Estimating the burden of disease attributable to four selected environmental risk factors in South Africa

INTRODUCTION

The first South African National Burden of Disease study quantified the underlying causes of premature mortality and morbidity experienced in South Africa in the year 2000. This was followed by a Comparative Risk Assessment to estimate the contributions of 17 selected risk factors to burden of disease in South Africa. This paper describes the health impact of exposure to four selected environmental risk factors: unsafe water, sanitation and hygiene; indoor air pollution from household use of solid fuels; urban outdoor air pollution and lead exposure.

METHODS

The study followed World Health Organization comparative risk assessment methodology. Population-attributable fractions were calculated and applied to revised burden of disease estimates (deaths and disability adjusted life years, [DALYs]) from the South African Burden of Disease study to obtain the attributable burden for each selected risk factor. The burden attributable to the joint effect of the four environmental risk factors was also estimated taking into account competing risks and common pathways. Monte Carlo simulation-modeling techniques were used to quantify sampling, uncertainty.

RESULTS

Almost 24 000 deaths were attributable to the joint effect of these four environmental risk factors, accounting for 4.6% (95% uncertainty interval 3.8-5.3%) of all deaths in South Africa in 2000. Overall the burden due to these environmental risks was equivalent to 3.7% (95% uncertainty interval 3.4-4.0%) of the total disease burden for South Africa, with unsafe water sanitation and hygiene the main contributor to joint burden. The joint attributable burden was especially high in children under 5 years of age, accounting for 10.8% of total deaths in this age group and 9.7% of burden of disease.

CONCLUSION

This study highlights the public health impact of exposure to environmental risks and the significant burden of preventable disease attributable to exposure to these four major environmental risk factors in South Africa. Evidence-based policies and programs must be developed and implemented to address these risk factors at individual, household, and community levels.

How far does screening women for domestic (partner) violence in different health-care settings meet criteria for a screening programme? Systematic reviews of nine UK National Screening Committee criteria

OBJECTIVES

The two objectives were: (1) to identify, appraise and synthesise research that is relevant to selected UK National Screening Committee (NSC) criteria for a screening programme in relation to partner violence; and (2) to judge whether current evidence fulfils selected NSC criteria for the implementation of screening for partner violence in health-care settings.

DATA SOURCES

Fourteen electronic databases from their respective start dates to 31 December 2006.

REVIEW METHODS

The review examined seven questions linked to key NSC criteria: QI: What is the prevalence of partner violence against women and what are its health consequences? QII: Are screening tools valid and reliable? QIII: Is screening for partner violence acceptable to women? QIV: Are interventions effective once partner violence is disclosed in a health-care setting? QV: Can mortality or morbidity be reduced following screening? QVI: Is a partner violence screening programme acceptable to health professionals and the public? QVII: Is screening for partner violence cost-effective? Data were selected using different inclusion/exclusion criteria for the seven review questions. The quality of the primary studies was assessed using published appraisal tools. We grouped the findings of the surveys, diagnostic accuracy and intervention studies, and qualitatively analysed differences between outcomes in relation to study quality, setting, populations and, where applicable, the nature of the intervention. We systematically considered each of the selected NSC criteria against the review evidence.

RESULTS

The lifetime prevalence of partner violence against women in the general UK population ranged from 13% to 31%, and in clinical populations it was 13-35%. The 1-year prevalence ranged from 4.2% to 6% in the general population. This showed that partner violence against women is a major public health problem and potentially appropriate for screening and intervention. The HITS (Hurts, Insults, Threatens and Screams) scale was the best of several short screening tools for use in health-care settings. Most women patients considered screening acceptable (range 35-99%), although they identified potential harms. The evidence for effectiveness of advocacy is growing, and psychological interventions may be effective, but not necessarily for women identified through screening. No trials of screening programmes measured morbidity and mortality. The acceptability of partner violence screening among health-care professionals ranged from 15% to 95%, and the NSC criterion was not met. There were no cost-effectiveness studies, but a Markov model of a pilot intervention to increase identification of survivors of partner violence in general practice found that such an intervention was potentially cost-effective.

CONCLUSIONS

Currently there is insufficient evidence to implement a screening programme for partner violence against women either in health services generally or in specific clinical settings. Recommendations for further research include: trials of system-level interventions and of psychological and advocacy interventions; trials to test theoretically explicit interventions to help understand what works for whom, when and in what contexts; qualitative studies exploring what women want from interventions; cohort studies measuring risk factors, resilience factors and the lifetime trajectory of partner violence; and longitudinal studies measuring the long-term prognosis for survivors of partner violence.

Poverty and non-communicable diseases in South Africa

BACKGROUND

High levels of wealth inequality with improved health statistics in South Africa (SA) provide an important opportunity to investigate non-communicable diseases (NCDs) among the poor.

AIMS

This paper uses two distinct national data sets to contrast patterns of mortality in rich and poor areas and explore the associations between poverty, risk factors, health care and selected NCDs diseases in South African adults.

METHODS

Causes of premature mortality in 1996 experienced in the poorest magisterial districts are compared with those in the richest, using average household wealth to classify districts. Logistic and multinomial regression are used to investigate the association of a household asset index and selected chronic conditions, related risk factors and healthcare indicators using data from the 1998 South African Demographic and Health Survey.

RESULTS

NCDs accounted for 39% and 33% of premature mortality in rich and poor districts respectively. The household survey data showed that the risk factors hypertension and obesity increased with increasing wealth, while most of the lifestyle factors, such as light smoking, domestic exposure to ;;smoky'' fuels and alcohol dependence were associated with poverty. Treatment status for hypertension and asthma was worse for poor people than for rich people.

CONCLUSIONS

The study suggests that NCDs and lifestyle-related risk factors are prevalent among the poor in SA and treatment for chronic diseases is lacking for poor people. The observed increase in hypertension and obesity with wealth suggests that unless comprehensive health promotion strategies are implemented, there will be an unmanageable chronic disease epidemic with future socioeconomic development in SA.

Factors influencing relapse during a 2-year follow-up of first-episode psychosis in a specialized early intervention service

BACKGROUND

Differential association of risk factors associated with relapse following treatment of first-episode psychosis (FEP) have not been studied adequately, especially for patients treated in specialized early intervention (SEI) services, where some of the usual risk factors may be ameliorated.

METHOD

Consecutive FEP patients treated in an SEI service over a 4-year period were evaluated for relapse during a 2-year follow-up. Relapse was based on ratings on the Scale for Assessment of Positive Symptoms (SAPS) and weekly ratings based on the Life Chart Schedule (LCS). Predictor variables included gender, duration of untreated psychosis (DUP), total duration of untreated illness (DUI), age of onset, pre-morbid adjustment, co-morbid diagnosis of substance abuse during follow-up and adherence to medication. Univariate analyses were followed by logistic regression for rate of relapse and survival analysis with the Cox proportional-hazards regression model for time to relapse as the dependent variables.

RESULTS

Of the 189 eligible patients, 145 achieved remission of positive symptoms. A high rate of medication adherence (85%) and relatively low relapse rates (29.7%) were observed over the 2-year follow-up. A higher relapse rate was associated with a co-morbid diagnosis of substance abuse assessed during the follow-up period [odds ratio (OR) 2.84, 95% confidence interval (CI) 1.24-6.51]. The length of time to relapse was not associated with any single predictor.

CONCLUSIONS

Specialized treatment of substance abuse may be necessary to further reduce risk of relapse even after improving adherence to medication.

Long-term effects of a community intervention for early identification of first-episode psychosis

OBJECTIVE

To assess whether an Early Case Identification Program (ECIP) for first-episode psychosis (FEP), which showed no significant short-term effects, has a delayed impact on duration of untreated psychosis (DUP).

METHOD

Using a historical control design, FEP patients were assessed on clinical variables over three consecutive phases, 2 years prior, 2 years during and 3 years after implementation of the ECIP. Additional analyses were conducted on non-affective and schizophrenia spectrum psychoses cases only.

RESULTS

There was no overall significant difference in DUP across the three phases. For cases treated within the first year of illness a nonsignificant reduction in DUP to less than 2 months observed during the active phase was sustained post-ECIP.

CONCLUSION

In some jurisdictions community-wide early case detection may fail to have an immediate or delayed effect on DUP, especially for cases who normally present for treatment with DUP >1 year.

Determinants and treatment of hypertension in South Africans: the first Demographic and Health Survey

OBJECTIVES

To identify the groups of patients with high prevalence and poor control of hypertension in South Africa.

METHODS

In the first national Demographic and Health Survey, 12 952 randomly selected South Africans aged 15 years and older were surveyed. Trained interviewers completed questionnaires on socio-demographic characteristics, lifestyle and the management of hypertension. This cross-sectional survey included blood pressure, height and weight measurements. Logistic regression analyses identified the determinants of hypertension and the treatment status.

RESULTS

A high risk of hypertension was associated with less than tertiary education, older age groups, overweight and obese people, excess alcohol use, and a family history of stroke and hypertension. Hypertension risk was lowest in rural blacks and significantly higher in obese black women than in women with a normal body mass index. Improved hypertension control was found in the wealthy, women, older persons, Asians, and persons with medical insurance.

CONCLUSIONS

Rural black people had lower hypertension prevalence rates than the other groups. Poorer, younger men without health insurance had the worst level of hypertension control.

EEG abnormalities and 3-year outcome in first episode psychosis

OBJECTIVE

This study assesses the relationship of EEG to several aspects of 3 year symptomatic and functional outcome in first episode psychosis.

METHOD

A total of 117 patients with first episode psychosis had their baseline EEG classified by modified Mayo Clinic criteria as normal, essentially normal or dysrhythmia. Socio-demographic variables, duration of illness and of untreated psychosis and premorbid adjustment were also recorded. Positive and negative symptoms of psychoses, depression, anxiety and global functioning were rated on entry and after 3 years of treatment.

RESULTS

Patients with a dysrhythmic EEG at entry into treatment showed significantly greater persistence in both positive and negative symptoms of psychoses as well as anxiety and depression over 3 years. These findings were independent of duration of untreated illness or premorbid adjustment.

CONCLUSION

An abnormal baseline EEG in patients with first episode psychosis is associated with a poorer symptomatic outcome at 3-year follow-up.

415. Increased expression of an androgen receptor regulated gene, kit ligand, in polycystic ovaries

Polycystic ovaries (PCO) are induced by pathological or pharmacological female androgen excess, but the role of the androgen receptor (AR) in the pathogenesis of PCO is unknown. We therefore tested the hypothesis that PCO have increased expression of AR or kit ligand (KITL), a cytokine that was recently identified as a candidate AR-regulated gene in the ovary (1). Immunohistochemical analysis of AR and KITL expression was performed on archival paraffin-embedded sections of 8 morphologically normal and 8 polycystic ovaries from women under the age of 40 years. Stained sections were scanned with a NanoZoomer Digital Pathology System and immunoreactivity was qualitatively assessed using a 0-3+ scale, where 3+ represents the most intense staining. Electronic images of follicles at different stages of folliculogenesis were assessed by two independent observers who were blinded to the morphology of the source ovary. Each individual ovary contributed a minimum of 1 follicle per size class and a minimum of 10 follicles per size class were analysed. AR immunoreactivity was present in granulosa cells at all stages of folliculogenesis, in thecal cells of large antral follicles, and in the ovarian stroma. Staining intensity for AR did not differ between normal and polycystic ovaries. KITL expression, summarised in Table 1, was found to be significantly elevated in the oocytes of primordial and primary follicles and in the granulosa cells of follicles at all stages of folliculogenesis. These results show that AR expression is normal in PCO but expression of an AR-regulated gene is increased, potentially due to an excess of androgen hormone that is characteristic of women with PCO. Based on the roles of KITL established by murine studies, increased expression of KITL could explain many of the features of PCO including follicle excess, hyperthecosis and abnormal androgen secretion.

The high burden of injuries in South Africa

OBJECTIVE

To estimate the magnitude and characteristics of the injury burden in South Africa within a global context.

METHODS

The Actuarial Society of South Africa demographic and AIDS model (ASSA 2002) - calibrated to survey, census and adjusted vital registration data - was used to calculate the total number of deaths in 2000. Causes of death were determined from the National Injury Mortality Surveillance System profile. Injury death rates and years of life lost (YLL) were estimated using the Global Burden of Disease methodology. National years lived with disability (YLDs) were calculated by applying a ratio between YLLs and YLDs found in a local injury data source, the Cape Metropole Study. Mortality and disability-adjusted life years' (DALYs) rates were compared with African and global estimates.

FINDINGS

Interpersonal violence dominated the South African injury profile with age-standardized mortality rates at seven times the global rate. Injuries were the second-leading cause of loss of healthy life, accounting for 14.3% of all DALYs in South Africa in 2000. Road traffic injuries (RTIs) are the leading cause of injury in most regions of the world but South Africa has exceedingly high numbers - double the global rate.

CONCLUSION

Injuries are an important public health issue in South Africa. Social and economic determinants of violence, many a legacy of apartheid policies, must be addressed to reduce inequalities in society and build community cohesion. Multisectoral interventions to reduce traffic injuries are also needed. We highlight this heavy burden to stress the need for effective prevention programmes.

Estimating the burden of disease attributable to high cholesterol in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributable to high cholesterol in adults aged 30 years and older in South Africa in 2000.

DESIGN

World Health Organization comparative risk assessment (CRA) methodology was followed. Small community studies were used to derive the prevalence by population group. Population-attributable fractions were calculated and applied to revised burden of disease estimates for the relevant disease categories for each population group. The total attributable burden for South Africa in 2000 was obtained by adding the burden attributed to high cholesterol for the four population groups. Monte Carlo simulation-modelling techniques were used for uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Black African, coloured, white and Indian adults aged 30 years and older.

OUTCOME MEASURES

Mortality and disability-adjusted life years (DALYs) from ischaemic heart disease (IHD) and ischaemic stroke.

RESULTS

Overall, about 59% of IHD and 29% of ischaemic stroke burden in adult males and females (30+ years) were attributable to high cholesterol (>or= 3.8 mmol/l), with marked variation by population group. High cholesterol was estimated to have caused 24,144 deaths (95% uncertainty interval 22,404 - 25,286) or 4.6% (95% uncertainty interval 4.3 - 4.9%) of all deaths in South Africa in 2000. Since most cholesterol-related cardiovascular disease events occurred in middle or old age, the loss of life years comprised a smaller proportion of the total: 222,923 DALYs (95% uncertainty interval 206,712 - 233,460) or 1.4% of all DALYs (95% uncertainty interval 1.3 - 1.4%) in South Africa in 2000.

CONCLUSIONS

High cholesterol is an important cardiovascular risk factor in all population groups in South Africa.

Estimating the burden of disease attributable to vitamin A deficiency in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributable to vitamin A deficiency in children aged 0 - 4 years and pregnant women aged 15 - 49 years in South Africa in 2000.

DESIGN

The framework adopted for the most recent World Health Organization comparative risk assessment (CRA) methodology was followed. Population-attributable fractions were calculated from South African Vitamin A Consultative Group (SAVACG) survey data on the prevalence of vitamin A deficiency in children and the relative risks of associated health problems, applied to revised burden of disease estimates for South Africa in the year 2000. Small community studies were used to derive the prevalence in pregnant women. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Children under 5 years and pregnant women 15 - 49 years.

OUTCOME MEASURES

Direct sequelae of vitamin A deficiency, including disability-adjusted life years (DALYs), as well as mortality associated with measles, diarrhoeal diseases and other infections, and mortality and DALYs associated with malaria in children and all-cause maternal mortality.

RESULTS

One-third of children aged 0 - 4 years and 1 - 6% of pregnant women were vitamin A-deficient. Of deaths among young children aged 0 - 4 years in 2000, about 28% of those resulting from diarrhoeal diseases, 23% of those from measles, and 21% of those from malaria were attributed to vitamin A deficiency, accounting for some 3,000 deaths. Overall, about 110,467 ( 95% uncertainty interval 86,388 - 136,009) healthy years of life lost, or between 0.5% and 0.8% of all DALYs in South Africa in 2000 were attributable to vitamin A deficiency.

CONCLUSIONS

The vitamin A supplementation programme for children and the recent food fortification programme introduced in South Africa in 2003 should prevent future morbidity and mortality related to vitamin A deficiency. Monitoring the effectiveness of these interventions is strongly recommended.

Estimating the burden of disease attributable to smoking in South Africa in 2000

OBJECTIVES

To quantify the burden of disease attributable to smoking in South Africa for 2000.

DESIGN

The absolute difference between observed lung cancer death rate and the level in non-smokers, adjusted for occupational and indoor exposure to lung carcinogens, was used to estimate the proportion of lung cancer deaths attributable to smoking and the smoking impact ratio (SIR). The SIR was substituted for smoking prevalence in the attributable fraction formula for chronic obstructive pulmonary disease (COPD) and cancers to allow for the long lag between exposure and outcome. Assuming a shorter lag between exposure and disease, the current prevalence of smoking was used to estimate the population-attributable fractions (PAF) for the other outcomes. Relative risks (RR) from the American Cancer Society cancer prevention study (CPS-II) were used to calculate PAF.

SETTING

South Africa.

OUTCOME MEASURES

Deaths and disability-adjusted life years (DALYs) due to lung and other cancers, COPD, cardiovascular conditions, respiratory tuberculosis, and other respiratory and medical conditions.

RESULTS

Smoking caused between 41,632 and 46,656 deaths in South Africa, accounting for 8.0 - 9.0% of deaths and 3.7 - 4.3% of DALYs in 2000. Smoking ranked third (after unsafe sex/ sexually transmitted disease and high blood pressure) in terms of mortality among 17 risk factors evaluated. Three times as many males as females died from smoking. Lung cancer had the largest attributable fraction due to smoking. However, cardiovascular diseases accounted for the largest proportion of deaths attributed to smoking.

CONCLUSION

Cigarette smoking accounts for a large burden of preventable disease in South Africa. While the government has taken bold legislative action to discourage tobacco use since 1994, it still remains a major public health priority.

Estimating the burden of disease attributable to physical inactivity in South Africa in 2000

OBJECTIVES

To quantify the burden of disease attributable to physical inactivity in persons 15 years or older, by age group and sex, in South Africa for 2000.

DESIGN

The global comparative risk assessment (CRA) methodology of the World Health Organization was followed to estimate the disease burden attributable to physical inactivity. Levels of physical activity for South Africa were obtained from the World Health Survey 2003. A theoretical minimum risk exposure of zero, associated outcomes, relative risks, and revised burden of disease estimates were used to calculate population-attributable fractions and the burden attributed to physical inactivity. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Adults >or= 15 years.

OUTCOME MEASURES

Deaths and disability-adjusted life years (DALYs) from ischaemic heart disease, ischaemic stroke, breast cancer, colon cancer, and type 2 diabetes mellitus.

RESULTS

Overall in adults >or= 15 years in 2000, 30% of ischaemic heart disease, 27% of colon cancer, 22% of ischaemic stroke, 20% of type 2 diabetes, and 17% of breast cancer were attributable to physical inactivity. Physical inactivity was estimated to have caused 17,037 (95% uncertainty interval 11,394 - 20,407), or 3.3% (95% uncertainty interval 2.2 - 3.9%) of all deaths in 2000, and 176,252 (95% uncertainty interval 133,733 - 203,628) DALYs, or 1.1% (95% uncertainty interval 0.8 - 1.3%) of all DALYs in 2000.

CONCLUSIONS

Compared with other regions and the global average, South African adults have a particularly high prevalence of physical inactivity. In terms of attributable deaths, physical inactivity ranked 9th compared with other risk factors, and 12th in terms of DALYs. There is a clear need to assess why South Africans are particularly inactive, and to ensure that physical activity/inactivity is addressed as a national health priority.

Estimating the burden of disease attributable to unsafe water and lack of sanitation and hygiene in South Africa in 2000

OBJECTIVES

to estimate the burden of disease attributable to unsafe water, sanitation and hygiene (wsh) by age group for South Africa in 2000.

DESIGN

World Health Organization comparative risk assessment methodology was used to estimate the disease burden attributable to an exposure by comparing the observed risk factor distribution with a theoretical lowest possible population distribution. A scenario-based approach was applied for estimating diarrhoeal disease burden from unsafe WSH. Six exposure scenarios were defined based on the type of water and sanitation infrastructure and environmental faecal-oral pathogen load. For 'intestinal parasites' and schistosomiasis, the burden was assumed to be 100% attributable to exposure to unsafe WSH.

SETTING

South Africa.

OUTCOME MEASURES

Disease burden from diarrhoeal diseases, intestinal parasites and schistosomiasis, measured by deaths and disability-adjusted life years (DALYs).

RESULTS

13,434 deaths were attributable to unsafe WSH accounting for 2.6% (95% uncertainty interval 2.4 - 2.7%) of all deaths in South Africa in 2000. The burden was especially high in children under 5 years, accounting for 9.3% of total deaths in this age group and 7.4% of burden of disease. Overall, the burden due to unsafe WSH was equivalent to 2.6% (95% uncertainty interval 2.5 - 2.7%) of the total disease burden for South Africa, ranking this risk factor seventh for the country.

CONCLUSIONS

Unsafe WSH remains an important risk factor for disease in South Africa, especially in children under 5. High priority needs to be given to the provision of safe and sustainable sanitation and water facilities and to promoting safe hygiene behaviours, particularly among children.

Estimating the burden of disease attributable to low fruit and vegetable intake in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributed to low fruit and vegetable intake by sex and age group in South Africa for the year 2000.

DESIGN

The analysis follows the World Health Organization comparative risk assessment (CRA) methodology. Population-attributable fractions were calculated from South African prevalence data from dietary surveys and applied to the revised South African burden of disease estimates for 2000. A theoretical maximum distribution of 600 g per day for fruit and vegetable intake was chosen. Monte Carlo simulation-modelling techniques were used for uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Adults >or= 15 years.

OUTCOME MEASURES

Mortality and disability-adjusted life years (DALYs), from ischaemic heart disease, ischaemic stroke, lung cancer, gastric cancer, colorectal cancer and oesophageal cancer.

RESULTS

Low fruit and vegetable intake accounted for 3.2% of total deaths and 1.1% of the 16.2 million attributable DALYs. For both males and females the largest proportion of total years of healthy life lost attributed to low fruit and vegetable intake was for ischaemic heart disease (60.6% and 52.2%, respectively). Ischaemic stroke accounted for 17.8% of attributable DALYs for males and 32.7% for females. For the related cancers, the leading attributable DALYs for men and women were oesophageal cancer (9.8% and 7.0%, respectively) and lung cancer (7.8% and 4.7%, respectively).

CONCLUSIONS

A high intake of fruit and vegetables can make a significant contribution to decreasing mortality from certain diseases. The challenge lies in creating the environment that facilitates changes in dietary habits such as the increased intake of fruit and vegetables.

Estimating the burden of disease attributable to alcohol use in South Africa in 2000

OBJECTIVES

To make quantitative estimates of the burden of disease attributable to alcohol use by sex and age group in South Africa in 2000.

DESIGN

The analysis follows the World Health Organization comparative risk assessment (CRA) methodology. Population-attributable fractions (PAFs) calculated from modelled prevalence estimates and relative risks based on the global review were applied to the burden of disease estimates from the revised South African National Burden of Disease study for 2000. The alcohol-attributable fractions for injuries were directly determined from blood alcohol concentrations (BAC > 0.05 g/100 ml) at the time of injury. Monte Carlo simulation-modelling techniques were used to quantify uncertainty in the estimates.

SETTING

South Africa.

SUBJECTS

Adults >or= 15 years.

OUTCOME MEASURES

Deaths and disability-adjusted life years (DALYs) from ischaemic heart disease, stroke, hypertensive disease, diabetes, certain cancers, liver cirrhosis, epilepsy, alcohol use disorder, depression and intentional and unintentional injuries as well as burden from fetal alcohol syndrome (FAS) and low birth weight.

RESULTS

Alcohol harm accounted for an estimated 7.1% (95% uncertainty interval 6.6 - 7.5%) of all deaths and 7.0% (95% uncertainty interval 6.6 - 7.4%) of total DALYs in 2000. Injuries and cardiovascular incidents ranked first and second in terms of attributable deaths. Top rankings for overall attributable burden were interpersonal violence (39.0%), neuropsychiatric conditions (18.4%) and road traffic injuries (14.3%). Interpersonal violence accounted for 42.8% of the injury DALYs attributed to alcohol in males and 25.9% in females. In terms of alcohol-attributable disability, alcohol use disorders ranked first (44.6%), interpersonal violence second (23.2%), and FAS third (18.1%).

CONCLUSIONS

Particular attention needs to be given to preventing and reducing the burden of alcohol-related homicide and violence, alcohol-related road traffic accidents, alcohol use disorders, and FAS. Multilevel interventions are required to target high-risk drinkers, in addition to creating awareness in the general population of the problems associated with alcohol abuse.

Estimating the burden of disease attributable to childhood and maternal undernutrition in South Africa in 2000

OBJECTIVES

To estimate the disease burden attributable to being underweight as an indicator of undernutrition in children under 5 years of age and in pregnant women for the year 2000.

DESIGN

World Health Organization comparative risk assessment (CRA) methodology was followed. The 1999 National Food Consumption Survey prevalence of underweight classified in three low weight-for-age categories was compared with standard growth charts to estimate population-attributable fractions for mortality and morbidity outcomes, based on increased risk for each category and applied to revised burden of disease estimates for South Africa in 2000. Maternal underweight, leading to an increased risk of intra-uterine growth retardation and further risk of low birth weight (LBW), was also assessed using the approach adopted by the global assessment. Monte Carlo simulation-modeling techniques were used for the uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Children under 5 years of age and pregnant women.

OUTCOME MEASURES

Mortality and disability-adjusted life years (DALYs) from protein- energy malnutrition and a fraction of those from diarrhoeal disease, pneumonia, malaria, other non- HIV/AIDS infectious and parasitic conditions in children aged 0 - 4 years, and LBW.

RESULTS

Among children under 5 years, 11.8% were underweight. In the same age group, 11,808 deaths (95% uncertainty interval 11,100 - 12,642) or 12.3% (95% uncertainty interval 11.5 - 13.1%) were attributable to being underweight. Protein-energy malnutrition contributed 44.7% and diarrhoeal disease 29.6% of the total attributable burden. Childhood and maternal underweight accounted for 2.7% (95% uncertainty interval 2.6 - 2.9%) of all DALYs in South Africa in 2000 and 10.8% (95% uncertainty interval 10.2 - 11.5%) of DALYs in children under 5.

CONCLUSIONS

The study shows that reduction of the occurrence of underweight would have a substantial impact on child mortality, and also highlights the need to monitor this important indicator of child health.

Estimating the burden of disease attributable to lead exposure in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributable to lead exposure in South Africa in 2000.

DESIGN

World Health Organization comparative risk assessment (CRA) methodology was followed. Recent community studies were used to derive mean blood lead concentrations in adults and children in urban and rural areas. Population-attributable fractions were calculated and applied to revised burden of disease estimates for the relevant disease categories for South Africa in the year 2000. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Children under 5 and adults 30 years and older.

OUTCOME MEASURES

Cardiovascular mortality and disability-adjusted life years (DALYs) in adults 30 years and older and mild mental disability DALYs in children under 5 years.

RESULTS

Lead exposure was estimated to cause 1,428 deaths (95% uncertainty interval 1,086-1,772) or 0.27% (95% uncertainty interval: 0.21 - 0.34%) of all deaths in South Africa in 2000. Burden of disease attributed to lead exposure was dominated by mild mental disability in young children, accounting for 75% of the total 58,939 (95% uncertainty interval 55,413 - 62,500) attributable DALYs. Cardiovascular disease in adults accounted for the remainder of the burden.

CONCLUSIONS

Even with the phasing out of leaded petrol, exposure to lead from its ongoing addition to paint, para-occupational exposure and its use in backyard 'cottage industries' will continue to be an important public health hazard in South Africa for decades. Young children, especially those from disadvantaged communities, remain particularly vulnerable to lead exposure and poisoning.

Estimating the burden of disease attributable to high blood pressure in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributable to high blood pressure (BP) in adults aged 30 years and older in South Africa in 2000.

DESIGN

World Health Organization comparative risk assessment (CRA) methodology was followed. Mean systolic BP (SBP) estimates by age and sex were obtained from the 1998 South African Demographic and Health Survey adult data. Population-attributable fractions were calculated and applied to revised burden of disease estimates for the relevant disease categories for South Africa in 2000. Monte Carlo simulation-modelling techniques were used for uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Adults aged 30 years and older.

OUTCOME MEASURES

Mortality and disability-adjusted life years (DALYs) from ischaemic heart disease (IHD), stroke, hypertensive disease and other cardiovascular disease (CVD).

RESULTS

High BP was estimated to have caused 46,888 deaths (95% uncertainty interval 44,878 - 48,566) or 9% (95% uncertainty interval 8.6 - 9.3%) of all deaths in South Africa in 2000, and 390,860 DALYs (95% uncertainty interval 377,955 - 402,256) or 2.4% of all DALYs (95% uncertainty interval 2.3 - 2.5%) in South Africa in 2000. Overall, 50% of stroke, 42% of IHD, 72% of hypertensive disease and 22% of other CVD burden in adult males and females (30+ years) were attributable to high BP (systolic BP >or= 115 mmHg).

CONCLUSIONS

High BP contributes to a considerable burden of CVD in South Africa and results indicate that there is considerable potential for health gain from implementing BP-lowering interventions that are known to be highly costeffective.

Estimating the burden of disease attributable to urban outdoor air pollution in South Africa in 2000

OBJECTIVES

To quantify the mortality burden attributed to urban outdoor air pollution in South Africa in 2000.

DESIGN

The study followed comparative risk assessment (CRA) methodology developed by the World Heath Organization (WHO). In most urban areas, annual mean concentrations of particulate matter (PM) with diameters less than 10 microm (PM10) from monitoring network data and PM with diameters less than 2.5 microm (PM2.5) derived using a ratio method were weighted according to population size. PM(10) and PM(2.5) data from air-quality assessment studies in areas not covered by the network were also included. Population-attributable fractions calculated using risk coefficients presented in the WHO study were weighted by the proportion of the total population (33%) in urban environments, and applied to revised estimates of deaths and years of life lost (YLLs) for South Africa in 2000.

SETTING

South Africa.

SUBJECTS

Children under 5 years and adults 30 years and older.

OUTCOME MEASURES

Mortality and YLLs from lung cancer and cardiopulmonary disease in adults (30 years and older), and from acute respiratory infections (ARIs) in children aged 0 - 4 years.

RESULTS

Outdoor air pollution in urban areas in South Africa was estimated to cause 3.7% of the national mortality from cardiopulmonary disease and 5.1% of mortality attributable to cancers of the trachea, bronchus and lung in adults aged 30 years and older, and 1.1% of mortality from ARIs in children under 5 years of age. This amounts to 4,637 or 0.9% (95% uncertainty interval 0.3 - 1.5%) of all deaths and about 42,000 YLLs, or 0.4% (95% uncertainty interval 0.1 - 0.7%) of all YLLs in persons in South Africa in 2000.

CONCLUSION

Urban air pollution has under-recognised public health impacts in South Africa. Fossil fuel combustion emissions and traffic-related air pollution remain key targets for public health in South Africa.

Estimating the burden of disease attributable to diabetes in South Africa in 2000

OBJECTIVES

To estimate the burden of disease attributable to diabetes by sex and age group in South Africa in 2000.

DESIGN

The framework adopted for the most recent World Health Organization comparative risk assessment (CRA) methodology was followed. Small community studies used to derive the prevalence of diabetes by population group were weighted proportionately for a national estimate. Population-attributable fractions were calculated and applied to revised burden of disease estimates. Monte Carlo simulation-modelling techniques were used for uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Adults 30 years and older.

OUTCOME MEASURES

Mortality and disability-adjusted life years (DALYs) for ischaemic heart disease (IHD), stroke, hypertensive disease and renal failure.

RESULTS

Of South Africans aged >or= 30 years, 5.5% had diabetes which increased with age. Overall, about 14% of IHD, 10% of stroke, 12% of hypertensive disease and 12% of renal disease burden in adult males and females (30+ years) were attributable to diabetes. Diabetes was estimated to have caused 22,412 (95% uncertainty interval 20,755 - 24,872) or 4.3% (95% uncertainty interval 4.0 - 4.8%) of all deaths in South Africa in 2000. Since most of these occurred in middle or old age, the loss of healthy life years comprises a smaller proportion of the total 258,028 DALYs (95% uncertainty interval 236,856 - 290,849) in South Africa in 2000, accounting for 1.6% (95% uncertainty interval 1.5 - 1.8%) of the total burden.

CONCLUSIONS

Diabetes is an important direct and indirect cause of burden in South Africa. Primary prevention of the disease through multi-level interventions and improved management at primary health care level are needed.