American journal of epidemiology最新文献

Emerging evidence links per- and polyfluoroalkyl substances (PFAS) exposure and metabolic disruptions to fetal growth retardation. However, earlier studies on singletons could not fully account for genetic factors. Therefore, we used a cotwin control study design to identify cord metabolomic signatures of PFAS exposure and assess its mediating role in twin birthweight discordance. We analyzed 204 twin neonates born from the Wuhan Twin Birth Cohort (August 2016 to January 2018). Cord serum PFAS concentrations and untargeted metabolomic profiles were determined using liquid chromatography-tandem mass spectrometry. Within-twin metabolome-wide association analyses identified 69 metabolites (effect coefficients: 0.09-0.35) positively associated with log2-transformed perfluorooctanoic acid difference and 51 metabolites (effect coefficients: 0.08-0.38) positively associated with log2-transformed perfluoroheptane sulfonate (PFHpS) difference after false discovery rate correction. PFAS-associated metabolites were primarily enriched in steroid hormone biosynthesis, arginine and proline metabolism, glycerophospholipid metabolism, and unsaturated fatty acid biosynthesis pathways. Five amino acids, one carbohydrate, one cofactor and vitamin, and five lipids mediated the relationship between PFHpS exposure difference and intratwin birthweight difference, with mediation proportions ranging from 32.0% to 72.7%. This study is the first to use a within-twin comparison, providing new insights into the underlying mechanisms linking PFAS exposure with twin birthweight discordance.

The COVID Infection Survey monitored daily positivity through the COVID-19 pandemic from April 26, 2020 to March 13, 2023. In total, 451 079 participants in private residential households were enrolled in England and tested at regular intervals for SARS-CoV-2. Here, we estimated the cumulative incidence of polymerase chain reaction-positive infections using a multilevel regression and poststratification model to obtain estimates of daily positivity, combined with a distribution of the duration of positivity from regular testing data. We estimated cumulative incidence by epoch (approximated by the dominance of successive SARS-CoV-2 variants) and calculated the corresponding infection hospitalization ratios. We found that cumulative incidence was relatively low during pre-Alpha and Alpha-dominant epochs, rose steadily during the Delta-dominant epoch, and was highest during successive Omicron-dominant epochs. High cumulative incidences in successive Omicron-dominant epochs are consistent with lack of protection from previous infections. However, infection hospitalization ratios, whilst higher at the start of the pandemic, remained low after the Delta-dominant epoch and vaccine introduction. Stratified estimates show hospitalization risk was consistently very low for younger age groups, increasing with age. Surveys with random sampling and longitudinal designs facilitate direct estimation of prevalence and incidence, however, should be complemented by dense sampling to estimate duration of infection to maximize their value.

Post-traumatic stress disorder (PTSD) has been related to ischemic heart disease (IHD), and the primary substrate for IHD is atherosclerotic burden. We aim to estimate the association between exposure to PTSD and atherosclerotic burden in PTSD-discordant twin pairs. This is a cross-sectional examination of 212 male twins during the 2016-2019 study visit of the Vietnam Era Twin Registry. Current PTSD symptom severity was assessed with the Clinician-Administered PTSD Scale for DSM-IV. PTSD-discordant twins were defined as pairs with different values of the PTSD Symptoms Scale. We regressed the log-transformed CAC Score on the PTSD Scale adjusted for potential confounders using linear mixed models and reported exponentiated coefficients. The sample had a median age of 68 (IQR67-70) years, a 15% prevalence of PTSD (median Symptom Score of 61; IQR53-81), and a median CAC Score of 111 (IQR5-346). The median CAC Score was 69 (IQR0.40-229) in twins with higher PTSD symptoms and 89 (IQR6.6-243) in their brothers with lower PTSD symptoms. The model estimated a -0.95% difference in CAC Score per unit increment in PTSD Symptoms Score within pairs (95%CI -2.6%;+0.7%), not implying a relationship between PTSD and coronary atherosclerosis in a design that inherently controls for familial and early environmental factors.

Nonvaccination and undervaccination with the COVID-19 vaccine may be attributed to multifaceted barriers including hesitancy and access issues. Using data from the CDC's Research and Development Survey, a nationally representative survey fielded from November 3 to December 12, 2022 (n = 6821), we examined the adjusted population attribution fraction (PAF) of COVID-19 nonvaccination and undervaccination attributed to vaccine hesitancy by sociodemographic characteristics. Overall, the adjusted PAF of nonvaccination attributed to vaccine hesitancy was 84.8%, and the adjusted PAF of undervaccination attributed to vaccine hesitancy decreased with increasing COVID-19 vaccine doses (76.0%, 41.0%, and 16.9% for ≥2, ≥3, and ≥4 doses, respectively). The proportion of adults who considered the social benefit of the vaccine, risk of contracting COVID-19, and information received from a medical provider increased with greater number of COVID-19 vaccine doses received. In contrast, the proportion of adults who were concerned about long-term impacts, speed of vaccine development, and personal risk of getting vaccinated decreased with greater number of COVID-19 vaccine doses received. Understanding the PAF estimates from the acute phase of the pandemic serves as an important comparison for postpandemic vaccination estimates, and is needed for messaging as COVID-19 cases, hospitalizations, and deaths resurge in the fall of 2024.

The COVID-19 pandemic has disproportionately impacted Black nursing home (NH) residents. Alzheimer's disease and related dementias (ADRDs) may exacerbate disparities, but little empirical evidence exists on the degree to which race and ADRDs intersect to impact COVID-19-related outcomes. We conducted a cohort study (April-December 2020) leveraging electronic health records from 12 US NH corporations. We used the parametric g-formula to obtain standardized estimates of incident COVID-19 infection and 30-day COVID-19-associated hospitalization or death by race, both overall and within strata of ADRD status. The cohort comprised 127 913 resident-episodes, including 15 379 incident COVID-19 infections, 1522 deaths, and 2548 hospitalizations. Black residents were more likely than White residents to experience incident COVID-19 and subsequent hospitalization, but not more likely to subsequently die. Disparities in hospitalization and a combined endpoint of hospitalization or death were more pronounced among residents with ADRDs compared to residents without ADRDs. These results suggest the presence of disparities in COVID-19 outcomes by race and provide evidence that ADRD status may exacerbate racial disparities in COVID-19 outcomes among nursing home residents. Our findings offer valuable insights for current and future preparedness efforts in NHs in the United States and countries with similarly underresourced long-term care settings. This article is part of a Special Collection on Methods in Social Epidemiology.

Mendelian randomization (MR) is a technique that uses genetic variation to address causal questions about how modifiable exposures influence health. For some time-varying phenotypes, genetic effects may have differential importance at different periods in the lifecourse. MR studies often employ conventional instrumental variable (IV) methods designed to estimate average lifetime effects. Recently, several extensions of MR have been proposed to investigate time-varying effects, including structural mean models (SMMs). SMMs exploit IVs through g-estimation and circumvent some of the parametric assumptions required by other MR methods. In this study, we applied g-estimation of SMMs within an MR framework to estimate the period effects of adiposity measured at two life stages, childhood and adulthood, on cardiovascular disease (CVD), type 2 diabetes (T2D), and breast cancer. We found persistent period effects of higher adulthood adiposity on increased risk of CVD and T2D. Higher childhood adiposity had a protective period effect on breast cancer risk. We compared this approach with an inverse variance weighted multivariable MR method, which also uses multiple IVs to assess time-varying effects but relies on a different set of assumptions. We highlight the strengths and limitations of each approach and conclude by emphasizing the importance of underlying methodological assumptions in the application of MR to lifecourse research.

The United States is the only high-income country without a national paid family leave (PFL) policy, although several states have implemented policies recently. This study evaluated whether PFL policies in 6 states improved maternal and infant health. We used difference-in-differences, a quasi-experimental approach, to estimate the impact of state-level policy implementation. We leveraged recently developed methods designed to account for staggered policy implementation and treatment effect heterogeneity. Data were drawn from the 2004-2021 waves of the Pregnancy Risk Assessment Monitoring System. Primary outcomes included breastfeeding, maternal postpartum depressive symptoms, and attendance at a postpartum checkup; secondary outcomes included birth outcomes. Multivariable regressions were adjusted for possible confounders. PFL policies led to increased breastfeeding duration (0.53 weeks; 95% CI, 0.06-0.99) and decreased depressive symptoms (-0.93 percentage points; 95% CI, -1.84 to -0.01). Policies were also associated with worsening of some birth outcomes, possibly reflecting selection in utero, data limitations, or true negative effects. Estimates were largely robust to alternative specifications, with subgroup differences by race/ethnicity and income. This study adds important evidence on the health effects of state-level PFL policies at a critical point when many states are considering or enacting policies and during ongoing conversations about national PFL policy implementation. This article is part of a Special Collection on Methods in Social Epidemiology.