Tracking poison ingestion deaths for South Africa: The need for access to timely reliable data

The President of South Africa addressed the nation on 15 November 2024 regarding the rise in food-borne illnesses and related child deaths. In the absence of a clear profile of injury deaths from official cause-of-death data, we used empirical, nationally representative surveys from 2017 and 2020/21 to analyse poisoning deaths. For children (aged 0 - 17 years), deaths from poison ingestion increased in 2020/21 for Gauteng Province, and became more prominent in KwaZulu-Natal, Eastern Cape and Mpumalanga provinces. Adults (≥18 years) showed similar developments, but on a larger scale. Among children in 2020/21, poison ingestion deaths were mostly unintentional (274 cases). Adults had higher proportions for suicide-related poisoning, but unintentional poisoning deaths (791 cases) accounted for 43.8% in males and 32.5% in females. Overall, pesticides were the most common cause of poisoning deaths in children (42%) and adults (29%). A promising intervention is that suspected agricultural or stock remedy poisoning, as a notifiable medical condition (NMC), should now be reported to the NMC Surveillance System within 24 hours. For a rapid public health response to the country’s burden of disease, we call on the government for a collaborative approach, to improve the quality and timeliness of death notification data, and to implement electronic capturing of deaths nationally

Estimating the changing burden of disease attributable to low levels of physical activity in South Africa for 2000, 2006 and 2012

Background. Physical activity is associated with a lower risk of cardiovascular outcomes, certain cancers and diabetes. The previous South African Comparative Risk Assessment (SACRA1) study assessed the attributable burden of low physical activity for 2000, but updated estimates are required, as well as an assessment of trends over time. Objective. To estimate the national prevalence of physical activity by age, year and sex and to quantify the burden of disease attributable to low physical activity in South Africa (SA) for 2000, 2006 and 2012. Methods. Comparative risk assessment methodology was used. Physical activity was treated as a categorical variable with four categories, i.e. inactive, active, very active and highly active. Prevalence estimates of physical activity levels, representing the three different years, were derived from two national surveys. Physical activity estimates together with the relative risks from the Global Burden of Disease, Injuries, and Risk Factors (GBD) 2016 study were used to calculate population attributable fractions due to inactive, active and very active levels of physical activity relative to highly active levels considered to be the theoretical minimum risk exposure (>8 000 metabolic equivalent of time (MET)-min/wk), in accordance with the GBD 2016 study. These were applied to relevant disease outcomes sourced from the Second National Burden of Disease Study to calculate attributable deaths, years of life lost, years lived with disability and disability adjusted life years (DALYs). Uncertainty analysis was performed using Monte Carlo simulation. Results. The prevalence of physical inactivity (<600 METS) decreased by 16% and 8% between 2000 and 2012 for females and males, respectively. Attributable DALYs due to low physical activity increased between 2000 (n=194 284) and 2006 (n=238 475), but decreased thereafter in 2012 (n=219 851). The attributable death age-standardised rates (ASRs) declined between 2000 and 2012 from 60/100 000 population in 2000 to 54/100 000 population in 2012. Diabetes mellitus type 2 displaced ischaemic heart disease as the largest contributor to attributable deaths, increasing from 31% in 2000 to 42% in 2012. Conclusions. Low physical activity is responsible for a large portion of disease burden in SA. While the decreased attributable death ASR due to low physical activity is encouraging, this burden may be lowered further with an additional reduction in the overall prevalence of physical inactivity, in particular. It is concerning that the attributable burden for diabetes mellitus is growing, which suggests that existing non-communicable disease policies need better implementation, with ongoing surveillance of physical activity, and population- and community-based interventions are required in order to reach set targets

Estimating the changing disease burden attributable to high body mass index for South Africa for 2000, 2006 and 2012

Background. A high body mass index (BMI) is associated with several cardiovascular diseases, diabetes and chronic kidney disease, cancers, and other selected health conditions. Objectives. To quantify the deaths and disability-adjusted life years (DALYs) attributed to high BMI in persons aged ≥20 years in South Africa (SA) for 2000, 2006 and 2012. Methods. The comparative risk assessment (CRA) methodology was followed. Meta-regressions of the BMI mean and standard deviation from nine national surveys spanning 1998 - 2017 were conducted to provide estimates by age and sex for adults aged ≥20 years. Population attributable fractions were calculated for selected health outcomes using relative risks identified by the Global Burden of Disease Study (2017), and applied to deaths and DALY estimates from the second South African National Burden of Disease Study to estimate the burden attributed to high BMI in a customised Microsoft Excel workbook. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis. BMI was assumed to follow a log-normal distribution, and the theoretical minimum value of BMI below which no risk was estimated was assumed to follow a uniform distribution from 20 kg/m2 to 25 kg/m2. Results. Between 2000 and 2012, mean BMI increased by 6% from 27.7 kg/m2 (95% confidence interval (CI) 27.6 - 27.9) to 29.4 kg/m2 (95% CI 29.3 - 29.5) for females, and by 3% from 23.9 kg/m2 (95% CI 23.7 - 24.1) to 24.6 kg/m2 (95% CI 24.5 - 24.8) for males. In 2012, high BMI caused 58 757 deaths (95% uncertainty interval (UI) 46 740 - 67 590) or 11.1% (95% UI 8.8 - 12.8) of all deaths, and 1.42 million DALYs (95% UI 1.15 - 1.61) or 6.9% (95% UI 5.6 - 7.8) of all DALYs. Over the study period, the burden in females was ~1.5 - 1.8 times higher than that in males. Type 2 diabetes mellitus became the leading cause of death attributable to high BMI in 2012 (n=12 382 deaths), followed by hypertensive heart disease (n=12 146), haemorrhagic stroke (n=9 141), ischaemic heart disease (n=7 499) and ischaemic stroke (n=4 044). The age-standardised attributable DALY rate per 100 000 population for males increased by 6.6% from 3 777 (95% UI 2 639 - 4 869) in 2000 to 4 026 (95% UI 2 831 - 5 115) in 2012, while it increased by 7.8% for females from 6 042 (95% UI 5 064 - 6 702) to 6 513 (95% UI 5 597 - 7 033). Conclusion. Average BMI increased between 2000 and 2012 and accounted for a growing proportion of total deaths and DALYs. There is a need to develop, implement and evaluate comprehensive interventions to achieve lasting change in the determinants and impact of overweight and obesity, particularly among women

Estimating the burden of disease attributable to a diet low in fruit and vegetables in South Africa for 2000, 2006 and 2012

Background. Low intake of fruit and vegetables is associated with an increased risk of various non-communicable diseases, including major causes of death and disability such as cardiovascular disease, diabetes mellitus and cancers. Diets low in fruit and vegetables are prevalent in the South African (SA) population, and average intake is well below the internationally recommended threshold. Objectives. To estimate the burden of disease attributable to a diet low in fruit and vegetables by sex and age group in SA for the years 2000, 2006 and 2012. Methods. We followed World Health Organization and Global Burden of Disease Study comparative risk assessment methodology. Population attributable fractions – calculated from fruit and vegetable intake estimated from national and local surveys and relative risks for health outcomes based on the current literature – were applied to the burden estimates from the second South African National Burden of Disease Study (SANBD2). Outcome measures included deaths and disability-adjusted life years (DALYs) lost from ischaemic heart disease, stroke, type 2 diabetes, and five categories of cancers. Results. Between 2000 and 2012, the average intake of fruit of the SA adult population (≥25 years) declined by 7%, from 48.5 g/d (95% uncertainty interval (UI) 46.6 - 50.5) to 45.2 g/d (95% UI 42.7 - 47.6). Vegetable intake declined by 25%, from 146.9 g/d (95% UI 142.3 - 151.8) to 110.5 g/d (95% UI 105.9 - 115.0). In 2012, these consumption patterns are estimated to have caused 26 423 deaths (95% UI 24 368 - 28 006), amounting to 5.0% (95% UI 4.6 - 5.3%) of all deaths in SA, and the loss of 514 823 (95% UI 473 508 - 544 803) healthy life years or 2.5% (95% UI 2.3 - 2.6%) of all DALYs. Cardiovascular disease comprised the largest proportion of the attributable burden, with 83% of deaths and 84% of DALYs. Age-standardised death rates were higher for males (145.1 deaths per 100 000; 95% UI 127.9 - 156.2) than for females (108.0 deaths per 100 000; 95% UI 96.2 - 118.1); in both sexes, rates were lower than those observed in 2000 (–9% and –12%, respectively). Conclusion. Despite the overall reduction in standardised death rates observed since 2000, the absolute burden of disease attributable to inadequate intake of fruit and vegetables in SA remains of significant concern. Effective interventions supported by legislation and policy are needed to reverse the declining trends in consumption observed in most age categories and to curb the associated burden

A model-based approach to estimating the prevalence of disease combinations in South Africa

Background: The development of strategies to better detect and manage patients with multiple long-term conditions requires estimates of the most prevalent condition combinations. However, standard meta-analysis tools are not well suited to synthesising heterogeneous multimorbidity data. Methods: We developed a statistical model to synthesise data on associations between diseases and nationally representative prevalence estimates and applied the model to South Africa. Published and unpublished data were reviewed, and meta-regression analysis was conducted to assess pairwise associations between 10 conditions: arthritis, asthma, chronic obstructive pulmonary disease (COPD), depression, diabetes, HIV, hypertension, ischaemic heart disease (IHD), stroke and tuberculosis. The national prevalence of each condition in individuals aged 15 and older was then independently estimated, and these estimates were integrated with the ORs from the meta-regressions in a statistical model, to estimate the national prevalence of n a statistical model, to estimate the national prevalence of each condition combination. Results: The strongest disease associations in South Africa are between COPD and asthma (OR 14.6, 95% CI 10.3 to 19.9), COPD and IHD (OR 9.2, 95% CI 8.3 to 10.2) and IHD and stroke (OR 7.2, 95% CI 5.9 to 8.4). The most prevalent condition combinations in individuals aged 15+ are hypertension and arthritis (7.6%, 95% CI 5.8% to 9.5%), hypertension and diabetes (7.5%, 95% CI 6.4% to 8.6%) and hypertension and HIV (4.8%, 95% CI 3.3% to 6.6%). The average numbers of comorbidities are greatest in the case of COPD (2.3, 95% CI 2.1 to 2.6), stroke (2.1, 95% CI 1.8 to 2.4) and IHD (1.9, 95% CI 1.6 to 2.2). Conclusion: South Africa has high levels of HIV, hypertension, diabetes and arthritis, by international standards, and these are reflected in the most prevalent condition combinations. However, less prevalent conditions such as COPD, stroke and IHD contribute disproportionately to the multimorbidity burden, with high rates of comorbidity. This modelling approach can be used in other settings to characterise the most important disease combinations and levels of comorbidity

Estimating the changing burden of disease attributable to high sodium intake in South Africa for 2000, 2006 and 2012

Background. Elevated sodium consumption is associated with increased blood pressure, a major risk factor for cardiovascular and chronic kidney disease. Objectives. To quantify the deaths and disability-adjusted life years (DALYs) attributed to high sodium intake in persons aged ≥25 years in South Africa (SA) for 2000, 2006 and 2012. Methods. Comparative risk assessment (CRA) methodology was used and population attributable fractions (PAFs) of high sodium intake, mediated through high blood pressure (BP), for cardiovascular and chronic kidney disease were estimated. This was done by taking the difference between the PAF for elevated systolic BP (SBP) based on the estimated SBP level in the population and the PAF based on the estimated SBP that would result if sodium intake levels were reduced to the theoretical minimum risk exposure level (1 g/day) according to population group and hypertension categories. A meta-regression based on data from nine national surveys conducted between 1998 and 2017 was used to estimate the prevalence of hypertension by age, sex and population group. Relative risks identified from international literature were used and the difference in PAFs was applied to local burden estimates from the second South African National Burden of Disease Study. Age-standardised rates were calculated using World Health Organization (WHO) standard population weights. The attributable burden was also estimated for 2012 using an alternative target of 2 g/day proposed in the National Strategic Plan for the Prevention and Control of Non-communicable Diseases (NSP). Results. High sodium intake as mediated through high SBP was estimated to cause 8 071 (95% uncertainty interval (UI) 6 542 - 15 474) deaths in 2012, a drop from 9 574 (95% UI 8 158 - 16 526) in 2006 and 8 431 (95% UI 6 972 - 14 511) in 2000. In 2012, ischaemic heart disease caused the highest number of deaths in persons (n=1 832), followed by haemorrhagic stroke (n=1 771), ischaemic stroke (n=1 484) and then hypertensive heart disease (n=1 230). Ischaemic heart disease was the highest contributor to deaths for males (27%), whereas for females it was haemorrhagic stroke (23%). In 2012, 1.5% (95% UI 1.3 - 2.9) of total deaths and 0.7% (95% UI 0.6 - 1.2) of total DALYs were attributed to high sodium intake. If the NSP target of <2 g/day sodium intake had been achieved in 2012, ~2 943 deaths and 48 870 DALYs would have been averted. Conclusion. Despite a slight decreasing trend since 2006, high sodium intake mediated through raised BP accounted for a sizeable burden of disease in 2012. Realising SA’s target to reduce sodium intake remains a priority, and progress requires systematic monitoring and evaluation

Estimating the burden of disease attributable to household air pollution from cooking with solid fuels in South Africa for 2000, 2006 and 2012

Background. Household air pollution (HAP) due to the use of solid fuels for cooking is a global problem with significant impacts on human health, especially in low- and middle-income countries. HAP remains problematic in South Africa (SA). While electrification rates have improved over the past two decades, many people still use solid fuels for cooking owing to energy poverty. Objectives. To estimate the disease burden attributable to HAP for cooking in SA over three time points: 2000, 2006 and 2012. Methods. Comparative risk assessment methodology was used. The proportion of South Africans exposed to HAP was assessed and assigned the estimated concentration of particulate matter with a diameter <2.5 μg/m3 (PM2.5) associated with HAP exposure. Health outcomes and relative risks associated with HAP exposure were identified. Population-attributable fractions and the attributable burden of disease due to HAP exposure (deaths, years of life lost, years lived with disability and disability-adjusted life years (DALYs)) for SA were calculated. Attributable burden was estimated for 2000, 2006 and 2012. For the year 2012, we estimated the attributable burden at provincial level. Results. An estimated 17.6% of the SA population was exposed to HAP in 2012. In 2012, HAP exposure was estimated to have caused 8 862 deaths (95% uncertainty interval (UI) 8 413 - 9 251) and 1.7% (95% UI 1.6% - 1.8%) of all deaths in SA, respectively. Loss of healthy life years comprised 208 816 DALYs (95% UI 195 648 - 221 007) and 1.0% of all DALYs (95% UI 0.95% - 1.0%) in 2012, respectively. Lower respiratory infections and cardiovascular disease contributed to the largest proportion of deaths and DALYs. HAP exposure due to cooking varied across provinces, and was highest in Limpopo (50.0%), Mpumalanga (27.4%) and KwaZulu-Natal (26.4%) provinces in 2012. Age standardised burden measures showed that these three provinces had the highest rates of death and DALY burden attributable to HAP. Conclusion. The burden of disease from HAP due to cooking in SA is of significant concern. Effective interventions supported by legislation and policy, together with awareness campaigns, are needed to ensure access to clean household fuels and improved cook stoves. Continued and enhanced efforts in this regard are required to ensure the burden of disease from HAP is curbed in SA

Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants.

Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus remains largely unclarified. We performed size-fractionated aerosol sampling (Andersen cascade impactor) and evaluated viral culturability in human cell lines (infectiousness), viral genetics, and host immunity in ambulatory participants with COVID-19. Sixty-one percent (27/44) and 50% (22/44) of participants emitted variant-specific culture-positive aerosols &lt;10μm and &lt;5μm, respectively, for up to 9 days after symptom onset. Aerosol culturability is significantly associated with lower neutralizing antibody titers, and suppression of transcriptomic pathways related to innate immunity and the humoral response. A nasopharyngeal Ct &lt;17 rules-in ~40% of aerosol culture-positives and identifies those who are probably highly infectious. A parsimonious three transcript blood-based biosignature is highly predictive of infectious aerosol generation (PPV &gt; 95%). There is considerable heterogeneity in potential infectiousness i.e., only 29% of participants were probably highly infectious (produced culture-positive aerosols &lt;5μm at ~6 days after symptom onset). These data, which comprehensively confirm variant-specific culturable SARS-CoV-2 in aerosol, inform the targeting of transmission-related interventions and public health containment strategies emphasizing improved ventilation

Estimating the changing disease burden attributable to iron deficiency in South Africa, 2000, 2006 and 2012

Background. Worldwide, iron deficiency, and consequent iron-deficiency anaemia, remains the most common nutritional disorder. Iron-deficiency anaemia mostly affects young children and women of reproductive age, especially in Asia and Africa. Iron deficiency may contribute to disability directly or indirectly as a risk factor for other causes of death, and may rarely contribute to death. Objectives. To estimate the changing burden of disease attributable to iron deficiency in males and females (all ages) for the years 2000, 2006 and 2012 in South Africa (SA). Methods. The comparative risk assessment methodology developed by the World Health Organization (WHO) and the Global Burden of Diseases, Injuries, and Risk Factors Studies was used to estimate the burden attributable to iron deficiency in SA for the years 2000, 2006 and 2012. We attributed 100% of the estimated iron-deficiency anaemia burden across all age groups by sex to iron deficiency. For maternal conditions, the attributable burden to iron deficiency was calculated using the counterfactual method and applied to all women of reproductive age. The population attributable fraction calculated for these selected health outcomes was then applied to local burden estimates from the Second SA National Burden of Disease Study (SANBD2). Age-standardised rates were calculated using WHO world standard population weights and SA mid-year population estimates. Results. There was a slight decrease in the prevalence of iron-deficiency anaemia in women of reproductive age from ~11.9% in 2000 to 10.0% in 2012, although the prevalence of anaemia fluctuated over time (25.5% - 33.2%), with a peak in 2006. There has been a gradual decline in the number of deaths from maternal conditions attributable to iron deficiency in SA between 2000 (351 deaths (95% uncertainty interval (UI) 248 - 436)) and 2012 (307 deaths (95% UI 118 - 470)), with a peak in 2006 (452 deaths (95% UI 301 - 589)). Furthermore, our analysis showed a 26% decrease between 2000 and 2012 in the age-standardised burden rates from maternal conditions (truncated to 15 - 49 years) attributable to iron deficiency. Between 2000 and 2012, the age-standardised disability-adjusted life year (DALY) rate from iron-deficiency anaemia attributable to iron deficiency markedly decreased by 33% in males, and increased by 3% in females of all ages. Approximately 1.1 - 1.4% of all DALYs in SA from 2000 to 2012 were attributable to iron deficiency. Conclusion. Iron-deficiency anaemia prevalence can be markedly reduced if iron deficiency is eliminated. Hence it is essential to encourage, reappraise and strengthen the measures that have been put in place to address iron deficiency, especially in women of reproductive age and children