| 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, et al.
(author)
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Assessing the repeatability of verbal autopsy for determining cause of death : two case studies among women of reproductive age in Burkina Faso and Indonesia
- 2009
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 7:1, s. 6-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Verbal autopsy (VA) is an established tool for assessing cause-specific mortality patterns in communities where deaths are not routinely medically certified, and is an important source of data on deaths among the poorer half of the world's population. However, the repeatability of the VA process has never been investigated, even though it is an important factor in its overall validity. This study analyses repeatability in terms of the overall VA process (from interview to cause-specific mortality fractions (CSMF)), as well as specifically for interview material and individual causes of death, using data from Burkina Faso and Indonesia.METHODS: Two series of repeated VA interviews relating to women of reproductive age in Burkina Faso (n = 91) and Indonesia (n = 116) were analysed for repeatability in terms of interview material, individual causes of death and CSMFs. All the VA data were interpreted using the InterVA-M model, which provides 100% intrinsic repeatability for interpretation, and thus eliminated the need to consider variations or repeatability in physician coding.RESULTS: The repeatability of the overall VA process from interview to CSMFs was good in both countries. Repeatability was moderate in the interview material, and lower in terms of individual causes of death. Burkinabé data were less repeatable than Indonesian, and repeatability also declined with longer recall periods between the death and interview, particularly after two years.CONCLUSION: While these analyses do not address the validity of the VA process in absolute terms, repeatability is a prerequisite for intrinsic validity. This study thus adds new understanding to the quest for reliable cause of death assessment in communities lacking routine medical certification of deaths, and confirms the status of VA as an important and reliable tool at the community level, but perhaps less so at the individual level.
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| 6. |
- Byass, Peter, et al.
(author)
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DSS and DHS : longitudinal and cross-sectional viewpoints on child and adolescent mortality in Ethiopia
- 2007
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 5:1, s. Article nr 12-
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Journal article (peer-reviewed)abstract
- BACKGROUND: In countries where routine vital registration data are scarce, Demographic Surveillance Sites (DSS: locally defined populations under longitudinal surveillance for vital events and other characteristics) and Demographic and Health Surveys (DHS: periodic national cluster samples responding to cross-sectional surveys) have become standard approaches for gathering at least some data. This paper aims to compare DSS and DHS approaches, seeing how they complement each other in the specific instance of child and adolescent mortality in Ethiopia.METHODS: Data from the Butajira DSS 1987-2004 and the Ethiopia DHS rounds for 2000 and 2005 formed the basis of comparative analyses of mortality rates among those aged under 20 years, using Poisson regression models for adjusted rate ratios.RESULTS: Patterns of mortality over time were broadly comparable using DSS and DHS approaches. DSS data were more susceptible to local epidemic variations, while DHS data tended to smooth out local variation, and be more subject to recall bias.CONCLUSION: Both DSS and DHS approaches to mortality surveillance gave similar overall results, but both showed method-dependent advantages and disadvantages. In many settings, this kind of joint-source data analysis could offer significant added value to results.
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| 7. |
- 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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| 8. |
- 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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| 9. |
- 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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| 10. |
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