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European Journal of Public Health
......................................................................................................... European Journal of Public Health, Vol. 25, No. 4, 638–643 ß The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved. doi:10.1093/eurpub/ckv047 Advance Access published on 31 March 2015
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Smoking and obesity among pregnant women in Iceland 2001–2010 Ve´dı´s H. Eirı´ksdo´ttir1, Unnur A. Valdimarsdo´ttir1,2, Tinna L. A´sgeirsdo´ttir3, Agnes Gı´slado´ttir1, Sigru´n H. Lund1, Arna Hauksdo´ttir1, Helga Zoe¨ga1 1 Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland 2 Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA 3 Faculty of Economics, University of Iceland, Reykjavik, Iceland Correspondence: Ve´dı´s H. Eirı´ksdo´ttir, Stapi v/Hringbraut, 101 Reykjavik, Iceland, Tel: +354 525 5214; Fax: +354 552 1331; e-mail: [email protected]
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Introduction he harmful effects of smoking and obesity on pregnancy and outcomes are well documented.1–5 Smoking during pregnancy has been shown to increase the risk of stillbirths, preterm birth1,5 and low birth weight,5 with potential long-term health consequences for the unborn child.6,7 Similarly, studies have shown that high maternal body mass index (BMI) and, in particular, obesity are associated with a range of pregnancy and delivery complications, such as gestational diabetes,1,3 gestationalinduced hypertension and preeclampsia,1 foetal macrosomia, as well as with adverse birth outcomes such as dystocia, induction of labour,2 preterm birth, caesarean section2,4 and stillbirths.1,4 Because of their high prevalence, overweight and obesity are now considered to have replaced smoking as the most preventable factors for pregnancy complications and adverse birth outcomes.4 Smoking during pregnancy—as in general—has declined over the past 20 years in most Nordic countries; from 20.6 to 16.5% in Norway, 30.6 to 12.5% in Denmark and 31.4 to 6.9% in Sweden, whereas being stable around 15% in Finland.8 The prevalence of overweight and obesity has increased worldwide in the last decade.9 This also applies for pregnant women in the Nordic countries. In 2012, 38% of Swedish women were overweight or obese at the time of registration in antenatal care, which corresponds to a 51% increase over 20 years.10 In Denmark, the prevalence of overweight and obesity among pregnant women rose from 31.9% in 2004 to 36.0% in 2010.11,12 Until now, published data regarding maternal smoking and BMI from Iceland have been largely lacking, partly due to the fact that the Icelandic Medical Birth Register (MBR) does not include information on these behavioural risk factors. However, 5% of the 1111 pregnant women participating in the Icelandic
Tbirth
Childbirth and Health Study in 2009–10 reported smoking during early pregnancy.13 Furthermore, recent studies on body weight in the general population indicate a substantial increase in BMI over the last two decades.14–16 During 2000–10, the Icelandic population experienced profound economic changes. In this decade, Iceland was considered to be one of the richest nations in the world, but in the autumn of 2008, the country suffered a major economic breakdown when three of the largest banks were nationalized resulting in increased unemployment, bankruptcy of hundreds of firms and an increase in private and public debt.17 A growing body of literature indicates that macroeconomic conditions influence population health and health behaviours,18,19 and recent studies on the health effect of the Icelandic economic crisis indicate an overall reduction in health compromising behaviour,19 whereas early signs of mental- and cardiovascular health seemed negative, particularly among women.20,21 Furthermore, in our recent study, we observed an increase in lowbirth-weight deliveries in the year following the economic collapse.22 Yet, data are scarce on the influence of such massive societal changes on health behaviours among pregnant women. Using data from an existing cohort study, the aim of this study was therefore to examine the secular trend and patterns of smoking prevalence and body weight among pregnant women in Iceland between 2001 and 2010, a period during which dramatic changes in the nation’s economy occurred.
Methods Study design We used data from an ongoing study on the risk of adverse maternal health, obstetric and birth outcomes among women previously
Downloaded from http://eurpub.oxfordjournals.org/ at Acq Serials DeptPeriodicals on November 16, 2015
Background: The prevalence of smoking during pregnancy in Western societies has decreased in the last decades, whereas prevalence of overweight and obesity has increased. Our objective was to study secular trends and patterns of smoking and body weight among pregnant women in Iceland, during a period of dramatic changes in the nation’s economy. Methods: On the basis of the Medical Birth Registry, we used a random sample of 1329 births between 1 January 2001 and 31 December 2010. Information on smoking, body mass index and background factors during pregnancy was retrieved from the Medical Birth Register and maternity records. Trends in smoking, overweight, obesity and body mass index were assessed using logistic and linear regression analyses. Logistic regression analysis was used to examine the annual odds of smoking and obesity and by socio-demographic characteristics. Results: We found a decrease in the prevalence of continued smoking during pregnancy from 12.4% in 2001 to 7.9% in 2010 [odds ratio (OR) = 0.94, 95% confidence interval (CI) (0.88–1.00)], particularly among women with Icelandic citizenship [OR = 0.92, 95% CI (0.86–0.98)], whereas no changes in obesity [OR = 1.02, 95% CI (0.96–1.07)] were observed. The highest prevalence of maternal smoking and obesity was observed in 2005–06. Conclusion: Our results indicate that smoking during pregnancy decreased among Icelandic women in 2001–10, whereas an initial increase in obesity prevalence seemed to level off towards the end of the observation period. Interestingly, we found that both of these maternal risk factors reached their highest prevalence in 2005–06, which coincides with a flourishing period in the nation’s economy.
Smoking and obesity among pregnant Icelandic women
Study variables
when women reported discontinued smoking, although this is generally registered at the first antenatal visit at around gestational week 12. Women’s BMI was calculated according to measured height and weight at the first antenatal weight measurement, which on average occurred on the 97th day of gestation [standard deviation 29.3 days, median = 90 days]. Women were considered overweight if they had BMI 25.0 kg/m2 and
European Journal of Public Health
......................................................................................................... European Journal of Public Health, Vol. 25, No. 4, 638–643 ß The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved. doi:10.1093/eurpub/ckv047 Advance Access published on 31 March 2015
.........................................................................................................
Smoking and obesity among pregnant women in Iceland 2001–2010 Ve´dı´s H. Eirı´ksdo´ttir1, Unnur A. Valdimarsdo´ttir1,2, Tinna L. A´sgeirsdo´ttir3, Agnes Gı´slado´ttir1, Sigru´n H. Lund1, Arna Hauksdo´ttir1, Helga Zoe¨ga1 1 Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland 2 Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA 3 Faculty of Economics, University of Iceland, Reykjavik, Iceland Correspondence: Ve´dı´s H. Eirı´ksdo´ttir, Stapi v/Hringbraut, 101 Reykjavik, Iceland, Tel: +354 525 5214; Fax: +354 552 1331; e-mail: [email protected]
.........................................................................................................
Introduction he harmful effects of smoking and obesity on pregnancy and outcomes are well documented.1–5 Smoking during pregnancy has been shown to increase the risk of stillbirths, preterm birth1,5 and low birth weight,5 with potential long-term health consequences for the unborn child.6,7 Similarly, studies have shown that high maternal body mass index (BMI) and, in particular, obesity are associated with a range of pregnancy and delivery complications, such as gestational diabetes,1,3 gestationalinduced hypertension and preeclampsia,1 foetal macrosomia, as well as with adverse birth outcomes such as dystocia, induction of labour,2 preterm birth, caesarean section2,4 and stillbirths.1,4 Because of their high prevalence, overweight and obesity are now considered to have replaced smoking as the most preventable factors for pregnancy complications and adverse birth outcomes.4 Smoking during pregnancy—as in general—has declined over the past 20 years in most Nordic countries; from 20.6 to 16.5% in Norway, 30.6 to 12.5% in Denmark and 31.4 to 6.9% in Sweden, whereas being stable around 15% in Finland.8 The prevalence of overweight and obesity has increased worldwide in the last decade.9 This also applies for pregnant women in the Nordic countries. In 2012, 38% of Swedish women were overweight or obese at the time of registration in antenatal care, which corresponds to a 51% increase over 20 years.10 In Denmark, the prevalence of overweight and obesity among pregnant women rose from 31.9% in 2004 to 36.0% in 2010.11,12 Until now, published data regarding maternal smoking and BMI from Iceland have been largely lacking, partly due to the fact that the Icelandic Medical Birth Register (MBR) does not include information on these behavioural risk factors. However, 5% of the 1111 pregnant women participating in the Icelandic
Tbirth
Childbirth and Health Study in 2009–10 reported smoking during early pregnancy.13 Furthermore, recent studies on body weight in the general population indicate a substantial increase in BMI over the last two decades.14–16 During 2000–10, the Icelandic population experienced profound economic changes. In this decade, Iceland was considered to be one of the richest nations in the world, but in the autumn of 2008, the country suffered a major economic breakdown when three of the largest banks were nationalized resulting in increased unemployment, bankruptcy of hundreds of firms and an increase in private and public debt.17 A growing body of literature indicates that macroeconomic conditions influence population health and health behaviours,18,19 and recent studies on the health effect of the Icelandic economic crisis indicate an overall reduction in health compromising behaviour,19 whereas early signs of mental- and cardiovascular health seemed negative, particularly among women.20,21 Furthermore, in our recent study, we observed an increase in lowbirth-weight deliveries in the year following the economic collapse.22 Yet, data are scarce on the influence of such massive societal changes on health behaviours among pregnant women. Using data from an existing cohort study, the aim of this study was therefore to examine the secular trend and patterns of smoking prevalence and body weight among pregnant women in Iceland between 2001 and 2010, a period during which dramatic changes in the nation’s economy occurred.
Methods Study design We used data from an ongoing study on the risk of adverse maternal health, obstetric and birth outcomes among women previously
Downloaded from http://eurpub.oxfordjournals.org/ at Acq Serials DeptPeriodicals on November 16, 2015
Background: The prevalence of smoking during pregnancy in Western societies has decreased in the last decades, whereas prevalence of overweight and obesity has increased. Our objective was to study secular trends and patterns of smoking and body weight among pregnant women in Iceland, during a period of dramatic changes in the nation’s economy. Methods: On the basis of the Medical Birth Registry, we used a random sample of 1329 births between 1 January 2001 and 31 December 2010. Information on smoking, body mass index and background factors during pregnancy was retrieved from the Medical Birth Register and maternity records. Trends in smoking, overweight, obesity and body mass index were assessed using logistic and linear regression analyses. Logistic regression analysis was used to examine the annual odds of smoking and obesity and by socio-demographic characteristics. Results: We found a decrease in the prevalence of continued smoking during pregnancy from 12.4% in 2001 to 7.9% in 2010 [odds ratio (OR) = 0.94, 95% confidence interval (CI) (0.88–1.00)], particularly among women with Icelandic citizenship [OR = 0.92, 95% CI (0.86–0.98)], whereas no changes in obesity [OR = 1.02, 95% CI (0.96–1.07)] were observed. The highest prevalence of maternal smoking and obesity was observed in 2005–06. Conclusion: Our results indicate that smoking during pregnancy decreased among Icelandic women in 2001–10, whereas an initial increase in obesity prevalence seemed to level off towards the end of the observation period. Interestingly, we found that both of these maternal risk factors reached their highest prevalence in 2005–06, which coincides with a flourishing period in the nation’s economy.
Smoking and obesity among pregnant Icelandic women
Study variables
when women reported discontinued smoking, although this is generally registered at the first antenatal visit at around gestational week 12. Women’s BMI was calculated according to measured height and weight at the first antenatal weight measurement, which on average occurred on the 97th day of gestation [standard deviation 29.3 days, median = 90 days]. Women were considered overweight if they had BMI 25.0 kg/m2 and
