Smoking mothers, fuming babies: the effects of maternal smoking on birth weight by mother´s country of origin using a multilevel approach

Sol Juarez, Lund University
Juan Merlo, Lund University

We investigate the effects of maternal smoking on birthweight by mother´s country of origin in Sweden. Previous studies have shown that the prevalence of smoking is lower among foreigners than Swedes, within a similar downward trend. However, this does not necessarily capture all aspects of the consumption patterns (such as the number of cigarettes per day). In this sense, although they show the same general trends, the potential effects of smoking on reproductive health do not have to be the same for all groups of origin. Developing countries are experiencing an increase in the overall prevalence of smoking among women, which is related to the change in the social perception of tobacco and, consequently, in their consumption patterns. This transformation is mainly observed in non-western countries such as India, China, and the Russian Federation, where “westernization” has relaxed the strong taboo against smoking women. So, in this context, it is expected that for certain immigrants (such as the above-mentioned) consumption might tend to be different and, therefore, have a differential impact on health. This paper focuses on birthweight because of its importance in population health, and insofar as it is a strong predictor of early mortality and of some adult morbidities, not to mention other significant outcomes such as educational attainment. This study is based on data from the Swedish Medical Birth Register for years 2002-2009 (823,553 births), which contains all deliveries in Sweden in this period. Individual birthweight (in grams) is analyzed by using a multilevel linear regression model, with individuals at the first level and mother´s country of origin at the second level (more than 100 different countries). The associations between variables were assessed by using beta coefficient (95% confidence intervals) in the fixed-effect part of the models.