Retrospective Mortality Survey Research Articles

Nationwide retrospective mortality and seroprevalence of SARS-CoV-2 antibodies in Cameroon

BackgroundAlthough the first year of the COVID-19 pandemic in Africa did not produce the expected catastrophe, the true impact of COVID-19 in the Cameroonian population was unclear. We therefore assessed the seroprevalence of anti-SARS-CoV-2 antibodies and retrospective mortality in a representative sample of the general population in the 10 administrative regions of Cameroon more than one year after the first confirmed cases of COVID-19 in these regions. We aimed to assess the extent of SARS-COV-2 infection and to detect potential increases in the crude mortality rate (CMR) during the SARS-COV-2 pandemic phase. MethodsWe assessed retrospective mortality and seroprevalence of anti-SARS-CoV-2 antibodies in the 10 capital cities of Cameroon using representative samples of the general population. The study included nested anti-SARS-CoV-2 antibody prevalence surveys and retrospective mortality surveys and was conducted between 27 July 2021 and 31 August 2021. To further analyze crude mortality rates by age group and COVID wave, pre-pandemic and pandemic periods were stratified. Both laboratory-based assays (ELFA) and rapid diagnostic tests (RDT) were used to measure anti-SARS-CoV-2 seroprevalence. ResultsThe crude mortality rate (CMR) increased from 0.06 deaths per 10 000 persons per day (pre-pandemic) to 0.17 deaths per 10 000 persons per day (pandemic). The increase in CMR was more pronounced in people aged 20–35 years (pre-pandemic 0.02 deaths per 10 000 persons per day; pandemic 0.06 deaths per 10 000 persons per day). The estimated seroprevalence among unvaccinated persons was 9.5 % (RDT) and 15.4 % (laboratory-based). ConclusionThe seroprevalence results showed that cases were significantly underdetected by the national surveillance systems.

Seroprevalence of SARS-CoV-2 antibodies and retrospective mortality in two African settings: Lubumbashi, Democratic Republic of the Congo and Abidjan, Côte d'Ivoire.

Although seroprevalence studies have demonstrated the wide circulation of SARS-COV-2 in African countries, the impact on population health in these settings is still poorly understood. Using representative samples of the general population, we evaluated retrospective mortality and seroprevalence of anti-SARS-CoV-2 antibodies in Lubumbashi and Abidjan. The studies included retrospective mortality surveys and nested anti-SARS-CoV-2 antibody prevalence surveys. In Lubumbashi the study took place during April-May 2021 and in Abidjan the survey was implemented in two phases: July-August 2021 and October-November 2021. Crude mortality rates were stratified between pre-pandemic and pandemic periods and further investigated by age group and COVID waves. Anti-SARS-CoV-2 seroprevalence was quantified by rapid diagnostic testing (RDT) and laboratory-based testing (ELISA in Lubumbashi and ECLIA in Abidjan). In Lubumbashi, the crude mortality rate (CMR) increased from 0.08 deaths per 10 000 persons per day (pre-pandemic) to 0.20 deaths per 10 000 persons per day (pandemic period). Increases were particularly pronounced among <5 years old. In Abidjan, no overall increase was observed during the pandemic period (pre-pandemic: 0.05 deaths per 10 000 persons per day; pandemic: 0.07 deaths per 10 000 persons per day). However, an increase was observed during the third wave (0.11 deaths per 10 000 persons per day). The estimated seroprevalence in Lubumbashi was 15.7% (RDT) and 43.2% (laboratory-based). In Abidjan, the estimated seroprevalence was 17.4% (RDT) and 72.9% (laboratory-based) during the first phase of the survey and 38.8% (RDT) and 82.2% (laboratory-based) during the second phase of the survey. Although circulation of SARS-CoV-2 seems to have been extensive in both settings, the public health impact varied. The increases, particularly among the youngest age group, suggest indirect impacts of COVID and the pandemic on population health. The seroprevalence results confirmed substantial underdetection of cases through the national surveillance systems.

Effect of large-scale mass drug administration for malaria on mortality and morbidity in Angumu health zone, Ituri, Democratic Republic of Congo

BackgroundAngumu health zone in Ituri, Democratic Republic of Congo, is a highly malaria-endemic area with an overburdened health system and hosting internally displaced persons (IDP). The World Health Organization recommends mass drug administration (MDA) for malaria in complex emergencies. Therefore, three MDA rounds were implemented by Ministry of Public Health and Médecins sans Frontières from September 2020 to January 2021 in four health areas selected for epidemiological (high malaria incidence) and logistic reasons. Reported mortality and morbidity were compared in locations where MDA has been performed and locations where it has not.MethodsA non-randomized controlled population-based retrospective mortality survey was conducted in March 2021. Two-stage cluster sampling was used in villages; all IDP sites were surveyed with systematic random sampling. The main (mortality rates) and secondary (morbidity) outcomes were estimated and compared between locations where MDA had been conducted and where it had not, using mixed Poisson and binomial regression models respectively.ResultsData was collected for 2554 households and 15470 individuals, of whom 721 died in the 18-month recall period. The under-five mortality rate (U5MR) decreased in the locations where MDA had been implemented from 2.32 [1.48–3.16] “before” the MDA to 1.10 [0.5–1.71] deaths/10,000 children under 5 years/day “after”, whereas it remained stable from 2.74 [2.08–3.40] to 2.67 [1.84–3.50] deaths/10,000 children/day in the same time periods in locations where MDA had not been implemented. The U5MR and malaria-specific mortality was significantly higher in non-MDA locations after MDA was implemented (aRR = 2.17 [1.36–3.49] and 2.60 [1.56–4.33], respectively, for all-cause and malaria-specific mortality among children < 5 years). Morbidity (all age and < 5 years, all cause or malaria-specific) appeared lower in MDA locations 2.5 months after last round: reported malaria-specific morbidity was 14.7% [11–18] and 25.0% [19–31] in villages and IDP sites where MDA had been implemented, while it was 30.4% [27–33] and 49.3% [45–54] in villages and IDP sites with no MDA.ConclusionsDespite traditional limitations associated with non-randomized controlled retrospective surveys, the documented sharp decrease of under-5 mortality and morbidity shows that MDA has the potential to become an important malaria-control tool in emergency settings. Based on these results, new MDA rounds, along with indoor residual spraying campaigns, have been planned in the health zone in 2022. A set of surveys will be conducted before, during and after these rounds to confirm the effect observed in 2021 and assess its duration.

High mortality and high PCDD/Fs exposure among residents downwind of municipal solid waste incinerators: A case study in China

Studies on the human body burden of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in populations around municipal solid waste incinerators (MSWIs) in China are limited. The objective of this study was to assess the potential adverse health effects of an 8-year MSWI on the surrounding population and identify possible exposure pathways. We hypothesized that the MSWI would result in different environmental impacts and population health outcomes between upwind and downwind of its 3 km vicinity. We conducted a 10-year retrospective mortality survey on the population surrounding the MSWI. Then, we selected 50 residents aged 50 years or older on each of the upwind and downwind sides of MSWI to test serum PCDD/Fs. Meanwhile, environmental and food exposures to PCDD/Fs were tested for selected residents. The age-adjusted mortality rates were significantly higher for residents downwind than upwind, but no significant difference was found in the standardized mortality ratio before and after the MSWI operation. The toxic equivalents (TEQ) and major congeners of PCDD/Fs were significantly higher in the sera of the downwind residents than in the upwind. The PCDD/Fs in air, soil, dust, and vegetables on the downwind side were not significantly different from those on the upwind side, but the mean concentrations of PCDD/Fs in downwind hen eggs was significantly higher than those from upwind. In conclusion, downwind residents living within 3 km of the MSWI had higher age-adjusted mortality and serum level of PCDD/Fs than upwind residents. This higher mortality rate among downwind residents was not associated with MSWI. However, the higher levels of PCDD/Fs in downwind hen eggs suggest that the downwind population dioxin exposure was related to their location.

Association between biological sex and insecticide-treated net use among household members in ethnic minority and internally displaced populations in eastern Myanmar.

Malaria prevalence in Myanmar is highest among remote and ethnic minority populations living near forest fringes along the country's international borders. Insecticide-treated nets (ITNs) are a key intervention used to prevent malaria transmission, but insufficient ITN availability and low use can hinder effectiveness. This study assessed age and sex disparities in ITN possession, access, and use among household members of ethnic minority and internally displaced populations in eastern Myanmar. Cross-sectional data from the 2013 Eastern Burma Retrospective Mortality Survey were used to describe prevalence of ITN possession, access, and use. The association between a household member's biological sex and their ITN use was assessed using multilevel log binomial regression. Age and household ITN supply were tested as potential effect modifiers. Of 37927 household members, 89.8% (95% CI: 89.5, 90.1) of people lived in households with at least one ITN. Approximately half belonged to households with sufficient ITN supply and used an ITN. Pregnant women and children under five had the highest proportion of ITN use regardless of sufficient household ITN status. Female adults aged 15 to 49 years old (Risk ratio or RR: 1.4, 95% CI: 1.29, 1.52) were more likely to use ITNs. This relationship did not differ by sufficient household ITN status. The findings suggest that among ethnic minority populations in areas where ITN use is indicated, many households do not have adequate ITN supply, and many individuals are not using ITNs. Children under five and pregnant women appear to be prioritized for ITN use and overall, women are slightly more likely to use ITNs than men. This study's findings can support efforts ensuring that all household members belonging to ethnic minority and displaced populations in Eastern Myanmar benefit from sufficient ITN access and use for malaria prevention.

Migration patterns & their associations with health and human rights in eastern Myanmar after political transition: results of a population-based survey using multistaged household cluster sampling

BackgroundMyanmar transitioned to a nominally civilian government in March 2011. It is unclear how, if at all, this political change has impacted migration at the household level.MethodsWe present household-level in- and out-migration data gathered during the Eastern Burma Retrospective Mortality Survey (EBRMS) conducted in 2013. Household level in-and out-migration information within the previous year was gathered via a cross-sectional, retrospective, multi-stage population-based cluster randomized survey conducted in eastern Myanmar. Univariate, bivariate and regression analyses were conducted.ResultsWe conducted a cross-sectional survey of 6620 households across Eastern Myanmar between July and September of 2013. Out-migration outstripped in-migration more than 6:1 overall during the year prior to the survey – for international migration this ratio was 29:1. Most in-migrants had moved to their present location in the study area from other areas in Myanmar (87%). Only 11.3% (27 individuals) had returned from another country (Thailand). Those who migrated out of eastern Myanmar during the previous year were more likely to be male (55.2%), and three times more likely to be between the ages of 15–25 (49.5%) than non-migrants. The primary reason cited for a return to the household was family (26.3%) followed by work (23.2%). The primary reason cited for migrating out of the household was for education (46.4%) followed by work (40.2%). Respondents from households that reported out-migration in the past year were more likely to screen positive for depressive symptoms than households with no migration (PR 1.85; 95% CI 1.16, 2.97). Women in households with in-migration were more likely to be malnourished and had a higher unmet need for contraception. Forced labor, one subset of human rights violations experienced by this population, was reported by more in-migrant (8%) than out-migrant households (2.2%), though this finding did not reach statistical significance.ConclusionsThese analyses suggest that opportunities for employment and education are the primary drivers of migration out of the household, despite an overall improvement in stability and decrease in prevalence of human rights violations found by EBRMS 2013. Additionally, migration into and out of households in eastern Myanmar is associated with changes in health outcomes.

Mortality rates above emergency threshold in population affected by conflict in North Kivu, Democratic Republic of Congo, July 2012-April 2013.

The area of Walikale in North Kivu, Democratic Republic of Congo, is intensely affected by conflict and population displacement. Médecins-Sans-Frontières (MSF) returned to provide primary healthcare in July 2012. To better understand the impact of the ongoing conflict and displacement on the population, a retrospective mortality survey was conducted in April 2013. A two-stage randomized cluster survey using 31 clusters of 21 households was conducted. Heads of households provided information on their household make-up, ownership of non-food items (NFIs), access to healthcare and information on deaths and occurrence of self-reported disease in the household during the recall period. The recall period was of 325 days (July 2012–April 2013). In total, 173 deaths were reported during the recall period. The crude mortality rate (CMR) was of 1.4/10,000 persons/day (CI95%: 1.2–1.7) and the under-five- mortality rate (U5MR) of 1.9/10,000 persons per day (CI95%: 1.3–2.5). The most frequently reported cause of death was fever/malaria 34.1% (CI95%: 25.4–42.9). Thirteen deaths were due to intentional violence. Over 70% of all households had been displaced at some time during the recall period. Out of households with someone sick in the last two weeks, 63.8% sought health care; the main reason not to seek health care was the lack of money (n = 134, 63.8%, CI95%: 52.2–75.4). Non Food Items (NFI) ownership was low: 69.0% (CI95%: 53.1–79.7) at least one 10 liter jerry can, 30.1% (CI95%: 24.3–36.5) of households with visible soap available and 1.6 bednets per household. The results from this survey in Walikale clearly illustrate the impact that ongoing conflict and displacement are having on the population in this part of DRC. The gravity of their health status was highlighted by a CMR that was well above the emergency threshold of 1 person/10,000/day and an U5MR that approaches the 2 children/10,000/day threshold for the recall period.

High incidence of lung cancer and malignant mesothelioma linked to erionite fibre exposure in a rural community in Central Mexico

ObjectiveTo report the high incidence of lung cancer (LC) and malignant mesothelioma (MM) linked to environmental exposure to erionite fibres in a rural village of central Mexico.MethodsThis is a retrospective...

Reliable direct measurement of causes of death in low- and middle-income countries.

BackgroundMost of the 48 million annual deaths in low- and middle-income countries (LMICs) occur without medical attention at the time of death so that the causes of death (COD) are largely unknown. A review of low-cost methods of obtaining nationally representative COD data is timely.DiscussionDespite clear historic evidence of their usefulness, most LMICs lack reliable nationally representative COD data. Indirect methods to estimate COD for most countries are inadequate, mainly because they currently rely on an average ratio of 1 nationally representative COD to every 850 estimated deaths in order to measure the cause of 25 million deaths across 110 LMICs. Direct measurement of COD is far more reliable and relevant for country priorities. Five feasible methods to expand COD data are: sample registration systems (which form the basis for the ongoing Million Death Study in India; MDS); strengthening the INDEPTH network of 42 demographic surveillance sites; adding retrospective COD surveys to the demographic household and health surveys in 90 countries; post-census retrospective mortality surveys; and for smaller countries, systematic assembly of health records. Lessons learned from the MDS, especially on low-cost, high-quality methods of verbal autopsy, paired with emerging use of electronic data capture and other innovations, can make COD systems low-cost and relevant for a wide range of childhood and adult conditions.SummaryLow-cost systems to obtain and report CODs are possible. If implemented widely, COD systems could identify disease control priorities, help detect emerging epidemics, enable evaluation of disease control programs, advance indirect methods, and improve the accountability for expenditures of disease control programs.

Association between smoking and deaths due to colorectal malignant carcinoma: a national population-based case-control study in China.

Background:This study explored the association between smoking and colorectal malignant carcinoma (CRC) in the Chinese population at the national level for the first time.Methods:In the China Nationwide Retrospective Mortality Survey conducted during 1989–1991, 12 942 CRC cases among 1 136 336 all-cause deaths aged ⩾30 years were randomly assigned 25 884 control interviews from 325 255 surviving spouses of all-cause deaths across 103 urban and rural areas.Results:Compared with non-smokers, smoking significantly increased the risk of CRC-specific mortality by 9.8% (odds ratio (OR)=1.098, 95% confidence interval (CI)=1.046–1.153) adjusted for sex, age, and residence. There were significant dose–response relationships between smoking and CRC, such as smoking years, cigarettes smoked daily, and age at onset of smoking. Long-term heavy smokers aged ⩾50 years with ⩾30 smoking years and ⩾20 cigarettes daily had an excess risk of CRC deaths of 30.2% (OR=1.302, 95% CI=1.214–1.397). The strongest association between these smoking variables, such as long-term heavy smokers (OR=1.604, 95% CI=1.341–1.919), and CRC was observed among rural men.Conclusions:Quitting smoking at any time would likely be beneficial to CRC prevention. Long-term heavy smokers and rural men should be viewed as special targets for smoking prevention and cessation programs.

Contributions of major smoking-related diseases to reduction in life expectancy associated with smoking in Chinese adults: a cross-sectional study

BackgroundCigarette smoking is a prominent risk factor for a wide range of diseases. The current study aimed to evaluate the impact of smoking on deaths from major smoking-related diseases (neoplasms, vascular diseases and respiratory diseases) in Chinese adults by estimating the potential gains in life expectancy (LE) that would accrue from eliminating deaths from these diseases, and to determine the contribution of each disease to the reduction in LE associated with smoking.MethodsTwo cohorts of Chinese smokers and non-smokers were constructed from a retrospective national mortality survey that had been conducted in 1989–1991 and included one million all-cause deaths among adults during 1986–1988 in 103 geographical regions. For each cohort, potential gains in LE by eliminating deaths from each major smoking-related disease were estimated. The contributions of each disease to smoking-associated reduction in LE were assessed using the LE decomposition approach.ResultsAmong the major smoking-related diseases, it was estimated that elimination of vascular diseases would provide the greatest potential gain in LE (years), regardless of smoking status. The gains for smokers versus non-smokers in populations of urban men, urban women, rural men and rural women aged 35 years were 3.5 vs. 4.3, 3.8 vs. 4.1, 2.4 vs. 3.0, and 2.6 vs. 2.9 years, respectively. Respiratory diseases contributed most to smoking-associated LE reductions in urban women, rural men and rural women of 43.6%, 46.4%, and 62.9%, respectively. In urban men, neoplasms contributed most to smoking-associated LE reduction, their contribution being estimated as 45.8%.ConclusionsRespiratory disease has the greatest influence on the LE reduction associated with smoking. Thus, smoking prevention could significantly reduce deaths from respiratory disease and improve LE.

Misclassification of pregnancy‐related deaths in adult mortality surveys: case study in Senegal

In countries with limited vital registration data, maternal mortality levels are often estimated using siblings' survival histories (SSH) collected during retrospective adult mortality surveys. We explored how accurately adult deaths can be classified as pregnancy related using such data. The study was conducted in a rural area of south-eastern Senegal with high maternal mortality, Bandafassi. We used data from a demographic surveillance system (DSS) in this area to identify deaths of women at reproductive ages between 2003 and 2009 and to locate the surviving adult sisters of the deceased and interview them. Siblings' survival histories were linked at the individual level to death records, and verbal autopsy data obtained by the demographic surveillance system. We compared the classification of adult female deaths as pregnancy related or not in interviews and DSS records. There were 91 deaths at reproductive ages in the Bandafassi DSS between 2003 and 2009, but only 59 had known surviving sisters. Some deaths were omitted by respondents, or reported as alive or as having occurred during childhood (n = 8). Among deaths reported both in the SSH and DSS data, 94% of deaths classified as pregnancy related in the DSS data were also classified as such by siblings' survival histories. Only 70% of deaths classified as not pregnancy related in the DSS data were also classified as such by siblings' survival histories. Misclassifications of pregnancy-related deaths in retrospective adult mortality surveys may affect estimates of pregnancy-related mortality rates.

Economic feasibility of a new method to estimate mortality in crisis-affected and resource-poor settings.

IntroductionMortality data provide essential evidence on the health status of populations in crisis-affected and resource-poor settings and to guide and assess relief operations. Retrospective surveys are commonly used to collect mortality data in such populations, but require substantial resources and have important methodological limitations. We evaluated the feasibility of an alternative method for rapidly quantifying mortality (the informant method). The study objective was to assess the economic feasibility of the informant method.MethodsThe informant method captures deaths through an exhaustive search for all deaths occurring in a population over a defined and recent recall period, using key community informants and next-of-kin of decedents. Between July and October 2008, we implemented and evaluated the informant method in: Kabul, Afghanistan; Mae La camp for Karen refugees, Thai-Burma border; Chiradzulu District, Malawi; and Lugufu and Mtabila refugee camps, Tanzania. We documented the time and cost inputs for the informant method in each site, and compared these with projections for hypothetical retrospective mortality surveys implemented in the same site with a 6 month recall period and with a 30 day recall period.FindingsThe informant method was estimated to require an average of 29% less time inputs and 33% less monetary inputs across all four study sites when compared with retrospective surveys with a 6 month recall period, and 88% less time inputs and 86% less monetary inputs when compared with retrospective surveys with a 1 month recall period. Verbal autopsy questionnaires were feasible and efficient, constituting only 4% of total person-time for the informant method's implementation in Chiradzulu District.ConclusionsThe informant method requires fewer resources and incurs less respondent burden. The method's generally impressive feasibility and the near real-time mortality data it provides warrant further work to develop the method given the importance of mortality measurement in such settings.

Epidemiologic application of verbal autopsy to investigate the high occurrence of cancer along Huai River Basin, China

BackgroundIn 2004, the media repeatedly reported water pollution and "cancer villages" along the Huai River in China. Due to the lack of death records for more than 30 years, a retrospective survey of causes of death using verbal autopsy was carried out to investigate cancer rates in this area.MethodsAn epidemiologic study was designed to compare numbers of deaths and causes of death between the study areas with water pollution and the control areas without water pollution in S County and Y District in 2005. The study areas were selected based on the distribution of the Huai River and its tributaries. Verbal autopsy was used to assist cause of death (COD) diagnoses and to verify mortality rates. The standard mortality rates (SMRs) of cancer in the study area were compared with those in the control areas. In order to verify the difference between mortality rates due to cancers in the study and the control areas, patients who reported having cancer in the survey received a second diagnosis by national and provincial oncologists with pathological and laboratory examinations. Comparisons were made to determine if differential cancer prevalence rates in the study and control areas were similar to the difference in mortality due to cancer in these study and control areas. Mortality rates of cancers in study and control areas were also compared with national statistics for the rural population of China.ResultsOver five years, 3,301 deaths were identified, including 1,158 cancer deaths. The annual average SMRs of cancer in the study areas of S County and Y District were 277.8/100,000 and 223.6/100,000, respectively, which is three to four times higher than those in the control areas. In addition, a total of 626 cases of cancer in the study and control areas were confirmed. The prevalence rates of cancer were 545/100,000 and 128.1/100,000 per year in the study and control areas in S County, respectively, and 440.9/100,000 and 200/100,000 per year in the study and control areas in Y District, respectively. The mortality and prevalence rates of digestive cancers were higher in the study areas than the control areas. In 2000, the SMR for cancer in rural areas nationwide was 120.9/100,000, and in study areas in S County and Y District, the excess rates of deaths were 184/100,000 and 138.8/100,000, respectively.ConclusionsThe death rates of digestive cancers were much higher in the study areas of S County and Y District. The patterns for between-area differences in prevalence and mortality rates of cancer were similar. Verbal autopsy is shown to be a useful tool in retrospective mortality surveys in low-resource areas with limited access to health care.

P1-47 An innovative case-spouse control design in practice: an experience in estimating smoking and all cause deaths in Chinese adults

IntroductionWe aimed to show that utilising information from a population-based, retrospective mortality survey for the main determinants of disease is feasible.MethodsDuring 1989–1991, a nationwide retrospective survey of mortality was conducted....

Large-Scale “Expert” Mortality Surveys in Conflicts—Concerns and Recommendations

SEVERAL LARGE-SCALE RETROSPECTIVE MORTALITY SURveys in conflict settings in Darfur, the Democratic Republic of Congo (DRC), Northern Uganda, and Iraq have had major political implications, and, thus, were scrutinized by policy makers, researchers, and the media. The controversies they generated led to serious criticism—some well-founded, some less so—that may have undermined the credibility of mortality surveys in conflict settings. For example, a 2006 survey estimated that more than 650 000 Iraqis died mostly from violence since the USled invasion in 2003; in contrast, another study found a substantially lower estimate of violence-related deaths at approximately 151 000. A 2007 study estimated that 5.4 million have died in DRC since 1998; another report questioned the methods of this study and claimed that the excess death estimate was at least 3 times too high. Rebuttals from various sources and conflicting studies focused on sampling and nonsampling biases. Given these concerns, higher standards and improved methods are needed for undertaking and reporting large-scale mortality surveys. To track mortality prospectively, a surveillance system should be established as early as possible in humanitarian emergencies. However, humanitarian organizations often rely on cross-sectional surveys to estimate death rates retrospectively. These surveys are time consuming, costly, logistically challenging, and require technical expertise. Methodologies to measure mortality have not been sufficiently validated. Mortality surveys are useful at the beginning of emergencies to document baseline mortality rates, monitor effectiveness of programs, prioritize interventions, and advocate for funding. These surveys generally are not published in peer-reviewed journals and may not attract much attention. These are the “operational” surveys that allow humanitarian organizations to make practical field decisions. They are neither designed to meet publication standards nor to establish precise benchmarks. Although their quality can be improved, these operational surveys are essential surveys to guide field programs. Large-scale mortality surveys in conflict settings—often seeking to measure mortality at a national level and over a relatively long period—have different objectives from smaller operational surveys. These “expert” surveys are rare and primarily conducted for advocacy purposes, to document severity of crises and possible human rights violations, and to call for additional international attention and funding. Their findings are broader in nature and often do not directly effect field interventions. These surveys are complex, expensive, and time consuming to implement and to disseminate results. Sampling design and methods of retrospective mortality surveys in conflict settings are areas of unsettled science. Lack of accurate population data before the crisis is complicated by population displacement, so accurate population listings necessary for random sampling are rarely available. Thus, cluster sampling is a default method in most humanitarian settings and has often meant reliance on 30 30 cluster surveys. Given the uneven distribution of violence, sample sizes, particularly number of clusters, should be significantly larger than have previously been used; especially because many surveys attempt to interpret findings by age, sex, or location. Therefore, 30 30 cluster surveys should rarely, if ever, be used in expert mortality surveys if the purpose is to estimate mortality at a national level. Larger sample sizes with more clusters are needed. Recall periods are another important issue. Shorter periods (eg, 1-3 months) may reduce recall bias and focus results on more proximate mortality events. However, they tend to increase imprecision in estimating rates for a given sample size because the number of deaths in shorter periods is likely to be fewer. Calendar error may also prove more significant in shorter recall periods because an error of only 1 week (eg, when a death occurred) would have a greater effect on estimates. Duration of recall periods in expert surveys should be appropriate to the time dimensions of the crisis-related mortality of interest while ensuring the sample power is sufficient for precision and valid comparisons. Nonsampling errors may be particularly important in expert surveys. Surveyors and survey participants may be under pressure to increase or decrease reported deaths. Who the surveyors are, how they are trained and super-

Case-Spouse Control Design in Practice: An Experience in Estimating Smoking and Chronic Obstructive Pulmonary Disease Deaths in Chinese Adults

We assessed the effect of smoking on death from chronic obstructive pulmonary disease (COPD) in China by employing a large population-based, case-spouse control study design using data from a nationwide survey of mortality. During 1989-1991, a nationwide retrospective survey of mortality was conducted in China. For approximately 1,000,000 adults dying from all causes during 1986-1988, their surviving spouses or other informants provided detailed information about their own as well as the deceased person's smoking history. For this study, 183,393 individuals who died of COPD at age > or = 40 years were taken as cases, while 272,984 sex-matched surviving spouses of subjects who died from any cause were taken as controls. COPD death rates for smokers were more than twice as high as those of non-smokers, with a dose-response risk pattern, despite the fact that COPD death rates varied widely by region and age. Tobacco accounted for 41.4% of COPD deaths in men, but only 13.5% of those in women, who had a lower rate of smoking. A case-spouse control study, as an alternative design, is valid and feasible in utilizing information from population-based, retrospective mortality survey data for an analytical epidemiological study of disease etiology.

Patterns of mortality rates in Darfur conflict

Several mortality estimates for the Darfur conflict have been reported since 2004, but few accounted for conflict dynamics such as changing displacement and causes of deaths. We analyse changes over time for crude and cause-specific mortality rates, and assess the effect of displacement on mortality rates. Retrospective mortality surveys were gathered from an online database. Quasi-Poisson models were used to assess mortality rates with place and period in which the survey was done, and the proportions of displaced people in the samples were the explanatory variables. Predicted mortality rates for five periods were computed and applied to population data taken from the UN's series about Darfur to obtain the number of deaths. 63 of 107 mortality surveys met all criteria for analysis. Our results show significant reductions in mortality rates from early 2004 to the end of 2008, although rates were higher during deployment of fewer humanitarian aid workers. In general, the reduction in rate was more important for violence-related than for diarrhoea-related mortality. Displacement correlated with increased rates of deaths associated with diarrhoea, but also with reduction in violent deaths. We estimated the excess number of deaths to be 298 271 (95% CI 178 258-461 520). Although violence was the main cause of death during 2004, diseases have been the cause of most deaths since 2005, with displaced populations being the most susceptible. Any reduction in humanitarian assistance could lead to worsening mortality rates, as was the case between mid 2006 and mid 2007.

Smoking-attributable deaths and potential years of life lost from a large, representative study in China

ObjectivesTo provide a more accurate estimate of early smoking-attributable mortality and potential years of life lost using data from a representative study of 103 study areas in China.MethodsTwo datasets were...

Age-related Effects of Smoking on Lung Cancer Mortality: A Nationwide Case-Control Comparison in 103 Population Centers in China

To examine age-related effects of smoking on lung cancer mortality in a large population-based case-control study that was incorporated into a nationwide retrospective survey of mortality in China. Two data sets were pooled for this analysis: national mortality survey data and data from a nationwide case-control comparison. These pooled data were used to calculate age-specific lung cancer death rates by smoking status and expected years of lost life expectancy for each smoking-associated death. There was a significant excess of deaths (54% of urban deaths, 51% of rural deaths) at 35 to 69 years of age among male smokers and the average loss of life expectancy per smoking-associated death at these ages was 18.3 years. For women ages 35 to 69 years of age, 29% and 11% excess lung cancer mortality was observed in urban and rural smokers, respectively, with an average loss of life expectancy per smoking-associated death of 21.3 years. Tobacco smoking was associated with a large number of deaths from lung cancer. Utilizing information from a population-based retrospective mortality survey for conducting an analytic epidemiological study of main determinants of disease is feasible and can generate important results.