Category: Statistics

Biostatistics. 2021 Aug 26:kxab032. doi: 10.1093/biostatistics/kxab032. Online ahead of print.

ABSTRACT

With mammography being the primary breast cancer screening strategy, it is essential to make full use of the mammogram imaging data to better identify women who are at higher and lower than average risk. Our primary goal in this study is to extract mammogram-based features that augment the well-established breast cancer risk factors to improve prediction accuracy. In this article, we propose a supervised functional principal component analysis (sFPCA) over triangulations method for extracting features that are ordered by the magnitude of association with the failure time outcome. The proposed method accommodates the irregular boundary issue posed by the breast area within the mammogram imaging data with flexible bivariate splines over triangulations. We also provide an eigenvalue decomposition algorithm that is computationally efficient. Compared to the conventional unsupervised FPCA method, the proposed method results in a lower Brier Score and higher area under the ROC curve (AUC) in simulation studies. We apply our method to data from the Joanne Knight Breast Health Cohort at Siteman Cancer Center. Our approach not only obtains the best prediction performance comparing to unsupervised FPCA and benchmark models but also reveals important risk patterns within the mammogram images. This demonstrates the importance of utilizing additional supervised image-based features to clarify breast cancer risk.

PMID:34435196 | DOI:10.1093/biostatistics/kxab032

Ann Work Expo Health. 2021 Aug 26:wxab029. doi: 10.1093/annweh/wxab029. Online ahead of print.

ABSTRACT

OBJECTIVES: This study aims to assess the health effects on mining workers of exposure to chronic intermittent hypoxia (CIH) at high- and very high-altitude mining compared with similar work at lower altitudes in Chile, and it also aims to constitute the baseline of a 5-year follow-up study.

METHODS: We designed a cross-sectional study to assess health conditions in 483 miners working at 2 levels of altitude exposure: 336 working at a very high or high altitude (HA; 247 above 3900-4400 m, and 89 at 3000-3900 m), and 147 below 2400 m. Subjects were randomly selected in two stages. First, a selection of mines from a census of mines in each altitude stratum was made. Secondly, workers with less than 2 years of employment at each of the selected mines were recruited. The main outcomes measured at the baseline were mountain sickness, sleep alterations, hypertension, body mass index, and neurocognitive functions.

RESULTS: Prevalence of acute mountain sickness (AMS) was 28.4% in the very high-altitude stratum (P = 0.0001 compared with the low stratum), and 71.7% experienced sleep disturbance (P = 0.02). The adjusted odds ratio for AMS was 9.2 (95% confidence interval: 5.2-16.3) when compared with the very high- and low-altitude groups. Motor processing speed and spatial working memory score were lower for the high-altitude group. Hypertension was lower in the highest-altitude subjects, which may be attributed to preoccupational screening even though this was not statistically significant.

CONCLUSIONS: Despite longer periods of acclimatization to CIH, subjects continue to present AMS and sleep disturbance. Compromise of executive functions was detected, including working memory at HA. Further rigorous research is warranted to understand long-term health impacts of high-altitude mining, and to provide evidence-based policy recommendations.

PMID:34435202 | DOI:10.1093/annweh/wxab029

Front Sports Act Living. 2021 Aug 9;3:715833. doi: 10.3389/fspor.2021.715833. eCollection 2021.

ABSTRACT

The aim of the study was to (1) assess the within-session reliability of a unilateral isometric hex bar pull (UIHBP) maximal voluntary contraction (MVC) test and, (2) determine unilateral isometric absolute peak force (PF_abs) and relative peak force (PF) values in freeski athletes. Twenty-one male and eight female academy to national team freeskiers performed the novel UIHBP MVC task on a force plate and PF_abs and relative PF were assessed (1000 Hz). Within-session measures of PF_abs offered high reliability on left and right limbs for males (ICC = 0.91-0.94, CV = 2.6-2.2%) and females (ICC = 0.94-0.94, CV = 1.4-1.6%), while relative PF measures showed good to high reliability in both left and right limbs for males (ICC = 0.8-0.84, CV = 2.6-2.2%) and females (ICC = 0.92-0.90, CV = 1.4-1.7%). We observed significantly lower PF_abs (p < 0.001) and relative PF (p < 0.001) in females compared to males. No statistical difference was found between left and right limbs in males and females in PF_abs (p = 0.98) and relative PF measures (p = 0.93). The UIHBP MVC test appears to be a reliable method for assessing PF_abs and relative PF in male and female freeski athletes.

PMID:34435187 | PMC:PMC8380774 | DOI:10.3389/fspor.2021.715833

Brain Commun. 2021 Jul 19;3(3):fcab133. doi: 10.1093/braincomms/fcab133. eCollection 2021.

ABSTRACT

The recognition, diagnosis and management of mild traumatic brain injuries are difficult and confusing. It is unclear how the severity and number of injuries sustained relate to brain injuries, such as diffuse axonal injury, diffuse vascular injury and progressive neurodegeneration. Advances in neuroimaging techniques enable the investigation of neuropathologies associated with acute and long-term effects of injury. Head injuries are the most commonly reported injury seen during professional rugby. There is increased vigilance for the immediate effects of these injuries in matches, but there has been surprisingly little research investigating the longer-term effects of rugby participation. Here, we present a longitudinal observational study investigating the relationship of exposure to rugby participation and sub-acute head injuries in professional adult male and female rugby union and league players using advanced MRI. Diffusion tensor imaging and susceptibility weighted imaging was used to assess white matter structure and evidence of axonal and diffuse vascular injury. We also studied changes in brain structure over time using Jacobian Determinant statistics extracted from serial volumetric imaging. We tested 41 male and 3 female adult elite rugby players, of whom 21 attended study visits after a head injury, alongside 32 non-sporting controls, 15 non-collision-sport athletic controls and 16 longitudinally assessed controls. Eighteen rugby players participated in the longitudinal arm of the study, with a second visit at least 6 months after their first scan. Neuroimaging evidence of either axonal injury or diffuse vascular injury was present in 23% (10/44) of players. In the non-acutely injured group of rugby players, abnormalities of fractional anisotropy and other diffusion measures were seen. In contrast, non-collision-sport athletic controls were not classified as showing abnormalities. A group level contrast also showed evidence of sub-acute injury using diffusion tensor imaging in rugby players. Examination of longitudinal imaging revealed unexpected reductions in white matter volume in the elite rugby players studied. These changes were not related to self-reported head injury history or neuropsychological test scores and might indicate excess neurodegeneration in white matter tracts affected by injury. Taken together, our findings suggest an association of participation in elite adult rugby with changes in brain structure. Further well-designed large-scale studies are needed to understand the impact of both repeated sports-related head impacts and head injuries on brain structure, and to clarify whether the abnormalities we have observed are related to an increased risk of neurodegenerative disease and impaired neurocognitive function following elite rugby participation.

PMID:34435188 | PMC:PMC8381344 | DOI:10.1093/braincomms/fcab133

AEM Educ Train. 2021 Aug 1;5(4):e10639. doi: 10.1002/aet2.10639. eCollection 2021 Aug.

ABSTRACT

BACKGROUND: The chief resident role often includes additional administrative and educational experiences beyond those of nonchief senior residents. It is unclear to what extent these experiences influence the postresidency career path of those selected as chief residents. The objective of this study was to evaluate the association of chief resident status on immediate postresidency career characteristics relative to nonchief residents in emergency medicine (EM).

METHODS: We retrospectively analyzed graduate data from 2016 to 2020 at six accredited EM residency programs. Participating sites were geographically diverse and included 3- and 4-year training formats. Each site abstracted data using a standardized form including program, year of graduation, chief resident status, publications during residency, and immediate postresidency position (academic vs. nonacademic). We calculated descriptive statistics and performed logistic regression to explore differences between the chief resident cohort and other graduates.

RESULTS: We gathered information on 365 total graduates (45.8% from 3-year programs and 54.2% from 4-year programs) including 93 (25.5%) chief residents. A total of 129 (35%) graduates assumed an academic position immediately following residency. Fifty-six (60%) of 93 chief residents assumed an academic position immediately following residency, compared to 74 (27%) of 272 other graduates. After program, year of graduation, and number of publications completed during residency were controlled for, chief resident status was a significant predictor of immediate postresidency academic career (odds ratio for a chief resident assuming an academic job = 5.36, 95% confidence interval = 3.10 to 9.27).

CONCLUSION: The chief resident role within EM is significantly associated with pursuit of an academic position immediately following residency compared to nonchiefs.

PMID:34435169 | PMC:PMC8364741 | DOI:10.1002/aet2.10639

Br Ir Orthopt J. 2021 Aug 13;17(1):127-133. doi: 10.22599/bioj.175. eCollection 2021.

ABSTRACT

BACKGROUND: To assess the feasibility, as well as viability, of utilising gaming using virtual reality (VR) to treat accommodative and vergence infacilities.

METHODS: Forty-two emmetropic and asymptomatic participants between the ages of 18 and 30, with normal binocular visual function, were selected for the study in 2018. Participants with binocular accommodative infacilities and/or vergence infacilities comprised the study population. The binocular accommodative facilities (BAF) were assessed using amplitude-scaled facilities (probe lens = 30% amplitude of accommodation; test distance = 45% amplitude of accommodation). All those with less than 10 cycles per minute (cpm) were regarded as failing. Vergence facilities were assessed using 12 pd base out and 3 pd base in prisms. All those with less than 15 cpm were regarded as failing. The participants were separated into age-matched experimental and control groups. The experimental group played a fast-paced game using Samsung Gear VR (SM-R323), whilst the control group watched a television film projected onto a two-dimensional screen at a distance of one metre. Pre-test and post-test binocular amplitude-scaled facilities and vergence facilities were measured for both groups after exposure for 25 minutes.

RESULTS: There was a significant, mean increase in binocular accommodative facilities of 4.67 ± 5.05 cpm (p = 0.008) for the experimental group (n = 12). There was a significant mean increase in vergence facilities of 3.72 ± 3.18 cpm (p < 0.001) for the experimental group (n = 32). A statistically significant mean difference of 4.07 cpm (95%CI: 0.97, 9.19; p = 0.03) between the respective control and experimental groups was found for binocular accommodative facilities and 2.45 cpm (95%CI: 0.68, 4.22; p = 0.008) for vergence facilities.

CONCLUSION: Binocular accommodative facilities and vergence facilities increased after 25 minutes of VR gaming in asymptomatic emmetropic participants with accommodative infacilities and vergence infacilities. However, due to the small-scale, unmasked and unrandomised nature of the study more research is needed to confirm the results of this study.

PMID:34435174 | PMC:PMC8362637 | DOI:10.22599/bioj.175

Spine Surg Relat Res. 2021 Jan 12;5(4):278-283. doi: 10.22603/ssrr.2020-0189. eCollection 2021.

ABSTRACT

INTRODUCTION: Previous studies have reported differences in lumbopelvic alignment between standing and supine positions. Computed tomography (CT) images taken in the supine position are often used for clinical studies in addition to standing radiographs, although not frequently. Our study aims to clarify normative values of CT-evaluated lumbopelvic parameters and the characteristics of age- and gender-related lumbopelvic alignment in the supine position.

METHODS: Patients undergoing CT scans of abdominal or lumbar regions for reasons other than low back disorders were included (n=581). Sagittal multiplanar reconstruction CT images were obtained, and lumbar lordosis (LL), L5-S1 angle, and sacral slope (SS) were measured. Mean values of the parameters in patients aged 59 years and under, 60-69, 70-79, and 80 and over, and in males and females, were calculated. Age- and gender-related differences in these parameters were statistically analyzed.

RESULTS: Among the four age groups, patients 80 years and over showed significantly lower LL and SS than patients aged 70-79. Females 80 years and over showed significantly lower LL and SS than all other age groups, but those in males did not. The comparison between males and females showed no significant differences in LL and SS; however, the L5-S1 angle was significantly higher in males than in females. In patients 80 years and over, females showed significantly lower LL and SS than in males.

CONCLUSIONS: This study provides normative CT-evaluated lumbopelvic parameters, such as LL, L5-S1 angle, and SS, which will be utilized for comparisons in future studies. The present study first revealed that pelvic retroversion and lumbar kyphosis occur in elderly females in the supine position, which raised a possibility that age-related decrease of LL and SS in females occurs at an older age in the supine position than in the standing position.

PMID:34435152 | PMC:PMC8356231 | DOI:10.22603/ssrr.2020-0189

Int J Surg Protoc. 2021 Aug 9;25(1):165-170. doi: 10.29337/ijsp.158. eCollection 2021.

ABSTRACT

INTRODUCTION: Postoperative ileus (poi) is defined as a temporary cessation of bowel movement after a surgical procedure. Cessation of bowel movement not only leads to disturbing constipation but also may lead to nausea, loss of appetite, and food intolerance. Literature reports “sham feeding” (gum-chewing) effect as an increase in chewing and saliva which enhances the gastric emptying and overall motility of gut as a cephalic phase of digestion. Therefore, we aim to assess the effect of adding gum-chewing to the conventional postoperative feeding regimen on restoring postoperative bowel function and length of stay in hospital of patients undergoing elective hip arthroplasty.

METHODS AND ANALYSIS: This is a single-center, open-label, parallel design, superiority randomized-controlled trial with 2 treatment arms. The primary and secondary outcomes will be the time interval in hours from the end of surgery until the passage of flatus and the time interval in hours from the end of surgery until the passage of stool. Statistical analysis will be done using STATA software. Length of stay will be calculated by Kaplan-Meier analysis, with unadjusted comparison of groups by Mantel-Cox log rank test. Risk ratios for the time-to-become ileus free and time-to-discharge from hospital will be calculated by Cox regression modeling. P value as 0.05 or less will be taken as significant.

ETHICS AND DISSEMINATION: This protocol is exempted from Ethical review at this stage however all the required approvals will be taken from the ethical review committee before starting the study. Informed consent will be taken form the patient to enroll him/her in the study. Results of the study will be disseminated to the study participants, public health, and clinical professionals. The results would also be published in a reputable international journal.

TRIAL REGISTRATION: This trial is registered on clinicaltrials.gov with ID: NCT04489875.

HIGHLIGHTS: Cessation of bowel movement not only leads to disturbing constipation but also may lead to nausea, loss of appetite, and food intolerance.These patients tend to have more pain scores and dissatisfaction with the surgical management and team.The “sham feeding” (gum-chewing) effect causes an increase in chewing and saliva formation and therefore enhances the gastric emptying and overall motility of gut as a cephalic phase of digestion even in non-gastro or colorectal surgeries.We hypothesize that there is an association between gum chewing and the relief from postoperative ileus in hip arthroplasty patients.

PMID:34435165 | PMC:PMC8362622 | DOI:10.29337/ijsp.158

Spine Surg Relat Res. 2020 Nov 20;5(4):252-263. doi: 10.22603/ssrr.2020-0083. eCollection 2021.

ABSTRACT

INTRODUCTION: Chronic low back pain (CLBP) is a leading cause of disability, yet there is limited high-quality evidence to identify the most suitable pharmacological therapy. The purpose of this Japanese nationwide, multicenter, prospective study was to compare the effectiveness of four representative drug therapies-acetaminophen, celecoxib, loxoprofen, and a tramadol and acetaminophen (T+A) combination drug-to establish evidence for a drug of choice for CLBP.

METHODS: Patients with CLBP (N=471) received one of the four treatments and were evaluated, prospectively and comprehensively, once every month for six months using a visual analog scale (VAS) for LBP, the Japanese Orthopedic Association (JOA) score, the JOA Back Pain Evaluation Questionnaire (JOABPEQ), the Roland-Morris Disability Questionnaire (RDQ), the EuroQol five-dimensions three-levels (EQ-5D-3L), and the Short Form-8 item health survey (SF-8). We conducted multivariable linear regression analyses of the four drugs at 1 and 6 months after drug allocation. Differences with P<0.05 were considered statistically significant.

RESULTS: Patients who received acetaminophen showed a significant improvement from baseline in the mental health subscale of the JOABPEQ at one month (P=0.02) and the JOA score at six months (P<0.01). None of the other outcome measures among the four drugs differed significantly. Across groups, all outcome measures, except the mental component summary (MCS) score of the SF-8, improved equivalently, although most measurements showed no obvious cumulative effect over six months. The MCS score of the SF-8 decreased gradually over six months in all groups.

CONCLUSIONS: Most of the outcome measures among the treated groups were not significantly different, indicating similar treatment effects of the four drugs for CLBP. Our study indicated the limit of each outcome measure for evaluating the patient status, suggesting that a single outcome measure is insufficient to reflect treatment effectiveness.

PMID:34435149 | PMC:PMC8356229 | DOI:10.22603/ssrr.2020-0083

Eur J Dent. 2021 Aug 25. doi: 10.1055/s-0041-1731925. Online ahead of print.

ABSTRACT

OBJECTIVES: This clinical trial compared the efficacy of atraumatic restorative treatment (ART) sealants against resin-based sealants in terms of their retention and fissure caries preventive benefits over a period of 24 months among a section of school children in the Southern Indian state of Telangana.

MATERIALS AND METHODS: A split mouth clinical trial employed 198 children, who received these sealants on their lower permanent first molars. Retention was assessed 6 monthly and caries annually STATISTICAL ANALYSIS: Chi-square tests were utilized to analyze the retention rate and the incidence of dental caries between the two groups. Kaplan-Meier survival analysis plotted the cumulative survival percentage of partially, and fully retained sealants and the survival of dentin carious free pits and fissures among both the groups. A linear binary logistical regression analysis calculated the odds ratio.

RESULTS: A statistical significant difference was observed in the retention rate between these sealants at every follow-up stage. The cumulative survival percentage of ART and resin sealants was calculated to be 30.9 and 37.5% by the end of 2 years. The Kaplan-Meier analysis showed no significant difference with regard to the survival of dentin carious free pits and fissures. The odds ratio for this trial was 0.747 (95% confidence interval: 0.493-1.13) CONCLUSION: Resin sealants fared better than ART sealants in the field of retention. However, no significant differences were observed with regard to fissure caries prevention by the end of the study period.

PMID:34433220 | DOI:10.1055/s-0041-1731925