Unreliable estimation of prevalence of fetal alcohol syndrome – Authors' reply
Authors: Svetlana Popova, Shannon Lange, Charlotte Probst, Gerrit Gmel, Jürgen Rehm
Journal: The Lancet Global Health (2017)

We thank Katrine Strandberg-Larsen and colleagues from Denmark and Simona Pichini and colleagues from Italy for their comments on our paper.1Popova S Lange S Probst C Gmel G Rehm J Estimation of national, regional, and global prevalence of alcohol use during pregnancy and fetal alcohol syndrome: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e290-e329Summary Full Text Full Text PDF PubMed Scopus (429) Google Scholar Both comments underline the immense interest in the related public health problems of alcohol use during pregnancy and fetal alcohol syndrome (FAS). With respect to the comment of Strandberg-Larsen and colleagues from Denmark, the authors question our finding that the prevalence of alcohol use during pregnancy in the WHO European Region was estimated to be the highest among the six WHO regions. According to the latest Global Status Report on Alcohol and Health 2014,2World Health OrganizationGlobal status report on alcohol and health 2014. WHO, Geneva, Switzerland2014http://apps.who.int/iris/bitstream/10665/112736/1/9789240692763_eng.pdfGoogle Scholar however, almost all major alcohol indicators such as prevalence and level of consumption, rates of chronic and heavy episodic drinking, and alcohol use disorders are the highest in this region. Thus, the high prevalence of alcohol use during pregnancy and FAS in the WHO European Region, which exceed global levels, should not come as a surprise. Second, concern raised that our estimated pooled prevalence of alcohol use during pregnancy for Denmark was higher than two recent estimates, which were not included in our meta-analysis because they were published outside of the timeframe covered in our study. However, the study by Iversen and colleagues3Iversen ML Sorensen NO Broberg L et al.Alcohol consumption and binge drinking in early pregnancy. A cross-sectional study with data from the Copenhagen Pregnancy Cohort.BMC Pregnancy Childbirth. 2015; 15: 327Crossref PubMed Scopus (21) Google Scholar reported that the proportion of women that disclosed binge drinking, defined as the consumption of at least 60 g of pure alcohol on a single occasion, during early pregnancy was 35%. This is alarming, given that binge drinking is the drinking pattern most strongly causally associated with FAS and fetal alcohol spectrum disorder (FASD). Given that our pooled prevalence estimate was based on any amount of alcohol consumed at any time during pregnancy, the Danish results are actually within the confidence interval of our pooled prevalence for Denmark. Third, Strandberg-Larsen and colleagues indicate that the predicted FAS prevalence for Denmark is high compared with that of the National Danish Patient Registry. As they acknowledge, it is well known that record-based ascertainment severely underestimates the true prevalence of FAS and FASD,4May PA Gossage JP Kalberg WO et al.Prevalence and epidemiologic characteristics of FASD from various research methods with an emphasis on recent in-school studies.Dev Disabil Res Rev. 2009; 15: 176-192Crossref PubMed Scopus (647) Google Scholar and active case ascertainment is considered the gold standard. It is for this reason that we excluded any estimates obtained via passive methods from our analysis. Last, Strandberg-Larsen and colleagues also express concern that our predicted prevalence estimates of FAS might be overestimated for other countries, presumably because drinking during pregnancy is reducing. We did test for such a time-trend of decreasing prevalence of drinking during pregnancy in our prediction model and did not find a significant contribution, although there was a trend in this direction. Pichini and colleagues express concern that Italy was reported to be among the top five countries with the highest prevalence of FAS globally. Although the correspondents were of the understanding that this prevalence was predicted, Italy was actually one of the very few countries with existing empirical data obtained via studies using active case ascertainment, which screened 3035 children.1Popova S Lange S Probst C Gmel G Rehm J Estimation of national, regional, and global prevalence of alcohol use during pregnancy and fetal alcohol syndrome: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e290-e329Summary Full Text Full Text PDF PubMed Scopus (429) Google Scholar Thus, the prevalence of FAS for Italy was the result of a meta-analysis of the existing empirical studies. Additionally, Pichini and colleagues point to the findings of meconium analyses, which for Italy seem to suggest a lower prevalence of alcohol use during pregnancy. To ensure consistency across studies and countries, we restricted ourselves to self-report data, which has also been found to be a more conservative measure of alcohol use during pregnancy.5Lange S Shield K Koren G Rehm J Popova S A comparison of the prevalence of prenatal alcohol exposure obtained via maternal self-reports versus meconium testing: a systematic literature review and meta-analysis.BMC Pregnancy Childbirth. 2014; 14: 127Crossref PubMed Scopus (100) Google Scholar However, some of the Italian studies cited by the correspondents, reported a higher prevalence when obtained via self-reports compared to meconium analysis.6Morini L Marchei E Vagnarelli F et al.Ethyl glucuronide and ethyl sulfate in meconium and hair-potential biomarkers of intrauterine exposure to ethanol.Forensic Sci Int. 2010; 196: 74-77Summary Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 7Pichini S Marchei E Vagnarelli F et al.Assessment of prenatal exposure to ethanol by meconium analysis: results of an Italian multicenter study.Alcohol Clin Exp Res. 2012; 36: 417-424Crossref PubMed Scopus (52) Google Scholar In any case, the prevalence obtained via self-reports in one of the cited studies6Morini L Marchei E Vagnarelli F et al.Ethyl glucuronide and ethyl sulfate in meconium and hair-potential biomarkers of intrauterine exposure to ethanol.Forensic Sci Int. 2010; 196: 74-77Summary Full Text Full Text PDF PubMed Scopus (77) Google Scholar was above our estimated pooled prevalence for Italy and was within the range of uncertainty.1Popova S Lange S Probst C Gmel G Rehm J Estimation of national, regional, and global prevalence of alcohol use during pregnancy and fetal alcohol syndrome: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e290-e329Summary Full Text Full Text PDF PubMed Scopus (429) Google Scholar Moreover, meconium studies can rarely be used in population health because it is difficult to obtain large representative samples using this technique. In conclusion, although we did not find a significant time-trend for decreasing rates of alcohol use during pregnancy overall, such a trend might be happening in some European countries. Surely, countries like Italy where dietary guidelines as early as 1979 recommended drinking less than 300 mL of wine during pregnancy per day8Istituto Nazionale della NutrizioneIndicazioni nutrizionali per la popolazione italiana. Istituto Nazionale della Nutrizione, Rome, Italy1979Google Scholar have changed their attitudes towards this phenomenon. Hopefully, such country-specific guideline changes will also lead to changes in the behaviour, which in the future could be reflected in a decreasing trend globally. Furthermore, we completely agree with the correspondents that many existing studies are outdated, and more epidemiological studies on the prevalence of alcohol use during pregnancy and FAS and FASD are needed not only in Denmark and Italy, but worldwide. With respect to the WHO European Region, the high prevalence of alcohol use during pregnancy and FAS is alarming, and requires urgent action. This is in line with the Global strategy to reduce the harmful use of alcohol9World Health OrganizationGlobal strategy to reduce the harmful use of alcohol. WHO, Geneva, Switzerland2010http://apps.who.int/iris/bitstream/10665/44395/1/9789241599931_eng.pdf?ua=1&ua=1Google Scholar and other WHO initiatives on prevention of harm caused by prenatal alcohol exposure.10WHO Regional Office for EuropePrevention of harm caused by alcohol exposure in pregnancy.Available from http://www.euro.who.int/__data/assets/pdf_file/0005/318074/Prevention-harm-caused-alcohol-exposure-pregnancy.pdf?ua=1Google Scholar We declare no competing interests. Introducing The Lancet Global Health Commission on High-Quality Health Systems in the SDG EraThe Millennium Development Goals on health have expanded access to basic health interventions to millions of people in low-income and middle-income countries (LMICs). However, access alone will not be sufficient to meet the Sustainable Development Goals (SDGs) if health systems cannot provide high quality care—ie, care that improves health outcomes and provides value to people. Emerging data show that many LMIC health systems struggle to consistently provide good quality of care.1,2 Yet change is possible. Full-Text PDF Open AccessUnreliable estimation of prevalence of fetal alcohol syndromeSvetlana Popova and colleagues (March, 2017)1 estimated that about one quarter of pregnant women in Europe drink alcohol. The authors state that this estimate is 2·6 times higher than the global prevalence and estimate that Europe has the world's highest fetal alcohol syndrome (FAS) prevalence of 37·4 per 10 000 people. If true, these numbers are alarming and require urgent action; however, we are not convinced that they are valid for contemporary Europe. Full-Text PDF Open AccessUnreliable estimation of prevalence of fetal alcohol syndromeSvetlana Popova and colleagues (March, 2017)1 sought to estimate the global, regional, and national prevalence of alcohol use during pregnancy and fetal alcohol syndrome (FAS). The authors reviewed international literature from 1984 for country-specific quantitative studies and for countries with one or no studies they predicted gestational alcohol use prevalence by fractional response regression modelling and prevalence of FAS by an estimated quotient for the average number of women consuming alcohol during pregnancy per one case of FAS. Full-Text PDF Open Access