Tag: statistics

Risk Anal. 2021 Dec;41(12):2392-2414. doi: 10.1111/risa.13758. Epub 2021 Jun 2.

ABSTRACT

In risk analysis, sensitivity measures quantify the extent to which the probability distribution of a model output is affected by changes (stresses) in individual random input factors. For input factors that are statistically dependent, we argue that a stress on one input should also precipitate stresses in other input factors. We introduce a novel sensitivity measure, termed cascade sensitivity, defined as a derivative of a risk measure applied on the output, in the direction of an input factor. The derivative is taken after suitably transforming the random vector of inputs, thus explicitly capturing the direct impact of the stressed input factor, as well as indirect effects via other inputs. Furthermore, alternative representations of the cascade sensitivity measure are derived, allowing us to address practical issues, such as incomplete specification of the model and high computational costs. The applicability of the methodology is illustrated through the analysis of a commercially used insurance risk model.

PMID:35088442 | DOI:10.1111/risa.13758

Stat Med. 2022 Jan 27. doi: 10.1002/sim.9330. Online ahead of print.

ABSTRACT

The control of ambient air quality in the United States has been a major public health success since the passing of the Clean Air Act, with particulate matter (PM) reductions resulting in an estimated 160 000 premature deaths prevented in 2010 alone. Currently, public policy is oriented around lowering the levels of individual pollutants and this focus has driven the nature of much epidemiological research. Recently, attention has been given to viewing air pollution as a complex mixture and to developing a multi-pollutant approach to controlling ambient concentrations. We present a statistical approach for estimating the health impacts of complex environmental mixtures using a mixture-altering contrast, which is any comparison, intervention, policy, or natural experiment that changes a mixture’s composition. We combine the notion of mixture-altering contrasts with sliced inverse regression, propensity score matching, and principal stratification to assess the health effects of different air pollution chemical mixtures. We demonstrate the application of this approach in an analysis of the health effects of wildfire PM air pollution in the Western US.

PMID:35088427 | DOI:10.1002/sim.9330

Int J Eat Disord. 2022 Jan 27. doi: 10.1002/eat.23686. Online ahead of print.

ABSTRACT

OBJECTIVE: Fear of weight gain (FOWG) is increasingly implicated in the maintenance of binge-spectrum eating disorders (EDs; e.g., bulimia nervosa [BN], binge-eating disorder [BED]) through the pathway of increased dietary restriction. However, particularly in binge-spectrum EDs, research is nascent and based on retrospective self-report. To improve treatment outcomes, it is critical to better understand the momentary relations between FOWG and dietary restriction.

METHOD: Sixty-seven adults with binge spectrum EDs completed a 7-14-day ecological momentary assessment protocol that included items regarding FOWG, ED behaviors, and types of dietary restriction (e.g., attempted restraint vs. actual restriction) several times per day. Multilevel models were used to evaluate reciprocal associations between FOWG and dietary restriction, and to evaluate the indirect of effects of dietary restriction on the relation between FOWG and binge eating.

RESULTS: While main effects were not statistically significant, ED presentation significantly moderated the association between increases in FOWG at time1 and both attempted and actual avoidance of enjoyable foods at time2 such that those with BN-spectrum EDs were more likely to avoid enjoyable foods following increased FOWG compared to those with BED-spectrum EDs. Engagement in restriction at time1 was not associated with decreased FOWG at time2.

DISCUSSION: Prospective associations between FOWG and restriction suggest that individuals with BN may be more likely to restrict their eating following increased FOWG. These findings suggest FOWG may be an important target for future treatments.

PMID:35088433 | DOI:10.1002/eat.23686

Thromb Haemost. 2022 Jan 27. doi: 10.1055/a-1753-2748. Online ahead of print.

ABSTRACT

In certain clinical situations, it is necessary to determine whether clinically relevant plasma levels of direct oral anticoagulants (DOACs) are present. We examined whether qualitative testing of DOACs in urine samples can exclude DOAC plasma concentrations of >30 ng/mL. This prospective single centre cohort study included consecutive patients treated with an oral direct factor Xa inhibitor (DXI) (apixaban, n=31, rivaroxaban, n=53) and direct thrombin inhibitor (DTI) (dabigatran, n=44). We aimed to define the negative predictive value (NPV) and other statistical parameters of detecting DXIs and DTIs by DOAC Dipstick at plasma concentrations of >30 ng/mL. We also determined the best-fit threshold plasma levels using chromogenic substrate assays by logistic regression analysis. Between July 2020 and July 2021, 128 eligible patients (mean age 66 years, 55 females) were included into the study. The NPVs and sensitivities for DXI and DTI of DOAC Dipstick were 100% at >30 ng/ml plasma, for specificities 6% and 21% and for positive predictive values 62% and 72%, respectively. All diagnostic statistical tests improved to values between 86% and 100% at best fitting plasma thresholds of >14 ng/mL for DXI and >19 ng/mL for DTI. Visual analysis using the DOAC Dipstick was 100% in agreement with that of the optoeletronic DOASENSE Reader for all three DOACs. DOAC Dipstick testing can reliably exclude the presence of DOACs in urine samples at best fitting thresholds of >14 and >19 ng/mL in plasma. The performance of the DOAC Dipstick at detecting lower DOAC concentrations in plasma requires confirmation.

PMID:35088395 | DOI:10.1055/a-1753-2748

Acta Obstet Gynecol Scand. 2022 Jan 27. doi: 10.1111/aogs.14318. Online ahead of print.

ABSTRACT

INTRODUCTION: Conflicting reports of increases and decreases in rates of preterm birth (PTB) and stillbirth in the general population during the coronavirus disease 2019 (COVID-19) pandemic have surfaced. The objective of our study was to conduct a living systematic review and meta-analyses of studies reporting pregnancy and neonatal outcomes by comparing the pandemic and pre-pandemic periods.

MATERIAL AND METHODS: We searched the PubMed and Embase databases and reference lists of articles published up until November 20, 2021, and included English language studies that compared outcomes between the COVID-19 pandemic time period with pre-pandemic time periods. Risk of bias was assessed using the Newcastle-Ottawa scale. We conducted random-effects meta-analysis using the inverse variance method.

RESULTS: Fifty-two studies with low-to-moderate risk of bias, reporting on 2 372 521 pregnancies during the pandemic period and 28 518 300 pregnancies during the pre-pandemic period, were included. There was significant reduction in unadjusted estimates of PTB (43 studies, unadjusted odds ratio [uaOR] 0.95, 95% CI 0.93-0.98), but not in adjusted estimates (five studies, adjusted OR [aOR] 0.94, 95% CI 0.74-1.19). This reduction was noted in studies from single centers/health areas (29 studies, uaOR 0.90, 95% CI 0.85-0.94) but not in regional/national studies (14 studies, uaOR 0.99, 95% CI 0.99-1.01). There was reduction in spontaneous PTB (nine studies, uaOR 0.91, 95% CI 0.88-0.94) but not in induced PTB (eight studies, uaOR 0.90, 95% CI 0.79-1.01). There was no difference in the odds of stillbirth between the pandemic and pre-pandemic time periods (32 studies, uaOR 1.07, 95% CI 0.97-1.18 and three studies, aOR 1.18, 95% CI 0.86-1.63). There was an increase in mean birthweight during the pandemic period compared with the pre-pandemic period (nine studies, mean difference 21 g, 95% CI 13-30 g). The odds of maternal mortality were increased (five studies, uaOR 1.15, 95% CI 1.05-1.26); however, only unadjusted estimates were available, and the result was mostly influenced by one study from Mexico. There was significant publication bias for the outcome of PTB.

CONCLUSIONS: The COVID-19 pandemic may be associated with a reduction in PTB; however, referral bias cannot be excluded. There was no statistically significant difference in stillbirths between pandemic and pre-pandemic periods.

PMID:35088409 | DOI:10.1111/aogs.14318

J Racial Ethn Health Disparities. 2022 Jan 27. doi: 10.1007/s40615-022-01241-6. Online ahead of print.

ABSTRACT

PURPOSE: Underrepresented minority student recruitment initiatives from medical school admissions and diversity offices can bring equity for those learners underrepresented in medicine. Measuring growth of the applicant pool helps determine the impact of such initiatives in helping diversify the healthcare workforce.

AIM: The authors evaluated underrepresented minority applicant pool growth at the Brody School of Medicine to determine whether predominantly White institutions or historically Black colleges and universities have accounted for the most growth in minority applicants in recent years.

METHODS: Outreach outcomes across the state were obtained by comparing applicant and matriculant demographics. Data on all applicants and matriculants were retrieved from the school’s institutional records and classified according to student self-identification as underrepresented minority. Using Chi-square tests, authors aimed to determine whether the proportion of minority students increased among applicants and matriculants since 2016, the year of restructuring outreach. In further analysis, the number of graduates from historically Black colleges and universities as compared to minority graduates from predominantly White schools was evaluated.

RESULTS: The authors identified 7,848 applicants and 654 matriculants over the evaluation period. The proportion of learners identifying as underrepresented minority increased from 17% before 2016 (622/3,672) to 20% after 2016 (835/4,176; p = 0.001). The proportion of applicants who did not graduate from a historically Black college or university increased slightly after 2016 (89% of underrepresented minority applicants before 2016 vs. 92% of underrepresented minority applicants after 2016), but this increase was not statistically significant (p = 0.097).

CONCLUSION: Applicant growth has been more significant for underrepresented minority applicants from predominantly White institutions. Graduates of targeted historically Black colleges and universities who applied to Brody School of Medicine were better prepared, resulting in increased chances of admission.

PMID:35088390 | DOI:10.1007/s40615-022-01241-6

Brain Imaging Behav. 2022 Jan 28. doi: 10.1007/s11682-021-00601-w. Online ahead of print.

ABSTRACT

This study aimed to systematically review the literature to identify clinical studies assessing neuroplasticity changes induced by or associated with bruxism or a tooth-clenching task using neurophysiological techniques. Searches were performed in five electronic databases (PubMed, EMBASE, Scopus, Web of Science, and Google Scholar) in April 2020. This review included clinical studies using neurophysiological techniques to assess neuroplasticity changes in healthy participants before and after a tooth-clenching task or comparing bruxers and non-bruxers. The quality assessment was performed with the Joanna Briggs Institute tool and Grading of Recommendations Assessment, Development, and Evaluation. Meta-analyses were conducted with studies reporting similar comparisons regarding masseter motor evoked potential amplitude and signal change outcomes. Of 151 articles identified in the searches, nine were included, and five proceeded to meta-analysis. Included studies presented moderate to very low methodological quality. From these included studies, eight evaluated bruxers and non-bruxers, of which five of them observed brain activity differences between groups, and three found no differences. Even so, all studies have suggested distinct difference in the central excitability between bruxers and non-bruxers, the meta-analysis revealed no statistically significant differences (P > 0.05). It appears that bruxism seems, indeed, to be associated with distinct differences in the neural pathways related to the control of the jaw-closing muscles, but that considerable variability in terms of classification of bruxism and assessment of neuroplasticity hamper a definite conclusion. Future research projects should take these concerns into consideration in order to further the understanding of bruxism physiology and pathophysiology.

PMID:35088353 | DOI:10.1007/s11682-021-00601-w

Int Ophthalmol. 2022 Jan 28. doi: 10.1007/s10792-021-02185-2. Online ahead of print.

ABSTRACT

PURPOSE: To assess the peripapillary retinal nerve fiber layer (RNFL) and macular choroidal thickness (CT) of children who have Type 1 diabetes mellitus (DM), both with and without vitamin D deficiency (VDD).

METHODS: The prospective, case-control study herein comprised that included 46 children with DM and VDD (Group 1), 42 children with DM and normal vitamin D levels (Group 2), and 73 healthy children (Control group). The peripapillary RNFL thickness and macular CT were measured at three different points (subfoveal, 1500 μm nasal, and 1500 μm temporal from the fovea) and compared.

RESULTS: The subfoveal, 1500 μm nasal, and 1500 μm temporal CT values were determined to be lower in the patients in Group 1 and Group 2 when compared to those in the Control group (P < 0.001). The same parameters were determined to be lower in the patients in Group 1 when compared to those in Group 2, although this difference was not found to be statistically significant (P > 0.05). In all of the quadrants, the RNFL thickness was determined to be similar between the groups, with P > 0.05 for all of the groups, except for the nasal quadrant (P = 0.031). In the correlation analysis of the patients in Group 1, it was revealed that a positive correlation existed between the CT and the vitamin D levels (P < 0.05).

CONCLUSION: The choroids of pediatric diabetic children were thinner when compared to those of healthy children. The alterations in these parameters were more prominent in subjects who were determined to have lower levels of vitamin D.

PMID:35088355 | DOI:10.1007/s10792-021-02185-2

Environ Sci Pollut Res Int. 2022 Jan 28. doi: 10.1007/s11356-021-18246-z. Online ahead of print.

ABSTRACT

Environmental exposure to vanadium has been on the increase in recent time. This metal is a known toxicant. The current study was conducted to investigate the reproductive toxicity of sodium metavanadate (SMV) in male African giant rats. Administration of SMV was done intraperitoneally daily for 14 consecutive days at a dosage of 3 mg/kg body weight. Sterile water was administered to the control group. Serum reproductive hormones, sperm reserve and quality as well as testicular ultrastructural changes following SMV treatment were analysed. Results showed SMV-exposed AGR group had statistically decreased concentrations of testosterone (4.7 ng/ml), FSH (3.4 IU/L) and LH (3.8 IU/L). Also, SMV-treated group had statistically decreased sperm motility and mass activity with increased percentage of abnormal morphophenotypes of spermatozoa and upregulation of P53 immunopositive cells. Ultrastructural study revealed vacuolation of germ and Sertoli cells cytoplasm and nucleus, and mitochondrial swelling and vacuolations were also observed. There was severe disintegration of the seminiferous tubules, atrophy and degeneration of myeloid cells and apoptosis of the Leydig, Sertoli and germ cells. In conclusion, intraperitoneal SMV exposure exerts severe adverse effects on some serum reproductive hormones, reduction in the sperm reserve and quality, apoptosis and degenerative changes of the Leydig, Sertoli and germ cells which can lead to infertility.

PMID:35088257 | DOI:10.1007/s11356-021-18246-z

J Osteopath Med. 2022 Jan 27. doi: 10.1515/jom-2021-0214. Online ahead of print.

ABSTRACT

CONTEXT: With the rise of the Delta variant of SARS-CoV-2 and the low vaccination rates in the United States, mitigation strategies to reduce the spread of SARS-CoV-2 are essential for protecting the health of the general public and reducing strain on healthcare facilities. This study compares US counties with and without mask mandates and determines if the mandates are associated with reduced daily COVID-19 infection. US counties have debated whether masks effectively decrease COVID-19 cases, and political pressures have prevented some counties from passing mask mandates. This article investigates the utility of mask mandates in small US counties.

OBJECTIVES: This study aims to analyze the effectiveness of mask mandates in small US counties and places where the population density may not be as high as in larger urban counties and to determine the efficacy of countywide mask mandates in reducing daily COVID-19 infection.

METHODS: The counties studied were those with populations between 40,000 and 105,000 in states that did not have statewide mask mandates. A total of 38 counties were utilized in the study, half with and half without mask mandates. Test counties were followed for 30 days after implementing their mask mandate, and daily new SARS-CoV-2 infection was recorded during this timeframe. The counties were in four randomly selected states that did not have statewide mask mandates. The controls utilized were from counties with similar populations to the test counties and were within the same state as the test county. Controls were followed for the same 30 days as their respective test county. Data were analyzed utilizing t-test and difference-in-difference analyses comparing counties with mask mandates and those without.

RESULTS: These data showed statistically significant lower averages of SARS-CoV-2 daily infection in counties that passed mask mandates when compared with counties that did not. The difference-in-difference analysis revealed a 16.9% reduction in predicted COVID-19 cases at the end of 30 days.

CONCLUSIONS: These data support the effectiveness of mask mandates in reducing SARS-CoV-2 infection spread in small US counties where the population density may be less than in urban counties. Small US counties that are considering passing mask mandates for the population can utilize these data to justify their policy considerations.

PMID:35086185 | DOI:10.1515/jom-2021-0214