Faculty Bibliography

BACKGROUND:Sickle cell trait affects approximately 8% of Black individuals in the United States, along with many other individuals with ancestry from malaria-endemic regions worldwide. While traditionally considered a benign condition, recent evidence suggests that sickle cell trait is associated with lower eGFR and higher risk of kidney diseases, including kidney failure. The mechanisms underlying these associations remain poorly understood. We used proteomic profiling to gain insight into the pathobiology of sickle cell trait. METHODS:We measured proteomics ( N =1285 proteins assayed by Olink Explore) using baseline plasma samples from 592 Black participants with sickle cell trait and 1:1 age-matched Black participants without sickle cell trait from the prospective Women's Health Initiative cohort. Age-adjusted linear regression was used to assess the association between protein levels and sickle cell trait. RESULTS:In age-adjusted models, 35 proteins were significantly associated with sickle cell trait after correction for multiple testing. Several of the sickle cell trait-protein associations were replicated in Black participants from two independent cohorts (Atherosclerosis Risk in Communities study and Jackson Heart Study) assayed using an orthogonal aptamer-based proteomic platform (SomaScan). Many of the validated sickle cell trait-associated proteins are known biomarkers of kidney function or injury ( e.g. , hepatitis A virus cellular receptor 1 [HAVCR1]/kidney injury molecule-1 [KIM-1], uromodulin [UMOD], ephrins), related to red cell physiology or hemolysis (erythropoietin [EPO], heme oxygenase 1 [HMOX1], and α -hemoglobin stabilizing protein) and/or inflammation (fractalkine, C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 [MCP-1], and urokinase plasminogen activator surface receptor [PLAUR]). A protein risk score constructed from the top sickle cell trait-associated biomarkers was associated with incident kidney failure among those with sickle cell trait during Women's Health Initiative follow-up (odds ratio, 1.32; 95% confidence interval, 1.10 to 1.58). CONCLUSIONS:We identified and replicated the association of sickle cell trait with a number of plasma proteins related to hemolysis, kidney injury, and inflammation.

The discrete-time Wright-Fisher (DTWF) model and its diffusion limit are central to population genetics. These models can describe the forward-in-time evolution of allele frequencies in a population resulting from genetic drift, mutation, and selection. Computing likelihoods under the diffusion process is feasible, but the diffusion approximation breaks down for large samples or in the presence of strong selection. Existing methods for computing likelihoods under the DTWF model do not scale to current exome sequencing sample sizes in the hundreds of thousands. Here, we present a scalable algorithm that approximates the DTWF model with provably bounded error. Our approach relies on two key observations about the DTWF model. The first is that transition probabilities under the model are approximately sparse. The second is that transition distributions for similar starting allele frequencies are extremely close as distributions. Together, these observations enable approximate matrix-vector multiplication in linear (as opposed to the usual quadratic) time. We prove similar properties for Hypergeometric distributions, enabling fast computation of likelihoods for subsamples of the population. We show theoretically and in practice that this approximation is highly accurate and can scale to population sizes in the tens of millions, paving the way for rigorous biobank-scale inference. Finally, we use our results to estimate the impact of larger samples on estimating selection coefficients for loss-of-function variants. We find that increasing sample sizes beyond existing large exome sequencing cohorts will provide essentially no additional information except for genes with the most extreme fitness effects.

IMPORTANCE/UNASSIGNED:After the initial disruption from the COVID-19 pandemic, it is unclear how patterns of e-cigarette use in the US have changed. OBJECTIVE/UNASSIGNED:To examine recent patterns in current and daily e-cigarette use among US adults in 2021. DESIGN, SETTING, AND PARTICIPANTS/UNASSIGNED:This cross-sectional study used data from the 2021 Behavioral Risk Factor Surveillance System (BRFSS) database. The BRFSS is the largest national telephone-based survey of randomly sampled adults in the US. Adults aged 18 years or older, residing in 49 US states (all except Florida), the District of Columbia, and 3 US territories (Guam, Puerto Rico, and the US Virgin Islands), were included in the data set. Data analysis was performed in January 2023. MAIN OUTCOMES AND MEASURES/UNASSIGNED:The main outcome was age-adjusted prevalence of current and daily e-cigarette use overall and by participant characteristics, state, and territory. Descriptive statistical analysis was conducted, applying weights to account for population representation. RESULTS/UNASSIGNED:This study included 414 755 BRFSS participants with information on e-cigarette use. More than half of participants were women (51.3%). In terms of race and ethnicity, 0.9% of participants were American Indian or Alaska Native, 5.8% were Asian, 11.5% were Black, 17.3% were Hispanic, 0.2% were Native Hawaiian or Other Pacific Islander, 62.2% were White, 1.4% were of multiple races or ethnicities, and 0.6% were of other race or ethnicity. Individuals aged 18 to 24 years comprised 12.4% of the study population. The age-standardized prevalence of current e-cigarette use was 6.9% (95% CI, 6.7%-7.1%), with almost half of participants using e-cigarettes daily (3.2% [95% CI, 3.1%-3.4%]). Among individuals aged 18 to 24 years, there was a consistently higher prevalence of e-cigarette use, with more than 18.6% reporting current use and more than 9.0% reporting daily use. Overall, among individuals reporting current e-cigarette use, 42.2% (95% CI, 40.7%-43.7%) indicated former combustible cigarette use, 37.1% (95% CI, 35.6%-38.6%) indicated current combustible cigarette use, and 20.7% (95% CI, 19.7%-21.8%) indicated never using combustible cigarettes. Although relatively older adults (aged ≥25 years) who reported current e-cigarette use were more likely to report former or current combustible cigarette use, younger adults (aged 18-24 years) were more likely to report never using combustible cigarettes. Notably, the proportion of individuals who reported current e-cigarette use and never using combustible cigarettes was higher in the group aged 18 to 20 years (71.5% [95% CI, 66.8%-75.7%]) compared with those aged 21 to 24 years (53.0% [95% CI, 49.8%-56.1%]). CONCLUSION AND RELEVANCE/UNASSIGNED:These findings suggest that e-cigarette use remained common during the COVID-19 pandemic, particularly among young adults aged 18 to 24 years (18.3% prevalence). Notably, 71.5% of individuals aged 18 to 20 years who reported current e-cigarette use had never used combustible cigarettes. These results underscore the rationale for the implementation and enforcement of public health policies tailored to young adults.

BACKGROUND:Drinking water is a common source of exposure to inorganic arsenic. In the US, the Safe Drinking Water Act (SDWA) was enacted to protect consumers from exposure to contaminants, including arsenic, in public water systems (PWS). The reproductive effects of preconception and prenatal arsenic exposure in regions with low to moderate arsenic concentrations are not well understood. OBJECTIVES:This study examined associations between preconception and prenatal exposure to arsenic violations in water, measured via residence in a county with an arsenic violation in a regulated PWS during pregnancy, and five birth outcomes: birth weight, gestational age at birth, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). METHODS:Data for arsenic violations in PWS, defined as concentrations exceeding 10 parts per billion, were obtained from the Safe Drinking Water Information System. Participants of the Environmental influences on Child Health Outcomes Cohort Study were matched to arsenic violations by time and location based on residential history data. Multivariable, mixed effects regression models were used to assess the relationship between preconception and prenatal exposure to arsenic violations in drinking water and birth outcomes. RESULTS:Compared to unexposed infants, continuous exposure to arsenic from three months prior to conception through birth was associated with 88.8 g higher mean birth weight (95% CI: 8.2, 169.5), after adjusting for individual-level confounders. No statistically significant associations were observed between any preconception or prenatal violations exposure and gestational age at birth, preterm birth, SGA, or LGA. CONCLUSIONS:Our study did not identify associations between preconception and prenatal arsenic exposure, defined by drinking water exceedances, and adverse birth outcomes. Exposure to arsenic violations in drinking water was associated with higher birth weight. Future studies would benefit from more precise geodata of water system service areas, direct household drinking water measurements, and exposure biomarkers.

CONTEXT/BACKGROUND:Children with medical complexity (CMC) are at risk for adverse outcomes after discharge. Difficulties with comprehension of and adherence to discharge instructions contribute to these errors. Comprehensive reviews of patient-, caregiver-, provider-, and system-level characteristics and interventions associated with discharge instruction comprehension and adherence for CMC are lacking. OBJECTIVE:To systematically review the literature related to factors associated with comprehension of and adherence to discharge instructions for CMC. DATA SOURCES/METHODS:PubMed/Medline, Embase, Cochrane Central Register of Controlled Trials, PsycInfo, Cumulative Index to Nursing and Allied Health Literature, Web of Science (database initiation until March 2023), and OAIster (gray literature) were searched. STUDY SELECTION/METHODS:Original studies examining caregiver comprehension of and adherence to discharge instructions for CMC (Patient Medical Complexity Algorithm) were evaluated. DATA EXTRACTION/METHODS:Two authors independently screened titles/abstracts and reviewed full-text articles. Two authors extracted data related to study characteristics, methodology, subjects, and results. RESULTS:Fifty-one studies were included. More than half were qualitative or mixed methods studies. Few interventional studies examined objective outcomes. More than half of studies examined instructions for equipment (eg, tracheostomies). Common issues related to access, care coordination, and stress/anxiety. Facilitators included accounting for family context and using health literacy-informed strategies. LIMITATIONS/CONCLUSIONS:No randomized trials met inclusion criteria. Several groups (eg, oncologic diagnoses, NICU patients) were not examined in this review. CONCLUSIONS:Multiple factors affect comprehension of and adherence to discharge instructions for CMC. Several areas (eg, appointments, feeding tubes) were understudied. Future work should focus on design of interventions to optimize transitions.

BACKGROUND:Management of orthostatic hypotension (OH) prioritizes prevention of standing hypotension, sometimes at the expense of supine hypertension. It is unclear whether supine hypertension is associated with adverse outcomes relative to standing hypotension. OBJECTIVES:To compare the long-term clinical consequences of supine hypertension and standing hypotension among middle-aged adults with and without OH. METHODS:The ARIC study (Atherosclerosis Risk in Communities) measured supine and standing blood pressure (BP) in adults aged 45 to 64 years, without neurogenic OH, between 1987 and 1989. We defined OH as a positional drop in systolic BP ≥20 mm Hg or diastolic BP ≥10 mm Hg, supine hypertension as supine BP≥140/≥90 mm Hg, and standing hypotension as standing BP≤105/≤65 mm Hg. Participants were followed for >30 years. We used Cox regression models to examine associations with cardiovascular disease events, all-cause mortality, falls, and syncope. RESULTS:-interactions >0.25). Supine hypertension was associated with heart failure (hazard ratio, 1.83 [95% CI, 1.68-1.99]), falls (hazard ratio, 1.12 [95% CI, 1.02-1.22]), and all-cause mortality (hazard ratio, 1.45 [95% CI, 1.37-1.54]), while standing hypotension was only significantly associated with mortality (hazard ratio, 1.06 [95% CI, 1.00-1.14]). CONCLUSIONS:Supine hypertension was associated with higher risk of adverse events than standing hypotension, regardless of OH status. This challenges conventional OH management, which prioritizes standing hypotension over supine hypertension.

AIMS/OBJECTIVE:Neutrophil activity contributes to adverse cardiac remodelling in experimental acute cardiac injury and is modifiable with pharmacologic agents like colchicine. METHODS AND RESULTS/RESULTS:Neutrophil activity-related plasma proteins known to be affected by colchicine treatment were measured at Visit 3 (1993-1995) and Visit 5 (2011-2013) of the ARIC cohort study. A protein-based neutrophil activity score was derived from 10 candidate proteins using LASSO Cox regression. Associations with incident heart failure (HF) and with cardiac function using Cox proportional hazards regression and linear regression models, respectively. The mean ages at Visits 3 and 5 were 60 ± 6 and 75 ± 5 years, respectively, and 54% and 57% were women, respectively. Each 1-standard deviation increase in the neutrophil activity score was associated with a higher risk of incident HF in mid-life (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.25-1.37) and late-life (HR 1.23, 95% CI 1.14-1.34), with a higher HR for HF with preserved than reduced ejection fraction (HR 1.30, 95% CI 1.16-1.47 vs. HR 1.13, 95% CI 0.98-1.30). Higher neutrophil activity was associated with greater left ventricular end-diastolic volume index, mass index and diastolic and systolic dysfunction. CONCLUSIONS:Plasma proteins related to neutrophil function associate with incident HF in mid- and late-life and with adverse cardiac remodelling. Therapies that modify these proteins, such as colchicine, may represent promising targets for the prevention or treatment of HF.

Proteomic approaches have unique advantages in the identification of biological pathways that influence physical frailty, a multifactorial geriatric syndrome predictive of adverse health outcomes in older adults. To date, proteomic studies of frailty are scarce, and few evaluated prefrailty as a separate state or examined predictors of incident frailty. Using plasma proteins measured by 4955 SOMAmers in the Atherosclerosis Risk in Community study, we identified 134 and 179 proteins cross-sectionally associated with prefrailty and frailty, respectively, after Bonferroni correction (p < 1 × 10^-5 ) among 3838 older adults aged ≥65 years, adjusting for demographic and physiologic factors and chronic diseases. Among them, 23 (17%) and 82 (46%) were replicated in the Cardiovascular Health Study using the same models (FDR p < 0.05). Notably, higher odds of prefrailty and frailty were observed with higher levels of growth differentiation factor 15 (GDF15; p_prefrailty  = 1 × 10^-15 , p_frailty  = 2 × 10^-19 ), transgelin (TAGLN; p_prefrailty  = 2 × 10^-12 , p_frailty  = 6 × 10^-22 ), and insulin-like growth factor-binding protein 2 (IGFBP2; p_prefrailty  = 5 × 10^-15 , p_frailty  = 1 × 10^-15 ) and with a lower level of growth hormone receptor (GHR, p_prefrailty  = 3 × 10^-16 , p_frailty  = 2 × 10^-18 ). Longitudinally, we identified 4 proteins associated with incident frailty (p < 1 × 10^-5 ). Higher levels of triggering receptor expressed on myeloid cells 1 (TREM1), TAGLN, and heart and adipocyte fatty-acid binding proteins predicted incident frailty. Differentially regulated proteins were enriched in pathways and upstream regulators related to lipid metabolism, angiogenesis, inflammation, and cell senescence. Our findings provide a set of plasma proteins and biological mechanisms that were dysregulated in both the prodromal and the clinical stage of frailty, offering new insights into frailty etiology and targets for intervention.