Genotyping, sequencing and analysis of 140,000 adults from Mexico City.

The Mexico City Prospective Study is a prospective cohort of more than 150,000 adults recruited two decades ago from the urban districts of Coyoacán and Iztapalapa in Mexico City1. Here we generated genotype and exome-sequencing data for all individuals and whole-genome sequencing data for 9,950 selected individuals. We describe high levels of relatedness and substantial heterogeneity in ancestry composition across individuals. Most sequenced individuals had admixed Indigenous American, European and African ancestry, with extensive admixture from Indigenous populations in central, southern and southeastern Mexico. Indigenous Mexican segments of the genome had lower levels of coding variation but an excess of homozygous loss-of-function variants compared with segments of African and European origin. We estimated ancestry-specific allele frequencies at 142 million genomic variants, with an effective sample size of 91,856 for Indigenous Mexican ancestry at exome variants, all available through a public browser. Using whole-genome sequencing, we developed an imputation reference panel that outperforms existing panels at common variants in individuals with high proportions of central, southern and southeastern Indigenous Mexican ancestry. Our work illustrates the value of genetic studies in diverse populations and provides foundational imputation and allele frequency resources for future genetic studies in Mexico and in the United States, where the Hispanic/Latino population is predominantly of Mexican descent.

Educational and social inequalities and cause-specific mortality in Mexico City: a prospective study.

BACKGROUND: Social inequalities in adult mortality have been reported across diverse populations, but there is no large-scale prospective evidence from Mexico. We aimed to quantify social, including educational, inequalities in mortality among adults in Mexico City. METHODS: The Mexico City Prospective Study recruited 150 000 adults aged 35 years and older from two districts of Mexico City between 1998 and 2004. Participants were followed up until Jan 1, 2021 for cause-specific mortality. Cox regression analysis yielded rate ratios (RRs) for death at ages 35-74 years associated with education and examined, in exploratory analyses, the mediating effects of lifestyle and related risk factors. FINDINGS: Among 143 478 participants aged 35-74 years, there was a strong inverse association of education with premature death. Compared with participants with tertiary education, after adjustment for age and sex, those with no education had about twice the mortality rate (RR 1·84; 95% CI 1·71-1·98), equivalent to approximately 6 years lower life expectancy, with an RR of 1·78 (1·67-1·90) among participants with incomplete primary, 1·62 (1·53-1·72) with complete primary, and 1·34 (1·25-1·42) with secondary education. Education was most strongly associated with death from renal disease and acute diabetic crises (RR 3·65; 95% CI 3·05-4·38 for no education vs tertiary education) and from infectious diseases (2·67; 2·00-3·56), but there was an apparent higher rate of death from all specific causes studied with lower education, with the exception of cancer for which there was little association. Lifestyle factors (ie, smoking, alcohol drinking, and leisure time physical activity) and related physiological correlates (ie, adiposity, diabetes, and blood pressure) accounted for about four-fifths of the association of education with premature mortality. INTERPRETATION: In this Mexican population there were marked educational inequalities in premature adult mortality, which appeared to largely be accounted for by lifestyle and related risk factors. Effective interventions to reduce these risk factors could reduce inequalities and have a major impact on premature mortality. FUNDING: Wellcome Trust, the Mexican Health Ministry, the National Council of Science and Technology for Mexico, Cancer Research UK, British Heart Foundation, and the UK Medical Research Council Population Health Research Unit.

Diabetes and infectious disease mortality in Mexico City.

INTRODUCTION: Although higher risks of infectious diseases among individuals with diabetes have long been recognized, the magnitude of these risks is poorly described, particularly in lower income settings. This study sought to assess the risk of death from infection associated with diabetes in Mexico. RESEARCH DESIGN AND METHODS: Between 1998 and 2004, a total of 159 755 adults ≥35 years were recruited from Mexico City and followed up until January 2021 for cause-specific mortality. Cox regression yielded adjusted rate ratios (RR) for death due to infection associated with previously diagnosed and undiagnosed (HbA1c ≥6.5%) diabetes and, among participants with previously diagnosed diabetes, with duration of diabetes and with HbA1c. RESULTS: Among 130 997 participants aged 35-74 and without other prior chronic diseases at recruitment, 12.3% had previously diagnosed diabetes, with a mean (SD) HbA1c of 9.1% (2.5%), and 4.9% had undiagnosed diabetes. During 2.1 million person-years of follow-up, 2030 deaths due to infectious causes were recorded at ages 35-74. Previously diagnosed diabetes was associated with an RR for death from infection of 4.48 (95% CI 4.05-4.95), compared with participants without diabetes, with notably strong associations with death from urinary tract (9.68 (7.07-13.3)) and skin, bone and connective tissue (9.19 (5.92-14.3)) infections and septicemia (8.37 (5.97-11.7)). In those with previously diagnosed diabetes, longer diabetes duration (1.03 (1.02-1.05) per 1 year) and higher HbA1c (1.12 (1.08-1.15) per 1.0%) were independently associated with higher risk of death due to infection. Even among participants with undiagnosed diabetes, the risk of death due to infection was nearly treble the risk of those without diabetes (2.69 (2.31-3.13)). CONCLUSIONS: In this study of Mexican adults, diabetes was common, frequently poorly controlled, and associated with much higher risks of death due to infection than observed previously, accounting for approximately one-third of all premature mortality due to infection.

Body Composition and Risk of Vascular-Metabolic Mortality Risk in 113 000 Mexican Men and Women Without Prior Chronic Disease.

Background Body-mass index is the sum of fat mass index (FMI) and lean mass index (LMI), which vary by age, sex, and impact on disease outcomes. We investigated the separate and joint relevance of FMI and LMI with vascular-metabolic causes of death in Mexican adults. Methods and Results A total of 113 025 adults aged 35 to 74 years and free from diabetes or other chronic diseases when recruited into the Mexico City Prospective Study were followed for 19 years. Cox models estimated sex-specific death rate ratios from vascular-metabolic causes after adjustment for confounders and exclusion of the first 5 years of follow-up. To account for the strong correlation between FMI and LMI, additional models estimated rate ratios associated with "residual FMI" and "residual LMI" (ie, the residuals from linear regression analyses of FMI on LMI, or vice versa). In both sexes, higher FMI and LMI were associated with higher risks of vascular-metabolic mortality. For a given (ie, fixed) level of LMI, the rate ratio (95% CI) for vascular-metabolic mortality per 1 kg/m2 higher residual FMI strengthened and was higher in women (1.52 [1.38-1.68]) than in men (1.19 [1.13-1.25]). By contrast, for a given level of FMI, higher residual LMI was inversely associated with vascular-metabolic mortality (rate ratio per 1 kg/m2 0.67 [0.56-0.80] in women and 0.94 [0.90-0.98] in men). Conclusions In this study, higher residual FMI was more strongly associated with vascular-metabolic mortality in women than in men. Conversely, higher residual LMI was inversely associated with vascular-metabolic mortality, particularly in women.

Ethnicity and other COVID-19 death risk factors in Mexico.

Introduction: Patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may develop coronavirus disease 2019 (COVID-19). Risk factors associated with death vary among countries with different ethnic backgrounds. We aimed to describe the factors associated with death in Mexicans with confirmed COVID-19. Material and methods: We analysed the Mexican Ministry of Health's official database on people tested for SARS-CoV-2 infection by real-time reverse transcriptase-polymerase chain reaction (rtRT-PCR) of nasopharyngeal fluids. Bivariate analyses were performed to select characteristics potentially associated with death, to integrate a Cox-proportional hazards model. Results: As of May 18, 2020, a total of 177,133 persons (90,586 men and 86,551 women) in Mexico received rtRT-PCR testing for SARS-CoV-2. There were 5332 deaths among the 51,633 rtRT-PCR-confirmed cases (10.33%, 95% CI: 10.07-10.59%). The median time (interquartile range, IQR) from symptoms onset to death was 9 days (5-13 days), and from hospital admission to death 4 days (2-8 days). The analysis by age groups revealed that the significant risk of death started gradually at the age of 40 years. Independent death risk factors were obesity, hypertension, male sex, indigenous ethnicity, diabetes, chronic kidney disease, immunosuppression, chronic obstructive pulmonary disease, age > 40 years, and the need for invasive mechanical ventilation (IMV). Only 1959 (3.8%) cases received IMV, of whom 1893 were admitted to the intensive care unit (96.6% of those who received IMV). Conclusions: In Mexico, highly prevalent chronic diseases are risk factors for death among persons with COVID-19. Indigenous ethnicity is a poorly studied factor that needs more investigation.