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Peter Byass

Publications and source records attributed to Peter Byass.

At least 19 recordsLinked to original sources
PubMed2006

Burden of premature mortality in rural Vietnam from 1999-2003: analyses from a Demographic Surveillance Site.

BACKGROUND: Assessing the burden of disease contributes towards evidence-based allocation of limited health resources. However, such measures are not yet commonly available in Vietnam. Taking advantage of the FilaBavi Demographic Surveillance Site (FilaBavi DSS) in Vietnam, this study aimed to establish the feasibility of applying the Years of Life Lost (YLL) technique in the context of a defined DSS, and to estimate the importance of the principal causes of premature mortality in a rural area of Vietnam between 1999 and 2003. METHODS: Global Burden of Disease methods were applied. Causes of death were ascertained by verbal autopsy. RESULTS: In five years, 1,240 deaths occurred and for 1,220 cases cause of death information from verbal autopsy was available. Life expectancy at birth was 71.0 (95% confidence interval 69.9-72.1) in males and 80.9 (79.9-81.9) in females. The discounted, but not age weighted YLL per 1,000 population was 85 and 55 for males and females, respectively. The leading causes of YLL and death counts were cardiovascular diseases, malignant neoplasms, unintentional injuries, and neonatal causes. Males contributed 54% of total deaths and 59% of YLL. Males experienced higher YLL than women across all causes. Filabavi mortality estimates are considerably lower than 2002 WHO country estimates for Vietnam. Also the FilaBavi cause distribution varies considerably from the WHO result. CONCLUSION: The combination of localised demographic surveillance, verbal autopsy and the application of YLL methods enable new insights into the magnitude and importance of significant public health issues in settings where evidence for planning is otherwise scarce. Local mortality data vary considerably from the WHO model-based estimates.

Journal Article↗
PubMed2006

Cardiovascular disease mortality and its association with socioeconomic status: findings from a population-based cohort study in rural Vietnam, 1999-2003.

INTRODUCTION: Cardiovascular disease is an emerging epidemic in Vietnam, but because cause of death and other routine data are not widely available, it is difficult to characterize community-based disease patterns. Using 5-year data from an ongoing cause-specific mortality study conducted within a demographic surveillance system in Vietnam's Bavi district, this article estimates the rates of adult cardiovascular disease mortality in relation to the mortality rates of other noncommunicable diseases in rural northern Vietnam and examines the association of cardiovascular disease with certain demographic and socioeconomic factors. METHODS: All causes of death of adults aged 20 and older occurring from 1999 through 2003 (n = 1067) were determined by using an established demographic surveillance system and data collected by trained interviewers who asked caretakers or relatives of the deceased individuals about signs and symptoms of disease during quarterly household visits. Deaths were classified as cardiovascular disease, cancer, or other noncommunicable diseases. These records were linked to demographic and socioeconomic data. RESULTS: Of the 1067 adult deaths that were recorded, there was an overall noncommunicable disease mortality rate of 7.8 per 1000 person-years. Cardiovascular disease accounted for 33% of male and 31% of female deaths. Compared with cancer and other noncommunicable causes of death in a Cox proportional hazards model, higher cardiovascular disease mortality rates were observed among men, older age groups, and those without formal education. CONCLUSION: To date, cohort studies and population-based mortality data in Vietnam have been scarce; this study provides insights into the public health aspects of cardiovascular disease in transitional Vietnam. The rates of cardiovascular disease mortality in this rural Vietnamese community were high, suggesting the need for both primary prevention and secondary treatment initiatives. The demographic surveillance system is an important tool for characterizing such an epidemic.

Adult↗
PubMed2006

Socio-economic status inequality and major causes of death in adults: a 5-year follow-up study in rural Vietnam.

OBJECTIVES: This study aimed to analyse the associations between cause-specific mortality in adults (aged 20 years and above) and socio-economic status (SES) in a rural setting of Vietnam during a time of economic transition. STUDY DESIGN: The study was carried out as part of the FilaBavi demographic surveillance system, with a dynamic cohort of 50,000 inhabitants from January 1999 to December 2003. METHODS: Causes of death in the adult population were derived using verbal autopsy. A Cox regression model was employed to check the association of SES with three major causes of death: communicable diseases; non-communicable diseases; and injuries. RESULTS: The crude mortality rates were 9.2 and 6.6 per 1000 person-years in adult males and females, respectively. Men had higher mortality rates than women for all mortality categories and for all levels of education and household economic situation (HES). Mortality rates increased substantially with age, and showed similar age effects for all mortality categories with the strongest association for non-communicable diseases. Education was an important factor for survival in general, and high HES seemed to benefit men more than women. CONCLUSIONS: Interventions and policies to reduce exposure to risk factors for non-communicable diseases are needed in low-education groups. However, further study is needed to analyse the mortality inequity across all age groups.

Adult↗
PubMed2006

Assessing a new approach to verbal autopsy interpretation in a rural Ethiopian community: the InterVA model.

OBJECTIVE: Verbal autopsy (VA) -- the interviewing of family members or caregivers about the circumstances of a death after the event -- is an established tool in areas where routine death registration is non-existent or inadequate. We assessed the performance of a probabilistic model (InterVA) for interpreting community-based VA interviews, in order to investigate patterns of cause-specific mortality in a rural Ethiopian community. We compared results with those obtained after review of the VA by local physicians, with a view to validating the model as a community-based tool. METHODS: Two-hundred and eighty-nine VA interviews were successfully completed; these included most deaths occurring in a defined community over a 1-year period. The VA interviews were interpreted by physicians and by the model, and cause-specific mortality fractions were derived for the whole community and for particular age groups using both approaches. FINDINGS: The results of the two approaches to interpretation correlated well in this example from Ethiopia. Four major cause groups accounted for over 60% of all mortality, and patterns within specific age groups were consistent with expectations for an underdeveloped high-mortality community in sub-Saharan Africa. CONCLUSION: Compared with interpretation by physicians, the InterVA model is much less labour intensive and offers 100% consistency. It is a valuable new tool for characterizing patterns of cause-specific mortality in communities without death registration and for comparing patterns of mortality in different populations.

Adolescent↗
PubMed2006

Combining risk factors and demographic surveillance: potentials of WHO STEPS and INDEPTH methodologies for assessing epidemiological transition.

AIMS: Demographic surveillance systems (DSSs) create platforms to monitor population dynamics. This paper discusses the potential of combining the WHO STEPwise approach to Surveillance (STEPS) within ongoing DSSs, to assess changes in non-communicable disease (NCD) risk factors. METHODS: Three DSSs in Ethiopia, Vietnam, and Indonesia have collected NCD risk factors using WHO STEPS, focusing on self-reported lifestyle risk factors (Step 1) and measurement of blood pressure and anthropometric parameters (Step 2). RESULTS: DSSs provide sampling frames for NCD risk factor surveillance, which reveals the distribution of risk factors and their dynamics at the population level. The WHO STEPS approach with its add-on modules is feasible and adaptable in DSS settings. Available mortality data in the DSSs enable mortality assessment by cause of death using verbal autopsy, which is relevant in estimating the impact of NCDs. DSSs as well as risk factor surveillance data may potentially be a lever for hypothesis-driven research to address specific a priori hypotheses or research questions. CONCLUSION: Combining DSSs with the WHO STEPS approach can potentially address basic epidemiological questions on NCDs, which can be used as a powerful advocacy tool in public health decision-making for NCD prevention.

Adult↗
PubMed2006

Refining a probabilistic model for interpreting verbal autopsy data.

OBJECTIVE: To build on the previously reported development of a Bayesian probabilistic model for interpreting verbal autopsy (VA) data, attempting to improve the model's performance in determining cause of death and to reassess it. DESIGN: An expert group of clinicians, coming from a wide range geographically and in terms of specialization, was convened. Over a four-day period the content of the previous probabilistic model was reviewed in detail and adjusted as necessary to reflect the group consensus. The revised model was tested with the same 189 VA cases from Vietnam, assessed by two local clinicians, that were used to test the preliminary model. RESULTS: The revised model contained a total of 104 indicators that could be derived from VA data and 34 possible causes of death. When applied to the 189 Vietnamese cases, 142 (75.1%) achieved concordance between the model's output and the previous clinical consensus. The remaining 47 cases (24.9%) were presented to a further independent clinician for reassessment. As a result, consensus between clinical reassessment and the model's output was achieved in 28 cases (14.8%); clinical reassessment and the original clinical opinion agreed in 8 cases (4.2%), and in the remaining 11 cases (5.8%) clinical reassessment, the model, and the original clinical opinion all differed. Thus overall the model was considered to have performed well in 170 cases (89.9%). CONCLUSIONS: This approach to interpreting VA data continues to show promise. The next steps will be to evaluate it against other sources of VA data. The expert group approach to determining the required probability base seems to have been a productive one in improving the performance of the model.

Autopsy↗
PubMed2005

Helping northern Ethiopian communities reduce childhood mortality: population-based intervention trial.

OBJECTIVE: More than 10 million children die each year mostly from preventable causes and particularly in developing countries. WHO guidelines for the Integrated Management of Childhood Illness (IMCI) are intended to reduce childhood mortality and are being implemented in Ethiopia. As well as specific clinical interventions, the role of the community in understanding and acting on childhood sickness is an important factor in improving survival. This trial sought to assess the effect on survival of community-based health promotion activities. METHODS: Two districts in northern Ethiopia were studied, each with a random sample of more than 4000 children less than 5 years old. Regular six-monthly visits were made to document deaths among children. After the first year, communities in one district were educated about issues of good childcare and caring for sick children while the other district received this information only after the trial ended. FINDINGS: Although overall mortality was higher in the post-intervention period, most of the increase was seen in the control area. A Cox proportional hazards model gave an adjusted hazard ratio of 0.66 (95% confidence interval = 0.46-0.95) for the intervention area compared with the control area in the post-intervention period, with no significant pre-intervention difference. Significant survival advantages were found for females, children of younger fathers, those with married parents, those living in larger households, and those whose nearest health facility was a health centre. For all of the children who died, only 44% of parents or caregivers had sought health care before the child's death. CONCLUSION: This non-specific community-based public health intervention, as an addition to IMCI strategies in local health facilities, appears to have significantly reduced childhood mortality in these communities. The possibility that such interventions may not effectively reach certain social groups (for example single parents) is an important consideration for implementation of similar strategies in future. The synergy between community awareness and the availability of effective peripheral health services is also an issue that needs further exploration.

Child↗
PubMed2005

Does poverty lead to non-fatal unintentional injuries in rural Vietnam?

The aim of this study was to identify associations between poverty at the household level and unintentional injury morbidity. A cohort consisting of 24,874 person-time episodes, representing 24,776 people living in 5,801 households (classified into rich, middle income and poor by local authorities in 1999) was followed during 2000, in order to identify and assess non-fatal unintentional injuries. Incidence rate ratios were calculated using a Poisson regression model. The results showed that poverty was a risk factor for unintentional injuries generally. When looking at different types of injury, poverty was a risk for home, work and "other" injuries, protective for school injuries, while the risk of traffic injuries was not affected. The results also showed that communes in mountainous areas were at higher risk for home, work and other injuries. Overall, poverty was associated with unintentional injury morbidity. However, the relationship varied by sex, age and type of injury. Specifically, poverty increased the risk for children and elderly people being injured at home, and for adults (15-59 years) being affected by work injuries.

Adolescent↗
PubMed2005

Can source reduction of mosquito larval habitat reduce malaria transmission in Tigray, Ethiopia?

The development of irrigation schemes by dam construction has led to an increased risk of malaria in Tigray, Ethiopia. We carried out a pilot study near a microdam to assess whether environmental management could reduce malaria transmission by Anopheles arabiensis, the main vector in Ethiopia. The study took place in Deba village, close to a dam; Maisheru village, situated 3-4 km away from the dam, acted as a control. Baseline entomological and clinical data were collected in both villages during the first 12 months. Source reduction, involving filling, draining and shading of potential mosquito-breeding habitats was carried out by the community of Deba in the second year and routine surveillance continued in both villages during the second year. Anopheles arabiensis was highly anthropophilic (Human Blood Index=0.73), biting early in the night before people went to bed. The major breeding habitats associated with the dam were areas of seepage at the dam base (28%), leaking irrigation canals (16%), pools that formed along the bed of streams from the dam (13%), and man-made pools (12%). In the pre-intervention year, 5.9-7.2 times more adult vectors were found in the dam village compared with the control village. There was a 3.1% higher prevalence of an enlarged spleen in children under 10 years in the dam village than in the control village during the pre-intervention period, but no statistically significant difference was found in the incidence of falciparum malaria between the two villages during the same period. Source reduction was associated with a 49% (95% CI=46.6-50.0) relative reduction in An. arabiensis adults in the dam village compared with the pre-intervention period. There were very few cases of malaria during the intervention period in both villages making it impossible to judge whether malaria incidence had been reduced. These preliminary findings suggest that in areas of low intensity transmission community-led larval control may be a cheap and effective method of controlling malaria. Further, large-scale studies are needed to confirm these findings.

Animals↗
PubMed2003

Patterns of local migration and their consequences in a rural Ethiopian population.

AIMS: In the context of the Butajira Rural Health Programme (BRHP) in Ethiopia, which has maintained demographic surveillance in selected communities since 1987, this paper investigates patterns of migration and their consequences within that population over a ten year period 1987-1996. METHODS & RESULTS: Based on observations of over 336,000 person-years in nine rural villages and one small town, 48% of individuals migrated in or out of the study area at some stage, as recorded in monthly household visits. There was a net incidence of migration into the urban area, particularly among young adults. Mortality was higher among residents compared with in-migrants, with rates of 10.5 (95% CI 7.5 to 14.9) and 8.2 (95% CI 5.8 to 11.7) per 1,000 person-years respectively after adjustment for age, sex and area of residence, a rate ratio of 1.3. Fertility among in-migrant and resident women was similar, at rates of 0.26 and 0.28 births per reproductive year respectively. CONCLUSIONS: The causes of the observed differences in mortality are not clear, though they may be partly due to self-selection effects among migrants, and may have important implications for future health policy and planning in Ethiopia and other similar settings.

Adolescent↗
PubMed2003

Patterns of mortality in Bavi, Vietnam, 1999-2001.

AIMS: Demographic data including detailed mortality patterns for Vietnam are relatively sparse, mainly coming from national census data. This paper describes detailed mortality findings from a sample drawn from the population of one district of northern Vietnam, over the three-year period 1999-2001. METHODS: These data were based on quarterly household visits to collect data on vital events, covering 142,318 person-years of observation over a three-year period. RESULTS: Crude mortality was 5.1 per 1,000 person-years (4.7 for females and 5.6 for males). Infant mortality was 21.6 per 1,000 live births and crude birth rate was 14.7 per 1,000. Life expectancy at birth was 75.2 years (78.8 year for females and 71.1 for males). Residents of mountainous and highland areas experienced lower mortality than riverside and island dwellers. CONCLUSIONS: These findings are discussed in the light of two major demographic factors: the legacy of the Vietnam War and, more recently, the effect of Vietnam's two-child policy. Although these mortality estimates seem low, there is good reason to believe that they accurately reflect the current state of this population. Vietnam as a whole enjoys low mortality in relation to its socioeconomic status compared with neighbouring countries.

Adolescent↗
PubMed2003

Validity and completeness of death reporting and registration in a rural district of Vietnam.

AIMS: Assessment was made of the validity of mortality estimates based on data collected during 1999-2000 by quarterly follow-up visits and compared with other methods (re-census, communal death registration, and neighbourhood survey). METHODS: This study was carried out within a longitudinal epidemiological laboratory in Bavi, District, Vietnam (called FilaBavi), covering a sample of 11,089 households with 51,024 inhabitants. Deaths within FilaBavi during 1999-2000 were collected by four methods and compared: quarterly household follow-ups, the re-census carried out in 2001, the Commune Population Registration System (CPRS), and a neighbourhood survey. RESULTS: Within these four methods, a total of 471 deaths were detected in the FilaBavi sample. Quarterly household follow-ups detected 470 deaths (99.8%). The re-census missed 19 deaths, of which eight were infants, and two-thirds of the missed deaths fell in 1999. The CPRS missed 89 cases (19%), the majority being infant and elderly deaths. The neighbourhood survey over-reported deaths. CONCLUSIONS: Quarterly follow-ups were the best method for death registration. The re-census approach was less complete, with problems of recall bias. The completeness and quality of death registration by CPRS was low, especially for infant and elderly mortality.

Adolescent↗
PubMed2003

Applying verbal autopsy to determine cause of death in rural Vietnam.

AIMS: Verbal autopsy (VA) is an attractive method for ascertaining causes of death in settings where the proportion of people who die under medical care is low. VA has been widely used to determine causes of childhood and maternal deaths, but has had limited use in assessing causes in adults and across all age groups. The objective was to test the feasibility of using VA to determine causes of death for all ages in Bavi District, Vietnam, in 1999, leading to an initial analysis of the mortality pattern in this area. METHODS: Trained lay field workers interviewed a close caretaker of the deceased using a combination closed/open-ended questionnaire. RESULTS: A total of 189 deaths were studied. Diagnoses were made by two physicians separately, with good agreement (kappa = 0.84) and then combined to reach one single underlying cause of death for each case. The leading causes of death were cardiovascular and infectious diseases (accounting for 20.6% and 17.9% of the total respectively). Drowning was very prevalent in children under 15 (seven out of nine cases of drowning were in this age group). DISCUSSION: One month seemed an acceptable minimum recall period to ensure mourning procedures were over. A combination VA questionnaire was an appropriate instrument provided it was supported by adequate training of interviewers. Two physicians were appropriate for making the diagnoses but predefined diagnostic methods for common causes should be developed to ensure more replicable results and comparisons, as well as to observe trends of mortality over time. The causes of death in this study area reflect a typical pattern for developing countries that are in epidemiological transition. No maternal deaths and a low infant mortality rate may be the result of improvements in maternal and child health in this study area. Using the VA gave more precise causes of death than those reported at death registration. Although the validity of the VA method used has not been fully assessed, it appeared to be an appropriate method for ascertaining causes of death in the study area.

Adult↗
PubMed2003

Mortality from cardiovascular diseases in Bavi District, Vietnam.

AIMS: Like other developing countries, Vietnam is undergoing epidemiological transition, which is characterized by many changes in terms of morbidity and mortality patterns. The fact that cardiovascular diseases (CVD) are leading causes of death in hospitals in the whole country was ascertained from annual statistics. However, the magnitude of the burden of mortality from CVD at the community level remained unknown. The aims of the study were to outline CVD mortality during health transition in a rural community in the north of Vietnam and to examine associations between CVD mortality and the socioeconomic status of the population. METHODS: Within an established demographic surveillance system (DSS), verbal autopsy (VA) was used to identify the burden of mortality from CVD. Cohort analysis was used in this study to measure associations between CVD mortality and socioeconomic determinants. RESULTS: CVD emerged as a leading cause of death in the study area, accounting for more than infectious and parasitic diseases combined. CVD killed many people among the most economically productive age group, both men and women, in all socioeconomic groups. Occupational status was shown to be significantly associated with CVD mortality. DISCUSSION: Already at this point in the epidemiological transition, there is evidence of a substantial burden of CVD in rural Vietnam. Although this study was not able to show trends, the current situation is a cause for concern in health policy and planning. Verbal autopsy methods and CVD risk factor evaluations will form important parts of future research agendas.

Adolescent↗
PubMed2003

A probabilistic approach to interpreting verbal autopsies: methodology and preliminary validation in Vietnam.

AIMS: Verbal autopsy (VA) has become an important tool in the past 20 years for determining cause of death in communities where there is no routine registration. In many cases, expert physicians have been used to interpret the VA findings and so assign individual causes of death. However, this is time consuming and not always repeatable. Other approaches such as algorithms and neural networks have been developed in some settings. This paper aims to develop a method that is simple, reliable and consistent, which could represent an advance in VA interpretation. METHODS: This paper describes the development of a Bayesian probability model for VA interpretation as an attempt to find a better approach. This methodology and a preliminary implementation are described, with an evaluation based on VA material from rural Vietnam. RESULTS: The new model was tested against a series of 189 VA interviews from a rural community in Vietnam. Using this very basic model, over 70% of individual causes of death corresponded with those determined by two physicians increasing to over 80% if those cases ascribed to old age or as being indeterminate by the physicians were excluded. DISCUSSION: Although there is a clear need to improve the preliminary model and to test more extensively with larger and more varied datasets, these preliminary results suggest that there may be good potential in this probabilistic approach.

Autopsy↗
PubMed2003

Community-based assessment of unintentional injuries: a pilot study in rural Vietnam.

AIMS: Although unintentional injuries are recognised as a major public health problem globally, little is known about their patterns and rates at the community level in most low-income countries. Rapid social development, leading to increased traffic and industrialization, may be changing patterns of injury. Injuries within the home environment have not so far been recognized to the same extent as traffic and work-related injuries in Vietnam, largely because they have not been effectively counted. This study took place in northern Vietnam, in the context of a longitudinal community surveillance site called FilaBavi, as a pilot project aiming to determine the community incidence of unintentional injury and to explore appropriate methods for community-based injury surveillance. METHODS: An initial study population of 23,807 was identified and asked about their experience of injury in the preceding three months. RESULTS: Overall 450 new injuries were detected over 5,952 person-years, a rate of 76 per 1,000 person-years. Males were injured at 1.6 times the rate of females, and home and road traffic accidents were most common. Most injuries occurred during unpaid household tasks. Cutting and crushing injuries occurred most frequently. Of 221 deaths from all causes in the FilaBavi population during 1999 among 43,444 person-years, 25 were attributed to unintentional injuries and two to suicide. Unintentional injury was the third leading cause of death in this community, with a case-fatality rate of 0.8%. DISCUSSION: The findings suggest that greater attention needs to be directed toward the prevention of injuries occurring in the home in rural Vietnam. On the basis of this pilot study, a one-year study using the same approach is under way to characterize the patterns of unintentional injury in more detail, including any seasonal variation.

Accidents↗
PubMed2002

Gender, literacy, and survival among Ethiopian adults, 1987 - 96.

OBJECTIVE: To examine relationships between gender, literacy and survival among adults in Meskan and Mareko district, Ethiopia. METHODS: On the basis of an established demographic surveillance system, an open-cohort analysis of 172726 person-years covering the period January 1987 to December 1996 was conducted in 10 randomly selected local communities. FINDINGS: The crude mortality rate was 11.2 per 1000 person-years among adults aged > or =15 years; the values for males and females were 11.9 and 10.6 per 1000 person-years, respectively. Kaplan - Meier estimates showed that literacy and being female were both favourable for survival throughout adulthood. Cox's regression models showed that age, gender, literacy and area (rural lowland, rural highland and urban) were significant factors in survival: younger, female, literate urban dwellers were the most favoured. Gender differences in mortality were small in the rural areas, possibly because of the harsh living conditions and the marginalization of women. Literacy was a more significant factor for survival in the rural areas, where mortality was highest, while gender was more important in the one urban area studied. The levels of literacy were lowest among rural females. CONCLUSION: Special attention should be given to raising literacy levels among rural women with a view to improving their survival.

Adolescent↗