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Street scene in Mexico City

background

The Mexico City Prospective Study (MCPS) is the largest blood-based prospective study of the health of a Latino population. The study offers an opportunity to investigate how social, lifestyle, physical, metabolic and genetic factors influence the major causes of death in Mexican adults in a large cohort that has already been followed for two decades.

Between 1998 and 2004, over 150,000 middle-aged adults including 100,000 women from the Coyoacán and Iztapalapa, districts of Mexico City, were recruited. They gave information about their lifestyle, and disease history, had physical measurements taken, such as blood pressure, weight, waist and hip circumference, and provided blood samples.

A resurvey of 10,000 surviving participants was completed between 2015 and 2019. It captured how lifestyles, physical and biological measurements, and treatments for disease had changed over time. This resurvey allowed us to better assess the relevance of characteristics such as blood pressure and smoking that can vary over time on premature death. We also collected urine samples and additional information such as bioimpedance (providing measures of body fat) and cognitive function.

A follow up health survey is currently collecting information on major non-fatal diseases by house-to-house field work.

Using blood samples we have genotyped and exome sequenced all participants. We are currently in the final stages of compiling metabolomic data for all participants which includes important biomarkers such as cholesterol and triglycerides. All participants are tracked for mortality through linkage to Mexican national mortality records. By mid 2022 about 35,000 were confirmed to have died.

Major findings

DIABETES 

At recruitment, nearly half of women and a third of men aged 50-59 had obesity (ie, had a BMI ≥30 kg/m2) and by age 60 more than one in five had a confirmed diagnosis of diabetes. Those with diabetes had four times the overall death rate at ages 35-74 compared with people without diabetes.  The excess mortality among people with diabetes accounted for at least one-third of all deaths between the ages 35-74 years, which is twice that suggested by previous studies. Read full paper.

The biggest excess risk of death among people with diabetes was from kidney disease, followed by heart and other vascular disease, infection and acute diabetic crises. Subsequent analyses revealed the types of infection most strongly related to diabetes. Read full paper.

OBESITY

Obesity makes diabetes and several other chronic diseases more common, but these diseases can cause substantial weight loss, thereby hiding their initial cause. To try to counteract this concealment we looked at the association between obesity and mortality more than five years after recruitment and excluded people who had chronic disease at recruitment. We found that general obesity, as well as carrying excess fat around the waist, were major risk factors for premature death. Among those with BMI>25 kg/m2, each increase of 5 kg/m2 was associated with a 30% increase in mortality. Waist circumference was particularly strongly related to mortality suggesting that abdominal obesity is especially harmful. Read full paper.

By measuring nuclear magnetic resonance (NMR) blood biomarkers we found positive associations between both higher total fat and higher abdominal fat with numerous molecules in the blood that are linked to type 2 diabetes and heart disease. Conversely, higher hip and upper thigh fat were associated with a favourable NMR metabolic profile. Read full paper. 

BMI is the sum of Fat Mass Index (FMI) and Lean Mass Index (LMI). We found that FMI and LMI had independent but opposite associations with death from vascular and metabolic causes. This suggests that using BMI alone to assess disease risk may be less informative than using FMI and LMI. Read full paper. 

BMI was strongly associated with death due to COVID-19 in 2020. However, even in 2020 other causes of death accounted for more than twice as many deaths as COVID-19, so the absolute effect of BMI on mortality was still greater for the aggregate of those other causes than for COVID-19. Read full paper.

SMOKING AND CAUSE-SPECIFIC MORTALITY

Smoking a few cigarettes a day – ‘low intensity smoking’ - was associated with increased mortality, particularly from respiratory cancers, chronic obstructive pulmonary disease and gastrointestinal and vascular diseases. Of those smoking an average of about 10 cigarettes per day, about one third were killed by their habit. However, as in other populations, quitting substantially reduced these risks. Read full paper.

BLOOD PRESSURE 

Blood pressure was a major risk factor for death from a range of diseases. It was especially strongly related to death from vascular and kidney disease, with no ‘threshold’ levels below which lower blood pressure was not associated with lower risk. As those with diabetes were at substantially higher risk than those without diabetes, the mortality rates associated with elevated blood pressure were much higher in these individuals. Read full paper.

Socioeconomic Status

Participants with no formal education had about twice the mortality rate of participants with tertiary level education, resulting in an average reduction in life expectancy of approximately six years. Lifestyle factors such as smoking, alcohol drinking, and leisure time physical activity and the related physiological correlates of obesity, diabetes, and high blood pressure accounted for about four-fifths of the association of education with premature death. Read full paper.

Genetic Analyses

People with Latino ethnic background are under represented in genetic research. Through an academic-industry partnership with the  Regeneron Genetics Center® and AstraZeneca we generated genotype and exome data for the whole cohort, and whole-genome sequencing data for a subset of 9,950 participants. This is one of the most extensive sequencing studies of individuals from non-European ancestry and a major step forward for diversity in genetic research. Read full paper and press release.

These data have already contributed to several new discoveries:

  • Combining MCPS data with data from a further 500,000 people in the UK and the US led to the discovery of rare genetic variations in the GPR75 gene that were associated with protection against obesity. Read full paper  and press release.
  • Variants in the MAP3K15 gene were shown to protect against diabetes. The protective effect was stronger in individuals who did not carry the Latino-enriched SLC16A11 risk haplotype. Read full paper.
  • Truncations of the gene INHBE were associated with favourable fat distribution, favourable metabolic profile and protection from diabetes. Read full paper.
  • Rare loss-of-function mutations in the CHRNB2 gene were associated with a reduced likelihood of heavy smoking. Read full paper.

Team in Oxford

Study oversight

The MCPS represents a longstanding collaboration between researchers from the National Autonomous University of Mexico (UNAM) in Mexico City, who conceived and established the study, and the Nuffield Department of Population Health in Oxford, who provided support during its inception and have continued to enhance it over the years. This collaborative effort dates back to the 1990s, with both teams jointly responsible for managing and analysing the study's data.

Team in Mexico City

Adrián Garcilazo Ávila
PhD candidate
Universidad del Valle de Atemajac
 

Carlos González Carballo
PhD candidate
Universidad Nacional Autónoma de México
 

Jaime Berumen Campos
Molecular Geneticist
Universidad Nacional Autónoma de México

Jesύs Alegre-Dίaz
Study Principal Investigator and Professor of Epidemiology
Universidad Nacional Autónoma de México

Pablo Antonio Kuri Morales
Study Principal Investigator and Surgeon and Epidemiologist,
Universidad Nacional Autónoma de México
Consultant and Director of the OriGen Project at the Tecnológico de Monterrey
 

Raύl Ramίrez Reyes
Computer Systems Programmer
Universidad Nacional Autónoma de México

Roberto Tapia Conyer
Study Principal Investigator and Public Health Physician
Universidad Nacional Autónoma de México

Laura Leticia Tirado Gόmez
Professor of Public Health
Universidad Nacional Autónoma de México

Data Access

We welcome requests from researchers who wish to access data from the Mexico City Prospective Study. Any bona fide academic researcher can now apply to access the baseline data, the linked cause-specific mortality data and the 10,000 participant resurvey data. Mexican-based researchers can also access NMR biomarker data for a subset of 40,000 participants.

New data available to researchers based in Mexico:

  • Genetic data are available for 9,950 whole genome sequenced, 141,046 exome sequenced and 140,831 genotyped participants. An online variant browser summarising the genetic variation is available at: https://rgc-mcps.regeneron.comThe genetic data will be shared by granting access to an online research analysis platform enabled by DNAnexus technology and powered by Amazon Web Services (AWS), where researchers will be able to access both the genetic and non-genetic data and perform their analyses.  

If you are interested in obtaining any data from the study for research purposes or in collaborating with us on a specific research proposal, please read our Data and Sample Access Policy for full information including how to apply. 

Study data can be viewed in detail using our online Data Showcase. You can also email us at mcps-access@ndph.ox.ac.uk with any queries about data access. For queries about the study or to contact the investigators, email mcps@ndph.ox.ac.uk. To find out more about the Nuffield Department of Population Health’s approach to data access, please read its data access policy.

Previously approved projects 

How the University of Oxford uses your data

Universidad Nacional Autónoma de México and Oxford Population Health team up with DNAnexus and AWS to improve access to Mexico City Prospective Study data

Selected publications

Related research themes