Age-Specific Excess Mortality Patterns During the 1918-1920 Influenza Pandemic in Madrid, Spain.

Although much progress has been made to uncover age-specific mortality patterns of the 1918 influenza pandemic in populations around the world, more studies in different populations are needed to make sense of the heterogeneous death impact of this pandemic. We assessed the absolute and relative magnitudes of 3 pandemic waves in the city of Madrid, Spain, between 1918 and 1920, on the basis of age-specific all-cause and respiratory excess death rates. Excess death rates were estimated using a Serfling model with a parametric bootstrapping approach to calibrate baseline death levels with quantified uncertainty. Excess all-cause and pneumonia and influenza mortality rates were estimated for different pandemic waves and age groups. The youngest and oldest persons experienced the highest excess mortality rates, and young adults faced the highest standardized mortality risk. Waves differed in strength; the peak standardized mortality risk occurred during the herald wave in spring 1918, but the highest excess rates occurred during the fall and winter of 1918/1919. Little evidence was found to support a "W"-shaped, age-specific excess mortality curve. Acquired immunity may have tempered a protracted fall wave, but recrudescent waves following the initial 2 outbreaks heightened the total pandemic mortality impact.

Maternal education and perinatal outcomes among Spanish women residing in southern Spain (2001-2011).

Evidence suggests that educational differences in perinatal outcomes have increased in some countries (Eastern Europe) while remained stable in others (Scandinavian countries). However, less is known about the experience of Southern Europe. This study aims to evaluate the association between maternal education and perinatal outcomes derived from birthweight (low birthweight and macrosomia) and gestational age (pre-term and post-term births) among Spaniards living in the Autonomous Community of Andalusia during the period 2001-2011 (around 19 % of births in Spain); and to evaluate whether the educational differences narrowed or widened during that period, which includes both an economic boom (2001-2008) and the global economic crisis (2009-2011). This study uses the Andalusian Population Longitudinal Database and the Vital Statistics Data provided by the Spanish National Statistics Institute. We study live and singleton births of Spanish mothers who lived in Andalusia at the time of delivery (n = 404,951). ORs with 95 % confidence intervals (crude and adjusted) were estimated using multinomial regression models. A negative educational gradient is observed in all perinatal outcomes studied (i.e., the higher the educational status, the lower the risk of negative perinatal outcomes). However, when disaggregating the sample in two periods, the gradient is only statistically significant for pre-term birth during 2001-2008, while a full gradient is observed in all perinatal indicators in the period 2009-2011 with an increase in the educational inequalities in macrosomia and post-term. Further studies are needed in order to confirm whether there is a causal association between the widening of the educational differences in perinatal outcomes and the onset of the economic crisis in Spain, or the widening can be explained by other factors, such as changes in childbearing patterns and the composition of women accessing motherhood.

Bringing the individual back to small-area variation studies: a multilevel analysis of all-cause mortality in Andalusia, Spain.

We performed a multilevel analysis (including individuals, households, census tracts, municipalities and provinces) on a 10% sample (N=230,978) from the Longitudinal Database of the Andalusian Population (LDAP). We aimed to investigate place effects on 8-year individual mortality risk. Moreover, besides calculating association (yielding odds ratios, ORs) between area socio-economic circumstances and individual risk, we wanted to estimate variance and clustering using the variance partition coefficient (VPC). We explicitly proclaim the relevance of considering general contextual effects (i.e. the degree to which the context, as a whole, affects individual variance in mortality risk) under at least two circumstances. The first of these concerns the interpretation of specific contextual effects (i.e. the association between a particular area characteristic and individual risk) obtained from multilevel regression analyses. The second involves the interpretation of geographical variance obtained from classic ecological spatial analyses. The so-called "ecological fallacy" apart, the lack of individual-level information renders geographical variance unrelated to the total individual variation and, therefore, difficult to interpret. Finally, we stress the importance of considering the familial household in multilevel analyses. We observed an association between percentage of people with a low educational level in the census tract and individual mortality risk (OR, highest v. lowest quintile=1.14; 95% confidence interval, CI 1.08-1.20). However, only a minor proportion of the total individual variance in the probability of dying was at the municipality (M) and census tract (CT) levels (VPC(M)=0.2% and VPC(CT)=0.3%). Conversely, the household (H) level appeared much more relevant (VPC(H)=18.6%) than the administrative geographical areas. Without considering general contextual effects, both multilevel analyses of specific contextual effects and ecological studies of small-area variation may provide a misleading picture that overstates the role of administrative areas as contextual determinants of individual differences in mortality.

The quality of vital statistics for studying perinatal health: the Spanish case.

BACKGROUND: Birthweight and gestational age are key indicators for perinatal health obtained through the birth certificate. Knowing the validity of birth certificate data is crucial when identifying needs and evaluating birth outcomes. In Spain, vital information is reported by parents and is not checked for consistency with any hospital document. Therefore, to perform a validation study and describe the variables associated with misreporting is essential to improve the quality of birth certificates. METHODS: A database was created using birth information from hospital medical records that were individually linked with the Spanish National Institute of Statistics (INE) birth certificate files. Measures of reliability and validity were used to compare the data from the two sources. Logistic regression models were adjusted to model the odds of being misreported in birthweight and gestational age, controlling for relevant variables. RESULTS: INE overestimated the prevalence of birthweight and gestational age. The degree of agreement between the two sources was good for most gestational age groups (Kappa = 0.74), very good for the very preterm (Kappa = 0.85) and very good also for all categories of birthweight (Kappa = 0.88). Misreporting was significantly higher among immigrants, unmarried mothers and girls. Being a preterm birth increased the odds of being declared with errors in gestational age; having low birthweight and missing information on gestational age were associated with misreporting birthweight. CONCLUSIONS: The reliability of INE information could be greatly improved if hospitals included birthweight and gestational age on the document provided to parents for registering the birth.