Socioeconomic Inequalities in Small-for-Gestational-Age Births Before and During the Economic Crisis: An Ecologic Study of Trends in 13 Spanish Cities

Economic recessions can increase socioeconomic inequalities in health. The objective of this study was to analyze socioeconomic inequalities in small-for-gestational-age (SGA) births before and during the Spanish economic crisis. We conducted an ecological study of trends based on 2 periods before the crisis (1999-2003 and 2004-2008) and another during the crisis (2009-2013). The study population was Spanish women resident in 13 cities who had given birth during 1999-2013. The prevalence of SGA was calculated for each census tract. A hierarchical Bayesian model was used to obtain the prevalence ratio (PR) and 95% credible intervals (CI). We analyzed the association between SGA and socioeconomic deprivation in each period for each city and for 3 age groups. The PR was above 1 and statistically significant for all 3 time periods in most of the 13 cities. The differences in PR between periods were only statistically significant for Madrid (PR = 1.56, 95% CI 1.48-1.65 for 1999-2003; PR = 1.28, 95% CI 1.19-1.38 for 2004-2008) and Barcelona (PR = 0.99, 95% CI 0.87-1.12 for 2004-2008; PR = 1.20, 95% CI 1.05-1.36 for 2009-2013). Socioeconomic inequalities in SGA births in small areas (census tracts) of most Spanish cities studied remained stable before and during the economic crisis.