Cut-point values for classifying active children and validity and reliability of physical activity questionnaire for children in Morocco

BACKGROUND

The Physical Activity Questionnaire for Children (PAQ-C) is widely used to assess physical activity in populations; however, there is a lack of information about the psychometric properties (validity and reliability) and about the PAQ-C score meaning in populations from low-middle income countries.

AIMS

The aim of this study is to evaluate the reliability and validity of PAQ-C and to determine the cut-point values of PAQ-C using accelerometry as a reference in a group of Moroccan children.

METHODS

In a sample of 171 children and adolescents aged 8 to 14 years, physical activity was assessed with the GT3X + accelerometer and the PAQ-C. PAQ-C was administered for a second time (retest) after 1 week for a subsample (n = 73). Reliability was analyzed by intraclass correlation coefficient (ICC). The PAQ-C was compared against count per minute CPM and moderate to vigorous intensity PA (MVPA) obtained by accelerometry. Receiver operating curve analyses were performed to assess the performance of PAQ-C in identifying MVPA as measured by accelerometry (reference method).

RESULTS

Test-retest reliability was poor with an ICC = (0.48 [0.27; 0.63] for the whole sample, while for the ≥11 year group, the intra-class correlation coefficient was moderate (0.71 [0.42; 0.86]. PAQ-C scores were significantly related to accelerometry-derived metrics of physical activity, CPM (R = 0.29, P < 0.001) and MVPA (R = 0.26, P < 0.001). For the age group ≥11 years, the associations between PAQ-C Scores and CPM and MVPA were stronger, respectively, R = 0.37 (P < 0.001), R = 0.38 (P < 0.0001). We identified that a PAQ-C Score cut-point of 2.33 (95%CI [0.43-0.68]) discriminated adequately between those who met physical activity guidelines and those that did not in the overall sample.

CONCLUSIONS

The PAQ-C is valid and useful to assess population level physical activity in those ≥11 years in Morocco and so might be helpful in population surveillance of physical activity in Moroccan adolescents.

Association of precalving serum NEFA concentrations with postpartum diseases and reproductive performance in multiparous Holstein cows: Cut-off values

BACKGROUND

High concentrations of NEFA relative to a defined reference or 'cut-point' values before calving can predict the risk of specific or collective periparturient disease events.

OBJECTIVES

A field-based cohort study was conducted to evaluate the value and critical points of serum nonesterified fatty acids (NEFA) at the precalving time to predict the occurrence of postpartum diseases and reproductive performance in dairy cows.

METHODS

Blood samples were taken from 521 high-yielding dairy cows at 1 week (±3 days) before calving and NEFA levels were measured. Health and reproduction information of each cow includes dystocia, retained placenta, milk fever, metritis, mastitis, pregnancy in the first insemination and pregnancy in the first two inseminations, and culling in the first 60 days of lactation and milk production.

RESULTS

Our results show that there are significant relationships between precalving NEFA with the probability of pregnancy at the first and the first two inseminations after calving. The cows that had NEFA concentrations less than 0.5 mmol/L at the last week of pregnancy were 3.51 and 3.15 times more likely to be pregnant at first insemination and the first two inseminations, respectively. Also, our results showed that there are significant relationships between precalving NEFA concentration and the likelihood of dystocia and milk fever. The probability of dystocia and milk fever occurrence were 2.56 and 1.91 times greater in those cows that had NEFA concentrations more than 0.3 mmol/L, respectively.

CONCLUSIONS

The present results indicated that Increasing NEFA during the prepartum period could adversely affect the reproductive efficiency of dairy cows.

Corrigendum: Epidemiology, risk factors and outcomes of prolonged mechanical ventilation with different cut-points in a PICU

[This corrects the article DOI: 10.3389/fped.2023.1167595.].

Adverse Childhood Experiences and Chronic Diseases: Identifying a Cut-Point for ACE Scores

Adverse Childhood Experiences (ACEs) contribute to many negative physiological, psychological, and behavioral health consequences. However, a cut-point for adverse childhood experience (ACE) scores, as it pertains to health outcomes, has not been clearly identified. This ambiguity has led to the use of different cut-points to define high scores. The aim of this study is to clarify a cut-point at which ACEs are significantly associated with negative chronic health outcomes. To accomplish this aim, a secondary analysis using data from a cross-sectional study was conducted. The Adverse Childhood Experiences-International Questionnaire (ACE-IQ) was used for data collection. Descriptive statistics, nonparametric regression, and logistic regression analyses were performed on a sample of 10,047 adults. Data from demographic and self-report health measures were included. The results showed that a cut-point of four or more ACEs was significantly associated with increased rates of chronic disease. Participants with at least one chronic disease were almost 3 times more likely (OR = 2.8) to be in the high ACE group. A standardized cut-point for ACE scores will assist in future research examining the impact of high ACEs across cultures to study the effect of childhood experiences on health.

Epidemiology, risk factors and outcomes of prolonged mechanical ventilation with different cut-points in a PICU

Background

A consensus on the definition of prolonged mechanical ventilation (PMV) for children does not exist. There is still lack of published work presenting the epidemiology, risk factors and outcomes at different cut-points for PMV patients. These are important for planning the goals of treatment and counseling of the prognosis for patient families. We aimed to determine the incidence, baseline characteristics, risk factors and outcomes of PMV in pediatric patients at various cut-points (>14, >21 or >30days).

Methods

A retrospective cohort study among children <18-years-old who were PMV > 14 days in the PICU of King Chulalongkorn Memorial Hospital was conducted. The primary outcomes were incidence of PMV with various cut-points. We stratified patients into three groups (Group 1; PMV > 14-21, Group 2; >21-30, Group 3; >30 days) for evaluating the baseline characteristics, risk factors, and outcomes of PMV (extubation success, tracheostomy status and death). Factors associated with PMV and deaths were analyzed using univariate and multivariate logistic regression.

Results

From January 2018 to August 2022, 1,050 patients were screened. Of these, 114 patients were enrolled. The incidence of PMV > 14, >21 and >30 days were 10.9%, 7.3% and 5.0% respectively. Extubation success was significantly lower in Group 3 than in Groups 1 & 2 (15.4% vs. 62.2% & 56.0%, P < 0.001). Consequently, the tracheostomy rate (63.5% vs. 16.2% & 12.0%, P < 0.001), VAP rate (98.1% vs. 59.5% & 80.0%, P < 0.001), mortality rate by disease (34.6% vs. 5.4% & 20.0%, P = 0.003), median PICU LOS (50.5 vs. 22.0 & 28.0 days, P < 0.001) and median hospital LOS (124.5 vs. 55.0 & 62.0 days, P < 0.001) were also significantly higher for Group 3 compared with Groups 1 & 2. The factor associated with PMV > 30 days was VAP (aOR: 19.53, 95% CI: 2.38-160.34, P = 0.01). Factors associated with non-surviving patients were 3rd degree PEM (aOR: 5.14, 95% CI: 1.57-16.88, P = 0.01), PIM3 score ≥14 (aOR: 6.75, 95% CI: 2.26-20.15, P < 0.001) and muscle relaxant usage (aOR: 5.58, 95% CI: 1.65-18.86, P = 0.01).

Conclusion

Extubation failure, tracheostomy rate, VAP rate, mortality rate by disease, PICU LOS and hospital LOS were significantly higher for PMV >30 days. Consequently, we suggest that a 30-day duration as a cut-point for PMV in PICUs might be more appropriate.

Evaluation of Brix refractometer as an on-farm tool for colostrum IgG evaluation in Italian beef and dairy cattle

In this study it is hypothesized that there are differences between immunoglobulin G (IgG) content in colostrum from beef (Chianina, Podolica) and dairy (Holstein Friesian) cows and that variables such as breed, and parity can influence IgG content. The further objective was to determine if these factors may vary in terms of sensitivity, specificity and the cut point when data obtained with the digital Brix refractometer is compared with the gold standard radial immunodiffusion assay (RID). A total of 90 samples of first-milking colostrum were collected within 2 h after parturition. IgG concentration was determined indirectly by digital Brix refractometer and directly by RID. Results obtained by RID were compared among breed and parity. For the digital Brix refractometer, sensitivity and specificity to detect colostrum with an IgG concentration lower than 50 g/l were calculated and the optimal cut-point was selected for each breed. Samples containing less than <50 g/l IgG accounted for 15.9% of the total. Parity influenced colostral IgG concentration and beef cows had a higher mean concentration of IgG (101.1 g/l in Chianina and 90.6 g/l in Podolica) than dairy cows (71.1 g/l in Holstein Friesian) First parity Chianina cows had the highest IgG mean content (116.1 g/l). At the optimal cut-point for Brix refractometer (20%) sensitivity and specificity were 0.93 (0.84-0.97) and 0.81 (0.70-0.88), however, a breed-related cut-point could be used to reduce evaluation error. Linear regression modeling showed that refractometer data were related to RID (r = 0.78). Results obtained suggest that breed and parity can influence IgG content of colostrum and, despite the Brix refractometer being an excellent on-farm tool, a breed-based definition of optimal cut point is needed.

Concordance of Lumipulse cerebrospinal fluid t-tau/Aβ42 ratio with amyloid PET status

INTRODUCTION

Cerebrospinal fluid (CSF) biomarkers can identify individuals with Alzheimer's disease (AD) pathology (eg, amyloid plaques, neurofibrillary tangles), but defined analyte cut-points using high-throughput automated assays are necessary for general clinical use.

METHODS

CSF amyloid β42 peptide (Aβ42), t-tau, and t-tau/Aβ42 were quantified by the Lumipulse platform in two test cohorts (A/B: Eisai BAN2401-201/MISSION AD E2609-301/302, n = 138; C: Knight Alzheimer's Disease Research Center (ADRC), n = 198), and receiver operating characteristic (ROC) curve analyses defined cut-points corresponding best to amyloid determinations using positron emission tomography (PET) imaging. The best-performing cut-point was then validated as a predictor of amyloid status in an independent cohort (D: MISSION AD E2609-301/302, n = 240).

RESULTS

Virtually identical t-tau/Aβ42 cut-points (∼0.54) performed best in both test cohorts and with similar accuracy (areas under ROC curve [AUCs] [A/B: 0.95; C: 0.94]). The cut-point yielded an overall percent agreement with amyloid PET of 85.0% in validation cohort D.

DISCUSSION

Lumipulse CSF biomarker measures with validated cut-points have clinical utility in identifying AD pathology.

Distress Screening in Adolescents and Young Adults with Cancer: Development of Cut-Points for the Cancer Distress Scales-Adolescent and Young Adults

Purpose: Distress is an important issue facing adolescent and young adults (AYA) with cancer due to their stage of development. Metrics are necessary to help improve psychosocial outcomes in this population. This study determined cut-points for the newly developed Cancer Distress Scales (CDS)-AYA. Methods: The CDS-AYA is a new patient-reported outcomes measure that comprises five independently functioning scales, including the following: Impact of Cancer (12 items), Physical (12 items), Emotional (11 items), Cognitive (8 items), and Cancer Worry (5 items). Canadian AYA with cancer 15-39 years of age completed the CDS-AYA and the Hospital Anxiety and Depression Scale (HADS), as part of the CDS-AYA field test. Only patients who had completed responses to the CDS-AYA and HADS were included in these analyses. Receiver operating characteristic (ROC) curve analysis was used to generate cut-points for five CDS-AYA scales based on distress defined by the HADS anxiety and HADS depression scale. Results: In total 453 of 515 respondents had complete data for the CDS-AYA and HADS were included in analyses. Area under the curve (AUC) in the ROC analyses ranged from 0.75 to 0.85. The CDS-AYA Emotional scale had the greatest AUC. The cutoff value for the Emotional scale was 27 based on the HADS anxiety scores (78.3% and 78.9%). Conclusions: The five CDS-AYA scales had fair to good accuracy when classifying the none/low and moderate/severe distress categories based on HADS anxiety and depression scales. For screening purposes, it is recommended that the Emotional scale or Impact of Cancer scale be utilized.

A Threshold of Objectively-Assessed Daily Sedentary Time for All-Cause Mortality in Older Adults: A Meta-Regression of Prospective Cohort Studies

Background: This meta-analysis aimed to estimate the shape of the dose-response association between objectively-assessed daily sedentary time (ST) and all-cause mortality, and to explore whether there is a threshold of ST above which there is an increase in mortality risk in older adults. Methods: Searches for prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were undertaken in five databases up to 31 March 2019. A random-effects meta-regression model was conducted to quantify the dose-response relationship between daily ST and all-cause mortality. Sensitivity analyses were also performed to test the stability of the results. Results: Our analysis of pooled data from 11 eligible studies did not reveal a consistent shape of association between ST and mortality. After excluding three studies with potential confounding bias, there was a log-linear dose-response relationship between daily ST and all-cause mortality. Overall, higher amounts of time spent in sedentary behaviors were associated with elevated mortality risks in older adults. Visual assessments of dose-response relationships based on meta-regression analyses indicated that increased mortality risks became significant when total ST exceeded approximately 9 h/day. Conclusions: Based on a limited number of studies, this meta-analysis provides a starting point for considering a cut-off of daily sedentary time, suggesting older adults spend less time in daily sitting.

Feedback from the European Bioanalysis Forum: focus workshop on current analysis of immunogenicity: best practices and regulatory hurdles

European Bioanalysis Forum Workshop, Lisbon, Portugal, September 2016: At the recent European Bioanalysis Forum Focus Workshop, 'current analysis of immunogenicity: best practices and regulatory hurdles', several important challenges facing the bioanalytical community in relation to immunogenicity assays were discussed through a mixture of presentations and panel sessions. The main areas of focus were the evolving regulatory landscape, challenges of assay interferences from either drug or target, cut-point setting and whether alternative assays can be used to replace neutralizing antibody assays. This workshop report captures discussions and potential solutions and/or recommendations made by the speakers and delegates.

Sedentary Behaviour Profiling of Office Workers: A Sensitivity Analysis of Sedentary Cut-Points

Measuring sedentary behaviour and physical activity with wearable sensors provides detailed information on activity patterns and can serve health interventions. At the basis of activity analysis stands the ability to distinguish sedentary from active time. As there is no consensus regarding the optimal cut-point for classifying sedentary behaviour, we studied the consequences of using different cut-points for this type of analysis. We conducted a battery of sitting and walking activities with 14 office workers, wearing the Promove 3D activity sensor to determine the optimal cut-point (in counts per minute (m·s(-2))) for classifying sedentary behaviour. Then, 27 office workers wore the sensor for five days. We evaluated the sensitivity of five sedentary pattern measures for various sedentary cut-points and found an optimal cut-point for sedentary behaviour of 1660 × 10(-3) m·s(-2). Total sedentary time was not sensitive to cut-point changes within ±10% of this optimal cut-point; other sedentary pattern measures were not sensitive to changes within the ±20% interval. The results from studies analyzing sedentary patterns, using different cut-points, can be compared within these boundaries. Furthermore, commercial, hip-worn activity trackers can implement feedback and interventions on sedentary behaviour patterns, using these cut-points.

Optimal survival time-related cut-point with censored data

In biomedical research and practice, continuous biomarkers are often used for diagnosis and prognosis, with a cut-point being established on the measurement to aid binary classification. When survival time is examined for the purposes of disease prognostication and is found to be related to the baseline measure of a biomarker, employing a single cut-point on the biomarker may not be very informative. Using survival time-dependent sensitivity and specificity, we extend a concordance probability-based objective function to select survival time-related cut-points. To estimate the objective function with censored survival data, we adopt a non-parametric procedure for time-dependent receiver operational characteristics curves, which uses nearest neighbor estimation techniques. In a simulation study, the proposed method, when used to select a cut-point to optimally predict survival at a given time within a specified range, yields satisfactory results. We apply the procedure to estimate survival time-dependent cut-point on the prognostic biomarker of serum bilirubin among patients with primary biliary cirrhosis.

On the nullity of a graph with cut-points

Let G be a simple graph of order n and A(G) be its adjacency matrix. The nullity of a graph G, denoted by η(G), is the multiplicity of the eigenvalue zero in the spectrum of A(G). Denote by Ck and Lk the set of all connected graphs with k induced cycles and the set of line graphs of all graphs in Ck, respectively. In 1998, Sciriha [I. Sciriha, On singular line graphs of trees, Congr. Numer. 135 (1998) 73-91] show that the order of every tree whose line graph is singular is even. Then Gutman and Sciriha [I. Gutman, I. Sciriha, On the nullity of line graphs of trees, Discrete Math. 232 (2001) 35-45] show that the nullity set of L0 is {0,1}. In this paper, we investigate the nullity of graphs with cut-points and deduce some concise formulas. Then we generalize Scirihas' result, showing that the order of every graph G is even if such a graph G satisfies that G∈Ck and η(L(G))=k+1, and the nullity set of Lk is {0,1,…,k,k+1} for any given k, where L(G) denotes the line graph of the graph G.