Realidad, datos y espacio : revista internacional de estadistica y geografia最新文献

The way missing data in population surveys are treated can influence research results. Therefore, the aim of this paper is to explain the reasons and procedure for imputing anthropometric data such as height and weight self-reported by individuals in the first four waves of the Mexican Health & Aging Study (MHAS). We highlight the effect of the imputation versus the exclusion of the cases with missing data, by comparing the distribution of these values and their associated effects on the Body Mass Index using a regression model. We conclude that the incorporation of imputed data offers more solid results compared with elimination the cases with missing data. Hence the importance of applying these statistical procedures, with appropriate treatment of the data, making the methodology and the imputed data available to the users by the same source of information, as offered in the MHAS.

Non-response of cognitive data in cohort studies is a barrier to cognitive aging research. We describe the procedures for the imputation of non-responses for cognitive data in the Mexican Health and Aging Study (MHAS). Data came from the 2001-2015 MHAS waves. We also describe the association of cognition with education, age, and other variables in 2015 with and without the imputed values. Between 12.3% and 37.9% of participants were missing data for at least one cognition variable. When we conducted the analysis with and without the imputed values, the relationships between education, age, and cognition were similar in direction and significance, but different in magnitude. Non-response of cognitive data is common and non-random in the MHAS. Investigators should use the data sets that include the imputed values, which are publicly available.

Este trabajo analiza la atrición de la Encuesta Nacional sobre Salud y Envejecimiento en México entre el 2001 y el 2012, un proyecto longitudinal sobre adultos mayores. Para la tercera ronda de este operativo estadístico, la pérdida acumulada representó la tercera parte de la muestra inicial; la principal causa fue por fallecimiento, seguida por la no localización y el rechazo. Con modelos de regresión se examinan asociaciones de características económicas, de salud y sociodemográficas de los participantes en el 2001 con cada tipo de atrición en el 2003 y el 2012. Los resultados señalan que las variables de salud tuvieron mayor asociación con la pérdida por fallecimiento, mientras que las características económicas y sociodemográficas estuvieron asociadas con la no localización y el rechazo. Documentar el carácter de la atrición proporciona valiosos elementos para investigaciones basadas en la ENASEM, pues los resultados longitudinales podrían ser afectados por un posible sesgo selectivo en la muestra. The Mexican Health and Aging Study (MHAS) is a longitudinal project focused on older population. In this paper, we analyze attrition in three rounds of the study, between 2001 and 2012. The attrition represents a third of the initial sample in wave three. Death is the main cause of attrition, followed by lo to follow-up and refusal. Using regression models we examined associations of health, economic and demographic characteristics of participants and survey characteristics in 2001 on each cause of attrition in 2003 and 2012. Results indicate that health variables such as the number of chronic diseases have a greater association with death attrition, while economic and demographic characteristics of the study participants are associated with loss to follow-up and refusal. Documenting the character of attrition provides valuable information for research based on the MHAS data, since the results of longitudinal studies could be affected by a possible selectivity bias in the sample.

In this paper, we offer a general outlook of the health of Latin Americans (with a special emphasis on Mexicans) during the different stages of the migration process to the U.S. given the usefulness of the social vulnerability concept and given that said vulnerability varies conspicuously across the different stages of the migration process. Severe migrant vulnerability during the transit and crossing has serious negative health consequences. Yet, upon their arrival to the U.S., migrant health is favorable in outcomes such as mortality by many causes of death and in several chronic conditions and risk factors, though these apparent advantages seem to disappear during the process of adaptation to the host society. We discuss potential explanations for the initial health advantage and the sources of vulnerability that explain its erosion, with special emphasis in systematic timely access to health care. Given that migration can affect social vulnerability processes in sending areas, we discuss the potential health consequences for these places and conclude by considering the immigration and health policy implications of these issues for the United States and sending countries, with emphasis on Mexico.