Predicted impact of banning nonessential, energy-dense food and beverages in schools in Mexico: A microsimulation study.

BACKGROUND: Childhood obesity is a growing concern worldwide. School-based interventions have been proposed as effective means to improve nutritional knowledge and prevent obesity. In 2023, Mexico approved a reform to the General Education Law to strengthen the ban of sales and advertising of nonessential energy-dense food and beverages (NEDFBs) in schools and surroundings. We aimed to predict the expected one-year change in total caloric intake and obesity prevalence by introducing the ban of NEDFBs sales in schools, among school-aged children and adolescents (6 to 17 years old) in Mexico. METHODS AND FINDINGS: We used age-specific equations to predict baseline fat-free mass (FFM) and fat mass (FM) and then estimated total energy intake (TEI) per day. The TEI after the intervention was estimated under 4 scenarios: (1) using national data to inform the intervention effect; (2) varying law compliance; (3) using meta-analytic data to inform the intervention effect size on calories; and (4) using national data to inform the intervention effect by sex and socioeconomic status (SES). We used Hall's microsimulation model to estimate the potential impact on body weight and obesity prevalence of children and adolescents 1 year after implementing the intervention in Mexican schools. We found that children could reduce their daily energy intake by 33 kcal/day/person (uncertainty interval, UI, [25, 42] kcal/day/person), reducing on average 0.8 kg/person (UI [0.6, 1.0] kg/person) and 1.5 percentage points (pp) in obesity (UI [1.1, 1.9] pp) 1 year after implementing the law. We showed that compliance will be key to the success of this intervention: considering a 50% compliance the intervention effect could reduce 0.4 kg/person (UI [0.3, 0.5] kg/person). Our sensitivity analysis showed that the ban could reduce body weight by 1.3 kg/person (UI [0.8, 1.8] kg/person) and up to 5.4 kg/person (UI [3.4, 7.5] kg/person) in the best-case scenario. Study limitations include assuming that obesity and the contribution of NEDFBs consumed at school remain constant over time, assuming full compliance, and not considering the potential effect of banning NEDFBs in stores near schools. CONCLUSIONS: Even in the most conservative scenario, banning sales of NEDFBs in schools is expected to significantly reduce obesity, but achieving high compliance will be key to its success. WHY WAS THIS STUDY DONE?: - School-based interventions have been recognized as effective means to improve nutritional knowledge and prevent obesity-related diseases.- In December 2023, the Chamber of Representatives of Mexico approved an amendment that strengthens and updates the General Education Law (Article 75) and nutritional guidelines to ban the sales and advertising of nonessential energy-dense food and beverages (NEDFBs) in schools. WHAT DID THE RESEARCHERS DO AND FIND?: - We used age-specific equations to predict baseline fat-free mass (FFM) and fat mass (FM) and total energy intake (TEI) per day.- We used microsimulation modeling to predict body weight and obesity prevalence of children and adolescents 1 year after implementing the intervention in Mexican schools.- Our modeling study suggests that an important impact on obesity prevalence can be expected if the law is implemented and enforced as intended. WHAT DO THESE FINDINGS MEAN?: - If successful, this law could serve as an example beyond Mexico on how to achieve changes in body weight through school food regulation.- An important limitation of our main scenario is that we assumed full compliance of schools with the law, yet lower compliance will reduce its impact. We also did not consider historical trends on obesity or NEDFBs consumed in schools during our 1 year simulation, and we considered only the ban impact inside schools, excluding effects near and outside schools.

Caloric reductions needed to achieve obesity goals in Mexico for 2030 and 2040: A modeling study.

BACKGROUND: In Mexico, obesity prevalence among adults increased from 23% in 2000 to 36% in 2018, approximately. Mexico has not defined short- or long-term obesity goals, obscuring the level of effort required to achieve a relevant impact. We aimed to explore potential obesity goals for 2030 and 2040 in Mexico and to estimate the required caloric reductions to achieve them. METHODS AND FINDINGS: We obtained anthropometric and demographic information on the Mexican adult population (age ≥20 years) from the Health and Nutrition Surveys conducted in 2000, 2006, 2012, 2016, and 2018 (n = 137,907). Each survey wave is cross-sectional, multistage, and representative of the Mexican population at the national, regional, and urban/rural levels. Obesity prevalence was projected for 2030 and 2040 by combining population projections of energy intake by socioeconomic status (SES) with a weight-change microsimulation model taking into account individual-level information on sex, age, physical activity, and initial body weight and height. If current trends continue, Mexico's obesity prevalence is expected to increase from 36% (95% CI 35% to 37%) in 2018 to 45% (uncertainty interval [UI] 41% to 48%) in 2030 and to 48% (UI 41% to 55%) in 2040. Based on expert opinion, we identified 3 obesity goals scenarios: (1) plausible (38% in 2030 and 36% in 2040); (2) intermediate (33% in 2030 and 29% in 2040); and (3) ideal based on the average prevalence of Organization for Economic Co-operation and Development countries (OECD; 19%). We estimated the caloric reductions needed to achieve the goal scenarios using the microsimulation model. Obesity was projected to increase more rapidly in the low SES (around 34% in 2018 to 48% (UI 41% to 55%) in 2040), than in the middle (around 38% to 52% (UI 45% to 56%)), or high SES group (around 36% to 45% (UI 36% to 54%)). Caloric reductions of 40 (UI 13 to 60), 75 (UI 49 to 95), and 190 (UI 163 to 215) kcal/person/day would be needed to reach the plausible, intermediate, and the ideal (OECD) average scenarios for 2030, respectively. To reach the 2040 goals, caloric reductions of 74 (UI 28 to 114), 124 (UI 78 to 169), and 209 (UI 163 to 254) kcal/person/day would be required, respectively. Study limitations include assuming a constant and sedentary physical activity level, not considering cohort-specific differences that could occur in the future, and assuming the same caloric trends under no intervention and the obesity goal scenarios. CONCLUSIONS: To reach the 3 obesity goals in 2040, caloric reductions between 74 and 209 kcal/day/person would be needed in Mexico. A package of new and stronger interventions should be added to existing efforts such as food taxes and warning labels on non-nutritious food.

Mechanistic Modelling of Biomass Growth, Glucose Consumption and Ethanol Production by Kluyveromyces marxianus in Batch Fermentation.

This paper presents results concerning mechanistic modeling to describe the dynamics and interactions between biomass growth, glucose consumption and ethanol production in batch culture fermentation by Kluyveromyces marxianus (K. marxianus). The mathematical model was formulated based on the biological assumptions underlying each variable and is given by a set of three coupled nonlinear first-order Ordinary Differential Equations. The model has ten parameters, and their values were fitted from the experimental data of 17 K. marxianus strains by means of a computational algorithm design in Matlab. The latter allowed us to determine that seven of these parameters share the same value among all the strains, while three parameters concerning biomass maximum growth rate, and ethanol production due to biomass and glucose had specific values for each strain. These values are presented with their corresponding standard error and 95% confidence interval. The goodness of fit of our system was evaluated both qualitatively by in silico experimentation and quantitative by means of the coefficient of determination and the Akaike Information Criterion. Results regarding the fitting capabilities were compared with the classic model given by the logistic, Pirt, and Luedeking-Piret Equations. Further, nonlinear theories were applied to investigate local and global dynamics of the system, the Localization of Compact Invariant Sets Method was applied to determine the so-called localizing domain, i.e., lower and upper bounds for each variable; whilst Lyapunov's stability theories allowed to establish sufficient conditions to ensure asymptotic stability in the nonnegative octant, i.e., R+,03. Finally, the predictive ability of our mechanistic model was explored through several numerical simulations with expected results according to microbiology literature on batch fermentation.

SARS-CoV-2 infection fatality rate after the first epidemic wave in Mexico.

BACKGROUND: Estimates of SARS-CoV-2 infection fatality rates (IFRs) in developing countries remain poorly characterized. Mexico has one of the highest reported COVID-19 case-fatality rates worldwide, although available estimates do not consider serologic assessment of prior exposure nor all SARS-CoV-2-related deaths. We aimed to estimate sex- and age-specific IFRs for SARS-CoV-2 in Mexico. METHODS: The total number of people in Mexico with evidence of prior SARS-CoV-2 infection was derived from National Survey of Health and Nutrition-COVID-19 (ENSANUT 2020 Covid-19)-a nationally representative serosurvey conducted from August to November 2020. COVID-19 mortality data matched to ENSANUT's dates were retrieved from the death-certificate registry, which captures the majority of COVID-19 deaths in Mexico, and from the national surveillance system, which covers the subset of COVID-19 deaths that were identified by the health system and were confirmed through a positive polymerase chain reaction test. We analysed differences in IFRs by urbanization and region. RESULTS: The national SARS-CoV-2 IFR was 0.47% (95% CI 0.44, 0.50) using death certificates and 0.30% (95% CI 0.28, 0.33) using surveillance-based deaths. The IFR increased with age, being close to zero at age <30 years, but increasing to 1% at ages 50-59 years in men and 60-69 years in women, and being the highest at ≥80 years for men (5.88%) and women (6.23%). Across Mexico's nine regions, Mexico City (0.99%) had the highest and the Peninsula (0.26%) the lowest certificate-based IFRs. Metropolitan areas had higher certificate-based IFR (0.63%) than rural areas (0.17%). CONCLUSION: After the first wave of the COVID-19 pandemic, the overall IFR in Mexico was comparable with those of European countries. The IFR in Mexico increased with age and was higher in men than in women. The variations in IFRs across regions and places of residence within the country suggest that structural factors related to population characteristics, pandemic containment and healthcare capabilities could have influenced lethality at the local level.

Fraction of COVID-19 hospitalizations and deaths attributable to chronic diseases.

Evidence shows that chronic diseases are associated with COVID-19 severity and death. This study aims to estimate the fraction of hospitalizations and deaths from COVID-19 attributable to chronic diseases associated to poor nutrition and smoking among adults who tested positive to COVID-19 in Mexico. We analyzed 1,006,541 adults aged ≥20 who tested positive for COVID-19 from March 23 to December 5, 2020. Six chronic diseases were considered: obesity, chronic obstructive pulmonary disease (COPD), hypertension, diabetes, cardiovascular disease, and chronic kidney disease (CKD). We calibrated the database using a bias quantification method to consider undiagnosed disease cases. To estimate the total impact of multiple diseases, we defined a multimorbidity variable according to the number of diseases. Risks of hospitalization and death were estimated with Poisson regression models and used to calculate population attributable fractions (PAFs). Chronic diseases accounted for to 25.4% [95% CI: 24.8%-26.1%], 28.3% (95% CI: 27.8%-28.7%) and 15.3% (95% CI: 14.9%-15.7%) of the hospitalizations among adults below 40, 40-59, and 60 years and older, respectively. For COVID-19-related deaths, 50.1% (95% CI: 48.6%-51.5%), 40.5% (95% CI: 39.7%-41.3%), and 18.7% (95% CI, 18.0%-19.5%) were attributable to chronic diseases in adults under 40, 40-59, and 60 years and older, respectively. Chronic diseases linked to poor nutrition and smoking could have contributed to a large burden of hospitalization and deaths from COVID-19 in Mexico, particularly among younger adults. Medical and structural interventions to curb chronic disease incidence and facilitate disease control are urgently needed.

Ciclos de trabajo-confinamiento para reducir la transmisión de Covid-19: evidencia y recomendaciones en el contexto de México.

Este artículo propone intervenciones estructurales dirigidas a la reorganización del trabajo para evitar un repunte de casos de Covid-19, permitiendo la continuidad de la actividad económica. Se resume la evidencia disponible acerca de los ciclos de trabajo-confinamiento y la posible aplicación de ciclos de cuatro días de trabajo por tres de confinamiento (4x3) en el contexto mexicano. También se discuten otras intervenciones como la continuación del teletrabajo en algunos sectores y el escalonamiento de las jornadas de trabajo como medidas complementarias a los ciclos de trabajo-confinamiento. Esta discusión se da en el contexto de alta informalidad y escasos recursos para absorber una pérdida importante de la productividad por las empresas medianas y pequeñas en México. Se considera la necesidad de implementar apoyos para que personas y empresas puedan mitigar pérdidas en salarios y ganancias tanto del sector formal como informal.

Ciclos de trabajo-confinamiento para reducir la transmisión de Covid-19: evidencia y recomendaciones en el contexto de México / Cyclic schedules for working population to reduce Covid-19 transmission: evidence and recommendations for Mexico

Resumen: Este artículo propone intervenciones estructurales dirigidas a la reorganización del trabajo para evitar un repunte de casos de Covid-19, permitiendo la continuidad de la actividad económica. Se resume la evidencia disponible acerca de los ciclos de trabajo-confinamiento y la posible aplicación de ciclos de cuatro días de trabajo por tres de confinamiento (4x3) en el contexto mexicano. También se discuten otras intervenciones como la continuación del teletrabajo en algunos sectores y el escalonamiento de las jornadas de trabajo como medidas complementarias a los ciclos de trabajo-confinamiento. Esta discusión se da en el contexto de alta informalidad y escasos recursos para absorber una pérdida importante de la productividad por las empresas medianas y pequeñas en México. Se considera la necesidad de implementar apoyos para que personas y empresas puedan mitigar pérdidas en salarios y ganancias tanto del sector formal como informal.

Abstract: This paper proposes structural interventions to organize the working population which could be implemented to avoid a new wave of Covid-19 cases without halting economic activity. We summarize the evidence regarding cyclic schedules of work days followed by days in lockdown. We discuss the possible application of cycles of four days of work followed by three in lockdown for the Mexican context. We also discuss two complimentary interventions for these cycles: continuing to work from home for the sectors for which this is possible and staggered work shifts. This discussion takes into account the high informality context and the scarcity of resources to absorb productivity losses in middle and small companies. We consider the need to implement financial help for people and companies to mitigate lost earnings both in the formal and in the informal work sectors.

Predicting obesity reduction after implementing warning labels in Mexico: A modeling study.

BACKGROUND: In October 2019, Mexico approved a law to establish that nonalcoholic beverages and packaged foods that exceed a threshold for added calories, sugars, fats, trans fat, or sodium should have an "excess of" warning label. We aimed to estimate the expected reduction in the obesity prevalence and obesity costs in Mexico by introducing warning labels, over 5 years, among adults under 60 years of age. METHODS AND FINDINGS: Baseline intakes of beverages and snacks were obtained from the 2016 Mexican National Health and Nutrition Survey. The expected impact of labels on caloric intake was obtained from an experimental study, with a 10.5% caloric reduction for beverages and 3.0% caloric reduction for snacks. The caloric reduction was introduced into a dynamic model to estimate weight change. The model output was then used to estimate the expected changes in the prevalence of obesity and overweight. To predict obesity costs, we used the Health Ministry report of the impact of overweight and obesity in Mexico 1999-2023. We estimated a mean caloric reduction of 36.8 kcal/day/person (23.2 kcal/day from beverages and 13.6 kcal/day from snacks). Five years after implementation, this caloric reduction could reduce 1.68 kg and 4.98 percentage points (pp) in obesity (14.7%, with respect to baseline), which translates into a reduction of 1.3 million cases of obesity and a reduction of US$1.8 billion in direct and indirect costs. Our estimate is based on experimental evidence derived from warning labels as proposed in Canada, which include a single label and less restrictive limits to sugar, sodium, and saturated fats. Our estimates depend on various assumptions, such as the transportability of effect estimates from the experimental study to the Mexican population and that other factors that could influence weight and food and beverage consumption remain unchanged. Our results will need to be corroborated by future observational studies through the analysis of changes in sales, consumption, and body weight. CONCLUSIONS: In this study, we estimated that warning labels may effectively reduce obesity and obesity-related costs. Mexico is following Chile, Peru, and Uruguay in implementing warning labels to processed foods, but other countries could benefit from this intervention.

Study of the Enzymatic Capacity of Kluyveromyces marxianus for the Synthesis of Esters.

Recently, biotechnological opportunities have been found in non-Saccharomyces yeasts because they possess metabolic characteristics that lead to the production of compounds of interest. It has been observed that Kluyveromyces marxianus has a great potential in the production of esters, which are aromatic compounds of industrial importance. The genetic bases that govern the synthesis of esters include a large group of enzymes, among which the most important are alcohol acetyl transferases (AATases) and esterases (AEATases), and it is known that some are present in K. marxianus, because it has genetic characteristics like S. cerevisiae. It also has a physiology suitable for biotechnological use since it is the eukaryotic microorganism with the fastest growth rate and has a wide range of thermotolerance with respect to other yeasts. In this work, the enzymatic background of K. marxianus involved in the synthesis of esters is analyzed, based on the sequences reported in the NCBI database.