Cardiovascular disease (CVD) is the number one cause of death globally and evidence is steadily increasing on the role of non-traditional risk factors such as meteorology and air pollution. Nevertheless, many research gaps remain, such as the association between these non-traditional risk factors and subtypes of CVD, such as acute myocardial infarction (AMI). The objective of this study was to investigate the association between daily ambient temperature and AMI hospitalisations using a case-crossover design in Gothenburg, Sweden (1985–2010). A secondary analysis was also performed for out-of-hospital ischemic heart disease (IHD) deaths. Susceptible groups by age and sex were explored. The entire year as well as the warm (April−September) and cold periods (October–March) were considered. In total 28 215 AMI hospitalisations (of 22 475 people) and 21 082 out-of-hospital IHD deaths occurred during the 26-year study period. A linear exposure-response corresponding to a 3% and 7% decrease in AMI hospitalisations was observed for an inter-quartile range (IQR) increase in the 2-day cumulative average of temperature during the entire year (11°C) and the warm period (6°C), respectively, with and without adjustment for PM10, NO2, NOx or O3. No heat waves occurred during the warm period. No evidence of an association in the cold period nor any association between temperature and IHD deaths in the entire year, warm or cold periods - with and without adjusting for PM10, NO2, NOx or O3 was found. No susceptible groups, based on age or sex, were identified either. The inverse association between temperature and AMI hospitalisations (entire year and warm period) in Gothenburg is in accordance with the majority of the few other studies that investigated this subtype of CVD.
Little evidence is available on the strength of the association between ambient air pollution exposure and health effects in developing countries such as South Africa. The association between the 24-h average ambient PM(10), SO(2) and NO(2) levels and daily respiratory (RD), cardiovascular (CVD) and cerebrovascular (CBD) mortality in Cape Town (2001-2006) was investigated with a case-crossover design. For models that included entire year data, an inter-quartile range (IQR) increase in PM(10) (12 mg/m3) and NO(2) (12 mg/m3) significantly increased CBD mortality by 4% and 8%, respectively. A significant increase of 3% in CVD mortality was observed per IQR increase in NO(2) and SO(2) (8 mg/m3). In the warm period, PM(10) was significantly associated with RD and CVD mortality. NO(2) had significant associations with CBD, RD and CVD mortality, whilst SO(2) was associated with CVD mortality. None of the pollutants were associated with any of the three outcomes in the cold period. Susceptible groups depended on the cause-specific mortality and air pollutant. There is significant RD, CVD and CBD mortality risk associated with ambient air pollution exposure in South Africa, higher than reported in developed countries.
Background: Temperature and air pollution are often treated as separate risk factors and very few studies have investigated effect modification by temperature on air pollution, and the impact of this interaction on human health in Africa. This study therefore investigated the modifying effects of temperature on the association between air pollution and Respiratory disease (RD) hospital admission in South Africa.
Methods: RD admission data (ICD10 J00-J99) were obtained from two hospitals located in Secunda, South Africa beween 1 January 2011 to 31 October 2016. NO2, SO2, PM10, PM2.5, temperature and relative humidity data were obtained from the South African Weather Services. A case-crossover epidemiological study design was applied and lag0-1 was used. Models were adjusted for public holidays and Apparent Temperature (Tapp). Tapp was classified as warm (Tapp>75th percentile), cold (Tapp<25th percentile) and normal (Tapp 25th-75th percentile).
Results: Of the 14 568 RD admissions, approximately equal number of females and males were admitted. The average daily NO2, SO2, PM2.5 and PM10 levels were 12.4 μm/m3, 8.5 μm/m3, 32.3 μm/m3 and 68.6 μm/m3, respectively. Overall, a 10 μm/m3 increase in SO2 on warm days was associated with an increase in RD hospital admissions among the patients by 8.5% (95% Conf. Int: 0.4%, 17.2%) and 8.4% (95% Conf. Int: 0.3%, 17.1%) after adjustment for PM2.5 and PM10 respectively. However, increasing PM2.5 or PM10 by 10 μm/m3 was associated with an increase in RD hospital admissions when the temperature was normal after adjusting for SO2. On cold days there were significant associations between the SO2 and RD admissions among the 0-14 year age group after adjusting for either PM2.5 (6.5%; 95% Conf.Int: 0.9%, 12.4%) or PM10 (5.5%; 95% Conf.Int: 0.3%, 11.1%).
Conclusions: SO2 was affected by extremes of temperature while the particulate matters had effect on RD admission during normal temperature in Secunda.
This quantitative exploratory baseline study aimed to investigate whether allergy among adolescents was associated with household living conditions, including living near gold mine tailing dumps in South Africa. A questionnaire based on the International Study of Asthma and Allergies was used to collect information on allergy and household risk factors among adolescents (n = 5611). A chi-square test was applied to determine the relationship between community (exposed/unexposed) and confounding variables. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) were calculated using univariate and multiple logistic regression analysis (LRA) to estimate the likelihood of having doctor-diagnosed allergies. The overall prevalence of doctor-diagnosed allergies was 25.5%. The exposed communities had a higher prevalence of doctor-diagnosed allergies (26.97%) compared with the unexposed (22.69%) communities. The study found an association between doctor-diagnosed allergy and having fungus in the house, being female, currently having pets in and around the house, residing in the community for more than three years and living in communities located close to gold mine tailing dumps. Actions to implement buffer zones between gold mine tailing dumps and communities would support Sustainable Development Goals 3 (health) and 11 (sustainable cities and communities), while failing to address the current potential identified risk factors may pose a significant public health challenge. Local policymakers should also apply the precautionary principle to protect the health of children, especially with the location of human settlements relative to air pollution sources.
Air quality index (AQI) is an index based on calculating daily index values for pollutants and reporting the value that corresponds to the criteria pollutant with the highest index value. The index is used to communicate air quality levels to the public at any specific time and place. The AQI has been criticized for many reasons, which includes its inability to quantitatively account for the combined effects of exposure to multiple pollutants, it does not capture low-level effects and in some cases, health components are not included in the models. This has encouraged the development of multiple pollutant indices which are commonly called air quality health index (AQHI) that adequately captures the joint effects of multiple air pollutants on health outcomes. The AQHI is developed using multiple pollutants and obtaining estimates from each pollutants. It assumes an additive or overall effect to produce an index; this ensures the contribution to adverse health effects of each pollutant is considered. In this review, ten studies on the association between AQHIs and health outcomes were identified but only two compare health effects of AQHIs with those of AQIs. A Chinese study found that an IQR increase in AQHI vs AQI represented 3.61% (95%CI: 2.85% - 4.37%) vs 2.71% (95% CI: 1.98% - 3.43%), 3.73% (95% CI: 2.18% - 5.27%) vs 2.12% (95% CI: 0.63% - 3.61%) and 4.19% (95% CI: 2.87% - 5.52%) vs 1.88% (95% CI: 0.60% - 3.17%) increase in mortality, respiratory and cardiovascular disease respectively. An American study found that the AQHI was positively associated with respiratory emergency visits in low and high ozone-seasons compared to the AQI, which was only significant for low ozone-season. The AQHI demonstrated stronger effects per IQR. Whether AQHI also capture a larger burden attributable to daily exposure to air pollution will be further investigated.
BACKGROUND AND AIM: There is limited understanding on the short-term association between hospital admissions and ambient air pollution in sub-Sahara African countries. Therefore, this study investigated the short-term association of air pollution with daily counts of hospital admissions due to respiratory and cardiovascular diseases in Cape Town, South Africa. METHODS: Generalized additive quasi-Poisson models were used within a distributed lag linear modelling framework to estimate the cumulative effects of PM10, NO2 and SO2 up to a lag of 14 days. We further conducted multi-pollutant models and stratified our analysis by age group, sex and season. RESULTS:The relative risk (95% confidence interval (CI)) for PM10, NO2 and SO2 for all ages, both sexes, and seasons, at lag 0 – 1 for hospital admissions due to respiratory disease (RD) were 3.5% (1.8 – 5.2%), 3.2% (1.0 – 5.5%), 1.8% (0 – 3.6%), respectively. In cardiovascular disease (CVD), 2.2% (0.3% - 4%), 1.8% (-0.6% - 4.3%) and -0.5% (-2.3% - 1.3%), respectively, per inter-quartile range increase of 12 ug/m3 for PM10, 7.3 ug/m3 for NO2 and 3.6 ug/m3 for SO2. In multi-pollutant models, PM10 for associations RD remained significant despite some attenuation. The overall cumulative risk per IQR increase in PM10 for females of all ages was 2.7% (-0.2% - 5.6%), 2.9% (0.1% - 5.9%) for males and 6.8% (2.6% - 11.2%) for aged ≥ 65. However, in CVD the association were not significant for all the pollutants, the overall effect estimate for all ages and sexes were 1.4% (-0.8% – 3.7%), 1.4% (-1.4% - 4.3%) and -1% (-2.9% - 1%) for PM10, NO2 and SO2 in three-pollutant models. CONCLUSIONS:We found robust associations of daily respiratory disease hospital admissions with daily PM10 concentrations. Associations were strongest during the warm season and people aged ≥ 65. KEYWORDS: cardiovascular disease, respiratory disease, multi pollutant, short-term association, DLNM, South Africa
Objectives: This study developed an Air Quality Health Index (AQHI) based on global scientific evidence and applied it to data from Cape Town, South Africa. Methods: Effect estimates from two global systematic reviews and meta-analyses were used to derive the excess risk (ER) for PM2.5, PM10, NO2, SO2 and O3. Single pollutant AQHIs were developed and scaled using the ERs at the WHO 2021 long-term Air Quality Guideline (AQG) values to define the upper level of the "low risk" range. An overall daily AQHI was defined as weighted average of the single AQHIs. Results: Between 2006 and 2015, 87% of the days posed "moderate to high risk" to Cape Town's population, mainly due to PM10 and NO2 levels. The seasonal pattern of air quality shows "high risk" occurring mostly during the colder months of July-September. Conclusion: The AQHI, with its reference to the WHO 2021 long-term AQG provides a global application and can assist countries in communicating risks in relation to their daily air quality.
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