Tag: statistics

Dent Mater. 2021 Sep 27:S0109-5641(21)00269-4. doi: 10.1016/j.dental.2021.09.014. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of this systematic review and meta-analysis was to compare the bond strength between eroded and sound permanent enamel and dentin and to assess whether bonding performance (immediate and after aging) differs between etch&rinse and self-etch adhesives and can be improved by surface pretreatment prior to bonding.

METHODS: Electronic databases (PubMed, Scopus, Embase, Web of Science, CENTRAL, LILACS, BBO) were searched by two reviewers. Random-effect meta-analyses were performed to compare bond strength to sound and eroded dental hard tissues without and with surface pretreatment prior to bonding, respectively. The effect of adhesive mode (etch&rinse vs. self-etch) and aging (immediate vs. aged) was compared using subgroup analyses. Statistical heterogeneity was assessed using Cochran’s Q and I²-statistic. Funnel plots and Egger’s regression intercept tests were used to evaluate publication bias. Quality and risk of bias of included studies were also assessed.

RESULTS: Fourty-seven studies (45 in vitro, 2 in situ) were included in the systematic review and meta-analyses. Erosion impairs bond strength to dentin (p < 0.001; mean difference: -10.2 MPa [95%CI: -11.9 to -8.6 MPa]), but not to enamel (p = 0.260). Surface pretreatment measures removing or stabilizing the collagenous matrix can improve dentin bond strength (maximum mean difference: +12.4 MPa). Etch&rinse and self-etch adhesives did not perform significantly different on eroded enamel (p = 0.208) and dentin (p = 0.353). The majority of studies (32 of 47) presented a medium risk of bias.

SIGNIFICANCE: Data from in vitro and in situ studies showed that erosion impairs dentin bonding of etch&rinse and self-etch adhesives and makes surface pretreatment prior to bonding of composite restorations necessary.

PMID:34593245 | DOI:10.1016/j.dental.2021.09.014

J Dairy Sci. 2021 Sep 27:S0022-0302(21)00903-6. doi: 10.3168/jds.2021-20589. Online ahead of print.

ABSTRACT

Conscious consumerism is growing, along with consumer demand for socially conscious dairy products or dairy alternatives. To successfully position dairy products (especially conventional dairy) in this changing marketplace, dairy producers and processors must understand how to strategically use both on- and off-package messaging aligned with consumer perceptions. However, consumer perception of attributes such as sustainable, natural, and healthy is complex, and varies between product categories as well as among products within a category. The objective of this study was to characterize consumer definitions of the terms sustainable, natural, and healthy as they pertain to dried dairy ingredients. To meet this objective, we conducted an online survey with 3 maximum difference scaling exercises to determine the importance of 63 label claims to consumer definitions of the terms sustainable, natural, and healthy. The role of priming with dried ingredient processing information on consumer perception of these terms was also explored. Within the dried dairy ingredients category, there is extensive cognitive overlap between the terms sustainable, natural, and healthy. Priming did not affect consumer definitions of any of these terms. Certification-related claims were considered among the least important claims for consumer definitions of sustainable, natural, and healthy, whereas claims that were simple to read and visualize were considered among the most important. Claims related to animal welfare and happiness or simple, minimal ingredients and processing were considered by consumers to be important for all 3 terms. For each of these terms, there was a cluster of consumers who defined the term primarily by simple ingredients and minimal processing, and another cluster who defined the term primarily by happy cows and conscious farming practices. The terms sustainable and healthy each had a third, unique consumer cluster. This third definition cluster defined sustainability primarily by environmental effects, whereas this cluster defined healthy primarily in fitness and nutrition terms. Age and to a lesser extent, gender, affected importance placed on these 3 terms and also affected definition of the term. Understanding these consumer definitions provides insight on how to formulate marketing and educational messaging to speak to each consumer segment.

PMID:34593227 | DOI:10.3168/jds.2021-20589

J Dairy Sci. 2021 Sep 27:S0022-0302(21)00909-7. doi: 10.3168/jds.2021-20812. Online ahead of print.

ABSTRACT

The prevalence of “grass-fed” labeled food products on the market has increased in recent years, often commanding a premium price. To date, the majority of methods used for the authentication of grass-fed source products are driven by auditing and inspection of farm records. As such, the ability to verify grass-fed source claims to ensure consumer confidence will be important in the future. Mid-infrared (MIR) spectroscopy is widely used in the dairy industry as a rapid method for the routine monitoring of individual herd milk composition and quality. Further harnessing the data from individual spectra offers a promising and readily implementable strategy to authenticate the milk source at both farm and processor levels. Herein, a comprehensive comparison of the robustness, specificity, and accuracy of 11 machine-learning statistical analysis methods were tested for the discrimination of grass-fed versus non-grass-fed milks based on the MIR spectra of 4,320 milk samples collected from cows on pasture or indoor total mixed ration-based feeding systems over a 3-yr period. Linear discriminant analysis and partial least squares discriminant analysis (PLS-DA) were demonstrated to offer the greatest level of accuracy for the prediction of cow diet from MIR spectra. Parsimonious strategies for the selection of the most discriminating wavelengths within the spectra are also highlighted.

PMID:34593222 | DOI:10.3168/jds.2021-20812

J Environ Sci (China). 2021 Dec;110:150-159. doi: 10.1016/j.jes.2021.03.035. Epub 2021 May 24.

ABSTRACT

Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential, which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications.

PMID:34593186 | DOI:10.1016/j.jes.2021.03.035

J Environ Sci (China). 2021 Dec;110:38-47. doi: 10.1016/j.jes.2021.03.013. Epub 2021 Mar 26.

ABSTRACT

To assess groundwater nitrate contamination and its human health risks, 489 unconfined groundwater samples were collected and analyzed from Zhangjiakou, northern China. The spatial distribution of principle hydrogeochemical results showed that the average concentrations of ions in descend order was HCO₃^–, SO₄^2-, Na⁺, Ca²⁺, Cl^–, NO₃^–, Mg²⁺ and K⁺, among which the NO₃^– concentrations were between 0.25 and 536.73 mg/L with an average of 29.72 mg/L. In total, 167 out of 489 samples (~ 34%) exceeded the recommended concentration of 20 mg/L in Quality Standard for Groundwater of China. The high NO₃^– concentration groundwater mainly located in the northern part and near the boundary of the two geomorphic units. As revealed by statistical analysis, the groundwater chemistry was more significantly affected by anthropogenic sources than by the geogenic sources. Moreover, human health risks of groundwater nitrate through oral and dermal exposure pathways were assessed by model, the results showed that about 60%, 50%, 32% and 26% of the area exceeded the acceptable level (total health index>1) for infants, children, adult males and females, respectively. The health risks for different groups of people varied significantly, ranked: infants> children> adult males>adult females, suggesting that younger people are more susceptible to nitrate contamination, while females are more resistant to nitrate contamination than males. To ensure the drinking water safety in Zhangjiakou and its downstream areas, proper management and treatment of groundwater will be necessary to avoid the health risks associated with nitrate contamination.

PMID:34593193 | DOI:10.1016/j.jes.2021.03.013

Value Health. 2021 Oct;24(10):1499-1510. doi: 10.1016/j.jval.2021.03.007. Epub 2021 May 6.

ABSTRACT

OBJECTIVES: This study generates a preference-based measure for capturing the quality of life of people with Duchenne muscular dystrophy (DMD) from a new measure of quality of life, DMD-QoL.

METHODS: A health state classification system was derived from the DMD-QoL based on psychometric performance of items, factor analysis, and item response theory analysis. Preferences for health states described by the classification system were elicited using an online discrete choice experiment survey with life years as an additional attribute, from members of the UK general population (n = 1043). Discrete choice experiment data was modeled using a conditional fixed-effects logit model and utility estimates were directly anchored on the 1 to 0 full health-dead scale.

RESULTS: The health state classification system has 8 dimensions: mobility, difficulty using hands, difficulty breathing, pain, tiredness, worry, participation, and feeling good about yourself. The standard model had mostly statistically significant coefficients and reflected the instrument’s monotonic structure. However, 2 dimensions had inconsistent coefficients (where utility increased as health worsened) and a consistent model was estimated that merged adjacent inconsistent severity levels. The best state defined by the classification system has a value of 1 and the worst state has a value of -0.559.

CONCLUSION: The modeled results enable DMD-QoL-8D utility values to be generated using DMD-QoL or DMD-QoL-8D data to generate QALYs for people with DMD. QALYs can then be used to inform economic models of the cost-effectiveness of interventions in DMD. Future research comparing the psychometric performance of DMD-QoL-8D to existing generic preference-based measures, including EQ-5D-5L, is recommended.

PMID:34593174 | DOI:10.1016/j.jval.2021.03.007

Value Health. 2021 Oct;24(10):1531-1541. doi: 10.1016/j.jval.2021.04.003. Epub 2021 May 25.

ABSTRACT

OBJECTIVES: To systematically review studies eliciting monetary value of a statistical life (VSL) estimates within, and across, different sectors and other contexts; compare the reported estimates; and critically review the elicitation methods used.

METHODS: In June 2019, we searched the following databases to identify methodological and empirical studies: Cochrane Library, Compendex, Embase, Environment Complete, Informit, ProQuest, PubMed, Scopus, and Web of Science. We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines for reporting and a modified Consolidated Health Economic Evaluation Reporting Standards checklist to assess the quality of included studies.

RESULTS: We identified 1455 studies, of which we included 120 in the systematic review. A stated-preference approach was used in 76 articles, with 51%, 41%, and 8% being contingent valuation studies, discrete-choice experiments, or both, respectively. A revealed-preference approach was used in 43 articles, of which 74% were based on compensating-wage differentials. The human capital approach was used in only 1 article. We assessed most publications (87%) as being of high quality. Estimates for VSL varied substantially by context (sector, developed/developing country, socio-economic status, etc), with the median of midpoint purchasing power parity-adjusted estimates of 2019 US$5.7 million ($6.8 million, $8.7 million, and $5.3 million for health, labor market, and transportation safety sectors, respectively).

CONCLUSIONS: The large variation observed in published VSLs depends mainly on the context rather than the method used. We found higher median values for labor markets and developed countries. It is important that health economists and policymakers use context-specific VSL estimates. Methodological innovation and standardization are needed to maximize comparability of VSL estimates within, and across, sectors and methods.

PMID:34593177 | DOI:10.1016/j.jval.2021.04.003

Value Health. 2021 Oct;24(10):1391-1399. doi: 10.1016/j.jval.2021.03.022. Epub 2021 Jul 30.

ABSTRACT

OBJECTIVES: Incremental cost-effectiveness analyses may inform the optimal choice of healthcare interventions. Nevertheless, for many vaccines, benefits fluctuate with incidence levels over time. Reevaluating a vaccine after it has successfully decreased incidences may eventually cause a disease resurgence if switching to a vaccine with lower indirect benefits. Decisions may successively alternate between vaccines alongside repeated rises and falls in incidence and when indirect effects from historic use are ignored. Our suggested proposal aims to prevent suboptimal decision making.

METHODS: We used a conceptual model of demand to illustrate alternating decisions between vaccines because of time-varying levels of indirect effects. Similar to the concept of subsidies, we propose internalizing the indirect effects achievable with vaccines. In a case study over 60 years, we simulated a hypothetical 10-year reevaluation of 2 oncogenic human papillomavirus vaccines, of which only 1 protects additionally against anogenital warts.

RESULTS: Our case study showed that the vaccine with additional warts protection is initially valued higher than the vaccine without additional warts protection. After 10 years, this differential decreases because of declines in warts incidence, which supports switching to the nonwarts vaccine that causes a warts resurgence eventually. Instead, pricing the indirect effects separately supports continuing with the warts vaccine.

CONCLUSIONS: Ignoring how the observed incidences depend on the indirect effects achieved with a particular vaccine may lead to repeated changes in vaccines at successive reevaluations, with unintended resurgences, economic inefficiencies, and eroding vaccine confidence. We propose internalizing indirect effects to prevent vaccines falling victim to their own success.

PMID:34593161 | DOI:10.1016/j.jval.2021.03.022

Value Health. 2021 Oct;24(10):1423-1434. doi: 10.1016/j.jval.2021.05.018. Epub 2021 Aug 6.

ABSTRACT

OBJECTIVES: Although many reviews of the literature on cost-effectiveness thresholds (CETs) exist, the availability of new studies and the absence of a fully comprehensive analysis warrant a new review. This study systematically reviews demand-side methods for estimating the societal monetary value of health gain.

METHODS: Several electronic databases were searched from inception to October 2019. To be included, a study had to be an original article in any language, with a clearly described method for estimating the societal monetary values of health gain and with all estimated values reported. Estimates were converted to US dollars ($), using purchasing power parity (PPP) exchange rates and the gross domestic product (GDP) per capita (2019).

RESULTS: We included 53 studies; 45 used direct approach and 8 used indirect approach. Median estimates from the direct approach were PPP$ 24 942 (range 554-1 301 912) per quality-adjusted life-year (QALY), which were typically 0.53 (range 0.02-24.08) GDP per capita. Median estimates using the indirect approach were PPP$ 310 051 (range 36 402-7 574 870) per QALY, which accounted for 7.87 (range 0.68-116.95) GDP per capita.

CONCLUSIONS: Our review found that the societal values of health gain or CETs were less than GDP per capita. The great variety in methods and estimates suggests that a more standardized and internationally agreed methodology for estimating CET is warranted. Multiple CETs may have a role when QALYs are not equally valued from a societal perspective (eg, QALYs accruing to people near death compared with equivalent QALYs to others).

PMID:34593165 | DOI:10.1016/j.jval.2021.05.018

Phys Med Rehabil Clin N Am. 2021 Nov;32(4):779-790. doi: 10.1016/j.pmr.2021.05.012. Epub 2021 Jul 14.

ABSTRACT

Genicular nerve radiofrequency ablation has quickly become one of the most promising interventions for chronic knee pain secondary to osteoarthritis, with consistent improvements in pain and function. Although there are multiple techniques using slightly variable lesion locations, cannulas, lesion types, and imaging modalities, the clinical effectiveness targeting the anterior branches of the superior medial, superolateral, and inferior medial has reproducibly demonstrated clinically and statistically significant improvements up to 24 months after the procedure with minimal adverse events. This article summarizes the current knowledge of the sensory innervation of the knee joint, the principles of radiofrequency ablation, and the current literature on clinical outcomes.

PMID:34593143 | DOI:10.1016/j.pmr.2021.05.012