High altitude modulates concussion incidence, severity, and recovery in young athletes.

BACKGROUND: High altitude may affect concussion, but prior studies are limited . We tested whether high altitude affects sport-related concussion (SRC) incidence, severity, and recovery. METHODS: Twenty-five thousand eight hundred fifteen baseline and post-injury Immediate Post-Concussion Assessment and Cognitive Testing results were compiled from Florida and Colorado, low (27 m or 62 m) and high (1,640 m or 1,991 m) altitude locations, respectively. Incidence, severity, and recovery of injury were compared between altitudes. RESULTS: High altitude was associated with increased suspected concussion incidence (adjusted OR, 2.04 [95% CI, 1.86 to 2.24];P < .0001). However, high altitude was associated with lower concussion severity measured by Severity Index (SI) (adjusted OR, 0.42 [95% CI, 0.37 to 0.49];P < .0001). High altitude was associated with decreased recovery from post-concussive symptoms in the migraine (ß, -2.72 [95% CI, -3.31 to -2.13]; P < .0001), cognitive (ß, -1.88 [95% CI, -2.40 to -1.36]; P < .0001), and sleep symptom clusters (ß, -0.30 [95% CI, -0.52 to -0.08]; P = .007). Athletes with initial SI≥8 showed prolonged neurocognitive dysfunction at high altitude (HR, 1.38 [95% CI, 1.06 to 1.81]; P = .02). CONCLUSIONS: High altitude was associated with increased suspected concussions and prolonged recovery but less severe initial injury.

A Multivariable Analysis to Evaluate the Presence or Absence of Gender Differences in Baseline ImPACT Composite Scores and Symptom Severity Ratings in Student-Athletes Ages 12-18 Years.

INTRODUCTION: Gender differences in neurocognitive function have been reported over the past few decades. However, multiple studies that report gender differences in Immediate Post-Concussion Assessment and Cognitive Tests composite scores ignore potential confounders which may lead to inaccurate results. METHODS: A total of 4829 male and 2477 female baseline Immediate Post-Concussion Assessment and Cognitive Tests from 2009 to 2019 of subjects ages 12-18 years were used to evaluate gender differences in baseline neurocognitive scores and symptom severity ratings. Regression analyses were used to assess the effects of gender on neurocognitive performance at baseline while controlling for a number of potential confounders including symptom burden at the time of testing. RESULTS: Differences in 3 of 5 composite scores as well as severity rating scores were maintained in multivariate analysis. Females had increased Post-Concussion Symptom Scale (ß = 3.54, 95% confidence interval, 2.91 to 4.16, P < .0001) along with higher verbal memory (ß = 1.82, 95% confidence interval, 1.15 to 2.50, P < .0001) and visual motor (ß = 1.29, 95% confidence interval, 0.85-1.72, P < .0001) scores. CONCLUSIONS: Statistically significant gender differences were found in baseline neurocognitive function. This study clarifies for the first time that gender differences in these neurocognitive domains are not simply an artifact of differences in symptom burden. However, the small effect sizes call into question the clinical relevance of these differences.

Effects of Recurrent Mild Traumatic Brain Injuries on Incidence, Severity, and Recovery of Concussion in Young Student-Athletes.

OBJECTIVE: To examine the effects of recurrent concussions on the incidence, severity, and recovery of significant neurocognitive dysfunction (SND) in young athletes. SETTING: Various US youth sports organizations that utilize Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for baseline and postinjury concussion testing. PARTICIPANTS: Data from 11 563 ImPACT baseline evaluations of US student-athletes aged 12 to 22 years were separated into 2 cohorts: subjects reporting 2 or more previous concussions (PC; n = 976 baseline evaluations) at baseline and a control group reporting zero previous concussions (CT; n = 7743 baseline evaluations). Subjects reporting 1 prior concussion were excluded. DESIGN: Retrospective cohort. MAIN MEASURES: Differences in SND incidence, severity, and recovery between the 2 cohorts were assessed using chi-squared tests, t tests, survival analyses, and multivariate regressions. RESULTS: The PC cohort had a higher incidence of head injury leading to ImPACT (436.7 per 1000 person-years vs 194.4 per 1000 person-years, P < .0001) and a higher incidence of SND (140.4 vs 71.8, P < .0001) than controls. However, the Severity Index (SI) demonstrated that SND severity was lower in the PC group (7.55 vs 8.59, P = .04). Adjusted analyses similarly demonstrated that the PC cohort had increased SND incidence (odds ratio = 1.93; 95% CI, 1.61 to 2.31; P < .0001), decreased SI (ß = -1.37; 95% CI, -2.40 to -0.34; P = .009), and equivalent recovery (hazard ratio = 0.98; 95% CI, 0.76 to 1.72; P = .90). CONCLUSION: Participants with a history of concussion have a higher incidence of SND but present with lower severity SND, which may be a result of increased concussion education or symptom awareness. Recurrent concussion has no significant impact on acute neurocognitive recovery. Together, these results provide evidence against the supposition that a history of concussion increases the severity of future SND.

Novel Grading Scales for Static and Flexion-Extension Magnetic Resonance Imaging in Patients with Cervical Spondylotic Myelopathy.

BACKGROUND: Flexion-extension magnetic resonance imaging (MRI) has potential to identify cervical pathology not detectable on conventional static MRI. Our study evaluated standard quantitative and novel subjective grading scales for assessing the severity of cervical spondylotic myelopathy in dynamic sagittal MRI as well as in static axial and sagittal images. METHODS: Forty-five patients underwent both conventional and flexion-extension MRI prior to anterior cervical discectomy and fusion from C4 through C7. In addition to measuring Cobb angles and cervical canal diameter, grading scales were developed for assessment of vertebral body translation, loss of disc height, change in disc contour, deformation of cord contour, and cord edema. Data were collected at all levels from C2-C3 through C7-T1. Variations in measurements between cervical levels and from flexion through neutral to extension were assessed using Mann-Whitney, Kruskal-Wallis, and two-way ANOVA tests. RESULTS: Cervical canal diameter, vertebral translation, and posterior disc opening changed significantly from flexion to neutral to extension positions (P < 0.01). When comparing operative versus nonoperative cervical levels, significant differences were found when measuring sagittal cervical canal dimensions, vertebral translation, and posterior disc opening (P < 0.01). Degenerative loss of disc height, disc dehydration, deformation of ventral cord contour, and cord edema were all significantly increased at operative levels versus nonoperative levels (P < 0.01). CONCLUSIONS: Flexion-extension MRI demonstrated significant changes not available from conventional MRI. Subjective scales for assessing degenerative changes were significantly more severe at levels with operative cervical spondylotic myelopathy. The utility of these scales for planning surgical intervention at specific and adjacent levels is currently under investigation.

Loss of independence as a metric for racial disparities in lower extremity amputation for diabetes: A National Surgery Quality Improvement Program (NSQIP) analysis.

INTRODUCTION: This study assessed the association between race/ethnicity and amputation with mortality and loss of independence (LOI) for diabetic gangrene. METHODS: We analyzed the American College of Surgeons National Surgery Quality Improvement Program database from 2016 to 2019. Chi-squared tests were performed to evaluate differences in baseline characteristics and complications. Multivariable logistic regression was performed to model LOI and 30-day mortality. RESULTS: 5250 patients with diabetes underwent lower extremity amputation as treatment for gangrene. Hispanic patients were more likely to undergo below the knee amputation (BKA) (P = 0.006). Guillotine amputation (GA) was associated with age > 65 (P < 0.0001), independent functional status prior to admission (P < 0.0001), and mortality (OR 1.989, 95%CI 1.29-3.065), but was not associated with LOI. Mortality was less frequent in Black patients (OR 0.432, 95%CI 0.207-0.902), but loss of independence (LOI) was more frequent in Black patients (OR 1.373, 95%CI 1.017-1.853). Hispanic patients were less likely to experience LOI (OR 0.575, 95%CI 0.477-0.693). CONCLUSIONS: LOI and mortality provide contrasting perspectives on outcomes following lower extremity amputation. Further assessment of risk factors may illuminate healthcare disparities.

Risk Reduction Strategy to Decrease Incidence of Retained Surgical Items.

BACKGROUND: Retained surgical items (RSIs) are rare but serious events associated with significant morbidity and costs. We assessed the effectiveness of radiofrequency (RF) detection technology and Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) in reducing the incidence of RSIs. STUDY DESIGN: All RSIs reported to the New York Patient Occurrence Reporting and Tracking System at five large urban teaching hospitals from 2007 to 2017 were analyzed. In 2012, TeamSTEPPS training was provided to all perioperative staff at each site, and use of RF detection became required in all procedures. The incidence of events before and after the interventions were compared using odds ratios. RESULTS: A total of 997,237 operative procedures were analyzed. After the interventions, the incidence of RSIs decreased from 11.66 to 5.80 events per 100,000 operations (odds ratio [OR] [95% CI] = 0.50 [0.32 to 0.78]). The frequency of RSIs involving RF-detectable items decreased from 5.21 to 1.35 events per 100,000 operations (OR [95% CI] = 0.26 [0.11 to 0.60]). The difference in RSIs involving non-RF-detectable surgical items was not statistically significant. CONCLUSIONS: The incidence of RSIs was significantly lower during the time period after implementing RF detection technology and after TeamSTEPPS training, primarily driven by a decrease in retained RF-detectable items. RF detection technology may be worth pursuing for hospitals looking to decrease RSI frequency. The benefit of TeamSTEPPS training alone may not result in a reduction of RSIs.

Sport Contact Level Affects Post-Concussion Neurocognitive Performance in Young Athletes.

OBJECTIVE: Contact level affects the incidence of sports-related concussion. However, the effects of contact level on injury severity and recovery are less clear and are the focus of this study. METHOD: Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for athletes aged 12-22 was performed at baseline (n = 10,907 for 7,058 athletes), after suspected concussion determined by physicians or athletic trainers (n = 5,062 for 4,419 athletes), and during follow-up visits (n = 3,264 for 2,098 athletes). Athletes played contact/collision (CC), limited contact (LC), and noncontact (NC) sports. Injury incidence, severity, and recovery were measured using raw and change from baseline neurocognitive test scores. Comparisons between groups used univariate analysis and multivariable regression controlling for demographic variables. RESULTS: Compared to CC athletes, LC and NC athletes showed decreased suspected concussion incidence. At initial post-injury testing, all neurocognitive test scores were similar between groups except changes from baseline for processing speed were improved for LC compared to CC athletes. Upon follow-up testing, raw neurocognitive scores were better for NC compared to the contact collision athletes in verbal memory, processing speed, total symptom score, migraine cluster, cognitive cluster, and neuropsychiatric cluster scores. For change from baseline scores, LC athletes exhibited better performance on verbal memory, processing speed, and reaction time but also showed higher neuropsychiatric scores than CC athletes. CONCLUSION: Neurocognitive scores between contact levels were similar at the first post-injury test. However, follow up showed many improved scores and symptoms for limited and NC sports compared to CC sports, which may indicate faster recovery.

Impact of Psychiatric Illnesses and Selective Serotonin Reuptake Inhibitor Medications on Baseline Neurocognitive Testing.

INTRODUCTION: Neurocognitive tests are an integral component of sport-related concussion (SRC) workup. A history of psychiatric illness (HPI) is common among young athletes. Investigations of factors that influence athletes' baseline neurocognitive function are crucial for an accurate assessment of SRC. OBJECTIVE: In this study, we aim to elucidate the effect of HPI and selective-serotonin reuptake inhibitor (SSRI) medication use on baseline neurocognitive performance in young athletes. METHODS: We conducted a retrospective cross-sectional study of Immediate Post-Concussion Assessment and Cognitive Testing assessments. A total of 268 athletes with HPI and a control group of 6,364 athletes were included. The outcomes were total symptom score based on post-concussion symptom scale, verbal memory, visual memory, visual motor, reaction time, and impulse control scores with self-reported HPI status and SSRI use. RESULTS: Athletes with HPI had an elevated symptom score in both univariate analysis (p < .0001) and multivariate analysis (p < .0001). HPI influence on visual memory score was not robust to multivariate analysis (p = .24). Athletes with HPI who reported SSRI medication use had the same baseline neurocognitive performance as other athletes with HPI. HPI influences athletes' baseline neurocognitive performance by elevating symptom scores. HPI does not alter any of the objective neurocognitive composite scores in contrast to previous work. CONCLUSIONS: Clinicians should consider the impact of HPI on baseline neurocognitive performance during the assessment of a suspected SRC. Additional research is required to bolster our findings on SSRI use and ascertain the effects of other drug classes on baseline neurocognitive performance.

Evaluation of differences across age groups in the incidence, severity, and recovery of concussion in adolescent student-athletes from 2009 to 2019.

OBJECTIVE: Concussion incidence is known to be highest in children and adolescents; however, there is conflicting evidence about the effect of age on concussion risk and recovery within the adolescent age range. The heterogeneity of results may be partially due to the use of age groupings based on convenience, making comparisons across studies difficult. This study evaluated the independent effect of age on concussion incidence, severity, and recovery in student-athletes aged 12-18 years using cluster analysis to define groupings. METHODS: Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores of 11,403 baseline tests and 4922 postinjury tests were used to calculate the incidence rates for adolescent student-athletes grouped into 3 age bands (12-13, 14-15, and 16-18 years of age) on the basis of clustering analysis. The recently created Severity Index was used to compare concussion severity between groups. Follow-up tests for subjects who sustained a concussion were used to evaluate recovery time. The chi-square test and 1-way ANOVA were used to compare differences in demographic characteristics and concussion incidence, severity, and recovery. Multivariable logistic and linear regressions were used to evaluate the independent effects of age on concussion incidence and severity, respectively. Multivariable Cox hazard regression was used to evaluate differences in recovery time. Further analyses were conducted to directly compare findings across studies on the basis of the age groupings used in prior studies. RESULTS: Multivariable regression analyses demonstrated that the 14- to 15-year-old age group had a significantly higher concussion incidence than both the 12- to 13-year-old (14- to 15-year-old group vs 12- to 13-year-old group, OR 1.57, 95% CI 1.16-2.17, p = 0.005) and 16- to 18-year-old (16- to 18-year-old group vs 14- to 15-year-old group, OR 0.79, 95% CI 0.69-0.91, p = 0.0008) age groups. There was no difference in incidence between the 12- to 13-year-old and 16- to 18-year-old groups (16- to 18-year group vs 12- to 13-year group, OR 1.26, 95% CI 0.93-1.72, p = 0.15). There were also no differences in concussion severity or recovery between any groups. CONCLUSIONS: This study found that concussion incidence was higher during mid-adolescence than early and late adolescence, suggesting a U-shaped relationship between age and concussion risk over the course of adolescence. Age had no independent effect on concussion severity or recovery in the 12- to 13-, 14- to 15-, and 16- to 18-year-old groups. Further analysis of the various age groups revealed that results may vary significantly with minor changes to groupings, which may explain the divergent results in the current literature on this topic. Thus, caution should be taken when interpreting the results of this and all similar studies, especially when groupings are based on convenience.

Incidence and Severity of Concussions Among Young Soccer Players Based on Age, Sex, and Player Position.

BACKGROUND: Previously studied risk factors for sports-related concussion in soccer players include sex, age, and player position. However, prior studies were limited in number, they reported conflicting results, and most did not assess initial concussion severity. PURPOSE/HYPOTHESIS: The purpose of this study was to conduct an in-depth analysis of soccer players across key demographic groups (sex, age, position) for both concussion incidence and severity. It was hypothesized that concussion incidence and severity would be higher among male players, players aged ≥17 years, and goalkeepers. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The authors analyzed baseline and postinjury ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) scores for athletes aged 12 to 22 years between July 2009 and June 2019. Players were assigned to an age group based on when they had their most recent baseline test. Concussion incidence and concussion severity index were compared using t tests and multivariate logistic regression. RESULTS: For 1189 individuals who reported soccer as their primary sport, 1032 contributed 1754 baseline ImPACT tests (some individuals had multiple baseline tests), whereas 445 individuals were suspected of sustaining a concussion and then referred for a postinjury 1 test. Of these players, 254 (24.6%) had both a baseline and a postinjury test and were analyzed for concussion severity. Linear regression showed that forwards had a lower incidence of ImPACT-proxied concussions than goalkeepers had (P = .008). Female players had a significantly higher incidence of ImPACT concussions compared with male players (mean, 0.07 [female] vs 0.04 [male] concussions per person-year; P = .05). Players in the ≥17-year age group had a higher incidence of ImPACT concussions than players in the 15- to 16-year age group (P = .04), although the 15- to 16-year age group had more severe concussions than the ≥17-year age group (mean severity index, 2.91 [age 15-16 years] vs 1.73 [age ≥17 years]; P = .001). CONCLUSION: Female soccer players experienced a higher incidence of concussion than did male players, and goalkeepers experienced a greater incidence of ImPACT concussions than did forwards. Players of both sexes and all positions in the 15- to 16-year age group showed increased initial concussion severity compared with the ≥17-year age group, despite a lower comparative incidence of ImPACT concussions. Further study is needed to understand whether sex and player position affect concussion severity.

Concussion Incidence and Recovery Among Youth Athletes With ADHD Taking Stimulant-Based Therapy.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) may affect concussion risk and recovery in youth athletes. PURPOSE: To evaluate the association between incidence of concussion and postinjury recovery of symptoms and neurocognitive dysfunction among youth athletes with ADHD and differential stimulant use. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: From 2009 to 2019, the authors administered the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) to youth athletes at the beginning of each season. Throughout the season, athletes with concussions were examined and readministered the ImPACT both postinjury and again 7 days after the postinjury administration. These athletes (N = 7453) were divided into those with ADHD on stimulant-based therapy (ADHD+meds; n = 167), those with ADHD not on stimulant-based therapy (ADHD-only; n = 354), and those with no ADHD (non-ADHD; n = 6932). Recovery of neurocognitive dysfunction at postinjury and follow-up was calculated using the ImPACT symptom score, verbal memory, visual memory, visual motor skills, and reaction time (calculated as standardized deviations from baseline). Univariate results were confirmed with multivariate analysis. RESULTS: The ADHD+meds cohort had a lower incidence of concussion (37.3 concussions per 100 patient-years) compared with the ADHD-only group (57.0 concussions per 100 patient-years) (odds ratio [OR], 0.51 [95% CI, 0.37-0.71]; P < .0001) and non-ADHD group (52.8 concussions per 100 patient-years) (OR, 0.50 [95% CI, 0.37-0.67]; P < .0001). At postinjury, ImPACT scores were elevated from baseline to a similar extent in the ADHD+meds cohort compared with the other 2 groups. By follow-up, however, deviations from baseline were lower among the ADHD+meds group compared with the non-ADHD group in verbal memory (OR, 0.46 [95% CI, 0.28-0.76]; P = .002), visual memory (OR, 0.27 [95% CI, 0.10-0.66]; P = .005), and visual motor skills (OR, 0.58 [95% CI, 0.33-0.99]; P = .048). The deviation at follow-up was also lower among the ADHD+meds group compared with the ADHD-only group in visual memory (OR, 0.56 [95% CI, 0.33-0.96]; P = .04) and visual motor skills (OR, 0.42 [95% CI, 0.22-0.81]; P = .01). CONCLUSION: Stimulant use among youth athletes with ADHD was independently associated with reduced incidence for concussion and lower deviation from baseline in verbal memory, visual memory, and visual motor skills at 7 days postconcussion, suggesting lower neurocognitive impairment at follow-up in this group versus their peers.

Nonsteroidal anti-inflammatory drug use and concussions in adolescent athletes: incidence, severity, and recovery.

OBJECTIVE: Given concerns about the potential long-term effects of concussion in young athletes, concussion prevention has become a major focus for amateur sports leagues. Athletes have been known to frequently use anti-inflammatory medications to manage injuries, expedite return to play, and treat concussion symptoms. However, the effects of baseline nonsteroidal anti-inflammatory drug (NSAID) use on the susceptibility to head injury and concussion remain unclear. This study aims to assess the effects of preinjury NSAID use on concussion incidence, severity, and recovery in young athletes. METHODS: Data from 25,815 ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) tests were obtained through a research agreement with ImPACT Applications Inc. Subjects ranged in age from 12 to 22 years old. Those who reported NSAID use at baseline were assigned to one (anti-inflammatory [AI]) cohort, whereas all others were assigned to the control (CT) cohort. Differences in head trauma and concussion incidence, severity, and recovery were assessed using chi-square tests, unpaired t-tests, and Kaplan-Meier plots. RESULTS: The CT cohort comprised a higher percentage (p < 0.0001) of males (66.30%) than the AI cohort (44.16%) and had a significantly greater portion of athletes who played football (p = 0.004). However, no statistically significant differences were found between the two cohorts in terms of the incidence of head trauma (CT = 0.489, AI = 0.500, p = 0.9219), concussion incidence (CT = 0.175, AI = 0.169, p = 0.7201), injury severity, or median concussion recovery time (CT = 8, AI = 8, p = 0.6416). In a multivariable analysis controlling for baseline differences between the cohorts, no association was found between NSAID use and concussion incidence or severity. CONCLUSIONS: In this analysis, the authors found no evidence that preinjury use of NSAIDs affects concussion risk in adolescent athletes. They also found no indication that preinjury NSAID use affects the severity of initial injury presentation or concussion recovery.

Sex-Related Differences in the Incidence, Severity, and Recovery of Concussion in Adolescent Student-Athletes Between 2009 and 2019.

BACKGROUND: The sex of an athlete is thought to modulate concussion incidence; however, the effects of sex on concussion severity and recovery are less clear. PURPOSE: To evaluate sex differences in concussion severity and recovery using a large, heterogeneous sample of young student-athletes with the goal of understanding how sex affects concussion outcomes in young athletes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The Immediate Post-Concussion Assessment and Cognitive Testing results of 11,563 baseline and 5216 postinjury tests were used to calculate the incidence of concussion of adolescent male and female student-athletes ages 12 to 22 years (median, 15 years). The postinjury tests of 3465 male and 1751 female student-athletes evaluated for concussion or head trauma were used to assess differences in the Severity Index (SI) and recovery. Chi-square tests and t tests were used to compare differences in demographic characteristics, incidence, and SI between the 2 cohorts. Multivariable linear, logistic, and Cox proportional hazards regressions were used to control for differences between cohorts in analyses of incidence, SI, and recovery. RESULTS: When we controlled for demographic differences, female participants had higher odds of concussion (odds ratio, 1.62; 95% CI, 1.40-1.86; P < .0001) and higher SI after concussion (ß = 0.67; 95% CI, 0.02-1.32; P = .04). This discrepancy in SI was a result of differences in Symptom (2.40 vs 2.94; P < .0001) and Processing Speed (0.91 vs 1.06; P = .01) composite scores between male and female participants, respectively. We found no effect of sex on time to recovery when controlling for initial concussion SI (hazard ratio, 0.94; 95% CI, 0.78-1.12; P = .48). CONCLUSION: Using large, multisport cohorts, this study provides evidence that female athletes are at higher risk for more concussions and these concussions are more severe, but male and female athletes have similar recovery times when the analysis controls for initial concussion SI.

Incidence of concussion and recovery of neurocognitive dysfunction on ImPACT assessment among youth athletes with premorbid depression or anxiety taking antidepressants.

OBJECTIVE: Concussions in youth sports comprise an estimated 1.6-3.8 million annual injuries in the US. Sex, age, and attention-deficit hyperactivity disorder (ADHD) have been identified as salient risk factors for concussion. This study seeks to evaluate the role of premorbid depression or anxiety (DA), with or without antidepressant use, on the incidence of concussion and the recovery of symptoms and neurocognitive dysfunction after concussion. METHODS: Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) was administered to 7453 youth athletes at baseline. Throughout the season, concussions were examined by physicians and athletic trainers, followed by readministration of ImPACT postinjury (PI) and again at follow-up, a median of 7 days PI. Individuals were divided into three categories: 1) unmedicated athletes with DA (DA-only, n = 315), athletes taking antidepressants (DA-meds, n = 81), and those without DA or antidepressant use (non-DA, n = 7039). Concussion incidence was calculated as the total number of concussions per total number of patient-years. The recovery of neurocognitive measures PI was calculated as standardized deviations from baseline to PI and then follow-up in the 5 composite ImPACT scores: symptom score, verbal memory, visual memory, visual motor skills, and reaction time. Univariate results were confirmed with multivariate analysis. RESULTS: There was no difference in concussion incidence between the DA-only cohort and the non-DA group. However, the DA-meds group had a significantly greater incidence of concussion than both the DA-only group (OR 2.67, 95% CI 1.88-7.18, p = 0.0001) and the non-DA group (OR 2.19, 95% CI 1.16-4.12, p = 0.02). Deviation from baseline in PI symptom scores was greater among the DA-meds group as compared to the non-DA group (OR 1.14, 95% CI 1.01-1.28, p = 0.03). At follow-up, the deviation from baseline in symptom scores remained elevated among the DA-meds group as compared to the non-DA group (OR 1.62, 95% CI 1.20-2.20, p = 0.002) and the DA-only group (OR 1.87, 95% CI 1.12-3.10, p = 0.02). Deviation from baseline in follow-up verbal memory was also greater among the DA-meds group as compared to both the non-DA group (OR 1.57, 95% CI 1.08-2.27, p = 0.02) and the DA-only group (OR 1.66, 95% CI 1.03-2.69, p = 0.04). CONCLUSIONS: Premorbid DA itself does not seem to affect the incidence of concussion or the recovery of symptoms and neurocognitive dysfunction PI. However, antidepressant use for DA is associated with 1) increased concussion incidence and 2) elevated symptom scores and verbal memory scores up to 7 days after concussion, suggesting impaired symptomatic and neurocognitive recovery on ImPACT.

Policy Interventions, Social Distancing, and SARS-CoV-2 Transmission in the United States: A Retrospective State-level Analysis.

BACKGROUND: Various non-pharmaceutical interventions (NPIs) such as stay-at-home orders and school closures have been employed to limit the spread of Coronavirus disease (COVID-19). This study measures the impact of social distancing policies on COVID-19 transmission in US states during the early outbreak phase to assess which policies were most effective. METHODS: To measure transmissibility, we analyze the average effective reproductive number (Rt) in each state the week following its 500th case and doubling time from 500 to 1000 cases. Linear and logistic regressions were performed to assess the impact of various NPIs while controlling for population density, GDP, and certain health metrics. This analysis was repeated for deaths with doubling time to 100 deaths with several healthcare infrastructure control variables. RESULTS: States with stay-at-home orders in place at the time of their 500th case were associated with lower average Rt the following week compared to states without them (p<0.001) and significantly less likely to have an Rt>1 (OR 0.07, 95% CI 0.01-0.37, p = 0.004). These states also experienced longer doubling time from 500 to 1000 cases (HR 0.35, 95% CI 0.17-0.72, p = 0.004). States in the highest quartile of average time spent at home were also slower to reach 1000 cases than those in the lowest quartile (HR 0.18, 95% CI 0.06-0.53, p = 0.002). CONCLUSIONS: Stay-at-home orders had the largest effect of any policy analyzed. Multivariate analyses with cellphone tracking data suggest social distancing adherence drives these effects. States that plan to scale back such measures should carefully monitor transmission metrics.

Multivariate Analysis of Black Race and Environmental Temperature on COVID-19 in the US.

BACKGROUND: There has been much interest in environmental temperature and race as modulators of Coronavirus disease-19 (COVID-19) infection and mortality. However, in the United States race and temperature correlate with various other social determinants of health, comorbidities, and environmental influences that could be responsible for noted effects. This study investigates the independent effects of race and environmental temperature on COVID-19 incidence and mortality in United States counties. METHODS: Data on COVID-19 and risk factors in all United States counties was collected. 661 counties with at least 50 COVID-19 cases and 217 with at least 10 deaths were included in analyses. Upper and lower quartiles for cases/100,000 people and halves for deaths/100,000 people were compared with t-tests. Adjusted linear and logistic regression analyses were performed to evaluate the independent effects of race and environmental temperature. RESULTS: Multivariate regression analyses demonstrated Black race is a risk factor for increased COVID-19 cases (OR=1.22, 95% CI: 1.09-1.40, P=0.001) and deaths independent of comorbidities, poverty, access to health care, and other risk factors. Higher environmental temperature independently reduced caseload (OR=0.81, 95% CI: 0.71-0.91, P=0.0009), but not deaths. CONCLUSIONS: Higher environmental temperatures correlated with reduced COVID-19 cases, but this benefit does not yet appear in mortality models. Black race was an independent risk factor for increased COVID-19 cases and deaths. Thus, many proposed mechanisms through which Black race might increase risk for COVID-19, such as socioeconomic and healthcare-related predispositions, are inadequate in explaining the full magnitude of this health disparity.

Gestational exposure to nicotine and/or benzo[a]pyrene causes long-lasting neurobehavioral consequences.

Tobacco smoke is a complex mixture that includes thousands of compounds. Previously, we have found that gestational exposure to the complex mixture of tobacco smoke extract caused long-term neurobehavioral impairments. In this study, we examined the interaction of two of the most biologically active, nicotine and benzo[a]pyrene (BaP). Developmental effects were determined in Sprague-Dawley rats prenatally exposed to low doses of BaP and nicotine (0.03 mg/kg/day of BaP and 2 mg/kg/day of nicotine) via maternal osmotic minipumps throughout gestation. Behavioral function was assessed in the offspring via a battery of tests through adolescence into adulthood. There were sex-selective effects in four of the behavioral tests. In the elevated plus maze, there was a significant interaction of BaP and sex, where BaP-treated males showed a trend for increased activity. In the novelty suppressed feeding test, there were significant sex selective effects in males such that the normal sex difference in the behavior in this test was eliminated. Male offspring with prenatal exposure to either nicotine or BaP showed significant reductions in fear response. In the Figure-8 locomotor activity test, BAP-exposed male offspring were significantly hyperactive. This also eliminated the sex difference typically seen in this test. This effect persisted into adulthood. In the attention task, males exposed to nicotine during gestation showed a significant percent hit impairment. BaP reversed this effect. No significant effects were seen with percent correct rejection. These data show that both nicotine and BaP cause persisting sex-selective behavioral effects that persist into adulthood.