Exposure to low-dose radiation in occupational settings and ischaemic heart disease: a systematic review and meta-analysis

Ionising radiation is a human carcinogen, but the evidence is less clear that exposure to low-dose ionising radiation (LDIR) increases the risk of adverse cardiovascular outcomes. We synthesised the literature of chronic occupational exposure to LDIR and cardiovascular disease, particularly for ischaemic heart disease (IHD).The literature search was conducted using three databases including studies published between 1990 and 2022. A quality assessment of the studies was completed using the Office of Health and Assessment and Translation Risk of Bias Rating Tool. We conducted meta-analyses for IHD mortality using random effects models using measures of excess relative risk per sievert (ERR/Sv) obtained from internal cohort comparisons, as well as with standardised mortality ratios (SMRs) from external cohort comparisons.We identified 2189 articles, and of these, 26 provided data on IHD and were retained. Most studies were classified as having a 'moderate' level of risk of bias. Fourteen and 10 studies reporting external radiation doses were included in meta-analyses using SMR and ERR/Sv, respectively. The meta-summary SMR was 0.81 (95% CI 0.74 to 0.89) with evidence of reduced risk but high heterogeneity across studies. For internal cohort measures, the summary ERR/Sv for a lagged exposure of 10 years was 0.10 (95% CI 0.01 to 0.20) with low heterogeneity. The subgroup analysis by lagged exposure time showed the strongest association were for the 15 and 20 years lag.Our findings suggest that occupational exposure to LDIR increases the risk IHD mortality and highlight the relevance of internal cohort comparisons.

Barriers and facilitators to academia-government collaboration in the context of the COVID-19 pandemic in Colombia: a qualitative study

The COVID-19 pandemic highlighted the importance of strengthening collaborations between academia and government. The development and maintenance of these collaborative relationships is a complex and dynamic process, particularly during public health emergencies. This study was aimed at identifying and analyzing factors that acted as barriers and facilitators in the collaboration process between academia and government during the COVID-19 pandemic in the five largest cities in Colombia. The study used a qualitative approach based on the systematization of experiences. Twenty-five semi-structured interviews were conducted with local actors from government and academia during 2021. Participants identified a variety of situations that involved individual, institutional and relational factors that acted as barriers and facilitators, and which have been previously reported in other countries and contexts not related to pandemics. Based on participant reports, two additional factors emerged, one corresponding to situations related to the pandemic management process itself and another related to structural or systemic conditions that involved government processes and the Colombian health system. Despite the challenges posed by the pandemic, the health emergency brought about shared feelings of local commitment and a willingness to work through interdisciplinary teams to address the pandemic with the least adverse effects on the community. Other facilitators of the collaborative process that were recognized were the importance of timely access to data and transparent analyses, as well as government decisions being informed by the perspectives of academics. The main barriers identified by both actors were excessive centralization of the pandemic's management and the need for rapid decision-making processes under high levels of uncertainty. In addition, the fragmentation of services in the health system posed a barrier to the interventions that were suggested by the collaborative work. Our results suggest that government-academia collaborations should be implemented as ongoing participatory processes integrating various sectors, actors and disciplines.

Effectiveness of contact tracing to reduce fatality from COVID-19: preliminary evidence from Colombia

Objectives

Conducting contact tracing (CT) programs in low- and middle-income countries is challenging, and there is no evidence of their effectiveness in Latin America. We evaluated the effectiveness of CT on reducing fatality from COVID-19 in Colombia.

Study design

The study design is a retrospective cohort study with nation-wide data of suspected and confirmed cases of severe acute respiratory syndrome (SARS-CoV-2) infection and their registered contacts.

Methods

We analyzed confirmed and suspected COVID-19 cases and their chains of contact using a nation-wide registry from March 28, 2020 to January 13, 2021. To estimate the effect of CT on fatality, we adjusted a multilevel negative binomial model using the number of deaths and the number of people within a chain of contacts as the outcome variable and offset variable, respectively. Sensitivity analysis was conducted using different cutoff values of contacts traced and a logistic model for the effect of CT on death at an individual level.

Results

We analyzed 1.4 million cases, 542,936 chains of contact, and 46,087 deaths. Only, 5.8% of total cases and contacts were included in a chain of a case and five or more contacts. We found that tracing of at least five contacts per case reduces fatality by 48% (95% confidence interval: 45–51), and, at the current levels of tracing in Colombia, it prevents 1.8% of deaths. Results obtained from the sensitivity analysis were consistent with the reduction of fatality at an individual level and higher protective effect with the higher number of contacts traced.

Conclusions

In Colombia, tracing of at least five contacts per case reduces fatality from COVID-19. The coverage and intensity of tracing needs to be increased as a strategy to mitigate fatality in Colombia.

Socioeconomic inequalities associated with mortality for COVID-19 in Colombia: a cohort nationwide study

BACKGROUND

After 8 months of the COVID-19 pandemic, Latin American countries have some of the highest rates in COVID-19 mortality. Despite being one of the most unequal regions of the world, there is a scarce report of the effect of socioeconomic conditions on COVID-19 mortality in their countries. We aimed to identify the effect of some socioeconomic inequality-related factors on COVID-19 mortality in Colombia.

METHODS

We conducted a survival analysis in a nation-wide retrospective cohort study of confirmed cases of COVID-19 in Colombia from 2 March 2020 to 26 October 2020. We calculated the time to death or recovery for each confirmed case in the cohort. We used an extended multivariable time-dependent Cox regression model to estimate the HR by age groups, sex, ethnicity, type of health insurance, area of residence and socioeconomic strata.

RESULTS

There were 1 033 218 confirmed cases and 30 565 deaths for COVID-19 in Colombia between 2 March and 26 October. The risk of dying for COVID-19 among confirmed cases was higher in males (HR 1.68 95% CI 1.64 to 1.72), in people older than 60 years (HR 296.58 95% CI 199.22 to 441.51), in indigenous people (HR 1.20 95% CI 1.08 to 1.33), in people with subsidised health insurance regime (HR 1.89 95% CI 1.83 to 1.96) and in people living in the very low socioeconomic strata (HR 1.44 95% CI 1.24 to 1.68).

CONCLUSION

Our study provides evidence of socioeconomic inequalities in COVID-19 mortality in terms of age groups, sex, ethnicity, type of health insurance regimen and socioeconomic status.

Clustering of childhood cancer in Colombia: a nationwide study

Background: Childhood cancer is considered one the most important causes of death in children and adolescents, despite having a low incidence in this population. Spatial analysis has been previously used for the study of childhood cancer to study the geographical distribution of leukemias. This study aimed to identify the presence of space-time clusters of childhood of cancer excluding leukemia in Colombia between 2014 and 2017. Methods: All incident cancer cases (excluding leukemia) in children under the age of 15 years that had been confirmed by the National Surveillance System of Childhood Cancer between 2014 and 2017 were included. Kulldorf's circular scan test was used to identify clusters using the municipality of residence as the spatial unit of analysis and the year of diagnosis as the temporal unit of analysis. A sensitivity analysis was conducted with different upper limit parameters for the at-risk population. Results: A total of 2006 cases of non-leukemia childhood cancer were analyzed, distributed in 432 municipalities with a mean annual incidence rate of 44 cases per million children under the age of 15. Central nervous system (CNS) tumors were the most frequent type. Four spatial clusters and two space-time clusters were identified in the central and southwest regions of the country. In the analysis for CNS tumors, a spatial cluster was identified in the central region of the country.  Conclusions: The distribution of non-leukemia childhood cancer seems to have a clustered distribution in some Colombian regions that may suggest infectious or environmental factors associated with its incidence.

Clustering of non-leukemia childhood cancer in Colombia: a nationwide study

Background: Childhood cancer is considered one the most important causes of death in children and adolescents, despite having a low incidence in this population. Spatial analysis has been previously used for the study of childhood cancer to study the geographical distribution of leukemias. This study aimed to identify the presence of space-time clusters of childhood of cancer excluding leukemia in Colombia between 2014 and 2017. Methods: All incident cancer cases (excluding leukemia) in children under the age of 15 years that had been confirmed by the National Surveillance System of Childhood Cancer between 2014 and 2017 were included. Kulldorf's circular scan test was used to identify clusters using the municipality of residence as the spatial unit of analysis and the year of diagnosis as the temporal unit of analysis. A sensitivity analysis was conducted with different upper limit parameters for the at-risk population in the clusters. Results: A total of 2006 cases of non-leukemia childhood cancer were analyzed, distributed in 432 out of 1,122 municipalities with a mean annual incidence rate of 44 cases per million children under the age of 15. Central nervous system (CNS) tumors were the most frequent type. Two space-time clusters were identified in the central and southwest regions of the country. In the analysis for CNS tumors, a spatial cluster was identified in the central region of the country.  Conclusions: The distribution of non-leukemia childhood cancer seems to have a clustered distribution in some Colombian regions that may suggest infectious or environmental factors associated with its incidence although heterogeneity in access to diagnosis cannot be discarded.

Childhood Leukemia in Small Geographical Areas and Proximity to Industrial Sources of Air Pollutants in Three Colombian Cities

Acute leukemia is the most common childhood cancer and has been associated with exposure to environmental carcinogens. This study aimed to identify clusters of acute childhood leukemia (ACL) cases and analyze their relationship with proximity to industrial sources of air pollution in three capital cities in Colombia during 2000-2015. Incident ACL cases were obtained from the population cancer registries for the cities of Bucaramanga, Cali, and Medellín. The inventory of industrial sources of emissions to the air was obtained from the regional environmental authorities and industrial conglomerates were identified. The Kulldorf's circular scan test was used to detect city clusters and to identify clusters around industrial conglomerates. Multivariable spatial modeling assessed the effect of distance and direction from the industrial conglomerates controlling for socioeconomic status. We identified industrials sectors within a buffer of 1 km around industrial conglomerates related to the ACL clusters. Incidence rates showed geographical heterogeneity with low spatial autocorrelation within cities. The spatio-temporal tests identified one cluster in each city. The industries located within 1 km around the ACL clusters identified in the three cities represent different sectors. Exposure to air pollution from industrial sources might be contributing to the incidence of ACL cases in urban settings in Colombia.

A spatial analysis of childhood cancer and industrial air pollution in a metropolitan area of Colombia

BACKGROUND

Air pollutants are considered carcinogenic to humans. In some European countries, an association between industrial air pollution and childhood cancer has been established. This relationship has not been addressed in Latin America, despite the spatial variability of air pollutants that may limit the extrapolation of the results to other geographical areas.

OBJECTIVE

To conduct a spatial analysis of the relationship between childhood cancer and proximity to industrial sources of air pollution in a metropolitan area of Colombia.

METHODS

Incident cases of childhood cancers were obtained from the Population-based Cancer Registry of the Metropolitan Area of Bucaramanga during 2000-2015. Local and focused cluster tests were used for the detection of spatial clusters, and the Poisson multivariable model was used to evaluate the combined effects of spatial variables.

RESULTS

The Kulldorff's focused test found a significant spatial cluster (P < 0.001) around one industrial agglomerate and the multivariable model results suggests that the distance effect is modified by the directional effect of the wind.

CONCLUSION

A spatial cluster of incident cases of childhood cancer occurred in the municipality of Bucaramanga, Colombia. Our finding supports the hypothesis that childhood cancer might be related with industrial air pollution exposure in a Latin American city.

Space-time clustering of childhood leukemia in Colombia: a nationwide study

BACKGROUND

Leukemia is the most common cancer in childhood. The estimated incidence rate of childhood leukemia in Colombia is one of the highest in America and little is known about its spatial distribution.

PURPOSE

To explore the presence of space-time clustering of childhood leukemia in Colombia.

METHODS

We included children less than 15 years of age with confirmed diagnosis of acute leukemia reported to the national surveillance system for cancer between 2009 and 2017. Kulldorff's spatio-temporal scan statistics were used with municipality and year of diagnosis as units for spatial and temporal analysis.

RESULTS

There were 3846 cases of childhood leukemia between 2009 and 2017 with a specific mean incidence rate of 33 cases per million person-years in children aged 0-14 years. We identified five spatial clusters of childhood leukemia in different regions of the country and specific time clustering during the study period.

CONCLUSION

Childhood leukemia seems to cluster in space and time in some regions of Colombia suggesting a common etiologic factor or conditions to be studied.

The effects of air pollution on respiratory health in susceptible populations: a multilevel study in Bucaramanga, Colombia

We conducted a cohort study to investigate the association between exposure to three different levels of outdoor air pollution and incidence of respiratory symptoms in a population with chronic cardiovascular and respiratory disease. We accompanied 756 participants for a period of six months through the maintenance of a daily record of symptoms and clinic visits. The symptoms with highest incidence rates were sneezing and hacking cough. Multivariate analysis showed that incidence of total symptoms was 60% and 74% lower in areas with medium and low levels of pollution compared to areas with high levels of pollution. These results suggest that negative respiratory effects occur at concentrations of particulate matter PM10 > 60ug/m³.