Association between satellite-detected tropospheric nitrogen dioxide and acute respiratory infections in children under age five in Senegal: spatio-temporal analysis

The impact of environmental conditions on non-communicable diseases in sub-Saharan Africa: A scoping review of epidemiologic evidence

Background

The burden of non-communicable diseases (NCDs) in sub-Saharan Africa (SSA) is increasing. Environmental conditions such as heavy metals and air pollution have been linked with the incidence and mortality of chronic diseases such as cancer, as well as cardiovascular and respiratory diseases. We aimed to scope the current state of evidence on the impact of environmental conditions on NCDs in SSA.

Methods

We conducted a scoping review to identify environmental conditions linked with NCDs in SSA by identifying studies published from January 1986 through February 2023. We searched African Index Medicus, Ovid Medline, Scopus, Web of Science, and Greenfile. Using the PICOS study selection criteria, we identified studies conducted in SSA focussed on physical environmental exposures and incidence, prevalence, and mortality of NCDs. We included only epidemiologic or quantitative studies.

Results

We identified 6754 articles from electronic database searches; only 36 met our inclusion criteria and were qualitatively synthesised. Two studies were conducted in multiple SSA countries, while 34 were conducted across ten countries in SSA. Air pollution (58.3%) was the most common type of environmental exposure reported, followed by exposure to dust (19.4%), meteorological variables (13.8%), heavy metals (2.7%), soil radioactivity (2.7%), and neighbourhood greenness (2.7%). The examined NCDs included respiratory diseases (69.4%), cancer (2.7%), stroke (5.5%), diabetes (2.7%), and two or more chronic diseases (19.4%). The study results suggest an association between environmental exposures and NCDs, particularly for respiratory diseases. Only seven studies found a null association between environmental conditions and chronic diseases.

Conclusions

There is a growing body of research on environmental conditions and chronic diseases in the SSA region. Although some cities in SSA have started implementing environmental monitoring and control measures, there remain high levels of environmental pollution. Investment can focus on improving environmental control measures and disease surveillance.

Association between short-term exposure to ambient air pollution and upper respiratory tract infection in Kunshan

The health effects of air pollution have become a major public health problem. Studies on the relationship between short-term exposure to air pollutants and upper respiratory tract infection (URTI) related clinic visits and expenditures were scarce. From January 1, 2019, to December 31, 2021, we included all the URTI cases that turned to 11 public hospitals in Kunshan, and summarized individual medical cost. Daily meteorological factors and 24-h mean concentrations of four common air pollutants, including particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and 10 μm (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2), were consecutively recorded. Generalized additive regression model was adopted to quantify the associations between each air pollutant and the daily clinic visits of URTI cases. We further calculated attributable number (AN) and attributable fraction, and performed sensitivity analysis by gender, age, and season. A total of 934,180 cases were retrieved during the study period. PM2.5, PM10, SO2, and NO2 showed significant associations with hospital visits and expenditures due to URTI. Relative risks for them were 1.065 (95% confidence interval [CI] 1.055, 1.076), 1.045 (95% CI 1.037, 1.052), 1.098 (95% CI 1.038, 1.163), and 1.098 (95% CI 1.085, 1.111) on lag 0-5 days, respectively. Thirty-one thousand four hundred fifty-five (95% CI 27,457, 35,436) cases could be ascribed to increased NO2 and accounted for 3.37% (95% CI 2.94%, 3.79%) of all clinic visits. Sensitivity analyses indicated that the effects of air pollution were generally consistent for male and female. PM2.5, PM10, and NO2 had stronger associations among people aged ≤ 18 years, followed by those aged 19-64 years and ≥ 65 years. The association strengths of air pollution varied seasonally. Short-term exposure to ambient air pollutants had significant associations with clinic visits and expenditures owing to URTI. Children and adolescents appeared to be more susceptible to adverse health effects of air pollution. NO2 may be a priority when formulating pollution control measures.

Acute lower respiratory infections among children under five in Sub-Saharan Africa: a scoping review of prevalence and risk factors

BACKGROUND

Acute lower respiratory tract infections (ALRTIs) among children under five are still the leading cause of mortality among this group of children in low and middle-income countries (LMICs), especially countries in sub-Saharan Africa (SSA). This scoping review aims to map evidence on prevalence and risk factors associated with ALRTIs among children under 5 years to inform interventions, policies and future studies.

METHODS

A thorough search was conducted via four main databases (PubMed, JSTOR, Web of Science and Central). In all, 3,329 records were identified, and 107 full-text studies were considered for evaluation after vigorous screening and removing duplicates, of which 43 were included in this scoping review.

FINDINGS

Findings indicate a high prevalence (between 1.9% to 60.2%) of ALRTIs among children under five in SSA. Poor education, poverty, malnutrition, exposure to second-hand smoke, poor ventilation, HIV, traditional cooking stoves, unclean fuel usage, poor sanitation facilities and unclean drinking water make children under five more vulnerable to ALRTIs in SSA. Also, health promotion strategies like health education have doubled the health-seeking behaviours of mothers of children under 5 years against ALRTIs.

CONCLUSION

ALRTIs among children under five still present a significant disease burden in SSA. Therefore, there is a need for intersectoral collaboration to reduce the burden of ALRTIs among children under five by strengthening poverty alleviation strategies, improving living conditions, optimising child nutrition, and ensuring that all children have access to clean water. There is also the need for high-quality studies where confounding variables in ALRTIs are controlled.