4.17 Health effects of secondhand smoke for infants and children

Last updated: January 2017
Suggested citation: Campbell MA, Ford C, & Winstanley MH. Ch 4. The health effects of secondhand smoke. 4.17 Health effects of secondhand smoke for infants and children. In Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2017. Available from http://www.tobaccoinaustralia.org.au/chapter-4-secondhand/4-17-health-effects-of-secondhand-smoke-for-infants

Children are particularly susceptible to the effects of secondhand smoke due to their higher breathing rates, greater lung surface area,1 and relative immaturity of their lungs. Infants and children are also generally unable to control their environment, and therefore cannot take steps to avoid exposure to secondhand smoke.1 Children are most likely to be exposed to secondhand smoke in the home, and because exposure is common, even comparatively small increases in disease risk may translate into a substantial population burden of disease in infancy and childhood.2

There are several possible routes by which the effects of tobacco smoke may compromise infant health. Before birth, there is potential damage to sperm from paternal active smoking,3, 4 and in utero maternal active smoking or maternal secondhand smoke exposure can also cause fetal harm.1, 3 Following birth, infants may be exposed to parental secondhand smoke in the home,3 to thirdhand smoke in household dust and indoor surfaces,5 and to an increased bacterial load carried by a parent or carer who smokes.6-8 Both prenatal and postnatal exposure have been found to contribute to several health conditions.3, 9 Delineating the impact of each route of exposure in the causation of disease can sometimes be difficult, particularly for rare conditions.

Maternal smoking also has negative effects on the quality and quantity of breast milk (see Section 3.7.1). Various tobacco smoke constituents are found in the breast milk of smoking mothers, which are ingested by their child.10 However, even among smoking mothers who cannot quit, breastfeeding is considered to be better and safer than bottlefeeding.11 This is because of the significant protective effect of breastmilk for infants, particularly against respiratory and ear infections which are associated with secondhand smoke exposure.11-14

4.17.1 Infant death

Infant death is defined as the death of a child within its first year of life.3 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). The US Division of Vital Statistics (2006) reported that the infant mortality rate for children of mothers who smoked during pregnancy was 58% higher than among children of non-smokers.1

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.3 Secondhand smoke exposure during infancy increases the risk of SIDS,1, 3 and this is likely due to a number of mechanisms. Babies exposed to secondhand smoke are more likely to have thickening and inflammation of the airways, and are more susceptible to lung infections. Secondhand smoke may also impair the body’s control over respiration and heart rate, and the automatic response to start breathing again after an episode of apnoea.1, 3 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, 16

According to Australian estimates, infants exposed to maternal secondhand smoke after birth have nearly two and a half times the risk of dying from SIDS compared with unexposed infants.17 International reviews estimate that secondhand smoke exposure during infancy doubles the risk of SIDS,1, 3, 18 and the California Environmental Protection Agency has attributed approximately 10% of SIDS deaths in California to secondhand smoke.1 These findings make secondhand smoke exposure an important preventable risk factor for SIDS.3 In recent years, more parents have striven to protect their children from secondhand smoke by not smoking within their homes and this is likely to have contributed to the reduction in deaths from SIDS in recent years.17

4.17.3 Childhood asthma and other chronic respiratory symptoms

Exposure to secondhand smoke causes a range of respiratory symptoms, such as cough, phlegm production, breathlessness and wheezing in children of primary school age. These symptoms are common in childhood, and may restrict the activities of those who experience them.3, 19

The National Health and Medical Research Council (1997)2 and the California Environmental Protection Agency (2005)1 have both concluded that secondhand smoke causes and exacerbates asthma in children. The US Surgeon General’s 2006 report states that the evidence clearly shows that secondhand smoke exposure makes asthma more severe.3 A systematic review estimated that 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.19 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 In 2004–05, 11% of Australian children with asthma were living in homes where smoking took place indoors.20 It is estimated that 2% of asthma deaths in Australian children under 15 years are attributable to secondhand smoke.21

The evidence is unclear on whether there is an association between secondhand smoke exposure and allergic sensitisation,1, 3, 22-24 however some studies suggest there may be a synergy between hereditary risk for allergies and secondhand smoke exposure.3, 25, 26 Children exposed to secondhand smoke may be more likely to snore.27-29 One large study has reported that respiratory symptoms such as chronic dry cough and phlegm production may persist into adulthood among children who live with a smoker, independent of later exposure to secondhand smoke.30

4.17.4 Acute lower respiratory tract infections in infancy and early childhood

Children exposed to secondhand smoke in the home have a greater risk of contracting acute chest infections, including bronchitis, bronchiolitis and pneumonia.1, 3, 31 The effect is most pronounced in children aged under two.1, 3 Infants exposed to secondhand smoke in the home have a 50% higher chance of developing lower respiratory illness than unexposed children.18, 31 This risk is even greater for those children living in households in which the mother smokes (about 60%).3, 18, 31

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 lung is increasing. Secondhand smoke causes decreased lung function during childhood, leading to a reduced maximum level in adolescence and early adulthood.3, 32 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.1, 3

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.1, 33 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 35% increased risk for middle ear disease, and a 46% increased risk if their mother smokes.18 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.34

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 study has shown that children living with a parent who smoked a packet of cigarettes a day were more likely to misidentify aromas compared with a control group of children not living with a smoker.35, 36

4.17.8 Longer term developmental effects

There is increasing 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.1, 3, 37-43 However, studies in this area has produced mixed results and further research is needed.

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.1, 3, 44, 45 However, not all studies have found a positive relationship between secondhand smoke exposure and childhood cancers.46 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.45 Possible mechanisms include damage to sperm DNA and damage to the fetal liver from carcinogens in the blood of the pregnant mother, either from active smoking or secondhand smoke.47, 48 The 2009 IARC review also stated there was limited evidence to suggest that paternal smoking before pregnancy was associated with childhood leukaemia.4, 45 The relationship between secondhand smoke and childhood cancers requires further research.

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.49-51 There is also evidence that children exposed to secondhand smoke have a different metabolic response to drugs administered during surgery.52

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,53 tooth decay and poorer attachment of the teeth to the gum and supporting structures.1, 54-57 More research is needed.

Some studies indicate an association between exposure to secondhand smoke and gastrointestinal problems in children, such as diarrhoea and gastroenteritis.58-602 More research is needed.

There is some research suggesting that secondhand smoke exposure in utero or in childhood may be associated with an increased risk of obesity and central obesity.61-64 More research in this area is needed.

4.17.12 Mortality risk

[Content in development] 

Relevant news and research

For recent news items and research on this topic, click here.(Last updated October 2020)




1. 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

2. National Health and Medical Research Council. The health effects of passive smoking: A scientific information paper. Canberra: Australian Government Publishing Service, 1997.

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. Lee KM, Ward MH, Han S, Ahn HS, Kang HJ, et al. Paternal smoking, genetic polymorphisms in cyp1a1 and childhood leukemia risk. Leukaemia Research, 2009; 33(2):250–8. Available from: http://www.ncbi.nlm.nih.gov/entrez/pubmed/18691756

5. Matt GE, Quintana PJE, 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: http://tobaccocontrol.bmj.com/cgi/content/abstract/13/1/29

6. 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: http://www.annals.com/toc/auto_abstract.php?id=15299

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

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

9. US Department of Health and Human Services, The health consequences of smoking: A report of the Surgeon General. Atlanta, Georgia: 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; 2004. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/2004/complete_report/index.htm

10. Dahlström A, Ebersjö C, and Lundell B. Nicotine exposure in breastfed infants. Acta Pædiatrica, 2004; 93(6):810–16. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15244232

11. Dorea JG. Maternal smoking and infant feeding: Breastfeeding is better and safer. Maternal and Child Health Journal, 2007; 11(3):287–91. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17226091

12. Yilmaz G, Hizli S, Karacan C, Yurdakök K, Coşkun T, et al. Effect of passive smoking on growth and infection rates of breast-fed and non-breast-fed infants. Pediatrics International, 2009; 51(3):352–8. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1442-200X.2008.02757.x/abstract

13. Ladomenou F, Kafatos A, and Galanakis E. Environmental tobacco smoke exposure as a risk factor for infections in infancy. Acta Paediatrica, 2009; 98(7):1137–41. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1651-2227.2009.01276.x/full

14. Chatzimichael A, Tsalkidis A, Cassimos D, Gardikis S, Tripsianis G, et al. The role of breastfeeding and passive smoking on the development of severe bronchiolitis in infants. Minerva Pediatrica, 2007; 59(3):199–206. Available from: http://direct.bl.uk/bld/PlaceOrder.do?UIN=211194970&ETOC=RN&from=searchengine

15. Mathews T and MacDorman M. Infant mortality statistics from the 2006 period linked birth/infant death data set. National Vital Statistics Reports, 2010; 58(17):1–31. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20815136

16. US Surgeon General. The health consequences of smoking - 50 years of progress: A report of the Surgeon General. Atlanta, Georgia: 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.surgeongeneral.gov/library/reports/50-years-of-progress/full-report.pdf

17. 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: http://www.aihw.gov.au/publications/phe/qdcmma98/

18. Tobacco Advisory Group. Passive smoking and children. London: Royal College of Physicians, 2010. Available from: http://bookshop.rcplondon.ac.uk/details.aspx?e=305

19. 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 and Immunology, 2015; 115(5):396–401. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26411971

20. 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.aihw.gov.au/publications/index.cfm/title/10584

21. 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: http://www.nationaldrugstrategy.gov.au/internet/drugstrategy/publishing.nsf/Content/mono64/$File/mono64.pdf

22. 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: http://www.ncbi.nlm.nih.gov/pubmed/24958794

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

24. 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: http://www.ncbi.nlm.nih.gov/pubmed/25136039

25. 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: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2940890/?tool=pubmed

26. Raherison C, Pénard-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: http://titania.annallergy.org/vl=549803/cl=21/nw=1/rpsv/cw/acaai/10811206/v100n4/s11/p351

27. Zhang G, Spickett J, Rumchev K, Lee A, and Stick S. Snoring in primary school children and domestic environment: A Perth school based study. Respiratory Research, 2004; 4(5):19. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15527500

28. 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: http://www.ncbi.nlm.nih.gov/pubmed/12612236

29. 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: http://www.ncbi.nlm.nih.gov/pubmed/18032441

30. David G, Koh W, Lee H, Yu M, and London S. 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: http://www.ncbi.nlm.nih.gov/pubmed/16131525

31. 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: http://www.ncbi.nlm.nih.gov/pubmed/21219618

32. 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: http://www.ncbi.nlm.nih.gov/pubmed/27408998

33. Torpy JM, Lynm C, and Glass RM. Jama patient page. Acute otitis media. Journal of the American Medical Association, 2010; 304(19):2194. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21081734

34. Simpson S, Thomas C, van der Linden M, Macmillan H, van der Wouden J, 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:http://www.ncbi.nlm.nih.gov/pubmed/17253499

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

36. Nageris B, Hadar T, and Hansen M. The effects of passive smoking on olfaction in children. Revue de Laryngologie, Otologie, Rhinologie, 2002; 132(2):89–91. Available from: http://www.ncbi.nlm.nih.gov/pubmed/12360728

37. DiFranza JR, Aligne CA, and Weitzman M. Prenatal and postnatal environmental tobacco smoke exposure and children's health. Pediatrics, 2004; 113(suppl. 4):S1007–S15. Available from: http://www.ncbi.nlm.nih.gov/entrez/pubmed/15060193

38. 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: http://www3.interscience.wiley.com/cgi-bin/fulltext/123235906/HTMLSTART

39. 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: http://www.ncbi.nlm.nih.gov/pubmed/26726310

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

41. Padrón A, Galán I, García-Esquinas E, Fernández E, Ballbè 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: http://tobaccocontrol.bmj.com/content/25/3/307.abstract

42. Pagani L 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: http://www.ncbi.nlm.nih.gov/pubmed/23694963

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

44. Chang J. Parental smoking and childhood leukemia. Methods in Molecular Biology, 2009; 472:103–37. Available from: https://link.springer.com/protocol/10.1007%2F978-1-60327-492-0_5

45. 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. The Lancet Oncology, 2009; 10(11):1033–4. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19891056

46. 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: http://www.ncbi.nlm.nih.gov/pubmed/25058491

47. 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: http://www.ncbi.nlm.nih.gov/pubmed/12569379

48. 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: http://www.ncbi.nlm.nih.gov/pubmed/14997199

49. Skolnick E, Vomvolakis M, Buck K, Mannino S, and Sun L. 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: http://www.ncbi.nlm.nih.gov/pubmed/9605672

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

51. 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: http://www.ncbi.nlm.nih.gov/pubmed/8686817

52. 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

53. 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: http://www.ncbi.nlm.nih.gov/pubmed/24295007

54. Avşar A, Darka O, Topaloğlu 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: http://www.ncbi.nlm.nih.gov/pubmed/18672230

55. Erdemir E, Sonmez I, Oba A, Bergstrom J, and Caglayan O. Periodontal health in children exposed to passive smoking. Journal of Clinical Periodontology, 2009; 37(2):160–4. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1600-051X.2009.01510.x/full

56. 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: http://www.ncbi.nlm.nih.gov/pubmed/26492399

57. 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: http://www.ncbi.nlm.nih.gov/pubmed/26489750

58. Gilliland F, 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: http://aje.oxfordjournals.org/cgi/content/full/157/10/861

59. 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

60. 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: https://www.ncbi.nlm.nih.gov/pubmed/18661811

61. 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 and Tobacco Research, 2015; 18(5):1250–7. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26069035

62. 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: http://www.ncbi.nlm.nih.gov/pubmed/26699863

63. 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. Journal of Clinical Endocrinology and Metabolism, 2015; 101(1):52–8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26495750

64. 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. Childhood Obesity, 2016; 12(2):119–25. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26812049