Prediabetes as a risk factor for all-cause and cause-specific mortality: a prospective analysis of 115,919 adults without diabetes in Mexico City

BACKGROUND

Prediabetes has been associated with increased all-cause and cardiovascular mortality. However, no large-scale studies have been conducted in Mexico or Latin America examining these associations.

METHODS

We analyzed data from 115,919 adults without diabetes (diagnosed or undiagnosed) aged 35-84 years who participated in the Mexico City Prospective Study between 1998 and 2004. Participants were followed until January 1 st , 2021 for cause-specific mortality. We defined prediabetes according to the American Diabetes Association (ADA, HbA 1c 5.7% to 6.4%) and the International Expert Committee (IEC, HbA 1c 6.0-6.4%) definitions. Cox regression adjusted for confounders was used to estimate all-cause and cause-specific mortality rate ratios (RR) at ages 35-74 years associated with prediabetes.

FINDINGS

During 2,085,392 person-years of follow-up (median in survivors 19 years), there were 6,810 deaths at ages 35-74, including 1,742 from cardiovascular disease, 892 from renal disease and 108 from acute diabetic crises. Of 110,405 participants aged 35-74 years at recruitment, 28,852 (26%) had ADA-defined prediabetes and 7,203 (7%) had IEC-defined prediabetes. Compared with those without prediabetes, individuals with prediabetes had higher risk of all-cause mortality at ages 35-74 years (RR 1.13, 95% CI 1.07-1.19 for ADA-defined prediabetes and RR 1.28, 1.18-1.39 for IEC-defined prediabetes), as well as increased risk of cardiovascular mortality (RR 1.22 [1.10-1.35] and 1.42 [1.22-1.65], respectively), renal mortality (RR 1.35 [1.08-1.68] and 1.69 [1.24-2.31], respectively), and death from an acute diabetic crisis (RR 2.63 [1.76-3.94] and 3.43 [2.09-5.62], respectively). RRs were larger at younger than at older ages, and similar for men compared to women. The absolute excess risk associated with ADA and IEC-defined prediabetes at ages 35-74 accounted for6% and 3% of cardiovascular deaths respectively, 10% and 5% of renal deaths respectively, and 31% and 14% of acute diabetic deaths respectively.

INTERPRETATION

Prediabetes is a significant risk factor for all-cause, cardiovascular, renal, and acute diabetic deaths in Mexican adults. Identification and timely management of individuals with prediabetes for targeted risk reduction could contribute to reducing premature mortality from cardiometabolic causes in this population.

FUNDING

Wellcome Trust, the Mexican Health Ministry, the National Council of Science and Technology for Mexico, Cancer Research UK, British Heart Foundation, UK Medical Research Council. Instituto Nacional de Geriatría (Mexico City).

RESEARCH IN CONTEXT

Evidence before this study: We conducted a literature search in PubMed to identify articles published in English before February 27 th , 2024 that reported on prospective studies examining the association between prediabetes with all-cause or cause-specific mortality or progression to diabetes in a Mexican or Latin American population, using the terms ("prediabetes" OR "impaired fasting glucose" OR "impaired glucose tolerance") AND ("mortality" OR "death") AND ("Mexico" OR "Mexican" OR "Latin America" OR "Latin American"). There were no studies examining risk associated with prediabetes definitions and mortality among adults in Mexico. We identified one study from Peru that included 988 participants and investigated only all-cause mortality for impaired fasting glucose and HbA 1c -based definitions of prediabetes from ADA and IEC; this study reported increased mortality risk related to ADA-defined prediabetes based on HbA 1c measures. Generalizability of these findings to other Latin American countries and regions with distinct cardiometabolic profiles in unclear. Added value of this study: Our study included 115,919 participants without diabetes from Mexico City, of whom (26%) had ADA-defined prediabetes and 7,203 (7%) had IEC-defined prediabetes. We found that prediabetes is associated with higher risks of all-cause and cause-specific mortality (cardiovascular, renal, and acute diabetic causes) than among participants without prediabetes. We found RRs to be larger at younger than at older ages, and largely similar for men compared to women. Among those without previously diagnosed diabetes, we found that the excess risk associated with ADA- and IEC-defined prediabetes at ages 35-74 years accounted for 6% and 3% of cardiovascular deaths, 10% and 5% of renal deaths, and 31% and 14% of acute diabetic deaths, respectively. .Implications of all the available evidence: Our results show that prediabetes is a significant risk factor for cardiovascular, kidney, and acute diabetic deaths among Mexican adults and accounts for a notable fraction of such deaths. Identification of individuals with prediabetes should be prioritized for optimized management to improve cardiometabolic outcomes in Mexican adults.

Protein-truncating variants in BSN are associated with severe adult-onset obesity, type 2 diabetes and fatty liver disease

Obesity is a major risk factor for many common diseases and has a substantial heritable component. To identify new genetic determinants, we performed exome-sequence analyses for adult body mass index (BMI) in up to 587,027 individuals. We identified rare loss-of-function variants in two genes (BSN and APBA1) with effects substantially larger than those of well-established obesity genes such as MC4R. In contrast to most other obesity-related genes, rare variants in BSN and APBA1 were not associated with normal variation in childhood adiposity. Furthermore, BSN protein-truncating variants (PTVs) magnified the influence of common genetic variants associated with BMI, with a common variant polygenic score exhibiting an effect twice as large in BSN PTV carriers than in noncarriers. Finally, we explored the plasma proteomic signatures of BSN PTV carriers as well as the functional consequences of BSN deletion in human induced pluripotent stem cell-derived hypothalamic neurons. Collectively, our findings implicate degenerative processes in synaptic function in the etiology of adult-onset obesity.

Sequencing of 640,000 exomes identifies GPR75 variants associated with protection from obesity

Large-scale human exome sequencing can identify rare protein-coding variants with a large impact on complex traits such as body adiposity. We sequenced the exomes of 645,626 individuals from the United Kingdom, the United States, and Mexico and estimated associations of rare coding variants with body mass index (BMI). We identified 16 genes with an exome-wide significant association with BMI, including those encoding five brain-expressed G protein-coupled receptors (CALCR, MC4R, GIPR, GPR151, and GPR75). Protein-truncating variants in GPR75 were observed in ~4/10,000 sequenced individuals and were associated with 1.8 kilograms per square meter lower BMI and 54% lower odds of obesity in the heterozygous state. Knock out of Gpr75 in mice resulted in resistance to weight gain and improved glycemic control in a high-fat diet model. Inhibition of GPR75 may provide a therapeutic strategy for obesity.

HPV-16 and HLA-DRB1 alleles are associated with cervical carcinoma in Mexican Mestizo women

The aim of this report was to investigate the contribution of HLA-DRB1/DQB1 alleles to the expression of cervical cancer (CC) and squamous intraepithelial lesion (SIL) in Mexican patients. A total of 257 women were included in the study: 61with low-grade squamous intraepithelial lesions (LSIL), 30 with high-grade (HSIL), 73 with CC and 93 healthy females. All were Mexican Mestizos. For HLA class II typing, PCR-SSOP methodology was used. HPV-16 viral DNA was detected by PCR with specific primers for E6-E7 region. HPV-16 was found in 52% of the patients with CC as well as in 19% of women with HSIL and in 12.5% of females with LSIL. HLA-DRB1∗04:03 (OR = 5.88) was found increased in patients with HSIL as compared with controls, although significance (p = 0.04) was lost after correction (pc =NS). HLA-DRB1∗04:03 seems to influence the risk for developing HSIL, disregarding the presence of HPV-16. HLA-DRB1∗01:01 (OR = 0.12; p = 0.01) may confer protection to the development of CC. An analysis performed stratifying by the presence of HPV-16 infection showed that the frequency of HLA-DRB1∗04:07 (OR = 2.71) was increased in CC patients infected with HPV-16, confirming that the HLA association is HPV dependent. These results shed light on the influence that this virus may have in the expression of CC in the susceptible host. Genetic background is, therefore, a crucial factor in understanding the etiopathogenesis of CC in HPV-positive patients.

[Human papilloma virus and cervical cancer]

Cervical cancer (CC) is the second most common cause of death from cancer among women worldwide and about 80% of the half of million new cases detected every year, occurs in less-developed countries. Human papillomavirus is an obligate factor for the development of CC, since some HPVtype are detected in 100% of CC. HPV16 and HPV18 are the most common viral types, accounting for about 50% and 15% of CC, respectively. HPV infection is the most common sexual transmitted infection, with an estimated prevalence of about 2-44% among sexually active young women. However, only a very small fraction of these infections evolve to CC (1-2 out of 1000), indicating that some other factors should be important in the evolution of the disease. Preventive vaccines against HPVs 16 and 18 have been developed, and in phase III clinical trials they have demonstrated 100% efficacy for prevention of persistent infection and high risk cervical squamous intraepithelial neoplasias positive for these HPV types, suggesting that these vaccines, if made widely available, will dramatically reduce the burden of CC.

Oral manifestations as a hallmark of malignant acanthosis nigricans

We present a case of malignant acanthosis nigricans (AN) that initially manifested in the oral cavity. In the present report, the patient had typical clinical and histological findings of oral and esophageal AN, with subtle skin changes, associated with a gallbladder adenocarcinoma. The importance of the clinical oral examination is emphasized because the recognition of oral lesions led to the diagnosis of AN and to the following detection of the internal malignancy. Since the tumours associated with AN are highly malignant, it is of the utmost importance to recognize the skin and mucous membrane changes in adults.

Human papilloma virus 16-18 infection and cervical cancer in Mexico: a case-control study

Cervical cancer (CC) is one of the principal public health problems in Mexico. The national mortality rate due to CC was estimated at 21.8 per 100,000 among women over 15 years old during 1994. Despite this high incidence little is known in Mexico about the risk factors for CC. The objectives of the study were to evaluate the association between CC and HPV types 16 and 18 in women living in Mexico City. From August, 1990 to December, 1992, a case-control study was carried out in the metropolitan area of Mexico City. HPV 16-18 types were determined in a sample of 148 CC cases and 204 controls randomly selected from a sample frame representative of the metropolitan area of Mexico City. Sixty cases corresponded to in situ CC and 88 cases to the invasive phase. Determination of HPV 16 and 18 types was done by polymerase chain reaction using primers specific to E6/E7. Results showed that 48.3% of in situ CC cases and 48.8% of invasive CC cases were positive for HPV 16 while only 13.2% were positive among the 204 controls. Association between HPV 16 infection in the in situ cancer cases had an estimated odds ratio (OR) of 5.17 (95% CI 2.60-10.51). In the invasive cervical cancer cases, association between HPV 16 infection and invasive CC in this sample had an OR of 3.84 (95% CI 2.04-7.22). For the total sample, the estimated OR was 5.48 (95% CI 3.07-9.62). In the total sample, those women with a strong positive reaction to PCR were associated with a large increase in the risk, OR of 38.0 (95% CI 8.66-167.1). The prevalence the HPV 18 was 6.7%, only observed in the invasive cervical cancer cases. At present there is general consensus that HPV is the principal causal agent in C C etiology. This study intends to contribute to the knowledge concerning the etiology of cervical cancer. However, it is necessary to consider that the single most effective tool in the reduction of mortality due to cervical cancer has been the Pap test. Secondary prevention has proven to be highly effective in other populations, and this should be viewed as a priority activity for all at-risk populations. Although a vaccine for HPV may be available in the near future its efficacy in primary prevention has yet to be demonstrated.

[Genetic diversity of 3 DNA probes in the DNA fingerprinting of a Mexican population]

Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.