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Nevin Manimala Statistics

Statistical inference for the difference between two maximized Youden indices obtained from correlated biomarkers

Biom J. 2021 Apr 14. doi: 10.1002/bimj.202000128. Online ahead of print.

ABSTRACT

Currently, there is global interest in deriving new promising cancer biomarkers that could complement or substitute the conventional ones. Clinical decisions can often be based on the cutoff that corresponds to the maximized Youden index when maximum accuracy drives decisions. When more than one classification criteria are measured within the same individuals, correlated measurements arise. In this work, we propose hypothesis tests and confidence intervals for the comparison of two correlated receiver operating characteristic (ROC) curves in terms of their corresponding maximized Youden indices. We explore delta-based techniques under parametric assumptions, or power transformations. Nonparametric kernel-based methods are also examined. We evaluate our approaches through simulations and illustrate them using data from a metabolomic study referring to the detection of pancreatic cancer.

PMID:33852754 | DOI:10.1002/bimj.202000128

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Nevin Manimala Statistics

Pilot Randomized Clinical Trial of a Text Messaging-Based Intervention for Smoking Cessation Among Young People Experiencing Homelessness

Nicotine Tob Res. 2021 Apr 14:ntab055. doi: 10.1093/ntr/ntab055. Online ahead of print.

ABSTRACT

INTRODUCTION: Smoking rates are alarmingly high among young people experiencing homelessness (YEH), yet there are no evidence-based cessation programs for this population. This paper presents results from a pilot evaluation of a text messaging-based smoking cessation treatment, as an adjunct to brief group cessation counseling, to improve abstinence rates among 18-25 year old smokers experiencing homelessness. The goal of this study was to estimate effect sizes for a larger trial and it was not powered to detect group differences.

METHODS: YEH smokers who had a working cell phone with them at recruitment were randomized to receive a group counseling session, nicotine patches, and written material on quitting (n=37) or a similar program that also included a 6-week automated text messaging intervention (TMI) to provide ongoing support for quitting (n=40). Smoking outcomes were evaluated through a 90-day follow-up.

RESULTS: 7-day point prevalence abstinence at 90-day follow-up was higher in the TMI condition than standard condition (17.50% vs. 8.11%, respectively; Cohen’s h=.37); however, the 90-day continuous abstinence rate was not statistically different from zero in either condition. Reductions in the number of days smoked in the past 30 days from baseline to follow-up were greater in the TMI condition than the standard condition (-14.24 vs. -8.62, respectively; Cohen’s d=.49).

CONCLUSIONS: Adding a 6-week TMI support to a brief group counseling and pharmacotherapy protocol holds promise for smoking reduction and abstinence among YEH smokers. Results indicate that further development and evaluation of the TMI in this population is warranted.

IMPLICATIONS: This is the first study to evaluate the feasibility of using a text messaging-based intervention (TMI) for behavior change with 18-25 year olds experiencing homelessness, and more specifically, the first to test a TMI to provide ongoing support for smoking cessation. Small to medium effect sizes for the TMI are promising in terms of implementing a TMI using participants’ own cell phones, as well as the efficacy of this approach as an adjunct to standard care (brief group counseling and pharmacotherapy) for smoking cessation among young people experiencing homelessness.

PMID:33852730 | DOI:10.1093/ntr/ntab055

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Nevin Manimala Statistics

Evaluation of antibacterial efficacy of Triphala toothwipes on oral Streptococcus mutans count in intellectually disabled children

Spec Care Dentist. 2021 Apr 14. doi: 10.1111/scd.12597. Online ahead of print.

ABSTRACT

AIM: To evaluate antibacterial efficacy of Triphala toothwipes on oral Streptococcus mutans counts in intellectually disabled (ID) children.

METHODS: Twenty-seven children with a mild ID were randomly divided into two groups: A – Triphala and B – placebo group. Toothwipes were given to caregivers of children belonging to the respective groups, and were instructed to use them 1 h after their meals, twice a day for 7 days. Simplified Plaque index was recorded and plaque samples were collected for microbiological examination at baseline, 48 h, and 7 days. The obtained data were tabulated and analyzed.

RESULTS: Triphala group showed a statistically significant reduction of S. mutans after 48 h and 7 days. Both Triphala and placebo groups showed a statistically significant reduction in dental plaque after 48 h and 7 days.

CONCLUSION: Triphala toothwipes are effective against the oral S. mutans compared with placebo toothwipes, while both the toothwipes are equally effective in reducing dental plaque. Thus, Triphala toothwipes can be used as an adjunct aid along with routine oral hygiene practices in individuals who lack psychomotor skills or are dependent on others to maintain oral hygiene, including infants, preschoolers, geriatric population, and children with special health care needs.

PMID:33852738 | DOI:10.1111/scd.12597

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Nevin Manimala Statistics

Laboratory simulation of longitudinally-cracked teeth using the step-stress cyclic loading method

Int Endod J. 2021 Apr 14. doi: 10.1111/iej.13530. Online ahead of print.

ABSTRACT

AIM: To simulate in a laboratory setting longitudinal cracking in root filled premolar teeth, using cyclic mechanical fatigue.

METHODOLOGY: Mesial-occlusal-distal (MOD) cavities were prepared in twenty root filled, single-rooted, mandibular premolars restored with fibre posts and resin composites. The samples were randomly divided into two groups based on the loading approaches: static loading with a crosshead speed of 0.5 mm/min and step-stress cyclic loading (1 Hz) with increasing amplitude. The loads and numbers of cycles to failure were recorded. Micro-CT was also used to identify the fracture modes. Statistical analysis was performed using T-student test. The level of significance was set at 0.05 RESULTS: The mean fracture loads for the static-loading and cyclic-loading groups were 769±171 N and 720±92 N, respectively. There was no significant difference between the two groups (p>0.05). The proportions of longitudinal, cuspal and mixed-mode fractures under cyclic loading were 50, 20 and 30%, respectively. Longitudinal fractures occurred with larger numbers of cycles and higher average loads per cycle compared with the other fractures. Static loading produced only cuspal fractures.

CONCLUSIONS: Longitudinally-cracked premolar teeth with root fillings were successfully produced using the step-stress cyclic loading method. This provides a more clinically-representative methodology for studying cracked teeth in a laboratory setting..

PMID:33852743 | DOI:10.1111/iej.13530

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Nevin Manimala Statistics

Community social capital and cognitive function among older adults in rural north-east China: The moderator role of income

Health Soc Care Community. 2021 Apr 14. doi: 10.1111/hsc.13395. Online ahead of print.

ABSTRACT

This study investigated the moderating role of income in the relationship between community social capital and cognitive function among community-dwelling older adults in rural China. Data were derived from a community survey conducted in Dongliao county, Jilin province, China, in 2019. Trained interviewers completed face-to-face interviews with 458 respondents. Multiple group analysis was applied to examine the proposed model. The latent constructs of cognitive social capital and structural social capital were established in low-income and high-income groups in rural Chinese contexts. Factor loading invariance of social capital constructs was established across the two income groups. The results showed that income has moderating effects on the relationship between social capital constructs and cognitive function. Social capital that was significantly associated with cognitive function was statistically significant in low-income group only. The findings highlight the important role of income in understanding the mechanism linking social capital to cognitive function in a rural Chinese context. Social policies and interventions should pay particular attention to older adults with low economic status. Policy and intervention implications are discussed.

PMID:33852751 | DOI:10.1111/hsc.13395

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Nevin Manimala Statistics

Relationship of growth conditions to desiccation tolerance of Salmonella enterica, Escherichia coli, and Listeria monocytogenes

J Food Prot. 2021 Apr 14. doi: 10.4315/JFP-21-077. Online ahead of print.

ABSTRACT

Growth on solid media as sessile cells is believed to increase the desiccation tolerance of Salmonella enterica . However, the reasons behind increased resistance have not been well explored. In addition, the same effect has not been examined for other foodborne pathogens such as pathogenic Escherichia coli or Listeria monocytogenes . The purpose of this research was two-fold: first, to determine the role of oxygenation during growth on the desiccation resistance of S. enterica , E. coli , and L. monocytogenes , and second, to determine the effect of sessile versus planktonic growth on the desiccation resistance of these pathogens. Three different serotypes each of Salmonella , E. coli , and L. monocytogenes were cultured in trypticase soy broth with 0.6% yeast extract (TSBYE), with (aerobic) shaking or on TSBYE with agar (TSAYE) under either aerobic or anaerobic conditions and harvested in stationary phase. After adding cell suspensions to cellulose filter disks, pathogen survival was determined by enumeration at 0 and after drying for 24 h. Results showed statistical differences in harvested initial populations prior to drying (0 h). For Salmonella , a correlation was found between high initial population and greater survival on desiccation (p = 0.05). In addition, statistical differences (p ≤ 0.05) between survival based on growth type were identified. However, differences found were not the same for the three pathogens, or between their serotypes. In general, Salmonella and E. coli desiccation resistance followed the pattern of aerobic agar media ≥ liquid media ≥ anaerobic agar media. For L. monocytogenes serotypes, resistance to desiccation was not statistically different based on mode of growth. These results indicate growth on solid media under aerobic conditions is not always necessary for optimal desiccation survival but may be beneficial when the desiccation resistance of the test serotype is unknown.

PMID:33852728 | DOI:10.4315/JFP-21-077

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Nevin Manimala Statistics

Thermal Inactivation Kinetics of Salmonella and Enterococcus faecium NRRL-B2354 on whole chia seeds (Salvia hispanica L.)

J Food Prot. 2021 Apr 14. doi: 10.4315/JFP-20-468. Online ahead of print.

ABSTRACT

Intervention technologies for inactivating Salmonella in whole chia seeds are currently limited. The determination of the thermal inactivation kinetics of Salmonella o n chia seeds and selection of an appropriate nonpathogenic surrogate will provide a knowledge foundation for selecting and optimizing thermal pasteurization processes for chia seeds. In this study, chia seed samples from three separate production lots were inoculated with a five strain Salmonella cocktail or Enterococcus faecium NRRL-B2354 and equilibrated to 0.53 aw at room temperature (25 °C). After equilibration for at least three days, the inoculated seeds were subjected to isothermal treatments at 80, 85, or 90 °C. Samples were taken out at six timepoints and enumerated for survivors. Initial dilution of whole chia seeds was performed in a filter bag at a 1:30 ratio after it was shown to have similar recovery to grinding the seeds. Survivor data were fitted to consolidated models consisting of a primary model (log-linear or Weibull) and one secondary model (Bigelow). E. faecium exhibited higher thermal resistance than Salmonella , suggesting its suitability as a conservative nonpathogenic surrogate. The Weibull model was a better fit for the survivor data than the log-linear model for both bacteria due to its lower root mean square error and corrected Akaike’s Information Criterion values. Measurements of lipid oxidation and fatty acid content indicated a few statistically different values compared to the control samples, but the overall difference in magnitudes were relatively small. The thermal inactivation kinetics of Salmonella and E. faecium o n chia seeds as presented in this study can serve as a basis for developing thermal pasteurization processes for chia seeds.

PMID:33852729 | DOI:10.4315/JFP-20-468

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Nevin Manimala Statistics

Quality of children’s death records for regionalized spaces: a methodological route

Rev Bras Epidemiol. 2021 Apr 9;24:e210016. doi: 10.1590/1980-549720210016. eCollection 2021.

ABSTRACT

OBJECTIVES: To propose a methodological path to investigate the coverage and information filling of maternal-infant deaths recorded in the Ministry of Health’s Mortality Information System for regional spaces.

METHODS: Four steps were proposed: 1) Assessment of the completeness of the maternal and child variables, which was measured using the deterministic linkage technique between the Mortality Information System (Sistema de Informações sobre Mortalidade – SIM) and the Live Birth Information System (Sistema de Informações sobre Nascidos Vivos – SINASC); 2) Application of the multiple imputation technique to achieve the total filling of the missing information of the variables; 3) Estimation of death coverage; 4) The Unknown Variable Information Index (Índice de Informação Desconhecida da Variável – IIDV) was measured, which represents the combined effect of data completeness and coverage of deaths. The proposal of the methodological path was exemplified for neonatal deaths in the municipalities of Paraíba that are part of the new classification proposed by the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística – IBGE), as adjacent rural areas, in three triennium periods from 2009 to 2017.

RESULTS: The percentage of matching records was 45%. Most of the variables had a percentage of non-completion below 10% and around 17% for the mother’s education. Coverages ranged from 75 to 83%. The IIDV for all variables was between 21 and 36% after the linkage.

CONCLUSION: The path of the methodological proposal proved to be effective, which can be replicated to other regions, and can be extended to other categories of deaths such as post-neonatal. The combination of the proposed procedures demands low operating costs and their uses are relatively simple to be applied by the managers and technicians of the vital statistics information systems.

PMID:33852706 | DOI:10.1590/1980-549720210016

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Nevin Manimala Statistics

Trend in infant mortality rate caused by sepsis in Brazil from 2009 to 2018

Rev Inst Med Trop Sao Paulo. 2021 Apr 12;63:e26. doi: 10.1590/S1678-9946202163026. eCollection 2021.

ABSTRACT

Sepsis is the organ dysfunction resulting from an infection associated with an unregulated host inflammatory response, which generates high mortality rates in Brazil. The aim of this stydy was to analyze the trend of early, late and post-neonatal mortality rates due to sepsis in Brazilian regions, from 2009 to 2018. This is an ecological study of time series. The trend of infant mortality from sepsis was analyzed using the International Classification of Diseases (ICD10) according to the place of residence (North, Northeast, Southeast, South and Midwest). Death Certificate data were collected from the Mortality Information System database. The temporal trend was analyzed using the Prais-Winsten estimate, interpreted as increasing, decreasing or stable, through the dependent variable (logarithm of mortality rates) and interdependent variables (years of the historical series). The Stata 14.0 statistical software was used. There were 39,867 infant deaths due to sepsis (78.67% for unspecified bacterial sepsis of the neonate ). Most of the children were male, had mixed ethnicity (black and white) , were born preterm with low birth weight and most mothers were 20-34 years old. There were decreasing trends in mortality rates from 2009 to 2018: early neonatal, in the Southeast (-3.57%), North (-3.33%) and South (-2.91%); late neonatal, in the South (-4.12%), Southeast (-4.53%), North (-4.55%) and Midwest (-6.21%); and post-neonatal, in the Northeast (-1.84%), North (-3.62%), Southeast (-3.83%) and Midwest (-5.81%). The Northeast showed a stable trend in early and late neonatal mortality rates. It was concluded that most regions showed a decreasing trend in mortality rates from sepsis in all age components, despite regional differences.

PMID:33852709 | DOI:10.1590/S1678-9946202163026

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Nevin Manimala Statistics

Photocatalytic Ozonation Performance In Landfill Leachate Treatment

An Acad Bras Cienc. 2021 Apr 9;93(1):e20190137. doi: 10.1590/0001-3765202120190137. eCollection 2021.

ABSTRACT

This work aims to identify the best treatment condition for removal of chemical oxigen demand (COD) and increase of biodegradability in an advanced oxidative process of photocatalytic ozonation with titanium dioxide (TiO2), applied to the remediation of the leachate produced at the municipal landfill of Campo Mourão, Paraná. The experiment was carried out using a photocatalytic chamber and an ozonation system based on the corona effect. A statistical model of the central composite rotatable design (CCRD) was elaborated and three variables (pH, TiO2 dose and airflow) were analyzed, to define the optimum condition that allows the highest perfomance of the treatment. The statistical model was valid for the data. The best condition identified was: pH = 3.3 TiO2 dose = 0.012 g and flow = 9.0 L.min-1 (8.79 g, O3.min-1). The removal of filtrate COD was approximately 30% and increase in biodegradability (BOD/COD) = 0.59 in the optimum condition. Factors such as the complex composition of the leachate and treatment time were considered as possible limitants for better results. The treatment did not allow to reach the permissible limits for disposal of the effluent at the environment, in Brazil.

PMID:33852714 | DOI:10.1590/0001-3765202120190137