24 The mechanisms behind SIDS are believed to include disrupted cardio‐respiratory control combined with a failure of arousal from sleep.

Smoking is a cause of SIDS, from smoking by the parents during pregnancy and by exposure to secondhand smoke after birth.2, 3 Estimating individual risks from maternal smoking during pregnancy and secondhand smoke after birth can be challenging, as the two are closely associated.25 According to Australian estimates, infants exposed to maternal secondhand smoke after birth have nearly 2.5 times the risk of dying from SIDS compared with unexposed infants.26 International reviews estimate that secondhand smoke exposure during infancy doubles the risk of SIDS.2, 3, 27 When the mother is a non‐smoker, parental smoking has an estimated risk of 1.5 times that of non-smoking parents.25 A dose–dependent effect is predicted, where the risk of SIDS increases with the number of cigarettes smoked by the parents. Infants who die from SIDS have been found to have a higher concentration of nicotine in their lungs than infants who have died from other causes.3, 20 These findings make secondhand smoke exposure an important preventable risk factor for SIDS.3 In recent years, increasing numbers of parents have striven to protect their children from secondhand smoke by forgoing smoking within their homes, which is likely to have contributed to a substantial reduction in deaths from SIDS.26

The exact mechanisms by which secondhand smoke is causing SIDS are under investigation. Research in humans and from animal studies have uncovered numerous possibilities. The relative contributions of prenatal and post-natal secondhand smoke exposure to these mechanisms is difficult to determine, as most studies in humans involved parents that smoked before as well as after birth. Studies of human preterm infants show that exposure to cigarette smoke is associated with impaired recovery from hypoxia —a drop in oxygen supply to the body, such as from a breathing pause.20, 28 Human infants whose mothers smoke had less progression from sub-cortical activation to cortical arousal compared to unexposed infants.29 There was a significant dose-dependent association between cortical activation and urinary cotinine levels, a biomarker for nicotine.29 Animal studies are better able to separate the two exposures. Animals studies of secondhand, but not prenatal, smoke exposure have demonstrated changes to brain development that may contribute to SIDS. Some of these changes are known to affect cardio-respiratory function.3

4.17.3 Childhood asthma and other chronic respiratory conditions

Exposure to secondhand smoke causes a range of respiratory symptoms, such as cough, phlegm production, breathlessness and wheezing in children of primary school age.3 These symptoms are common in childhood, and may restrict the activities of those who experience them.3, 30

Asthma is a significant issue for the health of primary school children in Australia. Among all children aged 5–14, asthma was the leading cause of disease burden in 2015.15 The National Health and Medical Research Council (1997)31 and the California Environmental Protection Agency (2005)2 have both concluded that secondhand smoke causes asthma as well as exacerbates asthma in children. The US Surgeon General’s 2006 report states that secondhand smoke exposure is a cause of asthma in childhood and makes asthma more severe.3 A later meta-analysis supported the association of prenatal and postnatal secondhand smoking exposure and occurrence of childhood asthma (OR of 1.24), asthma-like syndrome, and wheezing.32 Worldwide data from 2004 showed that children (0 to 14 years) had a higher chance of having asthma if at least one parent smoked (OR 1.32 (1.24–1.41)).1 The prevalence of asthma is greater among children living in households with smokers and the risk of developing asthma increases in proportion with the number of smokers in the home.3 Among children with asthma, those exposed to secondhand smoke are nearly twice as likely to be hospitalised with an acute asthma episode and have poorer pulmonary function test results.30 In 2004–05, 11% of Australian children with asthma were living in homes where smoking took place indoors.33 It is estimated that 2% of asthma deaths in Australian children under 15 years in that year were attributable to secondhand smoke.34  

The evidence is unclear on whether there is an association between secondhand smoke exposure and allergic sensitisation (initiation of allergic responses due to exposure to an allergen).2, 3, 35-37 However, some studies suggest there may be a synergy between hereditary risk for allergies and secondhand smoke exposure.3, 38, 39 Children exposed to secondhand smoke may be more likely to snore40-42 or suffer sleep-related breathing problems.43, 44 One large study has reported that respiratory symptoms such as chronic dry cough and production of phlegm may persist into adulthood among children who live with a smoker, independent of later exposure to secondhand smoke.45

In an African study, children exposed to secondhand smoke had a 3-fold higher chance of catching tuberculosis than unexposed children.46

4.17.4 Acute respiratory tract infections in infancy and childhood

Children exposed to secondhand smoke in the home have a greater risk of contracting acute chest infections, including bronchitis, bronchiolitis and pneumonia.3, 47, 48 The effect is most pronounced in children aged under two.2, 3 Infants exposed to secondhand smoke in the home have a 50% higher chance of developing lower respiratory illness than unexposed children.27, 47 This risk is even greater for those children living in households in which the mother smokes (about 60%).3, 27, 47 In infants up to 2 years of age, there was an increased chance of admission to hospital for lower respiratory tract infection if either parent smoked (OR of 1.55).1, 49 Exposure to secondhand smoke is also associated with chronic rhinosinusitis in children (inflammation of the nose and the paranasal sinuses).50 More research is necessary to determine whether these associations are causative.

Implementation of comprehensive smoke-free legislation can result in a significant reduction in hospital admissions for childhood lower respiratory tract infections.51-53

4.17.5 Decreased lung function

The lungs continue to grow and develop throughout childhood and adolescence. The period between birth and four years of age is a particularly vulnerable time for lung growth and development, when the number of alveoli in the lungs is increasing. Secondhand smoke causes decreased lung function during childhood, leading to a reduced maximum level in adolescence and early adulthood.3, 54, 55 This impairment may potentially increase vulnerability to other lung damage, including damage caused by active smoking, secondhand smoke exposure later in life, and exposure to air pollution and occupational irritants.2, 3

Maternal smoking increases the risk of below-average lifetime lung function trajectories that increase the risk of chronic obstructive pulmonary disease in later life, according to results from the Tasmanian Longitudinal Health Study.56

4.17.6 Middle ear disease

Middle ear disease (otitis media) occurs when the eustachian tube, which connects the middle ear to the back of the throat, becomes blocked or swollen, causing fluid to build up in the middle ear. This fluid can become infected, usually by bacteria.2, 57 Exposure to secondhand smoke causes middle ear disease, including acute and recurrent otitis media and chronic middle ear effusion (fluid build-up without infection, also known as ‘glue ear’).3 Children exposed to secondhand smoke in the home have a 30% to 40% increased risk for middle ear disease,1, 58, 59 and a 46% increased risk if their mother smokes.27 Moreover, ear disease in children of smokers appears less likely to resolve spontaneously than among children of non-smokers.3 This has important implications for child health. Episodes of glue ear in early life are associated with hearing loss and may lead to long-term problems with speech, and a range of developmental, behavioural and social consequences.60

4.17.7 Reduced sense of smell

Children exposed to secondhand smoke in the home may have impaired olfactory function, but the research in this field is limited. One small study has shown that children living with a parent who smoked a packet of cigarettes a day were more likely to mis-identify aromas compared with a control group of children not living with a smoker.61, 62

4.17.8 Longer-term developmental effects

There is evidence suggesting an association between exposure to secondhand smoke and an impact on cognition and behaviour, including higher likelihood of childhood conduct problems and learning difficulties.2, 3, 63-72 Smoking by either parent was associated with a slower language development in their children.73 Postnatal exposure to secondhand smoke in children increased the risk of attention deficit hyperactivity disorder in one study, with an odds ratio of 1.60.74 Children up to the age of eight years with smoking mothers were more likely to be shorter and weigh less than their unexposed peers, indicating a negative effect on development.75 For all these potential developmental effects of secondhand smoke, more research is necessary to determine whether these associations are causal.

4.17.9 Childhood cancers

There is a growing body of evidence suggesting an association between parental smoking (during the preconception, prenatal and postnatal periods) and brain tumours, lymphomas and acute lymphocytic leukaemia in children.2, 3, 76, 77 However, not all studies have found a positive relationship between secondhand smoke exposure and childhood cancers.78 The 2009 review by the International Agency for Research in Cancer (IARC) concluded that children born of parents who smoke (father, mother or both, including in the preconception period and pregnancy) are at a significantly higher risk of hepatoblastoma, a rare childhood cancer of the liver.77 Possible mechanisms include damage to sperm DNA and damage to the foetal liver from carcinogens in the blood of the pregnant mother, either from active smoking or secondhand smoke.79, 80 The 2009 IARC review also stated there was limited evidence to suggest that paternal smoking before pregnancy was associated with childhood leukaemia.7, 77 Since this report, a longitudinal study has shown that maternal smoking during pregnancy and postnatally is associated with lower overall survival for children with acute lymphoblastic leukaemia.81 The relationship between secondhand smoke and childhood cancers requires further research to investigate causality.

4.17.10 Perioperative complications

A strong association has been observed between the incidence of respiratory complications in children undergoing general anaesthesia and a history of exposure to secondhand smoke.82-84 There is also evidence that children exposed to secondhand smoke have a different metabolic response to drugs administered during surgery.85

4.17.11 Other conditions in childhood

Limited research suggests an association between exposure to secondhand smoke and dental problems in children, such as delayed dental development,86 tooth decay87, 88 and poorer attachment of the teeth to the gum and supporting structures.2, 89-92

Some studies indicate an association between exposure to secondhand smoke and gastrointestinal problems in children, such as diarrhoea and gastroenteritis.93-95

There is some research suggesting that secondhand smoke exposure in utero or during childhood may be associated with an increased risk of obesity and central obesity.96-99

For children of parents who smoke, there is some evidence of impaired bone health as adults.100 Eye defects may also be associated with childhood exposure to secondhand smoke, although the affected children were more likely to have lower socioeconomic status.101

For all these conditions, further research is necessary to determine whether these associations with secondhand smoke exposure are causal.


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References

1. Oberg M, Jaakkola MS, Woodward A, Peruga A, and Pruss-Ustun A. Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries. Lancet, 2011; 377(9760):139-46. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21112082

2. Office of Environmental Health Hazard Assessment and California Air Resources Board. Health effects of exposure to environmental tobacco smoke: final report, approved at the Panel's June 24, 2005 meeting. Sacramento: California Environmental Protection Agency, 2005. Available from: http://www.oehha.ca.gov/air/environmental_tobacco/2005etsfinal.html

3. US Department of Health and Human Services. The health consequences of involuntary exposure to tobacco smoke: a report of the Surgeon General. Atlanta, Georgia: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2006. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/sgr_2006/index.htm.

4. Chao MR, Cooke MS, Kuo CY, Pan CH, Liu HH, et al. Children are particularly vulnerable to environmental tobacco smoke exposure: Evidence from biomarkers of tobacco-specific nitrosamines, and oxidative stress. Environental International, 2018; 120:238-45. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30103123

5. Fraga CG, Motchnik PA, Wyrobek AJ, Rempel DM, and Ames BN. Smoking and low antioxidant levels increase oxidative damage to sperm DNA. Mutation Research, 1996; 351(2):199-203. Available from: https://www.ncbi.nlm.nih.gov/pubmed/8622715

6. Horak S, Polanska J, and Widlak P. Bulky DNA adducts in human sperm: relationship with fertility, semen quality, smoking, and environmental factors. Mutation Research, 2003; 537(1):53-65. Available from: https://www.ncbi.nlm.nih.gov/pubmed/12742507

7. Lee KM, Ward MH, Han S, Ahn HS, Kang HJ, et al. Paternal smoking, genetic polymorphisms in CYP1A1 and childhood leukemia risk. Leukemia Research, 2009; 33(2):250-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18691756

8. Matt GE, Quintana PJ, Hovell MF, Bernert JT, Song S, et al. Households contaminated by environmental tobacco smoke: sources of infant exposures. Tobacco Control, 2004; 13(1):29-37. Available from: https://www.ncbi.nlm.nih.gov/pubmed/14985592

9. Arcavi L and Benowitz NL. Cigarette smoking and infection. Archives of Internal Medicine, 2004; 164(20):2206-16. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15534156

10. Brook I and Gober A. Recovery of potential pathogens in the nasopharynx of healthy and otitis media-prone children and their smoking and nonsmoking parents. Annals of Otology, Rhinology, and Laryngology, 2008; 117(10):727–30. Available from: https://pubmed.ncbi.nlm.nih.gov/18998498/

11. Robinson P, Taylor K, and Nolan T. Risk-factors for meningococcal disease in Victoria, Australia, in 1997. Epidemiology & Infection, 2001; 127(2):261-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11693503

12. US Department of Health and Human Services, The health consequences of smoking: a report of the Surgeon General. Atlanta, Georgia: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2004. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/2004/complete_report/index.htm.

13. Longman JM and Passey ME. Children, smoking households and exposure to second-hand smoke in the home in rural Australia: analysis of a national cross-sectional survey. BMJ Open, 2013; 3(7). Available from: https://www.ncbi.nlm.nih.gov/pubmed/23833145

14. Daly JB, Wiggers JH, Burrows S, and Freund M. Household smoking behaviours and exposure to environmental tobacco smoke among infants: are current strategies effectively protecting our young? Australian and New Zealand Journal of Public Health 2010; 34(3):269-73. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20618268

15. Australian Institute for Health and Welfare. Australia's children. Canberra, Australia: AIHW, 2020. Available from: https://www.aihw.gov.au/reports/children-youth/australias-children/contents/health/infant-child-deaths.

16. Malloy MH, Kleinman JC, Land GH, and Schramm WF. The association of maternal smoking with age and cause of infant death. American Journal of Epidemiology, 1988; 128(1):46-55. Available from: https://www.ncbi.nlm.nih.gov/pubmed/3381835

17. Rasmussen S, Irgens LM, and Dalaker K. The effect on the likelihood of further pregnancy of placental abruption and the rate of its recurrence. British Journal of Obstetrics and Gynaecology, 1997; 104(11):1292-5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9386031

18. van Oppenraaij RH, Jauniaux E, Christiansen OB, Horcajadas JA, Farquharson RG, et al. Predicting adverse obstetric outcome after early pregnancy events and complications: a review. Human Reproduction Update, 2009; 15(4):409-21. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19270317

19. US Department of Health and Human Services, Women and smoking : a report of the Surgeon General. Rockville, Maryland: US Department of Health and Human Services Public Health Service; 2001. Available from: https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5112a4.htm.

20. US Department of Health and Human Services. The health consequences of smoking - 50 years of progress. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. Available from: https://www.ncbi.nlm.nih.gov/books/NBK179276/.

21. Dietz PM, England LJ, Shapiro-Mendoza CK, Tong VT, Farr SL, et al. Infant morbidity and mortality attributable to prenatal smoking in the U.S. American Journal of Preventive Medicine, 2010; 39(1):45-52. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20547278

22. Andriani H, Putri S, Kosasih RI, and Kuo HW. Parental smoking and under-five child mortality in Southeast Asia: Evidence from demographic and health surveys. International Journal of Environmental Research and Public Health, 2019; 16(23). Available from: https://www.ncbi.nlm.nih.gov/pubmed/31783665

23. Australian Institute for Health and Welfare. Children's headline indicators, 2. Infant mortality. Canberra, Australia: AIHW, 2018. Available from: https://www.aihw.gov.au/reports/children-youth/childrens-headline-indicators/contents/2-infant-mortality.

24. Horne RSC. Sudden infant death syndrome: current perspectives. Internal Medicine Journal, 2019; 49(4):433-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30957377

25. Mitchell EA, Freemantle J, Young J, and Byard RW. Scientific consensus forum to review the evidence underpinning the recommendations of the Australian SIDS and Kids Safe Sleeping Health Promotion Programme--October 2010. Journal of Paediatrics and Child Health, 2012; 48(8):626-33. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22050484

26. Ridolfo B and Stevenson C. Quantification of drug-caused mortality and morbidity in Australia, 1998. Drug statistics series no. 7, AIHW cat. no. PHE 29.Canberra: Australian Institute of Health and Welfare, 2001. Available from: https://www.aihw.gov.au/getmedia/7e677c0d-e6c1-4ec8-a78f-62982758f61f/qdcmma98.pdf.aspx?inline=true.

27. Tobacco Advisory Group. Passive smoking and children. London: Royal College of Physicians, 2010. Available from: https://shop.rcplondon.ac.uk/products/passive-smoking-and-children?variant=6634905477.

28. Schneider J, Mitchell I, Singhal N, Kirk V, and Hasan SU. Prenatal cigarette smoke exposure attenuates recovery from hypoxemic challenge in preterm infants. American Journal of Respiratory and Critical Care Medicine, 2008; 178(5):520-6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18565950

29. Richardson HL, Walker AM, and Horne RS. Maternal smoking impairs arousal patterns in sleeping infants. Sleep, 2009; 32(4):515-21. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19413145

30. Wang Z, May SM, Charoenlap S, Pyle R, Ott NL, et al. Effects of secondhand smoke exposure on asthma morbidity and health care utilization in children: a systematic review and meta-analysis. Annals of Allergy, Asthma & Immunology, 2015; 115(5):396-401 e2. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26411971

31. National Health and Medical Research Council. The health effects of passive smoking: a scientific information paper. Canberra: Australian Government Publishing Service, 1997. Available from: https://catalogue.nla.gov.au/Record/165167.

32. He Z, Wu H, Zhang S, Lin Y, Li R, et al. The association between secondhand smoke and childhood asthma: A systematic review and meta-analysis. Pediatric Pulmonology, 2020; 55(10):2518-31. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32667747

33. Australian Centre for Asthma Monitoring. Asthma in Australia 2008. Asthma series no. 3 AIHW cat. no. ACM 14.Canberra: Australian Institute of Health and Welfare, 2008. Available from: http://www.asthmamonitoring.org/AinA08_html/Index.htm.

34. Collins D and Lapsley H. The costs of tobacco, alcohol and illicit drug abuse to Australian society in 2004–05. Canberra: Department of Health and Ageing, 2008. Available from: https://nadk.flinders.edu.au/files/3013/8551/1279/Collins__Lapsley_Report.pdf.

35. Feleszko W, Ruszczynski M, Jaworska J, Strzelak A, Zalewski BM, et al. Environmental tobacco smoke exposure and risk of allergic sensitisation in children: a systematic review and meta-analysis. Archives of Disease in Childhood, 2014; 99(11):985-92. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24958794

36. Shargorodsky J, Garcia-Esquinas E, Navas-Acien A, and Lin SY. Allergic sensitization, rhinitis, and tobacco smoke exposure in U.S. children and adolescents. International Forum of Allergy & Rhinology, 2015; 5(6):471-6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25884913

37. Thacher JD, Gruzieva O, Pershagen G, Neuman A, Wickman M, et al. Pre- and postnatal exposure to parental smoking and allergic disease through adolescence. Pediatrics, 2014; 134(3):428-34. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25136039

38. Hansen K, Mangrio E, Lindstrom M, and Rosvall M. Early exposure to secondhand tobacco smoke and the development of allergic diseases in 4 year old children in Malmo, Sweden. BMC Pediatrics, 2010; 10:61. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20731846

39. Raherison C, Penard-Morand C, Moreau D, Caillaud D, Charpin D, et al. Smoking exposure and allergic sensitization in children according to maternal allergies. Annals of Allergy, Asthma & Immunology, 2008; 100(4):351-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18450121

40. Kuehni CE, Strippoli MP, Chauliac ES, and Silverman M. Snoring in preschool children: prevalence, severity and risk factors. European Respiratory Journal, 2008; 31(2):326-33. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18032441

41. O'Brien LM, Holbrook CR, Mervis CB, Klaus CJ, Bruner JL, et al. Sleep and neurobehavioral characteristics of 5- to 7-year-old children with parentally reported symptoms of attention-deficit/hyperactivity disorder. Pediatrics, 2003; 111(3):554-63. Available from: https://www.ncbi.nlm.nih.gov/pubmed/12612236

42. Zhang G, Spickett J, Rumchev K, Lee AH, and Stick S. Snoring in primary school children and domestic environment: a Perth school based study. Respiratory Research, 2004; 5(5):19. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15527500

43. Groner JA, Nicholson L, Huang H, and Bauer JA. Secondhand Smoke Exposure and Sleep-Related Breathing Problems in Toddlers. Academic Pediatrics, 2019; 19(7):835-41. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30959225

44. Ramirez FD, Groner JA, Ramirez JL, McEvoy CT, Owens JA, et al. Prenatal and Childhood Tobacco Smoke Exposure Are Associated With Sleep-Disordered Breathing Throughout Early Childhood. Academic Pediatrics, 2020. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33161115

45. David GL, Koh WP, Lee HP, Yu MC, and London SJ. Childhood exposure to environmental tobacco smoke and chronic respiratory symptoms in non-smoking adults: the Singapore Chinese Health Study. Thorax, 2005; 60(12):1052-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/16131525

46. Adetifa IMO, Kendall L, Donkor S, Lugos MD, Hammond AS, et al. Mycobacterium tuberculosis infection in close childhood contacts of adults with pulmonary tuberculosis is increased by secondhand exposure to tobacco. American Journal of Tropical Medicine and Hygiene, 2017; 97(2):429-32. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28722570

47. Jones LL, Hashim A, McKeever T, Cook DG, Britton J, et al. Parental and household smoking and the increased risk of bronchitis, bronchiolitis and other lower respiratory infections in infancy: systematic review and meta-analysis. Respiratory Research, 2011; 12:5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21219618

48. Cao S, Yang C, Gan Y, and Lu Z. The health effects of passive smoking: An overview of systematic reviews based on observational epidemiological evidence. PLoS One, 2015; 10(10):e0139907. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26440943

49. Kwok MK, Schooling CM, Ho LM, Leung SS, Mak KH, et al. Early life second-hand smoke exposure and serious infectious morbidity during the first 8 years: evidence from Hong Kong's "Children of 1997" birth cohort. Tobacco Control, 2008; 17(4):263-70. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18505748

50. Christensen DN, Franks ZG, McCrary HC, Saleh AA, and Chang EH. A systematic review of the association between cigarette smoke exposure and chronic rhinosinusitis. Otolaryngology–Head and Neck Surgery, 2018; 158(5):801-16. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29460678

51. Been JV, Millett C, Lee JT, van Schayck CP, and Sheikh A. Smoke-free legislation and childhood hospitalisations for respiratory tract infections. European Respiratory Journal, 2015; 46(3):697-706. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26022951

52. Faber T, Been JV, Reiss IK, Mackenbach JP, and Sheikh A. Smoke-free legislation and child health. NPJ Primary Care Respiratory Medicine, 2016; 26:16067. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27853176

53. Lee SL, Wong WH, and Lau YL. Smoke-free legislation reduces hospital admissions for childhood lower respiratory tract infection. Tobacco Control, 2016; 25(e2):e90-e4. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26769122

54. Fernandez-Plata R, Rojas-Martinez R, Martinez-Briseno D, Garcia-Sancho C, and Perez-Padilla R. Effect of passive smoking on the growth of pulmonary function and respiratory symptoms in schoolchildren. Revista De Investigacion Clinica, 2016; 68(3):119-27. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27408998

55. Milanzi EB, Koppelman GH, Smit HA, Wijga AH, Vonk JM, et al. Timing of secondhand smoke, pet, dampness or mould exposure and lung function in adolescence. Thorax, 2020; 75(2):153-63. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31748257

56. Bui DS, Lodge CJ, Burgess JA, Lowe AJ, Perret J, et al. Childhood predictors of lung function trajectories and future COPD risk: a prospective cohort study from the first to the sixth decade of life. The Lancet Respiratory Medicine, 2018; 6(7):535-44. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29628376

57. Torpy JM, Lynm C, and Glass RM. JAMA patient page. Acute otitis media. JAMA, 2010; 304(19):2194. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21081734

58. Zhang Y, Xu M, Zhang J, Zeng L, Wang Y, et al. Risk factors for chronic and recurrent otitis media-a meta-analysis. PLoS One, 2014; 9(1):e86397. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24466073

59. Carreras G, Lugo A, Gallus S, Cortini B, Fernandez E, et al. Burden of disease attributable to second-hand smoke exposure: A systematic review. Preventive Medicine, 2019; 129:105833. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31505203

60. Simpson SA, Thomas CL, van der Linden MK, Macmillan H, van der Wouden JC, et al. Identification of children in the first four years of life for early treatment for otitis media with effusion. Cochrane Database of Systematic Reviews, 2007; 4(1):CD004163. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17253499

61. Nageris B, Braverman I, Hadar T, Hansen MC, and Frenkiel S. Effects of passive smoking on odour identification in children. Journal of Otolaryngology   2001; 30(5):263-5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11771017

62. Nageris B, Hadar T, and Hansen MC. The effects of passive smoking on olfaction in children. Revue de laryngologie - otologie - rhinologie, 2002; 123(2):89-91. Available from: https://www.ncbi.nlm.nih.gov/pubmed/12360728

63. DiFranza JR, Aligne CA, and Weitzman M. Prenatal and postnatal environmental tobacco smoke exposure and children's health. Pediatrics, 2004; 113(4 Suppl):1007-15. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15060193

64. Anderko L, Braun J, and Auinger P. Contribution of tobacco smoke exposure to learning disabilities. Journal of Obstetric, Gynecologic & Neonatal Nursing, 2010; 39(1):111-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20409109

65. De Alwis D, Tandon M, Tillman R, and Luby J. Nonverbal reasoning in preschool children: Investigating the putative risk of secondhand smoke exposure and attention-deficit/hyperactivity disorder as a mediator. Scandinavian Journal of Child and Adolescent Psychiatry and Psychology, 2015; 3(2):115-25. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26726310

66. Jorge JG, Botelho C, Silva AM, and Moi GP. Influence of passive smoking on learning in elementary school. J Pediatr (Rio J), 2016; 92(3):260-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26859248

67. Padron A, Galan I, Garcia-Esquinas E, Fernandez E, Ballbe M, et al. Exposure to secondhand smoke in the home and mental health in children: a population-based study. Tobacco Control, 2016; 25(3):307-12. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25808665

68. Chastang J, Baiz N, Cadwallader JS, Robert S, Dywer JL, et al. Postnatal environmental tobacco smoke exposure related to behavioral problems in children. PLoS One, 2015; 10(8):e0133604. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26244898

69. Pagani LS and Fitzpatrick C. Prospective associations between early long-term household tobacco smoke exposure and antisocial behaviour in later childhood. Journal of Epidemiology and Community Health, 2013; 67(7):552-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/23694963

70. Luk TT, Wang MP, Suen YN, Koh DS, Lam TH, et al. Early childhood exposure to secondhand smoke and behavioural problems in preschoolers. Scientific Reports, 2018; 8(1):15434. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30337640

71. Park S, Cho SC, Hong YC, Kim JW, Shin MS, et al. Environmental tobacco smoke exposure and children's intelligence at 8-11 years of age. Environmental Health Perspectives, 2014; 122(10):1123-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24911003

72. Rashidi M, Mohammadpoorasl A, and Sahebihagh MH. Environmental Tobacco Smoke and Educational Self-Regulation and Achievement in First Grade High School Students. Journal of Medicine and Life, 2020; 13(2):229-34. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32742519

73. Santos NF and Costa RA. Parental tobacco consumption and child development. Jornal de Pediatria, 2015; 91(4):366-72. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25727026

74. Huang A, Wu K, Cai Z, Lin Y, Zhang X, et al. Association between postnatal second-hand smoke exposure and ADHD in children: a systematic review and meta-analysis. Environmental Science and Pollution Research, 2021; 28(2):1370-80. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33097989

75. Nadhiroh SR, Djokosujono K, and Utari DM. The association between secondhand smoke exposure and growth outcomes of children: A systematic literature review. Tobacco Induced Diseases, 2020; 18:12. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32180689

76. Chang JS. Parental smoking and childhood leukemia. Methods in Molecular Biology, 2009; 472:103-37. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19107431

77. Secretan B, Straif K, Baan R, Grosse Y, El Ghissassi F, et al. A review of human carcinogens--Part E: tobacco, areca nut, alcohol, coal smoke, and salted fish. Lancet Oncology, 2009; 10(11):1033-4. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19891056

78. Huang Y, Huang J, Lan H, Zhao G, and Huang C. A meta-analysis of parental smoking and the risk of childhood brain tumors. PLoS One, 2014; 9(7):e102910. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25058491

79. Pang D, McNally R, and Birch JM. Parental smoking and childhood cancer: results from the United Kingdom Childhood Cancer Study. British Journal of Cancer, 2003; 88(3):373-81. Available from: https://www.ncbi.nlm.nih.gov/pubmed/12569379

80. Sorahan T and Lancashire RJ. Parental cigarette smoking and childhood risks of hepatoblastoma: OSCC data. British Journal of Cancer, 2004; 90(5):1016-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/14997199

81. Carceles-Alvarez A, Ortega-Garcia JA, Lopez-Hernandez FA, Fuster-Soler JL, Ramis R, et al. Secondhand smoke: A new and modifiable prognostic factor in childhood acute lymphoblastic leukemias. Environmental Research, 2019; 178:108689. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31479979

82. Lyons B, Frizelle H, Kirby F, and Casey W. The effect of passive smoking on the incidence of airway complications in children undergoing general anaesthesia. Anaesthesia, 1996; 51(4):324-6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/8686817

83. Skolnick ET, Vomvolakis MA, Buck KA, Mannino SF, and Sun LS. Exposure to environmental tobacco smoke and the risk of adverse respiratory events in children receiving general anesthesia. Anesthesiology, 1998; 88(5):1144-53. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9605672

84. Stasic AF. Perioperative implications of common respiratory problems. Seminars in Pediatric Surgery, 2004; 13(3):174-80. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15272425

85. Jones D and Bhattacharyya N. Passive smoke exposure as a risk factor for airway complications during outpatient pediatric procedures. Otolaryngology and Head and Neck Surgery, 2006; 135(1):12-6. Available from: http://www.ncbi.nlm.nih.gov/pubmed/16815175

86. Avsar A, Topaloglu B, and Hazar-Bodrumlu E. Association of passive smoking with dental development in young children. European Journal of Paediatric Dentistry, 2013; 14(3):215-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24295007

87. Gonzalez-Valero L, Montiel-Company JM, Bellot-Arcis C, Almerich-Torres T, Iranzo-Cortes JE, et al. Association between passive tobacco exposure and caries in children and adolescents. A systematic review and meta-analysis. PLoS One, 2018; 13(8):e0202497. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30114212

88. Saho H, Taniguchi-Tabata A, Ekuni D, Yokoi A, Kataoka K, et al. Association between household exposure to secondhand smoke and dental caries among Japanese young adults: A cross-sectional study. International Journal of Environmental Research and Public Health, 2020; 17(22). Available from: https://www.ncbi.nlm.nih.gov/pubmed/33233610

89. Erdemir EO, Sonmez IS, Oba AA, Bergstrom J, and Caglayan O. Periodontal health in children exposed to passive smoking. Journal of Clinical Periodontology, 2010; 37(2):160-4. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20041979

90. Tanaka K, Miyake Y, Nagata C, Furukawa S, and Arakawa M. Association of prenatal exposure to maternal smoking and postnatal exposure to household smoking with dental caries in 3-year-old Japanese children. Environmental Research, 2015; 143(Pt A):148-53. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26492399

91. Tanaka S, Shinzawa M, Tokumasu H, Seto K, Tanaka S, et al. Secondhand smoke and incidence of dental caries in deciduous teeth among children in Japan: population based retrospective cohort study. British Medical Journal, 2015; 351:h5397. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26489750

92. Avsar A, Darka O, Topaloglu B, and Bek Y. Association of passive smoking with caries and related salivary biomarkers in young children. Archives of Oral Biology, 2008; 53(10):969-74. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18672230

93. Gilliland FD, Berhane K, Islam T, Wenten M, Rappaport E, et al. Environmental tobacco smoke and absenteeism related to respiratory illness in schoolchildren. American Journal of Epidemiology, 2003; 157(10):861-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/12746237

94. Kum-Nji P, Mangrem C, Wells P, and Herrod H. Is environmental tobacco smoke exposure a risk factor for acute gastroenteritis in young children? Clinical Pediatrics, 2009; 48(7):756–62. Available from: http://cpj.sagepub.com/content/48/7/756.long

95. Ozmert E, Kilic M, and Yurdakök K. Environmental tobacco smoke: is it a risk factor for diarrhea in 6-18 months old infants? Central European Journal of Public Health, 2008; 16(2):85–6. Available from: http://www.unboundmedicine.com/medline/ebm/record/18661811/full_citation/Environmental_tobacco_smoke:_is_it_a_risk_factor_for_diarrhea_in_6_18_months_old_infants

96. Pagani LS, Nguyen AK, and Fitzpatrick C. Prospective associations between early long-term household tobacco smoke exposure and subsequent indicators of metabolic risk at age 10. Nicotine & Tobacco Research, 2016; 18(5):1250-7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26069035

97. Braithwaite I, Stewart AW, Hancox RJ, Beasley R, Murphy R, et al. Maternal post-natal tobacco use and current parental tobacco use is associated with higher body mass index in children and adolescents: an international cross-sectional study. BMC Pediatrics, 2015; 15(1):220. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26699863

98. Moore BF, Clark ML, Bachand A, Reynolds SJ, Nelson TL, et al. Interactions between diet and exposure to secondhand smoke on metabolic syndrome among children: NHANES 2007-2010. The Journal of Clinical Endocrinology & Metabolism, 2016; 101(1):52-8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26495750

99. Davis CL, Tingen MS, Jia J, Sherman F, Williams CF, et al. Passive smoke exposure and its effects on cognition, sleep, and health outcomes in overweight and obese children. Child Obesity, 2016; 12(2):119-25. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26812049

100. Juonala M, Pitkanen N, Tolonen S, Laaksonen M, Sievanen H, et al. Childhood exposure to passive smoking and bone health in adulthood: The Cardiovascular Risk in Young Finns Study. The Journal of Clinical Endocrinology & Metabolism, 2019; 104(6):2403-11. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30715377

101. Li J, Yuan N, Chu WK, Cheung CY, Tang S, et al. Exposure to secondhand smoke in children is associated with a thinner retinal nerve fiber layer: The Hong Kong Children Eye Study. American Journal of Ophthalmology, 2020; 223:91-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33129810