The Mexican Cognitive Aging Ancillary Study (Mex-Cog): Study Design and Methods

Objective: Describe the protocol sample and instruments of the Cognitive Aging Ancillary Study in Mexico (Mex-Cog). The study performs an in-depth cognitive assessment in a subsample of older adults of the ongoing Mexican Health and Aging Study (MHAS). The Mex-Cog is part of the Harmonized Cognitive Assessment Protocol (HCAP) design to facilitate cross-national comparisons of the prevalence and trends of dementia in aging populations around the world, funded by the National Institute on Aging (NIA). Methods: The study protocol consists of a cognitive assessment instrument for the target subject and an informant questionnaire. All cognitive measures were selected and adapted by a team of experts from different ongoing studies following criteria to warrant reliable and comparable cognitive instruments. The informant questionnaire is from the 10/66 Dementia Study in Mexico. Results: A total of 2,265 subjects aged 55-104 years participated, representing a 70% response rate. Validity analyses showed the adequacy of the content validity, proper quality-control procedures that sustained data integrity, high reliability, and internal structure. Conclusions: The Mex-Cog study provides in-depth cognitive data that enhances the study of cognitive aging in two ways. First, linking to MHAS longitudinal data on cognition, health, genetics, biomarkers, economic resources, health care, family arrangements, and psychosocial factors expands the scope of information on cognitive impairment and dementia among Mexican adults. Second, harmonization with other similar studies around the globe promotes cross-national studies on cognition with comparable data. Mex-Cog data is publicly available at no cost to researchers

Effectiveness of COVID-19 vaccines in older adults in Colombia: a retrospective, population-based study of the ESPERANZA cohort.

Background: Although clinical trials showed that vaccines have high efficacy and safety, differences in study designs and populations do not allow for comparison between vaccines and age groups. The objective of this study was to evaluate the effectiveness of vaccines against COVID-19 in real-world conditions in adults aged 60 years and older in Colombia. Methods: In this retrospective, population-based, matched cohort study, we evaluated the effectiveness of vaccines against COVID-19-related hospitalisation and death in people aged 60 years and older. The full cohort consisted of every person who was eligible to receive a COVID-19 vaccine in Colombia (the ESPERANZA cohort). The exposed cohort consisted of older adults who were fully vaccinated with Ad26.COV2-S, BNT162b2, ChAdOx1 nCoV-19, or CoronaVac, and who did not have a history of confirmed SARS-CoV-2 infection. The unexposed cohort were people aged 60 years and older who had not received any dose of a COVID-19 vaccine during the study period. Participant follow-up was done between March 11, 2021, and Oct 26, 2021. Vaccine effectiveness was estimated as 1- hazard ratio from cause-specific proportional hazards models in the presence of competing risks. We estimated the overall effectiveness of being fully vaccinated, as well as effectiveness for each vaccine, adjusting by main potential confounders. The effectiveness of each vaccine was also assessed by age groups (ages 60-69 years, 70-79 years, and ≥80 years). Findings: 2 828 294 participants were assessed between March 11 and Oct 26, 2021. For all ages, the overall effectiveness across all assessed COVID-19 vaccines at preventing hospitalisation without subsequent death was 61·6% (95% CI 58·0-65·0, p<0·0001), 79·8% (78·5-81·1, p<0·0001) for preventing death after hospitalisation with COVID-19, and 72·8% (70·1-75·3, p<0·0001) for preventing death without previous COVID-19 hospitalisation. The effectiveness of all vaccines analysed at preventing death after hospitalisation for COVID-19 was 22·6% lower in adults who were aged 80 and older (68·4% [65·7-70·9], p<0·0001) compared with adults aged between 60 and 69 years (91·0% [89·0-92·6], p<0·0001). Interpretation: All vaccines analysed in this study were effective at preventing hospitalisation and death from COVID-19 in fully vaccinated older adults, which is a promising result for the national vaccination programme against COVID-19 in Colombia and in countries where these biologics have been applied. Efforts should be improved to increase coverage among older adults. In addition, given that we observed that the effectiveness of vaccines declined with increasing age, a booster dose is also justified, which should be prioritised for older adults. Funding: Colombian Ministry of Health and Social Protection

Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Blood lead has been associated with an elevated risk of miscarriage. The plasmatic fraction of lead represents the toxicologically active fraction of lead. Women with a tendency to have a higher plasma/whole blood Pb ratio could tend towards an elevated risk of miscarriage due to a higher plasma Pb for a given whole blood Pb and would consequently have a history of spontaneous abortion.</p> <p>Methods</p> <p>We studied 207 pregnant Mexico City residents during the 1^sttrimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.</p> <p>Results</p> <p>The mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 μg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.</p> <p>Conclusion</p> <p>Women with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.</p

Asociación de factores regionales y culturales con la prevalencia de artritis reumatoide en la población mexicana

Background The overall estimated prevalence of rheumatoid arthritis (RA) in Mexico is 1.6%, but there are major variations in different geographic areas of the country. Objective This study aimed to determine the impact of individual and regional variables on the geographic distribution of RA in Mexico. Methods This multilevel analysis used data from a cross-sectional study that investigated the prevalence of RA among 19,213 individuals older than 18 years throughout 5 geographic regions in Mexico. Logistic regression models were used to determine predictors of RA, including individual and regional variables as well as cultural factors. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were determined. Results The prevalence of RA varied from 0.77% to 2.8% across the 5 regions. Individual factors associated with RA were sex (OR, 2.32; 95% CI, 1.74–3.07), previous medical diagnosis of RA (OR, 3.32; 95% CI, 2.19–2.20), disability (OR, 2.07; 95% CI, 1.48–2.93), and the 56- to 65-year age group (OR, 1.95; 95% CI, 1.08–3.74). The regional factor of speaking an indigenous language had an OR of 2.27 (95% CI, 1.13–4.55). Conclusions Various individual and regional factors were associated with variations in the prevalence of RA in the Mexican population

Validity assessment of self-reported weight and its correction process among Mexican adult women of reproductive age.

ObjectiveWe aimed to evaluate the agreement between self-reported weight (SRW) and measured weight (MW) in adult women of reproductive age, identify characteristics associated with the difference between SRW and MW (DW), and develop a correction procedure for SRW.MethodsWe used data from 3,452 non-pregnant or non-lactating adult women who participated in the Mexican Family Life Survey. Standardized personnel asked women about their weight before measuring weight and height. We conducted a Bland-Altman analysis for agreement and adjusted linear regression models for sociodemographic characteristics.ResultsMean DW was -0.59±3.21 kg. Difference varied according to Body Mass Index (BMI) and region of residence (pConclusionSRW has limitations to be considered as an alternative to MW among women of reproductive age with specific characteristics. Our proposed correction equation may decrease SRW imprecision improving the estimation of overweight and obesity. We suggest that studies consider and adjust the possible bias associated with weight misreporting on health outcomes

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Objective. To describe risk factors associated to the incidence of type 2 diabetes (T2D) in Mexican population and to define phenotypic (clinical, anthropometric, metabolic) characteristics present in the individual who will convert to diabetes, regardless of time of onset. Materials and methods. The Mexico City Diabetes Study began in 1990, with 2 282 participants, and had three subsequent phases: 1994, 1998, and 2008. A systematic evaluation with an oral glucose tolerance test was performed in each phase. For diagnosis of T2D, American Diabetes Association criteria were used. Results. The population at risk was 1939 individuals. Subjects who were in the converter stage (initially non diabetic that eventually converted to T2D) had, at baseline, higher BMI (30 vs 27), systolic blood pressure (119 vs 116 mmHg), fasting glucose (90 vs 82mg/dl), triglycerides (239 vs 196mg/dl), and cholesterol (192 vs 190mg/dl), compared with subjects who remained non converters (p menor que 0.05). Conclusion. The phenotype described represents a potentially identifiable phase and a target for preventive intervention

Trends in overweight and obesity in children under 24 months of age in Mexico (2012-2020): analysis of four national health surveys

Abstract: The prevalence of childhood obesity has increased rapidly in Mexico, with significant consequences for the population’s health in the future. Little is known about the prevalence of obesity in children under two years of age, even though this life stage is fundamental to prevent this condition. This study aims to determine the magnitude, distribution, and trends of overweight and obesity in children under 24 months of age using the Mexican National Health and Nutrition Surveys (ENSANUT) conducted in the last 10 years. The data presented here are derived from four ENSANUTs, carried out in Mexico in 2012, 2016, 2018, and 2020. They include 6,719 infants under 24 months with complete anthropometric data (weight/height) by age, gender, Indigeneity, area of residence, and socioeconomic status. The risk of overweight levels and overweight + obesity rates were calculated according to World Health Organization guidelines. We identified that infants < 12 months currently have a higher prevalence of overweight + obesity (10.3%) and that those aged 12 to 23 months are generally at a higher risk of overweight (26.1%). The most relevant findings of this study, linking weight trends to sex, region, socioeconomic status, and indigeneity, show that overweight and obesity prevalences vary across the Mexican population, without presenting a specific behavior. There is a high prevalence of overweight and obesity among Mexican infants and a slight trend toward increased obesity in infants < 12 months. Weight monitoring and obesity prevention interventions focused on the first 1,000 days of life are essential