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- Bonander, Carl
(författare)
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A (Flexible) Synthetic Control Method for Count Data and Other Nonnegative Outcomes
- 2021
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Ingår i: Epidemiology. - : Ovid Technologies (Wolters Kluwer Health). - 1044-3983. ; 32:5, s. 653-660
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Tidskriftsartikel (refereegranskat)abstract
- The synthetic control method is a covariate balancing method that exploits data from untreated regions to construct a synthetic control that approximates a single, aggregate treatment unit on a time series of preintervention outcomes and covariates. The method is increasingly being used to evaluate population-level interventions in epidemiology. Although the original version can be used with bounded outcomes, it imposes strong constraints on the balancing weights to ensure that the counterfactuals are based solely on interpolation. This feature, while attractive from a causal inference perspective, is sometimes too conservative and can lead to unnecessary bias due to poor covariate balance. Alternatives exist that allow for extrapolation to improve balance but existing procedures may produce negative estimates of the counterfactual outcomes and are therefore inappropriate for count data. We propose an alternative way to allow for extrapolation, although ensuring that the estimated counterfactuals remain nonnegative. Following a related proposal, we add a penalty to the balancing procedure that favors interpolation over extrapolation whenever possible. As we demonstrate theoretically and using empirical examples, our proposal can serve as a useful alternative when existing approaches yield demonstrably poor or unrealistic counterfactuals. Finally, we provide functions to implement the method in R.
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| 3. |
- Gedeborg, Rolf, et al.
(författare)
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An Aggregated Comorbidity Measure Based on History of Filled Drug Prescriptions : Development and Evaluation in Two Separate Cohorts
- 2021
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Ingår i: Epidemiology. - : Lippincott Williams & Wilkins. - 1044-3983 .- 1531-5487. ; 32:4, s. 607-615
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Tidskriftsartikel (refereegranskat)abstract
- Background: The ability to account for comorbidity when estimating survival in a population diagnosed with cancer could be improved by using a drug comorbidity index based on filled drug prescriptions.Methods: We created a drug comorbidity index from age-stratified univariable associations between filled drug prescriptions and time to death in 326,450 control males randomly selected from the general population to men with prostate cancer. We also evaluated the index in 272,214 control females randomly selected from the general population to women with breast cancer.Results: The new drug comorbidity index predicted survival better than the Charlson Comorbidity Index (CCI) and a previously published prescription index during 11 years of follow-up. The concordance (C)-index for the new index was 0.73 in male and 0.76 in the female population, as compared with a C-index of 0.67 in men and 0.69 in women for the CCI. In men of age 75-84 years with CCI = 0, the median survival time was 7.1 years (95% confidence interval [CI] = 7.0, 7.3) in the highest index quartile. Comparing the highest to the lowest drug comorbidity index quartile resulted in a hazard ratio (HR) of 2.2 among men (95% CI = 2.1, 2.3) and 2.4 among women (95% CI = 2.3, 2.6).Conclusions: A new drug comorbidity index based on filled drug prescriptions improved prediction of survival beyond age and the CCI alone. The index will allow a more accurate baseline estimation of expected survival for comparing treatment outcomes and evaluating treatment guidelines in populations of people with cancer.
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- Hiyoshi, Ayako, 1972-, et al.
(författare)
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Visual acuity and the risk of cycling injuries : register-based cohort study from adolescence to middle-age
- 2022
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Ingår i: Epidemiology. - : Lippincott Williams & Wilkins. - 1044-3983 .- 1531-5487. ; 33:2, s. 246-253
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cycling is increasingly encouraged in many countries as an inexpensive and healthy choice of transportation. Operating any vehicle on the road requires high visual acuity, but few studies to our knowledge have examined the association between vision and cycling injuries.METHODS: We examined whether poorer visual acuity is associated with increased risk of fatal and non-fatal cycling injuries. We used prospectively recorded register data for 691,402 men born between 1970 and 1992 in Sweden. We followed these men from an average age of 18 years, when visual acuity was assessed during the conscription assessment, to age 45 at the latest. We identified fatal and non-fatal cycling and car injuries using Patient and Cause of Death registers. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI).RESULTS: Based on visual acuity for the eye with the best vision, moderately impaired acuity 0.9 to 0.6 when wearing refractive correction was associated with increased risk for cycling injuries (HR=1.44, 95%CI 1.16-1.79) compared with unimpaired vision (uncorrected visual acuity 1.0) and after adjustment for a wide range of potential confounders. This association remained consistent across various sensitivity analyses. Visual acuity was not associated with car injury risk.CONCLUSIONS: In this cohort study, poorer vision was specifically associated with a higher rate of cycling injuries.
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- Masselot, Pierre, et al.
(författare)
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Differential mortality risks associated with PM2.5 components : a multi-country, multi-city study
- 2022
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Ingår i: Epidemiology. - : Wolters Kluwer. - 1044-3983 .- 1531-5487. ; 33:2, s. 167-175
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The association between fine particulate matter (PM2.5) and mortality widely differs between as well as within countries. Differences in PM2.5 composition can play a role in modifying the effect estimates, but there is little evidence about which components have higher impacts on mortality.METHODS: We applied a two-stage analysis on data collected from 210 locations in 16 countries. In the first stage, we estimated location-specific relative risks (RR) for mortality associated with daily total PM2.5 through time series regression analysis. We then pooled these estimates in a meta-regression model that included city-specific logratio-transformed proportions of seven PM2.5 components as well as meta-predictors derived from city-specific socio-economic and environmental indicators.RESULTS: We found associations between RR and several PM2.5 components. Increasing the ammonium (NH4+) proportion from 1% to 22%, while keeping a relative average proportion of other components, increased the RR from 1.0063 (95%CI: 1.0030-1.0097) to 1.0102 (95%CI:1.0070-1.0135). Conversely, an increase in nitrate (NO3-) from 1% to 71% resulted in a reduced RR, from 1.0100 (95%CI: 1.0067-1.0133) to 1.0037 (95%CI: 0.9998- 1.0077). Differences in composition explained a substantial part of the heterogeneity in PM2.5 risk.CONCLUSIONS: These findings contribute to the identification of more hazardous emission sources. Further work is needed to understand the health impacts of PM2.5 components and sources given the overlapping sources and correlations among many components.
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- Meyer, Anna C., et al.
(författare)
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Trends in Hip Fracture Incidence, Recurrence, and Survival by Education and Comorbidity : A Swedish Register-based Study
- 2021
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Ingår i: Epidemiology. - 1044-3983 .- 1531-5487. ; 32:3, s. 425-433
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hip fractures are common and severe conditions among older individuals, associated with high mortality, and the Nordic countries have the highest incidence rates globally. With this study, we aim to present a comprehensive picture of trends in hip fracture incidence and survival in the older Swedish population stratified by education, birth country, and comorbidity level.Methods: This study is based on a linkage of several population registers and included the entire population over the age of 60 living in Sweden. We calculated age-standardized incidence rates for first and recurrent hip fractures as well as age-standardized proportions of patients surviving 30 and 365 days through the time period 1998 to 2017. We calculated all outcomes for men and women in the total population and in each population stratum.Results: Altogether, we observed 289,603 first hip fractures during the study period. Age-standardized incidence rates of first and recurrent fractures declined among men and women in the total population and in each educational-, birth country-, and comorbidity group. Declines in incidence were more pronounced for recurrent than for first fractures. Approximately 20% of women and 30% of men died within 1 year of their first hip fracture. Overall, survival proportions remained constant throughout the study period but improved when taking into account comorbidity level.Conclusions: Hip fracture incidence has declined across the Swedish population, but mortality after hip fracture remained high, especially among men. Hip fracture patients constitute a vulnerable population group with increasing comorbidity burden and high mortality risk.
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| 8. |
- Shiba, K., et al.
(författare)
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Estimating the Impact of Sustained Social Participation on Depressive Symptoms in Older Adults
- 2021
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Ingår i: Epidemiology. - : Ovid Technologies (Wolters Kluwer Health). - 1044-3983. ; 32:6, s. 886-895
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Tidskriftsartikel (refereegranskat)abstract
- Background: Social participation has been suggested as a means to prevent depressive symptoms. However, it remains unclear whether a one-time boost suffices or whether participation needs to be sustained over time for long-term prevention. We estimated the impacts of alternative hypothetical interventions in social participation on subsequent depressive symptoms among older adults. Methods: Data were from a nationwide prospective cohort study of Japanese older adults >= 65 years of age (n = 32,748). We analyzed social participation (1) as a baseline exposure from 2010 (approximating a one-time boost intervention) and (2) as a time-varying exposure from 2010 and 2013 (approximating a sustained intervention). We defined binary depressive symptoms in 2016 using the Geriatric Depression Scale. We used the doubly robust targeted maximum likelihood estimation to address time-dependent confounding. Results: The magnitude of the association between sustained participation and the lower prevalence of depressive symptoms was larger than the association observed for baseline participation only (e.g., prevalence ratio [PR] for participation in any activity = 0.83 [95% confidence interval = 0.79, 0.88] vs. 0.90 [0.87, 0.94]). For activities with a lower proportion of consistent participation over time (e.g., senior clubs), there was little evidence of an association between baseline participation and subsequent depressive symptoms, while an association for sustained participation was evident (e.g., PR for senior clubs = 0.96 [0.90, 1.02] vs. 0.88 [0.79, 0.97]). Participation at baseline but withholding participation in 2013 was not associated with subsequent depressive symptoms. Conclusions: Sustained social participation may be more strongly associated with fewer depressive symptoms among older adults.
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| 10. |
- Vielot, Nadja A., et al.
(författare)
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First Episodes of Norovirus and Sapovirus Gastroenteritis Protect Against Subsequent Episodes in a Nicaraguan Birth Cohort
- 2022
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Ingår i: Epidemiology. - 1044-3983 .- 1531-5487. ; 33:5, s. 650-653
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Tidskriftsartikel (refereegranskat)abstract
- Background: Norovirus and sapovirus cause a large burden of acute gastroenteritis (AGE) in young children. We assessed protection conferred by norovirus and sapovirus AGE episodes against future episodes.Methods: Between June 2017 and July 2018, we recruited 444 newborns in León, Nicaragua. Weekly household surveys identified AGE episodes over 36 months, and AGE stools were tested by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) for norovirus genogroup (G)I/GII and sapovirus. We used recurrent-event Cox models and negative control methods to estimate protection conferred by first episodes, controlling for observed and unobserved risk factors, respectively.Results: Sapovirus episodes conferred a 69% reduced hazard of subsequent episodes using the negative control method. Norovirus GI (hazard ratio [HR] = 0.67; 95% confidence interval [CI] = 0.31, 1.3) and GII (HR = 0.20; 95% CI = 0.04, 0.44) episodes also appeared highly protective. Protection against norovirus GII was enhanced following two episodes.Conclusions: Evidence of natural immunity in early childhood provides optimism for the future success of pediatric norovirus and sapovirus vaccines.
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