Smoking ban and small-for-gestational age births in Ireland

Zubair Kabir, Sean Daly, Vanessa Clarke, Sheila Keogan, Luke Clancy, Zubair Kabir, Sean Daly, Vanessa Clarke, Sheila Keogan, Luke Clancy

Abstract

Background: Ireland introduced a comprehensive workplace smoke-free legislation in March, 2004. Smoking-related adverse birth outcomes have both health care and societal cost implications. The main aim of this study was to determine the impact of the Irish smoke-free legislation on small-for-gestationa- age (SGA) births.

Methods and findings: We developed a population-based birthweight (BW) percentile curve based on a recent study to compute SGA (BW <5(th) percentile) and very SGA (vSGA - BW<3(rd) percentile) for each gestational week. Monthly births born between January 1999 and December 2008 were analyzed linking with monthly maternal smoking rates from a large referral maternity university hospital. We ran individual control and CUSUM charts, with bootstrap simulations, to pinpoint the breakpoint for the impact of ban implementation ( = April 2004). Monthly SGA rates (%) before and after April 2004 was considered pre and post ban period births, respectively. Autocorrelation was tested using Durbin Watson (DW) statistic. Mixed models using a random intercept and a fixed effect were employed using SAS (v 9.2). A total of 588,997 singleton live-births born between January 1999 and December 2008 were analyzed. vSGA and SGA monthly rates declined from an average of 4.7% to 4.3% and from 6.9% to 6.6% before and after April 2004, respectively. No auto-correlation was detected (DW = ~2). Adjusted mixed models indicated a significant decline in both vSGA and SGA rates immediately after the ban [(-5.3%; 95% CI -5.43% to -5.17%, p<0.0001) and (-0.45%; 95% CI: -0.7% to -0.19%, p<0.0007)], respectively. Significant gradual effects continued post the ban periods for vSGA and SGA rates, namely, -0.6% (p<0.0001) and -0.02% (p<0.0001), respectively.

Conclusions: A significant reduction in small-for-gestational birth rates both immediately and sustained over the post-ban period, reinforces the mounting evidence of the positive health effect of a successful comprehensive smoke-free legislation in a vulnerable population group as pregnant women.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Yearly smoking rates (%) in…
Figure 1. Yearly smoking rates (%) in pregnant women and in mothers who gave birth to low weight (LBW), preterm, small-for-gestational age (SGA) and very (vSGA) babies from 2000 to 2008.
Figure 2. Monthly observed and modelled (expected)…
Figure 2. Monthly observed and modelled (expected) small-for-gestational age (SGA) and very SGA (vSGA) rates in Ireland by month of delivery, January 1999-December 2008 [the bar indicates month 64 ( = April 2004).

References

    1. International Agency for Research on Cancer (IARC) (2004) IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Tobacco Smoke and Involuntary Smoking. Vol 83. Lyon: IARC.
    1. Salmasi G, Grady R, Jones J, McDonald SD (2010) Knowledge Synthesis Group (2010) Environmental tobacco smoke exposure and perinatal outcomes: a systematic review and meta-analyses. Acta Obstet Gynecol Scand 89: 423–41.
    1. Cnattingius S (2005) The epidemiology of smoking during pregnancy: smoking prevalence, maternal characteristics, and pregnancy outcomes. Nicotine Tob Res Suppl 2: S125–40.
    1. Chiolero A, Bovet P, Paccaud F (2005) Association between maternal smoking and low birth weight in Switzerland: the EDEN study. Swiss Med Wkly 135: 525–30.
    1. Vielwerth SE, Jensen RB, Larsen T, Greisen G (2007) The impact of maternal smoking on fetal and infant growth. Early Hum Dev 83: 491–5.
    1. Kabir Z, Clarke V, Conroy R, McNamee E, Daly S, et al. (2009) Low birthweight and preterm birth rates 1 year before and after the Irish workplace smoking ban. BJOG 116: 1782–7.
    1. Mackay DF, Nelson SM, Haw SJ, Pell JP (2012) Impact of Scotland’s smoke-free legislation on pregnancy complications: retrospective cohort study. PLoS Med e1001175.
    1. Page RL 2nd, Slejko JF, Libby AM (2012) A citywide smoking ban reduced maternal smoking and risk for preterm births: a Colorado natural experiment. J Women’s Health 21: 621–7.
    1. Mikolajczyk RT, Zhang J, Betran AP, Souza JP, Mori R, et al. (2011) A global reference for fetal-weight and birthweight percentiles. Lancet 377: 1855–61.
    1. Khashan AS, Baker PN, Kenny LC (2010) Preterm birth and reduced birthweight in first and second teenage pregnancies: a register-based cohort study.BMC Pregnancy Childbirth. 10: 36.
    1. Gardosi J, Chang A, Kalyan B, Sahota D, Symonds EM (1992) Customised antenatal growth charts. Lancet 339: 283–7.
    1. Goodman P, Agnew M, McCaffrey M, Paul G, Clancy L (2007) Effects of the Irish smoking ban on respiratory health of bar workers and air quality in Dublin pubs. Am J Respir Crit Care Med 175: 840–5.
    1. Pell JP, Haw S, Cobbe S, Newby DE, Pell AC, et al. (2008) Smoke-free legislation and hospitalizations for acute coronary syndrome. N Eng J Med 359: 482–91.
    1. Bonellie S, Chalmers J, Gray R, Greer I, Jarvis S, et al. (2008) Centile charts for birthweight for gestational age for Scottish singleton births. BMC Pregnancy Childbirth 8: 5.
    1. Donnelly JC, Cooley SM, Walsh TA, Sarkar R, Durnea U, et al. (2008) Illegal drug use, smoking and alcohol consumption in a low-risk Irish primigravid population. J Perinat Med 36: 70–2.
    1. McDonnell-Naughton M, McGarvey C, O’Regan M, Matthews T (2012) Maternal smoking and alcohol consumption during pregnancy as risk factors for sudden death. Ir Med J 105: 105–8.
    1. Ashford KB, Hahn E, Hall L, Rayens MK, Noland M, et al. (2010) Measuring prenatal secondhand smoke exposure in mother-baby couplets. Nicotine Tob Res 12: 127–35.
    1. Shipton D, Tappin DM, Vadiveloo T, Crossley JA, Aitken DA, et al. (2009) Reliability of self reported smoking status by pregnant women for estimating smoking prevalence: a retrospective cross-sectional study. BMJ 339: b4347.
    1. El-Mohandes AA, Kiely M, Blake SM, Gantz MG, El-Khorazaty MN (2010) An intervention to reduce environmental tobacco smoke exposure improves pregnancy outcomes. Pediatrics 125: 721–8.
    1. Pfarrer C, Macara L, Leiser R, Kingdom J (1999) Adaptive angiogenesis in placentas of heavy smokers. Lancet 354: 303.
    1. Mook-Kanamori DO, Steegers EA, Ellers PH, Raat H, Hofman A, et al. (2010) Risk factors and outcomes associated with first-trimester fetal growth restriction. JAMA 303: 527–34.
    1. Lieberman E, Gremy I, Lang JM, Cohen AP (1994) Low birthweight at term and the timing of fetal exposure to maternal smoking. Am J Public Health 84: 1127–31.
    1. Reeves S, Bernstein I (2008) Effects of maternal tobacco-smoke exposure on fetal growth and neonatal size. Expert Rev Obstet Gynecol 3: 719–30.
    1. Kabir Z, Clancy L (2012) Smoking ban and pregnancy complications: new evidence. J Women’s Health 21: 616–8.
    1. Kabir Z, Manning PJ, Holohan J, Goodman PG, Clancy L (2010) Active smoking and second-hand-smoke exposure at home among Irish children, 1995–2007. Arch Dis Child 95: 42–5.
    1. Mons U, Nagelhout GE, Allwright S, Guignard R, van den Putte B, et al.. (2012) Impact of national smoke-free legislation on home smoking bans: findings from the International Tobacco Control Policy Evaluation Project Europe Surveys. Tob Control Feb 13 (ahead of print).
    1. Allwright S, Paul G, Greiner B, Mullally BJ, Pursell L, et al. (2005) Legislation for smoke-free workplaces and health of bar workers in Ireland: before and after study. BMJ 331: 1117.

Source: PubMed

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