| 1. |
- Stroh, Emilie, et al.
(author)
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Measured and modeled personal and environmental NO2 exposure
- 2012
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 10:10
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Journal article (peer-reviewed)abstract
- Abstract in Undetermined Background: Measured or modeled levels of outdoor air pollution are being used as proxies for individual exposure in a growing number of epidemiological studies. We studied the accuracy of such approaches, in comparison with measured individual levels, and also combined modeled levels for each subject's workplace with the levels at their residence to investigate the influence of living and working in different places on individual exposure levels. Methods: A GIS-based dispersion model and an emissions database were used to model concentrations of NO2 at the subject's residence. Modeled levels were then compared with measured levels of NO2. Personal exposure was also modeled based on levels of NO2 at the subject's residence in combination with levels of NO2 at their workplace during working hours. Results: There was a good agreement between measured facade levels and modeled residential NO2 levels (r(s) = 0.8, p > 0.001); however, the agreement between measured and modeled outdoor levels and measured personal exposure was poor with overestimations at low levels and underestimation at high levels (r(s) = 0.5, p > 0.001 and r(s) = 0.4, p > 0.001) even when compensating for workplace location (r(s) = 0.4, p > 0.001). Conclusion: Modeling residential levels of NO2 proved to be a useful method of estimating facade concentrations. However, the agreement between outdoor levels (both modeled and measured) and personal exposure was, although significant, rather poor even when compensating for workplace location. These results indicate that personal exposure cannot be fully approximated by outdoor levels and that differences in personal activity patterns or household characteristics should be carefully considered when conducting exposure studies. This is an important finding that may help to correct substantial bias in epidemiological studies.
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| 2. |
- Agardh, Emilie E, et al.
(author)
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Burden of type 2 diabetes attributed to lower educational levels in Sweden
- 2011
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 9, s. 60-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Type 2 diabetes is associated with low socioeconomic position (SEP) in high-income countries. Despite the important role of SEP in the development of many diseases, no socioeconomic indicator was included in the Comparative Risk Assessment (CRA) module of the Global Burden of Disease study. We therefore aimed to illustrate an example by estimating the burden of type 2 diabetes in Sweden attributed to lower educational levels as a measure of SEP using the methods applied in the CRA.METHODS: To include lower educational levels as a risk factor for type 2 diabetes, we pooled relevant international data from a recent systematic review to measure the association between type 2 diabetes incidence and lower educational levels. We also collected data on the distribution of educational levels in the Swedish population using comparable criteria for educational levels as identified in the international literature. Population attributable fractions (PAF) were estimated and applied to the burden of diabetes estimates from the Swedish burden of disease database for men and women in the separate age groups (30-44, 45-59, 60-69, 70-79, and 80+ years).RESULTS: The PAF estimates showed that 17.2% of the diabetes burden in men and 20.1% of the burden in women were attributed to lower educational levels in Sweden when combining all age groups. The burden was, however, most pronounced in the older age groups (70-79 and 80+), where lower educational levels contributed to 22.5% to 24.5% of the diabetes burden in men and 27.8% to 32.6% in women.CONCLUSIONS: There is a considerable burden of type 2 diabetes attributed to lower educational levels in Sweden, and socioeconomic indicators should be considered to be incorporated in the CRA.
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| 3. |
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| 4. |
- Björkenstam, Charlotte, et al.
(author)
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Suicide or undetermined intent? : A register-based study of signs of misclassification
- 2014
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 12
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Journal article (peer-reviewed)abstract
- Background: Several studies have concluded that some deaths classified as undetermined intent are in fact suicides, and it is common in suicide research in Europe to include these deaths. Our aim was to investigate if information on background variables would be helpful in assessing if deaths classified as undetermined intent should be included in the analyses of suicides. Methods: We performed a register study of 31,883 deaths classified as suicides and 9,196 deaths classified as undetermined intent in Sweden from 1987 to 2011. We compared suicide deaths with deaths classified as undetermined intent with regard to different background variables such as sex, age, country of birth, marital status, prior inpatient care for self-inflicted harm, alcohol and drug abuse, psychiatric inpatient care, and use of psychotropics. We also performed a multivariate analysis with logistic regression. Results: Our results showed differences in most studied background factors. Higher education was more common in suicides; hospitalization for self-inflicted harm was more common among female suicides as was prior psychiatric inpatient care. Deaths in foreign-born men were classified as undetermined intent in a higher degree and hospitalization for substance abuse was more common in undetermined intents of both sexes. Roughly 50% of both suicide and deaths classified as undetermined intent had a filled prescription of psychotropics during their last six months. Our multivariate analysis showed male deaths to more likely be classified as suicide than female: OR: 1.13 (1.07-1.18). The probability of a death being classified as suicide was also increased for individuals aged 15-24, being born in Sweden, individuals who were married, and for deaths after 1987-1992. Conclusion: By analyzing Sweden's unique high-validity population-based register data, we found several differences in background variables between deaths classified as suicide and deaths classified as undetermined intent. However, we were not able to clearly distinguish these two death manners. For future research we suggest, separate analyses of the two different manners of death.
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| 5. |
- Byass, Peter
(author)
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Integrated multisource estimates of mortality for Thailand in 2005
- 2010
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 8, s. Article nr 10-
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Journal article (peer-reviewed)abstract
- Estimates of mortality in Thailand during 2005 have been published, integrating multiple data sources including national vital registration and a national follow-up cluster sample, covering both deaths in health facilities (approximately one-third) and elsewhere. The methodological challenge is to make the best use of the existing data, supplemented by additional data that are feasible to obtain, in order to arrive at the best possible overall estimates of mortality. In this case, information from the national vital registration database was supplemented by a verbal autopsy survey of approximately 2.5% of deaths, the latter being used to validate routine cause-of-death data and information from medical records. This led to a revised national cause-specific mortality envelope for Thailand in 2005, amounting to 447,104 deaths. However, difficulties over standardizing verbal autopsy interpretation may mean that there are still some uncertainties in these revised estimates.
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| 6. |
- Byass, Peter, et al.
(author)
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Using verbal autopsy to track epidemic dynamics : the case of HIV-related mortality in South Africa.
- 2011
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 9, s. 46-
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Journal article (peer-reviewed)abstract
- Background Verbal autopsy (VA) has often been used for point estimates of cause-specific mortality, but seldom to characterize long-term changes in epidemic patterns. Monitoring emerging causes of death involves practitioners' developing perceptions of diseases and demands consistent methods and practices. Here we retrospectively analyze HIV-related mortality in South Africa, using physician and modeled interpretation.Methods Between 1992 and 2005, 94% of 6,153 deaths which occurred in the Agincourt subdistrict had VAs completed, and coded by two physicians and the InterVA model. The physician causes of death were consolidated into a single consensus underlying cause per case, with an additional physician arbitrating where different diagnoses persisted. HIV-related mortality rates and proportions of deaths coded as HIV-related by individual physicians, physician consensus, and the InterVA model were compared over time.Results Approximately 20% of deaths were HIV-related, ranging from early low levels to tenfold-higher later population rates (2.5 per 1,000 person-years). Rates were higher among children under 5 years and adults 20 to 64 years. Adult mortality shifted to older ages as the epidemic progressed, with a noticeable number of HIV-related deaths in the over-65 year age group latterly. Early InterVA results suggested slightly higher initial HIV-related mortality than physician consensus found. Overall, physician consensus and InterVA results characterized the epidemic very similarly. Individual physicians showed marked interobserver variation, with consensus findings generally reflecting slightly lower proportions of HIV-related deaths. Aggregated findings for first versus second physician did not differ appreciably.Conclusions VA effectively detected a very significant epidemic of HIV-related mortality. Using either physicians or InterVA gave closely comparable findings regarding the epidemic. The consistency between two physician coders per case (from a pool of 14) suggests that double coding may be unnecessary, although the consensus rate of HIV-related mortality was approximately 8% lower than by individual physicians. Consistency within and between individual physicians, individual perceptions of epidemic dynamics, and the inherent consistency of models are important considerations here. The ability of the InterVA model to track a more than tenfold increase in HIV-related mortality over time suggests that finely tuned "local" versions of models for VA interpretation are not necessary.
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| 7. |
- Byass, Peter
(author)
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Whither verbal autopsy?
- 2011
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 9, s. 23-
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Journal article (peer-reviewed)
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| 8. |
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| 10. |
- Rey, Grégoire, et al.
(author)
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Cause-specific mortality time series analysis : a general method to detect and correct for abrupt data production changes
- 2011
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 9, s. 52-
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Journal article (peer-reviewed)abstract
- BACKGROUND:Monitoring the time course of mortality by cause is a key public health issue. However, several mortality data production changes may affect cause-specific time trends, thus altering the interpretation. This paper proposes a statistical method that detects abrupt changes ("jumps") and estimates correction factors that may be used for further analysis.METHODS:The method was applied to a subset of the AMIEHS (Avoidable Mortality in the European Union, toward better Indicators for the Effectiveness of Health Systems) project mortality database and considered for six European countries and 13 selected causes of deaths. For each country and cause of death, an automated jump detection method called Polydect was applied to the log mortality rate time series. The plausibility of a data production change associated with each detected jump was evaluated through literature search or feedback obtained from the national data producers.For each plausible jump position, the statistical significance of the between-age and between-gender jump amplitude heterogeneity was evaluated by means of a generalized additive regression model, and correction factors were deduced from the results.RESULTS:Forty-nine jumps were detected by the Polydect method from 1970 to 2005. Most of the detected jumps were found to be plausible. The age- and gender-specific amplitudes of the jumps were estimated when they were statistically heterogeneous, and they showed greater by-age heterogeneity than by-gender heterogeneity.CONCLUSION:The method presented in this paper was successfully applied to a large set of causes of death and countries. The method appears to be an alternative to bridge coding methods when the latter are not systematically implemented because they are time- and resource-consuming.
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| 11. |
- van Raalte, Alyson A., et al.
(author)
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The contribution of educational inequalities to lifespan variation
- 2012
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 10:3
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Journal article (peer-reviewed)abstract
- BackgroundStudies of socioeconomic inequalities in mortality consistently point to higher death rates in lower socioeconomic groups. Yet how these between-group differences relate to the total variation in mortality risk between individuals is unknown.MethodsWe used data assembled and harmonized as part of the Eurothine project, which includes census-based mortality data from 11 European countries. We matched this to national data from the Human Mortality Database and constructed life tables by gender and educational level. We measured variation in age at death using Theil's entropy index, and decomposed this measure into its between- and within-group components.ResultsThe least-educated groups lived between three and 15 years fewer than the highest-educated groups, the latter having a more similar age at death in all countries. Differences between educational groups contributed between 0.6% and 2.7% to total variation in age at death between individuals in Western European countries and between 1.2% and 10.9% in Central and Eastern European countries. Variation in age at death is larger and differs more between countries among the least-educated groups.ConclusionsAt the individual level, many known and unknown factors are causing enormous variation in age at death, socioeconomic position being only one of them. Reducing variations in age at death among less-educated people by providing protection to the vulnerable may help to reduce inequalities in mortality between socioeconomic groups.
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| 12. |
- Vergnano, Stefania, et al.
(author)
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Adaptation of a probabilistic method (InterVA) of verbal autopsy to improve the interpretation of cause of stillbirth and neonatal death in Malawi, Nepal, and Zimbabwe.
- 2011
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 9, s. 48-
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Journal article (peer-reviewed)abstract
- BackgroundVerbal autopsy (VA) is a widely used method for analyzing cause of death in absence of vital registration systems. We adapted the InterVA method to extrapolate causes of death for stillbirths and neonatal deaths from verbal autopsy questionnaires, using data from Malawi, Zimbabwe, and Nepal.MethodsWe obtained 734 stillbirth and neonatal VAs from recent community studies in rural areas: 169 from Malawi, 385 from Nepal, and 180 from Zimbabwe. Initial refinement of the InterVA model was based on 100 physician-reviewed VAs from Malawi. InterVA indicators and matrix probabilities for cause of death were reviewed for clinical and epidemiological coherence by a pediatrician-researcher and an epidemiologist involved in the development of InterVA. The modified InterVA model was evaluated by comparing population-level cause-specific mortality fractions and individual agreement from two methods of interpretation (physician review and InterVA) for a further 69 VAs from Malawi, 385 from Nepal, and 180 from Zimbabwe.ResultsCase-by-case agreement between InterVA and reviewing physician diagnoses for 69 cases from Malawi, 180 cases from Zimbabwe, and 385 cases from Nepal were 83% (kappa 0.76 (0.75 - 0.80)), 71% (kappa 0.41(0.32-0.51)), and 74% (kappa 0.63 (0.60-0.63)), respectively. The proportion of stillbirths identified as fresh or macerated by the different methods of VA interpretation was similar in all three settings. Comparing across countries, the modified InterVA method found that proportions of preterm births and deaths due to infection were higher in Zimbabwe (44%) than in Malawi (28%) or Nepal (20%).ConclusionThe modified InterVA method provides plausible results for stillbirths and newborn deaths, broadly comparable to physician review but with the advantage of internal consistency. The method allows standardized cross-country comparisons and eliminates the inconsistencies of physician review in such comparisons.
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| 13. |
- Kabudula, Chodziwadziwa W., et al.
(author)
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Evaluation of record linkage of mortality data between a health and demographic surveillance system and national civil registration system in South Africa
- 2014
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In: Population Health Metrics. - : Springer Science and Business Media LLC. - 1478-7954. ; 12
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Journal article (peer-reviewed)abstract
- Background: Health and Demographic Surveillance Systems (HDSS) collect independent mortality data that could be used for assessing the quality of mortality data in national civil registration (CR) systems in low- and middle-income countries. However, the use of HDSS data for such purposes depends on the quality of record linkage between the two data sources. We describe and evaluate the quality of record linkage between HDSS and CR mortality data in South Africa with HDSS data from Agincourt HDSS. Methods: We applied deterministic and probabilistic record linkage approaches to mortality records from 2006 to 2009 from the Agincourt HDSS and those in the CR system. Quality of the matches generated by the probabilistic approach was evaluated using sensitivity and positive predictive value (PPV) calculated from a subset of records that were linked using national identity number. Matched and unmatched records from the Agincourt HDSS were compared to identify characteristics associated with successful matching. In addition, the distribution of background characteristics in all deaths that occurred in 2009 and those linked to CR records was compared to assess systematic bias in the resulting record-linked dataset in the latest time period. Results: Deterministic and probabilistic record linkage approaches combined linked a total of 2264 out of 3726 (60.8%) mortality records from the Agincourt HDSS to those in the CR system. Probabilistic approaches independently linked 1969 (87.0%) of the linked records. In a subset of 708 records that were linked using national identity number, the probabilistic approaches yielded sensitivity of 90.0% and PPV of 98.5%. Records belonging to more vulnerable people, including poorer persons, young children, and non-South Africans were less likely to be matched. Nevertheless, distribution of most background characteristics was similar between all Agincourt HDSS deaths and those matched to CR records in the latest time period. Conclusion: This study shows that record linkage of mortality data from HDSS and CR systems is possible and can be useful in South Africa. The study identifies predictors for death registration and data items and registration system characteristics that could be improved to achieve more optimal future matching possibilities.
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