1. Prospective Cohort Study of Thai Children SECONDHAND SMOKING IN PREGNANT WOMEN AND TIME OF THE FIRST TOOTH ERUPTION DIEN HOA ANH VU PhD Student – Faculty of Dentistry Khon Kaen University

2. CONTENTS INTRODUCTION OBJECTIVE METHODS RESULTS DISCUSSION CONCLUSION 10/12/20152

3. ABBREVIATION BWBirth Weight DTE Delayed first Tooth Eruption GAGestational Age PCTCProspective Cohort study of Thai Children SHSSecondhand Smoking 10/12/20153

4. INTRODUCTION DTE: problems / dental development hold space align into correct position chew and speak Influence factors 10/12/20154

5. INTRODUCTION Secondhand smoking (SHS) Negative effect Common in Thai males High prevalence (29.8%) of SHS 10/12/20155

6. OBJECTIVE 10/12/20156 To determine whether SHS during pregnancy period delayed the time of first tooth eruption in Thai infants

7. METHODS – Study Design Part of PCTC Large birth cohort study: > 4,000 infants, 5 sites in Thailand October 15, 2000 and September 14, 2002 10/12/20157

8. METHODS – Study Design Inclusion criteria: accessible year-round 800 to 900 newborns on average each year intend to live 5 years long-term commitment with the project 10/12/20158

9. METHODS – Study Design Informed consent The National Ethics Committee of the Ministry of Public Health of Thailand Khon Kaen University Ethics Committee for Human Research 10/12/20159

10. METHODS – Independent variables and outcomes Family members In-person interview, diary records, medical records Secondary data – community and demographic variables 10/12/201510

11. METHODS – Independent variables and outcomes Independent variables SHS during pregnancy: Yes/No Number of cigarettes Outcomes DTE: Yes/No Time to eruption of the first tooth 10/12/201511

12. METHODS – Potential bias Mother’s age, education level Income Alcohol consumption Child’s gender BW GA Study site 10/12/201512

13. METHODS – Statistical Analysis Description analysis Cox proportional regression Multiple logistic regression Generalized estimating equation (GEE) Stata SE 12.0 p-value <.05 10/12/201513

14. RESULTS – Study sites 10/12/201514 Figure 1. Number of study members and location of PCTC sites in Thailand

15. RESULTS – Demographic Characteristics CharacteristicsTotal (n)Sites (%) North (n=xxx) Northeast (n=xxx) Central (n=xxx) South (n=xxx) Bangkok (n=xxx) Mother’s age (mean ± SD) 27.1  6.3 26.8  6.327.6  6.524.8  5.427.9  6.529.5  5.9 Alcohol drinking17913.977.2620.6718.4439.66 Infant’s gender (females)2,27619.7326.1920.5218.3715.20 Low BW80216.3341.1520.3216.715.49 Preterm birth72516.2835.8628.4111.178.28 10/12/201515 Table 1. Demographic characteristics in five study sites

16. RESULTS Table 2. Percentage of SHS in pregnant women among five study sites 10/12/201516 Study siteNumber of SHS% of SHS North 43745.90 Northeast 68356.63 Central 53053.16 South 22727.82 Bangkok 25745.17 Total2,18246.76

17. RESULTS SHS statusCrude HR (95% CI)Adjusted HR* (95% CI) Non-SHS 1.00Reference1.00Reference SHS 0.940.89 – 1.000.980.89 – 1.08 10/12/201517 Table 3. Crude and adjusted HR of not having first tooth eruption *HR adjusted for child’s gender, maternal age, parents’ highest education level, income, BW, GA, and alcohol drinking during pregnancy, stratifying by study site.

18. FactorsCrude HR (95% CI)Adjusted HR* (95% CI) SHS Yes 1.221.05 – 1.42 No 1.00 Gender Female 0.670.58 – 0.78 Male 1.00 BW Normal BW 0.610.51 – 0.74 Low BW 1.00 GA Normal 0.790.64 – 0.96 Preterm birth 1.00 10/12/201518 Table 4. Crude and adjusted OR of DTE

19. RESULTS Figure 2. Difference in the probability of not having erupted tooth between SHS group and non-SHS group 10/12/201519

20. RESULTS Figure 2. Difference in the probability of not having erupted tooth between females and males 10/12/201520

21. DISCUSSION [to be added] The time of first tooth eruption was delayed in SHS women Biological plausible Consistent with other previous studies Similar with the study of Adler et al. Lawoyin et al. – Opposite relationship between BW and time of first tooth eruption. 10/12/201521

22. DISCUSSION – Strength Strongest observational design Multiple risk factors Large birth cohort study National representative Minimal loss to follow-up 10/12/201522

23. DISCUSSION – Limitation Information bias – trained and calibrated the interviewers Potential confounding factors – adjusting Causal inferences – suspect Change of association over time? 10/12/201523

24. CONCLUSION SHS in Thai pregnant women was associated with delayed time of the first tooth eruption in infants Many problems in the dental and nutritional development of infants Further studies 10/12/201524

25. REFERENCES 10/12/201525