A systematic evaluation of seven different scores representing the EAT-Lancet reference diet and mortality, stroke, and greenhouse gas emissions in three cohorts.

Different approaches have been used for translation of the EAT-Lancet reference diet into dietary scores that can be used to assess health and environmental impact. Our aim was to compare the different EAT-Lancet diet scores, and to estimate their associations with all-cause mortality, stroke incidence, and greenhouse gas emissions. We did a systematic review (PROSPERO, CRD42021286597) to identify different scores representing adherence to the EAT-Lancet reference diet. We then qualitatively compared the diet adherence scores, including their ability to group individuals according the EAT-Lancet reference diet recommendations, and quantitatively assessed the associations of the diet scores with health and environmental outcome data in three diverse cohorts: the Danish Diet, Cancer and Health Cohort (DCH; n=52 452), the Swedish Malmö Diet and Cancer Cohort (MDC; n=20 973), and the Mexican Teachers' Cohort (MTC; n=30 151). The DCH and MTC used food frequency questionnaires and the MDC used a modified diet history method to assess dietary intake, which we used to compute EAT-Lancet diet scores and evaluate the associations of scores with hazard of all-cause mortality and stroke. In the MDC, dietary greenhouse gas emission values were summarised for every participant, which we used to predict greenhouse gas emissions associated with varying diet adherence scores on each scoring system. In our review, seven diet scores were identified (Knuppel et al, 2019; Trijsburg et al, 2020; Cacau et al, 2021; Hanley-Cook et al, 2021; Kesse-Guyot et al, 2021; Stubbendorff et al, 2022; and Colizzi et al, 2023). Two of the seven scores (Stubbendorff and Colizzi) were among the most consistent in grouping participants according to the EAT-Lancet reference diet recommendations across cohorts, and higher scores (greater diet adherence) were associated with decreased risk of mortality (in the DCH and MDC), decreased risk of incident stroke (in the DCH and MDC for the Stubbendorff score; and in the DCH for the Colizzi score), and decreased predicted greenhouse gas emissions in the MDC. We conclude that the seven different scores representing the EAT-Lancet reference diet had differences in construction, interpretation, and relation to disease and climate-related outcomes. Two scores generally performed well in our evaluation. Future studies should carefully consider which diet score to use and preferably use multiple scores to assess the robustness of estimations, given that public health and environmental policy rely on these estimates.

Trends in the contribution of greenhouse gas emissions from food and beverage purchases in Mexico: 1989-2020.

BACKGROUND: Assessing the trends in dietary GHGE considering the social patterning is critical for understanding the role that food systems have played and will play in global emissions in countries of the global south. Our aim is to describe dietary greenhouse gas emissions (GHGE) trends (overall and by food group) using data from household food purchase surveys from 1989 to 2020 in Mexico, overall and by education levels and urbanicity. METHODS: We used cross-sectional data from 16 rounds of Mexico's National Income and Expenditure Survey, a nationally representative survey. The sample size ranged from 11,051 in 1989 to 88,398 in 2020. We estimated the mean total GHGE per adult-equivalent per day (kg CO2-eq/ad-eq/d) for every survey year. Then, we estimated the relative GHGE contribution by food group for each household. These same analyses were conducted stratifying by education and urbanicity. RESULTS: The mean total GHGE increased from 3.70 (95%CI: 3.57, 3.82) to 4.90 (95% CI 4.62, 5.18) kg CO2-eq/ad-eq/d between 1989 and 2014 and stayed stable between 4.63 (95% CI: 4.53, 4.72) and 4.89 (95% CI: 4.81, 4.96) kg CO2-eq/ad-eq/d from 2016 onwards. In 1989, beef (19.89%, 95% CI: 19.18, 20.59), dairy (16.87%, 95% CI: 16.30, 17.42)), corn (9.61%, 95% CI: 9.00, 10.22), legumes (7.03%, 95% CI: 6.59, 7.46), and beverages (6.99%, 95% CI: 6.66, 7.32) had the highest relative contribution to food GHGE; by 2020, beef was the top contributor (17.68%, 95%CI: 17.46, 17.89) followed by fast food (14.17%, 95% CI: 13.90, 14.43), dairy (11.21%, 95%CI: 11.06, 11.36), beverages (10.09%, 95%CI: 9.94, 10.23), and chicken (10.04%, 95%CI: 9.90, 10.17). Households with higher education levels and those in more urbanized areas contributed more to dietary GHGE across the full period. However, households with lower education levels and those in rural areas had the highest increase in these emissions from 1989 to 2020. CONCLUSIONS: Our results provide insights into the food groups in which the 2023 Mexican Dietary Guidelines may require to focus on improving human and planetary health.

Low-intensity daily smoking and mortality risk among Mexican women.

OBJECTIVE: To examine the association between low-intensity smoking (10 or less cigarettes per day) and all-cause and cause-specific mortality risk among women who smoke and by age at cessation among women who previously smoked. METHODS: In this study, 104 717 female participants of the Mexican Teachers' Cohort Study were categorised according to self-reported smoking status at baseline (2006/2008) and were followed for mortality through 2019. We estimated HRs and 95% CIs for all-cause and cause-specific mortality using multivariable Cox proportional hazards regression models with age as the underlying time metric. RESULTS: Smoking as few as one to two cigarettes per day was associated with higher mortality risk for all causes (HR: 1.36; 95% CI 1.10 to 1.67) and all cancers (HR: 1.46; 95% CI 1.05 to 2.02), compared with never smoking. Similarly, slightly higher HRs were observed among participants smoking ≥3 cigarettes per day (all causes HR: 1.43; 95% CI 1.19 to 1.70; all cancers HR: 1.48; 95% CI 1.10 to 1.97; cardiovascular disease HR: 1.58; 95% CI 1.09 to 2.28). CONCLUSIONS: In this large study of Mexican women, low-intensity smoking was associated with higher mortality risk for all causes and all cancers. Interventions are needed to promote cessation among women who smoke at low-intensity in Mexico, regardless of how few cigarettes they smoke per day.

Accessing medical care for infertility: a study of women in Mexico.

Objective: To investigate barriers in accessing care for infertility in Mexico, because little is known about this issue for low and middle-income countries, which comprise 80% of the world's population. Design: Cross-sectional analysis. Setting: Mexcian Teachers' Cohort. Patients: A total of 115,315 female public school teachers from 12 states in Mexico. Interventions: None. Main Outcome Measures: The participants were asked detailed questions about their demographics, lifestyle characteristics, access to the health care system, and infertility history via a self-reported questionnaire. Log-binomial models, adjusted a priori for potential confounding factors, were used to estimate the prevalence ratios (PRs) and 95% confidence intervals ( CIs) of accessing medical care for infertility among women reporting a history of infertility. Results: A total of 19,580 (17%) participants reported a history of infertility. Of those who experienced infertility, 12,470 (63.7%) reported seeking medical care for infertility, among whom 8,467 (67.9%) reported undergoing fertility treatments. Among women who reported a history of infertility, women who taught in a rural school (PR, 0.95; 95% CI, 0.92-0.97), spoke an indigenous language (PR, 0.88; 95% CI, 0.84-0.92), or had less than a university degree (PR, 0.93; 95% CI, 0.90-0.97) were less likely to access medical care for fertility. Women who had ever had a mammogram (PR, 1.07; 95% CI, 1.05-1.10), had a pap smear in the past year (PR, 1.08; 95% CI, 1.06-1.10), or who had used private health care regularly or in times of illness were more likely to access medical care for fertility. Conclusions: The usage of infertility care varied by demographic, lifestyle, and access characteristics, including speaking an indigenous language, teaching in a rural school, and having a private health care provider.

Avocado consumption is associated with a reduction in hypertension incidence in Mexican women.

Avocado is a fruit rich in dietary fibre, potassium, Mg, mono and PUFA and bioactive phytochemicals, which are nutritional components that have been associated with cardiovascular health. Yet, despite the boom in avocado consumption, we lack evidence on its association with CVD risk in the general population. To estimate the prospective association between avocado consumption and incident hypertension in Mexican women, we estimated the association in participants from the Mexican Teachers' Cohort who were ≥ 25 years, free of hypertension, CVD and cancer at baseline (n 67 383). We assessed baseline avocado consumption with a semi-quantitative FFQ (never to six or more times per week). Incident hypertension cases were identified if participants self-reported a diagnosis and receiving treatment. To assess the relation between categories of avocado consumption (lowest as reference) and incident hypertension, we estimated incidence rate ratios (IRR) and 95 % CI using Poisson regression models and adjusting for confounding. We identified 4002 incident cases of hypertension during a total of 158 706 person-years for a median follow-up of 2·2 years. The incidence rate of hypertension was 25·1 cases per 1000 person-years. Median avocado consumption was 1·0 (interquartile range: 0·23, 1·0) serving per week (half an avocado). After adjustment for confounding, consuming 5 + servings per week of avocado was associated with a 17 % decrease in the rate of hypertension, compared with non- or low consumers (IRR = 0·83; 95 % CI: 0·70, 0·99; Ptrend = 0·01). Frequent consumption of avocado was associated with a lower incidence of hypertension.

Covid-19 mortality in children and adolescents in Mexico / Mortalidad por Covid-19 en niños y adolescentes en México

Abstract: Objective: To estimate Covid-19 and pre-pandemic low respiratory infection (LRI) mortality in children and adolescents in Mexico. Materials and methods: We estimated the percentage of total mortality attributable to Covid-19 (95% confidence intervals; 95%CI) and made the corresponding estimates for pre-pandemic LRI mortality. Results: In 2019, LRIs represented 8.6% (95%CI 8.3, 8.9) of deaths in children aged 0-9 years, and 2.0% (95%CI 1.8, 2.3) in those aged 10-19 years. In 2020, the corresponding estimates for Covid-19 were 4.4% (95%CI 4.1, 4.6) and 3.7% (95%CI 3.4, 4.1). Conclusions: Relative to LRI, Covid-19 may be exerting a considerable mortality burden, particularly in older children and adolescents.

Resumen: Objetivo: Estimar la mortalidad por Covid-19 e infección respiratoria baja (IRB) pre-pandémica en niños y adolescentes en México. Material y métodos: Se estimó el porcentaje de mortalidad atribuible a Covid-19 (intervalos de confianza 95%; IC95%) y se realizaron las estimaciones correspondientes para IRB pre-pandémica. Resultados: En 2019, las IRB representaron 8.6% (IC95% 8.3, 8.9) de las muertes en niños de 0-9 años y 2.0% (IC95% 1.8, 2.3) en aquéllos entre 10-19 años. Los valores correspondientes en 2020 para Covid-19 fueron 4.4% (IC95% 4.1, 4.6) y 3.7% (IC95% 3.4, 4.1). Conclusiones: En comparación con IRB, Covid-19 puede estar ejerciendo una carga de mortalidad considerable, particularmente en niños mayores y adolescentes.

Greenhouse Gas Emissions Associated With the Mexican Diet: Identifying Social Groups With the Largest Carbon Footprint.

Background: Most studies of the climate footprint of diets have been conducted in countries in the global north, but the majority of the world population lives in global south countries. We estimated total dietary greenhouse gas emissions (GHGE) in Mexico, examined the contribution of major food and beverage groups, and assessed variation across social groups. Methods: We linked individual-level dietary data from the Mexican National Health and Nutrition Survey 2018 to the SHARP Indicators Database, containing GHGE estimates for 182 primary food and beverages. Results: Mean dietary GHGE was 3.9 kg of carbon dioxide equivalent per person per day. Dietary GHGE is highest among those in young adulthood and middle age versus adolescents and older adults, and among males, those with higher educational attainment, higher socioeconomic status, that do not speak an indigenous language, and that live in urban areas. Conclusion: The Mexican diet has a much lower carbon footprint than diets in other Latin American countries for which such estimates are available. In contrast to patterns observed in Argentina and Brazil, dietary GHGE was lowest in those in lower socioeconomic and educational strata and in rural areas. A better understanding of the differences in diet sustainability between and within countries will be needed for developing global and local strategies that meet the environmental sustainability goals.

Inversión en investigación en cáncer en México entre 2002 y 2017.

No disponible.

Epidemiologic evidence of exposure to polycyclic aromatic hydrocarbons and breast cancer: A systematic review and meta-analysis.

Breast cancer (BC) is the most frequently diagnosed cancer in women. However, only 58% of cases have been associated with known risk factors (reproductive, hormonal, lifestyles, and genetic), and the rest to unknown causes. Nevertheless, growing evidence suggests that exposure to environmental contaminants is an important risk factor for BC. Polycyclic aromatic hydrocarbons (PAHs) are formed during organic matter combustion, including smoking, grilled meat, and fuels, and are important carcinogenic constituents of environmental pollution. We examined the information generated by epidemiological studies evaluating the association between BC and PAHs exposure from multiple sources. Our work was conducted according to Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology (COSMOS-E) guidelines. We searched PubMed, Web of Science, and Scopus from January 2000 to December 2019. A total of 124 records were identified, and only 23 articles met all inclusion criteria. Occupational and/or environmental exposure to PAHs was significantly associated with BC, irrespective of exposure being assessed by direct or indirect methods. CYP1A1 and CYP1B1 adverse polymorphisms, familial BC history and smoking status, significantly strengthened the association between PAHs exposure and BC, whereas high fruit and vegetable intake had antagonistic associations. The positive relationships obtained in the studies here reviewed indicated that PAHs exposure is a risk factor for BC. Research needs include the improvement of exposure assessment, particularly identification of specific PAHs, reconstruction of time-varying and distant past exposures and further studies on the interaction between known BC factors and modifiable diet and life-style factors allowing BC prevention and control.

Seroprevalencia de SARS-CoV-2 en niños y adolescentes mexicanos en edad escolar / Seroprevalence of SARS-CoV-2 in Mexican children and adolescents in primary and secondary education age

Resumen: Objetivo: Estimar la seroprevalencia de SARS-CoV-2 en población de edad escolar en México. Material y métodos: Se categorizaron a niños y adolescentes que participaron en la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19 (Ensanut 2020 Covid-19) por edad escolar y nivel educativo. En participantes seropositivos, se identificó la proporción de infecciones asintomáticas. Se estimaron razones de prevalencia usando un modelo de regresión log-binomial. Resultados: La seroprevalencia en educación básica y media fue de 18.7% (IC95%: 14.9, 22.5) y 26.7% (IC95%: 22.1, 31.3), respectivamente. La infección asintomática fue más frecuente en educación básica (88.5% [IC95%: 80.5, 93.5]). Conclusiones: En población de educación básica la infección por SARS-CoV-2 es baja y usualmente asintomática.

Abstract: Objective: To estimate the seroprevalence of SARS-CoV-2 in school aged children in Mexico. Materials and methods: We categorized children and adolescents who participated in the 2020 National Health and Nutrition Survey on Covid-19 according to school age and educational level. In seropositive participants, we identified the proportion of asymptomatic infections. We estimated prevalence ratios using a log-binomial regression model. Results: Seroprevalence of SARS-CoV-2 for primary and secondary education were 18.7% (95%IC: 14.9, 22.5) and 26.7% (95%IC: 22.1, 31.3), respectively. Asymptomatic infection was more frequent among primary school children (88.5% [95%IC: 80.5, 93.5]). Conclusions: In primary schoolchildren seroprevalence for SARS-CoV-2 was low and infections were usually asymptomatic.

Family and household characteristics associated with seropositive cases to SARS-CoV-2 across Mexican households / Características de la estructura familiar y de la vivienda asociadas con casos seropositivos a SARS-CoV-2 en hogares mexicanos

Abstract: Objective: To assess the association of family and housing characteristics with the number of seropositive cases to SARS-CoV-2 in households. Materials and methods: We analyzed 874 households from Encuesta Nacional de Salud y Nutrición (Ensanut) 2020 Covid-19 using Poisson regression models. Results: The number of seropositive family members was higher among families composed of children/adolescents, adults and older adults, households with more than two members per bedroom, and among households with closed windows. No association was found for bathroom availability and piped water. Conclusions: Family composition and housing characteristics can impose significant structural barriers to safe home confinement.

Resumen: Objetivo: Determinar la asociación de la estructura familiar y de las características de la vivienda con el número de casos positivos a SARS-CoV-2 a nivel hogar. Material y métodos: Se analizaron 874 hogares de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2020 Covid-19 utilizando modelos de regresión de Poisson. Resultados: El número de miembros seropositivos fue mayor en los hogares compuestos por niños/adolescentes, adultos y adultos mayores, donde más de dos miembros ocupaban la misma habitación y en los hogares donde se observaron ventanas cerradas. No se encontró asociación con la disponibilidad de baño y de agua entubada. Conclusiones: La composición familiar y las características de la vivienda pueden representar barreras importantes para el confinamiento seguro en casa.

Acceptance, refusal, and hesitancy of Covid-19 vaccination in Mexico: Ensanut 2020 Covid-19 / Aceptabilidad, rechazo y duda ante la vacunación contra Covid-19 en México: Ensanut 2020 Covid-19

Abstract: Objective: To estimate the willingness to vaccinate against Covid-19 (acceptance) in the Mexican population and to identify socioeconomic factors associated with vaccine hesitancy and refusal. Materials and methods: We estimated the acceptance, refusal and hesitancy proportions using data from the Covid-19 National Health and Nutrition Survey conducted from August to November 2020. Factors associated with refusal and hesitancy were explored using multinomial logistic regression. Results: Covid-19 vaccination acceptance was 62.3%, refusal 28.2% and hesitancy 9.5%. Refusal and hesitancy were associated with being female, having older age, lower educational level, lower socioeconomic status and working in the informal sector. Conclusion: National campaigns to incentivize vaccine acceptance need to consider specific subgroups were the likelihood of hesitancy and refusal is high. In Mexico, refusal and hesitancy were higher in vulnerable groups, and people at a higher risk of Covid-19 complications and death.

Resumen: Objetivo: Estimar la aceptabilidad de la vacunación contra Covid-19 en la población mexicana e identificar factores socioeconómicos asociados con el rechazo o la duda. Material y métodos: Se estimó la proporción de aceptabilidad, rechazo y duda utilizando los datos de la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19 levantada durante agosto y noviembre de 2020. Se exploraron los factores asociados con rechazo y duda mediante un modelo de regresión multinomial. Resultados: La aceptabilidad de la vacunación contra Covid-19 fue de 62.3%, el rechazo de 28.2% y la duda de 9.5%. El rechazo y la duda se asociaron con ser mujer, tener mayor edad, menor nivel de educación, menor nivel socioeconómico y trabajar en el sector informal. Conclusión: Las campañas para incentivar la aceptabilidad de la vacuna necesitan considerar los subgrupos específicos con una alta proporción de rechazo y duda. En México observamos un mayor rechazo y duda en grupos con mayor riesgo de complicaciones y muerte por Covid-19.

On the increasing incidence of SARSCoV-2 in older adolescents and younger adults during the epidemic in Mexico / Sobre la incidencia creciente de SARS-CoV-2 en adolescentes mayores y adultos jóvenes durante la epidemia en México

Abstract Objective: To estimate temporary changes in the incidence of SARS-CoV-2-confirmed hospitalizations (by date of symptom onset) by age group during and after the national lockdown. Materials and methods: For each age group g, we computed the proportion E(g) of individuals in that age group among all cases aged 10-59y during the early lockdown period (April 20-May 3, 2020), and the corresponding proportion L(g) during the late lockdown (May 18-31, 2020) and post-lockdown (June 15-28, 2020) periods and computed the prevalence ratio: PR(g)=L(g)/E(g). Results: For the late lockdown and post-lockdown periods, the highest PR values were found in age groups 15-19y (late: PR=1.69, 95%CI 1.05,2.72; post-lockdown: PR=2.05, 1.30,3.24) and 20-24y (late: PR=1.43, 1.10,1.86; post-lockdown: PR=1.49, 1.15,1.93). These estimates were higher in individuals 15-24y compared to those ≥30y. Conclusions: Adolescents and younger adults had an increased relative incidence of SARS-CoV-2 during late lockdown and post-lockdown periods. The role of these age groups should be considered when implementing future pandemic response efforts.

Resumen Objetivo: Estimar los cambios temporales en la incidencia de hospitalizaciones confirmadas por SARS-CoV-2 (por fecha de inicio de los síntomas) por grupo de edad durante y después del cierre nacional. Material y métodos: Para cada grupo de edad g, calculamos la proporción E(g) de individuos en ese grupo de edad entre todos los casos de 10 a 59 años durante el periodo de cierre temprano (del 20 de abril al 3 de mayo de 2020) y la proporción correspondiente L(g) durante los periodos de cierre tardío (18-31 de mayo de 2020) y posterior al cierre (15-28 de junio de 2020), y se calculó la razón de prevalencia: RP(g)=L(g)/E(g). Resultados: Para los periodos de cierre tardío y posterior al cierre, los valores de RP más altos se dieron en los grupos de edad de 15 a 19 años (tardío: RP=1.69, IC95% 1.05,2.72; después del cierre: RP=2.05, 1.30,3.24) y 20-24 años (tardío: RP=1.43, 1.10,1.86; después del cierre: RP=1.49, 1.15,1.93). Estas estimaciones fueron más altas en personas de 15 a 24 años en comparación con las de ≥ 30 años Conclusiones: Los adolescentes y los adultos jóvenes tuvieron una mayor incidencia relativa de SARS-CoV-2 durante los periodos de cierre tardío y posteriores al cierre. El papel de estos grupos de edad en la transmisión de la enfermedad debe tenerse en cuenta al implementar futuros esfuerzos de respuesta a una pandemia.

Menarche characteristics in association with total and cause-specific mortality: a prospective cohort study of Mexican teachers.

PURPOSE: We evaluated the relation between age at menarche and time to menstrual regularity with all-cause and cause specific mortality in a cohort of Mexican women. METHODS: We followed 113,540 women from the Mexican Teachers' Cohort. After a mean follow-up time of 9.2 years, 1,355 deaths were identified. We estimated hazard ratios from Cox regression models for total mortality and a competitive risk models for cause-specific mortality adjusting for year of birth and childhood factors. RESULTS: Women with extreme age of menarche were at increased risk of all-cause mortality (HR [95% CI]: <11 years 1.50 [1.20, 1.87]; 14 years 1.19 [0.97, 1.43]) relative to those with menarche at 13 years. Extreme ages at menarche had higher risk of mortality for diabetes (HR: <11 years 1.66 [0.90, 3.05]; 14 years 1.47 [0.90, 2.40]), breast cancer (HR: <11 years 1.34 [0.56, 3.20]), and other cancer (HR:<11 years 1.65 [1.10, 2.48]) compared to menarche at 13 years. Women who took three or more years to achieve menstrual regularity had a higher risk of all-cause mortality compared to those who took less (HR: 1.27 [1.01, 1.58]). CONCLUSIONS: Extreme ages at menarche and longer time to reach menstrual regularity were associated with an increased rate of all-cause and cause-specific mortality.

Revisión rápida de la transmisión del SARS-CoV-2 por contacto con objetos y superficies / Rapid review of transmission of SARS-CoV-2 by contact with objects and surfaces

Resumen: Objetivo: Identificar evidencia científica sobre la transmisión indirecta del SARS-CoV-2 en espacios extrahospitalarios y medidas poblacionales para su prevención. Material y métodos: Una revisión rápida de lo publicado en PubMed y MedRxiv entre 01/12/2019 y 24/04/2020 sobre los temas 1) la contaminación y viabilidad del SARS-CoV-2 en distintas superficies inanimadas; 2) la efectividad desinfectante ante SARS-CoV-2 de productos accesibles a nivel domiciliario; 3) los casos y brotes de contagio de SARS-CoV-2 por medio de superficies. Resultados: Una alta proporción de los objetos de personas infectadas con SARS-CoV-2 (inodoro, ollas y tabletas electrónicas) se encuentran contaminados. Este virus permanece viable desde horas hasta días en papel, cartón, tela, vidrio, madera, plástico, acero y cubrebocas. El etanol, 2-propanol, cloro y jabón son efectivos para desactivarlo. Existe poca evidencia sobre casos y brotes por contagio indirecto. Conclusiones: Se requieren estudios que determinen la dosis mínima infectante por autoinoculación. Apelando al principio precautorio, se incluyeron recomendaciones para reducir el riesgo de contagio indirecto.

Abstract: Objective: To identify scientific evidence on the indirect transmission of SARS-CoV-2 in out-of-hospital spaces and population measures for its prevention. Materials and methods: A rapid review of what has been published in PubMed and MedRxiv between 12/01/2019 and 04/24/2020, on the topics: 1) the contamination and viability of SARS-CoV-2 in different inanimate surfaces; 2) products accessible at home level with disinfectant efficacy against SARS-CoV-2; 3) the cases and outbreaks of SARS-CoV-2 transmitted through surfaces. Results: A high proportion of the objects people infected with SARS-CoV-2 use (toilet, pots and electronic tablets) are contaminated. This virus remains viable from hours to days in paper, cardboard, cloth, glass, wood, plastic, steel and face masks. Ethanol, 2-propanol, chlorine, and soap are effective in deactivating it. There is little evidence on cases and outbreaks by indirect contact. Conclusions: Studies are required to determine the minimum infectious dose by autoinoculation. Appealing to the precautionary principle, we include recommendations to reduce the risk of indirect contagion.

Revisión rápida: probabilidad de contagio por infecciones respiratorias agudas en el transporte público colectivo / Quick review: probability of infection by acute respiratory infections on public transportation

Resumen: Objetivo: Determinar el nivel de evidencia sobre la probabilidad de transmisión de enfermedades respiratorias agudas en el transporte público colectivo. Material y métodos: Se utilizó la metodología de revisiones rápidas de Cochrane. La estrategia de búsqueda abarcó una base de datos académica hasta el 10 de diciembre de 2020. Resultados: Se identificaron 16 manuscritos que cumplieron los criterios de selección. En estudios de cohorte agrupados se encontró que el momio de seroconversión por influenza A o B fue 54% mayor en personas con uso frecuente de transporte público colectivo en comparación con las personas con un uso poco frecuente (razón de momios: 1.54; IC95%:1.06-2.01). Conclusión: La probabilidad de contagio por enfermedades respiratorias agudas puede incrementar con el uso del transporte público colectivo. Algunas recomendaciones para reducir la probabilidad de contagio en el transporte público colectivo son el uso de cubrebocas y reducir el número de pasajeros y tiempo de traslado.

Abstract: Objective: To determine the level of evidence on the probability of transmission of acute respiratory diseases on collective public transport. Materials and methods: We followed the Cochrane rapid review methodology. The search strategy encompasses one academic database until December 10, 2020. Results: 16 manuscripts met the inclusion criteria. Pooling of cohort studies showed that the odd of seroconversion to influenza A or B was 54% greater in people with frequent use of public transport compared to people with infrequent use (odds ratio: 1.54; 95%CI: 1.06-2.01). Conclusions: The probability of contagion from acute respiratory diseases may increase with the use of public transport. Some recommendations to reduce the probability of contagion in collective public transport include the use of face masks, to avoid speaking or singing, and to reduce the number of passengers and the travel time.

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.

Revisión rápida del uso de cubrebocas quirúrgicos en ámbito comunitario e infecciones respiratorias agudas / Rapid review of the community-wide use of surgical masks and acute respiratory infections

Resumen: Objetivo: Evaluar la efectividad del uso de cubrebocas quirúrgico en ámbitos comunitarios para reducir la probabilidad de contagio por SARS-CoV-2 u otra infección respiratoria aguda viral, en comparación con no usar cubrebocas. Material y métodos: Se utilizó la metodología de revisiones rápidas de Cochrane. La estrategia de búsqueda abarcó una base de datos académica y pre-prints hasta el 1 de abril de 2020. Los títulos y resúmenes fueron revisados por un investigador. La revisión de textos completos fue dividida entre tres investigadores. Los resultados fueron sintetizados de forma narrativa. Resultados: Se identificaron 713 manuscritos, de los cuales 21 cumplieron los criterios de inclusión. De seis revisiones sistemáticas, cuatro no encontraron reducciones en la probabilidad de contagio y seis estudios experimentales en hogares no encontraron diferencias en la probabilidad de contagio asociado con el uso de cubrebocas. Únicamente un estudio de modelaje estimó una reducción de 20% en la incidencia de enfermedad respiratoria, asumiendo que 10 a 50% de la población hace uso correcto de cubrebocas quirúrgicos. Conclusiones: La evidencia científica no es concluyente para recomendar o desalentar el uso de cubrebocas a nivel poblacional. Considerando los potenciales efectos negativos, las recomendaciones gubernamentales deberían esperar a los resultados de los experimentos naturales en países que han recomendado la utilización poblacional de cubrebocas.

Abstract: Objective: To assess the effectiveness of using surgical masks in community settings to reduce the probability of infection by SARS-CoV-2 or other acute viral respiratory infection, compared to not using surgical masks. Materials and methods: We followed the Cochrane rapid review methodology. The search strategy encompasses one academic database and pre-prints until April 1, 2020. Titles and abstracts were reviewed by one investigator. The full text review was divided among three researchers. The results were synthesized in a narrative way. Result: 713 manuscripts were identified, of which 21 met the inclusion criteria. Of six systematic reviews, four found no reduction in the probability of transmission. Experimental home studies found no differences in the probability of contagion associated with the use of mouth masks. Only one modeling study estimated a 20% reduction in the incidence of acute respiratory disease, assuming that 10 to 50% of the population use the surgical masks correctly. Conclusions: The scientific evidence is inconclusive to recommend or discourage the use of surgical masks at the population level. Considering the potential negative effects, official recommendations should await for the results of natural experiments currently occurring in countries that have recommended the use of face masks at the population level.

Soft drink intake is associated with weight gain, regardless of physical activity levels: the health workers cohort study.

BACKGROUND: While soft drink intake is positively associated with weight gain, no previous study has investigated whether leisure-time physical activity modifies this association. We estimated the association between soft drink intake and body weight, and explored if this association differed by levels of leisure-time physical activity. METHODS: We used data from the health workers cohort study, a prospective study of Mexican adults (20 to 85y old), including 1268 health workers and their families, who were assessed at baseline (2004-2006) and follow-up (2010-2012). We assessed soft drink intake (cola and flavored soda) using a validated food frequency questionnaire. We measured leisure-time physical activity using a self-report questionnaire, and categorized according to the 2010 World Health Organization (WHO) recommendations. Body weight was measured by trained personnel. The association between changes in soft drink intake and weight change, and if such association varied by levels of physical activity was estimated through fixed-effect models. RESULTS: An increase in one serving per day of soft drink was associated with 0.10 kg (95% CI 0.00, 0.19) increase in weight per year. This association was not modified by leisure-time physical activity, as demonstrated by the magnitude of the coefficient of the interaction between soft drink, leisure-time physical activity, and time (- 0.03 kg, 95% CI - 0.27 to 0.21); people who complied with the WHO physical activity recommendations gained 0.36 kg/year per serving of soft drink, compared to 0.48 kg/year for people without sufficient physical activity. CONCLUSIONS: Soft drink intake was associated with weight gain. Leisure-time physical activity did not modify the association between soft drink intake and weight gain. This finding challenges the idea that leisure-time physical activity is sufficient to counterbalance weight gain associated to soft drink intake.