Tag: statistics

Genetics. 2021 Nov 5;219(3):iyab115. doi: 10.1093/genetics/iyab115.

ABSTRACT

The Beavis effect in quantitative trait locus (QTL) mapping describes a phenomenon that the estimated effect size of a statistically significant QTL (measured by the QTL variance) is greater than the true effect size of the QTL if the sample size is not sufficiently large. This is a typical example of the Winners’ curse applied to molecular quantitative genetics. Theoretical evaluation and correction for the Winners’ curse have been studied for interval mapping. However, similar technologies have not been available for current models of QTL mapping and genome-wide association studies where a polygene is often included in the linear mixed models to control the genetic background effect. In this study, we developed the theory of the Beavis effect in a linear mixed model using a truncated noncentral Chi-square distribution. We equated the observed Wald test statistic of a significant QTL to the expectation of a truncated noncentral Chi-square distribution to obtain a bias-corrected estimate of the QTL variance. The results are validated from replicated Monte Carlo simulation experiments. We applied the new method to the grain width (GW) trait of a rice population consisting of 524 homozygous varieties with over 300 k single nucleotide polymorphism markers. Two loci were identified and the estimated QTL heritability were corrected for the Beavis effect. Bias correction for the larger QTL on chromosome 5 (GW5) with an estimated heritability of 12% did not change the QTL heritability due to the extremely large test score and estimated QTL effect. The smaller QTL on chromosome 9 (GW9) had an estimated QTL heritability of 9% reduced to 6% after the bias-correction.

PMID:34740243 | DOI:10.1093/genetics/iyab115

J Clin Pediatr Dent. 2021 Nov 1;45(5):352-358. doi: 10.17796/1053-4625-45.5.11.

ABSTRACT

AIM: To evaluate the effects produced by functional orthodontic appliances at dental and skeletal level in relation to the level of skeletal maturation in class II patients.

STUDY DESIGN: Longitudinal and observational study. Patients selected for the study had been wearing Sander Bite Jumping Appliance (SBJA) for at least 12 months; they were first diagnosed (T1) with skeletal class II according to Ricketts’ cephalometric analysis, and had had lateral cephalograms taken before and after orthopaedic treatment (T2). Variables studied at T1 and T2 were: facial convexity, inclination of the upper and lower incisors, and facial depth. Results were compared between T1 and T2 for each variable and in relation to cervical maturation stage (CVS) according to the Lamparski analysis. Statistical analysis was performed using Shapiro-Wilk, t-student, Analysis of Variance (ANOVA) and multiple comparison tests, taking as statistically significant a p-value <0.05.

RESULTS: A final sample of 235 patients was obtained. Statistically significant differences were found in the inclination of the mandibular incisors between T1 and T2 and among the different cervical stages when the functional appliances were placed in CVS1 (p = 0.000), CVS2 (p = 0.04) or CVS5 (p = 0.048). For the remaining variables, significant differences were also found between T1 and T2, but these differences were similar in all cervical stages.

CONCLUSIONS: A significant proclination of the mandibular incisors was found when the functional appliance was placed during CVS1, CVS2, or CVS5. Time of placement of the functional appliances was not statistically significant for the remaining variables studied.

PMID:34740259 | DOI:10.17796/1053-4625-45.5.11

Genetics. 2021 Nov 5;219(3):iyab140. doi: 10.1093/genetics/iyab140.

ABSTRACT

Transcriptional regulatory networks (TRNs) are enriched for certain “motifs.” Motif usage is commonly interpreted in adaptationist terms, i.e., that the optimal motif evolves. But certain motifs can also evolve more easily than others. Here, we computationally evolved TRNs to produce a pulse of an effector protein. Two well-known motifs, type 1 incoherent feed-forward loops (I1FFLs) and negative feedback loops (NFBLs), evolved as the primary solutions. The relative rates at which these two motifs evolve depend on selection conditions, but under all conditions, either motif achieves similar performance. I1FFLs generally evolve more often than NFBLs. Selection for a tall pulse favors NFBLs, while selection for a fast response favors I1FFLs. I1FFLs are more evolutionarily accessible early on, before the effector protein evolves high expression; when NFBLs subsequently evolve, they tend to do so from a conjugated I1FFL-NFBL genotype. In the empirical S. cerevisiae TRN, output genes of NFBLs had higher expression levels than those of I1FFLs. These results suggest that evolutionary accessibility, and not relative functionality, shapes which motifs evolve in TRNs, and does so as a function of the expression levels of particular genes.

PMID:34740240 | DOI:10.1093/genetics/iyab140

Clin Spine Surg. 2021 Nov 4. doi: 10.1097/BSD.0000000000001271. Online ahead of print.

ABSTRACT

STUDY DESIGN: Retrospective cohort study.

OBJECTIVE: The aim were to (1) evaluate differences in postoperative outcomes and cost associated with outpatient anterior lumbar interbody fusion (ALIF) compared with inpatient ALIF, and to (2) identify independent factors contributing to complications after outpatient ALIF.

SUMMARY OF BACKGROUND: While lumbar fusion is traditionally performed inpatient, outpatient spinal surgery is becoming more commonplace as surgical techniques improve.

METHODS: The study population included all patients below 85 years of age who underwent elective ALIF (CPT-22558). Patients were then divided into those who underwent single-level fusion and multilevel fusion using the corresponding additional level fusion codes (CPT-22585). These resulting populations were then split into outpatient and inpatient cohorts by using a service location modifier. To account for selection bias, propensity score matching was performed; the inpatient cohorts were matched with respect to the outpatient cohorts based on age, sex, and Charlson Comorbidity Index. Statistical significance was set at P<0.05 and the Bonferroni correction was used for each multiple comparison (P<0.004).

RESULTS: Patients undergoing outpatient procedure had decreased rates of medical complications following both single-level and multilevel ALIF. In addition, age above 60, female sex, Charlson Comorbidity Index>3, chronic obstructive pulmonary disease, diabetes mellitus, coronary artery disease, hypertension, and tobacco use were all identified as independent risk factors for increased complications. Finally, the cost of outpatient ALIF was $12,013 while the cost of inpatient ALIF was $27,271 (P<0.001).

CONCLUSION: The findings add to the growing body of literature advocating for the utilization of ALIF in the outpatient setting for a properly selected group of patients.

LEVEL OF EVIDENCE: Level IV.

PMID:34740230 | DOI:10.1097/BSD.0000000000001271

Genetics. 2021 Nov 5;219(3):iyab124. doi: 10.1093/genetics/iyab124.

ABSTRACT

Over the last decade, multiparental populations have become a mainstay of genetics research in diploid species. Our goal was to extend this paradigm to autotetraploids by developing software for quantitative trait locus (QTL) mapping in connected F1 populations derived from a set of shared parents. For QTL discovery, phenotypes are regressed on the dosage of parental haplotypes to estimate additive effects. Statistical properties of the model were explored by simulating half-diallel diploid and tetraploid populations with different population sizes and numbers of parents. Across scenarios, the number of progeny per parental haplotype (pph) largely determined the statistical power for QTL detection and accuracy of the estimated haplotype effects. Multiallelic QTL with heritability 0.2 were detected with 90% probability at 25 pph and genome-wide significance level 0.05, and the additive haplotype effects were estimated with over 90% accuracy. Following QTL discovery, the software enables a comparison of models with multiple QTL and nonadditive effects. To illustrate, we analyzed potato tuber shape in a half-diallel population with three tetraploid parents. A well-known QTL on chromosome 10 was detected, for which the inclusion of digenic dominance lowered the Deviance Information Criterion (DIC) by 17 points compared to the additive model. The final model also contained a minor QTL on chromosome 1, but higher-order dominance and epistatic effects were excluded based on the DIC. In terms of practical impacts, the software is already being used to select offspring based on the effect and dosage of particular haplotypes in breeding programs.

PMID:34740237 | DOI:10.1093/genetics/iyab124

Am J Phys Med Rehabil. 2021 Nov 3. doi: 10.1097/PHM.0000000000001918. Online ahead of print.

ABSTRACT

Intra-articular injections with hyaluronic acid are recommended in the treatment of knee osteoarthritis (KOA); however, hypertonic dextrose prolotherapy (HDP) has been reported as effective and safe. The aim was to evaluate the effectiveness of HDP for pain reduction and improvement of function in individuals with KOA in comparison with hyaluronic acid by meta – analysis. The search was performed in electronic databases. Six studies were included (395 participants). No statistically significant differences were found between prolotherapy and hyaluronic acid in pain control in the short term, however, in the sub-analysis where included only the studies that used intra-articular injection within the prolotherapy scheme, an effect was found in favor of the prolotherapy groups (d = -1.33, 95% CI -2.50 to -0.16, p (z) 0.03). Also, an effect was found in favor of the prolotherapy group in the improvement in function (d = -1.05, 95% CI -2.03 to -0.08, p (z) 0.03). No major adverse reactions or side effects were reported in any of the studies. HDP appears to be an effective intervention to decrease pain and improve function in KOA, with efficacy similar to intra-articular injections with hyaluronic acid in the short-term follow-up. Nonetheless, better-quality clinical trials are necessary.

PMID:34740224 | DOI:10.1097/PHM.0000000000001918

J Cardiovasc Nurs. 2021 Nov 2. doi: 10.1097/JCN.0000000000000866. Online ahead of print.

ABSTRACT

BACKGROUND: Individuals with a greater perceived risk of heart attack or type 2 diabetes tend to adopt recommended lifestyle changes to minimize their risks. Despite the rapidly growing Hispanic population in the United States, data regarding their perceived risks are lacking.

OBJECTIVE: This study aimed to examine the perceived risk of suffering a heart attack and/or developing type 2 diabetes and to explore the factors associated with these risk perceptions in Hispanic adults with overweight/obesity.

METHODS: We analyzed 69 Hispanic adults with overweight/obesity who participated in the screening/baseline visit for the Adelgaza study, a weight loss and diabetes prevention trial, using descriptive statistics and logistic regressions. Heart attack or type 2 diabetes risk perception was assessed using a single-item questionnaire.

RESULTS: The mean (SD) values for age and body mass index (BMI) were 43.8 (11.2) years and 31.7 (4.5) kg/m2, respectively. Of all participants, 46.4% perceived a low risk for heart attack and 29.0% perceived a low risk for developing type 2 diabetes in their lifetime, whereas only 11.6% reported both risk perceptions. Older age, lower BMI, and longer walking duration (minutes) per day were significantly associated with a lower perceived risk of heart attack (P < .05). Having no family history of heart attack, lower BMI, and lower fat intake were significant predictors of a lower diabetes-risk perception (P < .05).

CONCLUSIONS: Hispanic adults with overweight/obesity seem to underestimate their risks of heart attack and type 2 diabetes.

PMID:34740229 | DOI:10.1097/JCN.0000000000000866

Comput Inform Nurs. 2021 Nov 2. doi: 10.1097/CIN.0000000000000851. Online ahead of print.

ABSTRACT

The COVID-19 global pandemic caused major disruptions to the delivery of human Anatomy and Physiology courses to nursing students worldwide. The aim of the current study is to evaluate nursing students’ experiences and perceptions of transitioning from a blended to a purely online study mode for first year Anatomy and Physiology courses during the global pandemic. Qualitative and quantitative methodologies were used with a sample of undergraduate nursing students enrolled at a regional Australian university across its three campuses. Descriptive statistical analysis was used to describe the study population. Content analysis was used to evaluate the participants’ use of resources, experiences, and preferences in studying anatomy and physiology. There were 101 participants recruited in the study. Results indicated that face-to-face study mode (41.86%) was the preferred method of delivery during the global pandemic and participants were having a renewed appreciation for the blended study mode (38.37%). Online study mode was the least preferred (19.77%), with the participants’ opinions of this mode of study not altered by the global pandemic. Although the COVID-19 global pandemic shifted the traditional teaching of anatomy and physiology in nursing programs to an online environment, the long-term impacts of this disruption have yet to be ascertained.

PMID:34740220 | DOI:10.1097/CIN.0000000000000851

J Neurosurg Pediatr. 2021 Nov 5:1-8. doi: 10.3171/2021.8.PEDS21301. Online ahead of print.

ABSTRACT

OBJECTIVE: Catheter-based cerebral angiography is commonly used for neurovascular diagnosis in children. In this work, the authors aimed to quantify the complication rate of cerebral angiography in children, characterize these complications, and identify risk factors for complications.

METHODS: Relevant clinical data were retrospectively obtained for 587 consecutive cerebral angiography procedures performed in 390 children from March 2002 to March 2020. Complications were categorized as neurological or nonneurological, and severity was graded using a standard schema. Incidences of complications were reported as point estimates. Associations between risk factors and complications were characterized in univariate analysis using the two-tailed Fisher exact test and in multivariate analysis using multiple logistic regression with bidirectional elimination based on the Akaike information criterion. In both univariate and multivariate analyses, statistical significance was corrected for multiple comparisons using the Benjamini-Hochberg method.

RESULTS: Complications occurred in 6.5% of procedures, including neurological complications in 1.9% and nonneurological complications in 4.8%. Permanent deficits occurred in only 0.2% of cases. Overall, 0.5% of procedures resulted in major complications, while 6.0% resulted in minor complications. Female sex and a history of hypertension or ischemic stroke were associated with an increased risk of complications, while femoral artery access was associated with a decreased risk of complications.

CONCLUSIONS: Pediatric cerebral angiography was shown to have a low rate of major or permanent complications. Children who were female and those with a history of hypertension or ischemic stroke were shown to be at higher risk of complications, while the use of femoral access carried a lower risk of complications.

PMID:34740194 | DOI:10.3171/2021.8.PEDS21301

J Occup Environ Med. 2021 Nov 3. doi: 10.1097/JOM.0000000000002426. Online ahead of print.

ABSTRACT

OBJECTIVE: To examine long-haul truck drivers (LHTD) perceptions of COVID-19 their use of health and safety practices.

METHODS: 146 LHTD completed an online survey to collect data on their experiences with COVID-19. Data were analyzed using descriptive and inferential statistics, and thematic analysis for open-ended responses.

RESULTS: LHTD were aged from 11 to 79 years (mean age 48.1 ± 11.8); 82.2% were men. Almost half of the sample were not concerned about COVID-19. Those not concerned were significantly less likely to employ health and safety practices (e.g. wearing masks, social distancing), and were less educated and healthier. They also perceived COVID-19 to not be real or a serious threat to their health.

CONCLUSIONS: Tailored education approaches are needed to provide evidence-based data on COVID-19 risks and complication.

PMID:34740218 | DOI:10.1097/JOM.0000000000002426