Is the wealth index a proxy for consumption expenditure? A systematic review

BACKGROUND

Many epidemiological studies require a measure of socioeconomic position. The monetary measure preferred by economists is consumption expenditure; the wealth index has been proposed as a reliable, simple alternative to expenditure and is extensively used.

METHODS

A systematic review was conducted of the agreement between wealth indices and consumption expenditure, summarising the agreement and exploring factors affecting agreement.

RESULTS

Seventeen studies using 36 datasets met the inclusion criteria. Of these, 22 demonstrated weak agreement, 10 moderate agreement, and four strong agreement. There was some evidence that agreement is higher: in middle-income settings; in urban areas; for wealth indices with a greater number of indicators; and for wealth indices including a wider range of indicators.

CONCLUSIONS

The wealth index is mostly a poor proxy for consumption expenditure.

"They have opened our mouths": increasing women's skills and motivation for sexual communication with young people in rural South Africa

Communication between parents and young people about sex has been identified as a positive influence on young people's sexual behavior. This article presents findings from South Africa, where a social intervention to reduce levels of HIV and intimate partner violence actively promoted sexual communication between adults and young people. We assessed this component of the program using quantitative and qualitative methods, collecting data through surveys, direct observation, interviews, and focus group discussions. Women participating in intervention activities reported sexual communication with children significantly more often than matched women in the control group (80.3% vs. 49.4%, adjusted risk ratio 1.59 (1.31-1.93). The content of communication with young people also appears to have shifted from vague admonitions about the dangers of sex to concrete messages about reducing risks. The congruence between these findings and existing literature on parent-child sexual communication suggests that conceptual frameworks and programs from developed settings can be adapted effectively for resource-poor contexts.

The association between school attendance, HIV infection and sexual behaviour among young people in rural South Africa

OBJECTIVES

To investigate whether the prevalence of HIV infection among young people, and sexual behaviours associated with increased HIV risk, are differentially distributed between students and those not attending school or college.

DESIGN

A random population sample of unmarried young people (916 males, 1003 females) aged 14-25 years from rural South Africa in 2001.

METHODS

Data on school attendance and HIV risk characteristics came from structured face-to-face interviews. HIV serostatus was assessed by oral fluid ELISA. Logistic regression models specified HIV serostatus and high-risk behaviours as outcome variables. The primary exposure was school attendance. Models were adjusted for potential confounders.

RESULTS

HIV knowledge, communication about sex and HIV testing were similarly distributed among students and non-students. The lifetime number of partners was lower for students of both sexes (adjusted odds ratio (aOR) for more than three partners for men 0.67; 95% CI 0.44 to 1.00; aOR for more than two partners for women 0.69; 95% CI 0.46 to 1.04). Among young women, fewer students reported having partners more than three years older than themselves (aOR 0.58; 95% CI 0.37 to 0.92), having sex more than five times with a partner (aOR 0.57; 95% CI 0.37 to 0.87) and unprotected intercourse during the past year (aOR 0.60; 95% CI 0.40 to 0.91). Male students were less likely to be HIV positive than non-students (aOR 0.21; 95% CI 0.06 to 0.71).

CONCLUSIONS

Attending school was associated with lower-risk sexual behaviours and, among young men, lower HIV prevalence. Secondary school attendance may influence the structure of sexual networks and reduce HIV risk. Maximising school attendance may reduce HIV transmission among young people.

Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries

BACKGROUND

Epidemiological studies often require measures of socio-economic position (SEP). The application of principal components analysis (PCA) to data on asset-ownership is one popular approach to household SEP measurement. Proponents suggest that the approach provides a rational method for weighting asset data in a single indicator, captures the most important aspect of SEP for health studies, and is based on data that are readily available and/or simple to collect. However, the use of PCA on asset data may not be the best approach to SEP measurement. There remains concern that this approach can obscure the meaning of the final index and is statistically inappropriate for use with discrete data. In addition, the choice of assets to include and the level of agreement between wealth indices and more conventional measures of SEP such as consumption expenditure remain unclear. We discuss these issues, illustrating our examples with data from the Malawi Integrated Household Survey 2004-5.

METHODS

Wealth indices were constructed using the assets on which data are collected within Demographic and Health Surveys. Indices were constructed using five weighting methods: PCA, PCA using dichotomised versions of categorical variables, equal weights, weights equal to the inverse of the proportion of households owning the item, and Multiple Correspondence Analysis. Agreement between indices was assessed. Indices were compared with per capita consumption expenditure, and the difference in agreement assessed when different methods were used to adjust consumption expenditure for household size and composition.

RESULTS

All indices demonstrated similarly modest agreement with consumption expenditure. The indices constructed using dichotomised data showed strong agreement with each other, as did the indices constructed using categorical data. Agreement was lower between indices using data coded in different ways. The level of agreement between wealth indices and consumption expenditure did not differ when different consumption equivalence scales were applied.

CONCLUSION

This study questions the appropriateness of wealth indices as proxies for consumption expenditure. The choice of data included had a greater influence on the wealth index than the method used to weight the data. Despite the limitations of PCA, alternative methods also all had disadvantages.

Understanding the impact of a microfinance-based intervention on women's empowerment and the reduction of intimate partner violence in South Africa

OBJECTIVES

We sought to obtain evidence about the scope of women's empowerment and the mechanisms underlying the significant reduction in intimate partner violence documented by the Intervention With Microfinance for AIDS and Gender Equity (IMAGE) cluster-randomized trial in rural South Africa.

METHODS

The IMAGE intervention combined a microfinance program with participatory training on understanding HIV infection, gender norms, domestic violence, and sexuality. Outcome measures included past year's experience of intimate partner violence and 9 indicators of women's empowerment. Qualitative data about changes occurring within intimate relationships, loan groups, and the community were also collected.

RESULTS

After 2 years, the risk of past-year physical or sexual violence by an intimate partner was reduced by more than half (adjusted risk ratio=0.45; 95% confidence interval=0.23, 0.91). Improvements in all 9 indicators of empowerment were observed. Reductions in violence resulted from a range of responses enabling women to challenge the acceptability of violence, expect and receive better treatment from partners, leave abusive relationships, and raise public awareness about intimate partner violence.

CONCLUSIONS

Our findings, both qualitative and quantitative, indicate that economic and social empowerment of women can contribute to reductions in intimate partner violence.

Understanding the impact of a microfinance-based intervention on women's empowerment and the reduction of intimate partner violence in South Africa

OBJECTIVES

We sought to obtain evidence about the scope of women's empowerment and the mechanisms underlying the significant reduction in intimate partner violence documented by the Intervention With Microfinance for AIDS and Gender Equity (IMAGE) cluster-randomized trial in rural South Africa.

METHODS

The IMAGE intervention combined a microfinance program with participatory training on understanding HIV infection, gender norms, domestic violence, and sexuality. Outcome measures included past year's experience of intimate partner violence and 9 indicators of women's empowerment. Qualitative data about changes occurring within intimate relationships, loan groups, and the community were also collected.

RESULTS

After 2 years, the risk of past-year physical or sexual violence by an intimate partner was reduced by more than half (adjusted risk ratio=0.45; 95% confidence interval=0.23, 0.91). Improvements in all 9 indicators of empowerment were observed. Reductions in violence resulted from a range of responses enabling women to challenge the acceptability of violence, expect and receive better treatment from partners, leave abusive relationships, and raise public awareness about intimate partner violence.

CONCLUSIONS

Our findings, both qualitative and quantitative, indicate that economic and social empowerment of women can contribute to reductions in intimate partner violence.

Assessing household wealth in health studies in developing countries: a comparison of participatory wealth ranking and survey techniques from rural South Africa

BACKGROUND

Accurate tools for assessing household wealth are essential for many health studies in developing countries. Household survey and participatory wealth ranking (PWR) are two approaches to generate data for this purpose.

METHODS

A household survey and PWR were conducted among eight villages in rural South Africa. We developed three indicators of household wealth using the data. One indicator used PWR data only, one used principal components analysis to combine data from the survey, while the final indicator used survey data combined in a manner informed by the PWR. We assessed internal consistency of the indices and assessed their level of agreement in ranking household wealth.

RESULTS

Food security, asset ownership, housing quality and employment were important indicators of household wealth. PWR, consisting of three independent rankings of 9671 households, showed a high level of internal consistency (intraclass correlation coefficient 0.81, 95% CI 0.79-0.82). Data on 1429 households were available from all three techniques. There was moderate agreement in ranking households into wealth tertiles between the two indicators based on survey data (spearman rho = 0.69, kappa = 0.43), but only limited agreement between these techniques and the PWR data (spearman rho = 0.38 and 0.31, kappa = 0.20 and 0.17).

CONCLUSION

Both PWR and household survey can provide a rapid assessment of household wealth. Each technique had strengths and weaknesses. Reasons for differences might include data inaccuracies or limitations in the methods by which information was weighted. Alternatively, the techniques may measure different things. More research is needed to increase the validity of measures of socioeconomic position used in health studies in developing countries.

Effect of a structural intervention for the prevention of intimate-partner violence and HIV in rural South Africa: a cluster randomised trial

BACKGROUND

HIV infection and intimate-partner violence share a common risk environment in much of southern Africa. The aim of the Intervention with Microfinance for AIDS and Gender Equity (IMAGE) study was to assess a structural intervention that combined a microfinance programme with a gender and HIV training curriculum.

METHODS

Villages in the rural Limpopo province of South Africa were pair-matched and randomly allocated to receive the intervention at study onset (intervention group, n=4) or 3 years later (comparison group, n=4). Loans were provided to poor women who enrolled in the intervention group. A participatory learning and action curriculum was integrated into loan meetings, which took place every 2 weeks. Both arms of the trial were divided into three groups: direct programme participants or matched controls (cohort one), randomly selected 14-35-year-old household co-residents (cohort two), and randomly selected community members (cohort three). Primary outcomes were experience of intimate-partner violence--either physical or sexual--in the past 12 months by a spouse or other sexual intimate (cohort one), unprotected sexual intercourse at last occurrence with a non-spousal partner in the past 12 months (cohorts two and three), and HIV incidence (cohort three). Analyses were done on a per-protocol basis. This trial is registered with ClinicalTrials.gov, number NCT00242957.

FINDINGS

In cohort one, experience of intimate-partner violence was reduced by 55% (adjusted risk ratio [aRR] 0.45, 95% CI 0.23-0.91; adjusted risk difference -7.3%, -16.2 to 1.5). The intervention did not affect the rate of unprotected sexual intercourse with a non-spousal partner in cohort two (aRR 1.02, 0.85-1.23), and there was no effect on the rate of unprotected sexual intercourse at last occurrence with a non-spousal partner (0.89, 0.66-1.19) or HIV incidence (1.06, 0.66-1.69) in cohort three.

INTERPRETATION

A combined microfinance and training intervention can lead to reductions in levels of intimate-partner violence in programme participants. Social and economic development interventions have the potential to alter risk environments for HIV and intimate-partner violence in southern Africa.

Adherence to TB preventive therapy for HIV-positive patients in rural South Africa: implications for antiretroviral delivery in resource-poor settings?

OBJECTIVES

To explore patient and health worker perspectives on adherence to tuberculosis preventive therapy (TBPT), and to derive lessons for improving access to care amongst human immunodeficiency virus (HIV) infected individuals in resource-poor settings.

DESIGN

Both quantitative and qualitative methods were employed. Patient records were reviewed for HIV-positive individuals attending a hospital-based HIV clinic between January 2000 and March 2002. Eighteen patients and two health care workers underwent in-depth interviews exploring perspectives around adherence.

RESULTS

Of 229 HIV-positive clinic attendees, 94 (41.0%) were eligible for TBPT. Of 87 patients initiating a 6-month TBPT course of isoniazid 300 mg daily, 41 (47.1%) completed TBPT. Of the 46 interrupters, 16 (34.7%) did not return to the clinic after receiving their first dose of TBPT. Barriers to adherence included fear of stigmatization, lack of money for food and transport, the belief that HIV is incurable, competition between Western and traditional medicine, and a reluctance to take medication in the absence of symptoms. Disclosure of HIV status, social and family support, and a supportive clinic environment positively influenced adherence.

CONCLUSION

Interventions to improve the accessibility and quality of the care delivery system have the potential to support adherence to TBPT and other HIV care regimens, including antiretroviral therapy.

Childhood mortality among former Mozambican refugees and their hosts in rural South Africa

BACKGROUND

It is important to monitor health differentials between population groups to understand how they are generated. Internationally displaced people represent one potentially disadvantaged group. We investigated differentials in mortality between children from former Mozambican refugee and host South African households in a rural sub-district in the north-east of South Africa.

METHODS

Open prospective cohort of 30 276 children (80 462 person years of follow-up) followed from 1 January 1992 to 31 October 2000 in Limpopo Province, South Africa. Exposure and outcomes data came from the Agincourt Health and Demographic Surveillance System (DSS).

RESULTS

There was no difference in infant mortality between children from former Mozambican refugee households and those from South African homes (adjusted rate ratio [RR] = 1.02, 95% CI: 0.79, 1.32), but mortality levels were higher among former Mozambican refugee children during the next 4 years (adjusted RR = 1.91, 95% CI: 1.50, 2.42). Increased mortality levels were also seen among children from larger households and whose mother died, while children born to mothers aged >40 years or with higher education were at lower risk. Measured maternal, household, and health service utilization characteristics could not explain the difference in mortality between children from former Mozambican refugee and South African households. Former Mozambican refugee children residing in refugee settlements had higher mortality rates than those residing in more established villages.

CONCLUSIONS

This study demonstrates higher childhood, but not infant, mortality rates among children from former Mozambican refugee households compared with those from host South African households in rural South Africa. The lack of legal status and lower wealth of many former Mozambican refugees may partly explain this disparity.

Production of leucinostatins and nematicidal activity of Australian isolates of Paecilomyces lilacinus (Thom) Samson

AIMS

To evaluate the relationship between leucinostatin production by Paecilomyces lilacinus isolates and their biological activities.

METHODS AND RESULTS

The nematicidal, parasitic and enzymatic activity of Australian P. lilacinus isolates were investigated. Nematicidal activities of culture filtrates were measured by mortality and inhibition of reproduction of Caenorhabditis elegans, whereas egg-parasitic activity was measured by colonization on Meloidogyne javanica. Enzymatic activities (protease and chitinase) were assayed on solid media. The results suggest that leucinostatins in P. lilacinus are indicators of nematicidal activity, whereas chitinase activity might be related to parasitism.

CONCLUSIONS

Nematicidal activity of culture filtrates of Paecilomyces lilacinus strains related to their ability to produce leucinostatins.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study describing the leucinostatins as nematicides.

Undiagnosed pulmonary tuberculosis deaths in rural South Africa

This research explores death from pulmonary tuberculosis (PTB) using a verbal autopsy (VA) tool within the established Agincourt Health and Demographic Surveillance System site in South Africa's rural northeast. Previous work on active case finding in the area highlighted a modest burden of undiagnosed PTB in the community. This VA research confirms the existence of undiagnosed PTB deaths, with 13 (46%) of 28 PTB deaths among the permanent adult population (n = 38,251) going undetected by the health service. There was a median duration of coughing in the community of 16 weeks among these undiagnosed PTB deaths. As most undiagnosed cases present to the health service at some point during their illness, intervention strategies to support early diagnosis at this level can only be re-emphasised by this work.

Introduction of voluntary counselling and rapid testing for HIV in rural South Africa: from theory to practice

Expanding access to voluntary counselling and testing (VCT) for HIV is an important first step in the development of a comprehensive package of HIV services. This article describes the introduction of VCT among five primary health care (PHC) facilities in a rural South African setting, alongside a multidimensional impact assessment as part of a national pilot programme. A baseline review of services demonstrated low levels of VCT, which were predominantly hospital-based. Twenty health workers in five PHC facilities were trained to provide VCT using rapid-testing assays. The feasibility of VCT introduction and its overall acceptability to clients and providers were evaluated using clinic testing registers, semi-structured interviews with counsellors and mock client encounters. One year after its introduction, a major increase in the quantity of HIV testing, the proportion of clients who receive their results, and the proportion who present voluntarily was observed. The majority of those presenting were women, and 20-40 year olds predominated. There was a high level of acceptance among health workers, and the quality of VCT was rated very good in mock client encounters. This work demonstrates one effective model for improving access to VCT through existing primary health care services in a rural South African context.

Socioeconomic status and risk of HIV infection in an urban population in Kenya

OBJECTIVE

To examine the relationship between socioeconomic status (SES), risk factors for HIV infection and HIV status in an urban population with high prevalence of HIV infection in sub-Saharan Africa.

METHODS

Cross-sectional population survey of adults from the city of Kisumu, Kenya, in 1996. Around 1000 men and 1000 women aged 15-49 years were interviewed using a structured questionnaire, and most gave a venous blood sample for HIV testing. SES was represented by a composite variable of educational status, occupation and household utilities. Multiple regression was used to examine whether SES was associated with HIV infection or with risk factors for HIV infection.

RESULTS

Human immunodeficiency virus prevalence was 19.8% in males and 30.2% in females. Higher SES was associated with a more mobile lifestyle, later sexual debut and marriage among both sexes, and with circumcision among men aged 25-49 and condom use among women aged 25-49. Higher levels of alcohol consumption were associated with an increased risk of HIV infection and were more common amongst those of higher SES. HSV-2 infection was strongly associated with an increased risk of HIV infection and was more common among those of lower SES. HIV was associated with a lower SES among females aged 15-24 whereas in males aged 15-24 and females aged 25-49 there was some indication that it was associated with higher SES. Among males aged 25-49 there was no association between HIV infection and SES.

CONCLUSIONS

Risk of infection was high among groups of all SES. Risk profiles suggested men and women of lower SES maybe at greater risk of newly acquired HIV infection. New infections may now be occurring fastest among young women of the lowest SES.

Educational attainment and HIV-1 infection in developing countries: a systematic review

OBJECTIVES

To assess whether educational status is associated with HIV-1 infection in developing countries by conducting a systematic review of published literature.

METHODS

Articles were identified through electronic databases and hand searching key journals. Studies containing appropriately analysed individual level data on the association between educational attainment and HIV-1 status in general population groups were included.

RESULTS

Twenty-seven articles with appropriately analysed results from general population groups in developing countries were identified, providing information on only six countries. Large studies in four areas in Africa showed an increased risk of HIV-1 infection among the more educated, whilst among 21-year-old Thai army conscripts, longer duration of schooling was strongly protective against HIV infection. The association between education and schooling in Africa was stronger in rural areas and in older cohorts, but was similar in men and women. Serial prevalence studies showed little change in the association between schooling and HIV over time in Tanzania, but greater decreases in HIV prevalence among the more educated in Uganda, Zambia and Thailand.

CONCLUSIONS

In Africa, higher educational attainment is often associated with a greater risk of HIV infection. However, the pattern of new HIV infections may be changing towards a greater burden among less educated groups. In Thailand those with more schooling remain at lower risk of HIV infection.

Assessing health seeking behaviour among tuberculosis patients in rural South Africa

SETTING

South Africa's rural Northern Province.

OBJECTIVES

To examine patterns of health seeking behaviour among hospitalised tuberculosis patients.

DESIGN

Information on personal characteristics, health seeking behaviour and delays to presentation and hospitalisation was collected from hospitalised TB patients. Analysis of rates was used to investigate factors associated with delay.

RESULTS

Among 298 patients, median total delay to hospitalisation was 10 weeks, with patient delay contributing a greater proportion than service provider delay. Patients more often presented initially to public hospitals (41%) or clinics (31 %) than to spiritual/traditional healers (15%) or private GPs (13%). Total delay was shorter amongst those presenting to hospitals than those presenting to clinics (rate ratio 1.33, 95%CI 1.13-1.85), with a significantly smaller proportion of the total delay attributable to the health service provider (18% vs. 42%). Those exhibiting a conventional risk profile for TB (migrants, alcohol drinkers, history of TB) were diagnosed most quickly by health services, while women remained undiagnosed for longer.

CONCLUSION

Considerable delay exists between symptom onset and treatment initiation among pulmonary tuberculosis patients. While a substantial delay was attributable to late patient presentation, an important, preventable period of infectiousness was caused by the failure of recognised clinical services to diagnose tuberculosis among symptomatic individuals.

Active case finding: understanding the burden of tuberculosis in rural South Africa

SETTING

The Agincourt demographic and health surveillance site in South Africa's rural Northern Province.

OBJECTIVES

To accurately assess the true burden of tuberculosis in a rural sub-district with a known high prevalence of human immunodeficiency virus.

DESIGN

Data on hospital registrations of tuberculosis were combined with data from an ongoing demographic health and surveillance system to accurately describe the burden of tuberculosis in a well-defined community. Undiagnosed active cases of sputum-positive disease in the community were detected among chronic coughers identified by heads of household during a single-pass census interview.

RESULTS

The incidence of hospitalised tuberculosis among the permanently resident population (n = 56 566) was 212/100,000 person-years during 1999. The average point prevalence of detected tuberculosis (all forms) among patients aged over 10 years was 133/100,000, and 81/100,000 for sputum-positive pulmonary disease. This compares with a point prevalence of 16/100,000 cases of sputum-positive disease detected through active case finding.

CONCLUSION

For every nine cases of sputum positive pulmonary tuberculosis being treated at any one time, there are two cases of undiagnosed disease in the community. This study demonstrates a modest burden of undiagnosed tuberculosis among residents in a rural sub-district in South Africa.

Low molecular weight heparin for treatment of acute myocardial infarction (FAMI): Fragmin (dalteparin sodium) in acute myocardial infarction

The benefit of using subcutaneous low molecular weight heparin for the treatment of acute myocardial infarction is not known. The aim of this study was to determine the efficacy of a low molecular weight heparin (dalteparin sodium) for the treatment of acute myocardial infarction in patients not treated with thrombolytic therapy. Twenty-nine cardiological centres from leading hospitals in India participated in this prospective, multicentre, double-blind, placebo-controlled study in two phases which included 1128 patients with acute myocardial infarction. In the acute phase (between day 1 and 3 of admission) all the patients received a weight-adjusted dose of subcutaneous dalteparin (120 IU/kg twice daily). In the second, double-blind phase of acute myocardial infarction, patients were randomised to receive a fixed dose of dalteparin (7,500 IU) or an identical placebo injection for 30 days. A composite primary endpoint of death, reinfarction, recurrence of angina and emergency revascularisation was used. All the 1128 patients with acute myocardial infarction were included in the trial. In the acute phase, the composite primary endpoint was observed in 58 (5.1%) patients. Of 1037 paients who were randomly assigned to receive a fixed dose of dalteparin (n=519) or placebo (n=518), the composite primary event rate was 6.7 percent and 7.0 percent, respectively (RR 0.97; 95% CI 0.62-1.52; p=0.90). To conclude, treatment with dalteparin administered subcutaneously in a weight-adjusted dose of 120 IU/kg twice daily resulted in a lower than expected mortality during the acute phase of myocardial infarction. A lower fixed once daily dose of 7,500 IU during the chronic phase did not confer additional protection.