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Nevin Manimala Statistics

Wrist Accelerometer Estimates of Physical Activity Intensity During Walking in Older Adults and People Living With Complex Health Conditions: Retrospective Observational Data Analysis Study

JMIR Form Res. 2023 Mar 15;7:e41685. doi: 10.2196/41685.

ABSTRACT

BACKGROUND: Accurate measurement of daily physical activity (PA) is important as PA is linked to health outcomes in older adults and people living with complex health conditions. Wrist-worn accelerometers are widely used to estimate PA intensity, including walking, which composes much of daily PA. However, there is concern that wrist-derived PA data in these cohorts is unreliable due to slow gait speed, mobility aid use, disease-related symptoms that impact arm movement, and transient activities of daily living. Despite the potential for error in wrist-derived PA intensity estimates, their use has become ubiquitous in research and clinical application.

OBJECTIVE: The goals of this work were to (1) determine the accuracy of wrist-based estimates of PA intensity during known walking periods in older adults and people living with cerebrovascular disease (CVD) or neurodegenerative disease (NDD) and (2) explore factors that influence wrist-derived intensity estimates.

METHODS: A total of 35 older adults (n=23 with CVD or NDD) wore an accelerometer on the dominant wrist and ankle for 7 to 10 days of continuous monitoring. Stepping was detected using the ankle accelerometer. Analyses were restricted to gait bouts ≥60 seconds long with a cadence ≥80 steps per minute (LONG walks) to identify periods of purposeful, continuous walking likely to reflect moderate-intensity activity. Wrist accelerometer data were analyzed within LONG walks using 15-second epochs, and published intensity thresholds were applied to classify epochs as sedentary, light, or moderate-to-vigorous physical activity (MVPA). Participants were stratified into quartiles based on the percent of walking epochs classified as sedentary, and the data were examined for differences in behavioral or demographic traits between the top and bottom quartiles. A case series was performed to illustrate factors and behaviors that can affect wrist-derived intensity estimates during walking.

RESULTS: Participants averaged 107.7 (SD 55.8) LONG walks with a median cadence of 107.3 (SD 10.8) steps per minute. Across participants, wrist-derived intensity classification was 22.9% (SD 15.8) sedentary, 27.7% (SD 14.6) light, and 49.3% (SD 25.5) MVPA during LONG walks. All participants measured a statistically lower proportion of wrist-derived activity during LONG walks than expected (all P<.001), and 80% (n=28) of participants had at least 20 minutes of LONG walking time misclassified as sedentary based on wrist-derived intensity estimates. Participants in the highest quartile of wrist-derived sedentary classification during LONG walks were significantly older (t16=4.24, P<.001) and had more variable wrist movement (t16=2.13, P=.049) compared to those in the lowest quartile.

CONCLUSIONS: The current best practice wrist accelerometer method is prone to misclassifying activity intensity during walking in older adults and people living with complex health conditions. A multidevice approach may be warranted to advance methods for accurately assessing PA in these groups.

PMID:36920452 | DOI:10.2196/41685

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Nevin Manimala Statistics

Using Parametric g-Computation to Estimate the Effect of Long-Term Exposure to Air Pollution on Mortality Risk and Simulate the Benefits of Hypothetical Policies: The Canadian Community Health Survey Cohort (2005 to 2015)

Environ Health Perspect. 2023 Mar;131(3):37010. doi: 10.1289/EHP11095. Epub 2023 Mar 15.

ABSTRACT

BACKGROUND: Numerous epidemiological studies have documented the adverse health impact of long-term exposure to fine particulate matter [particulate matter 2.5μm in aerodynamic diameter (PM2.5)] on mortality even at relatively low levels. However, methodological challenges remain to consider potential regulatory intervention’s complexity and provide actionable evidence on the predicted benefits of interventions. We propose the parametric g-computation as an alternative analytical approach to such challenges.

METHOD: We applied the parametric g-computation to estimate the cumulative risks of nonaccidental death under different hypothetical intervention strategies targeting long-term exposure to PM2.5 in the Canadian Community Health Survey cohort from 2005 to 2015. On both relative and absolute scales, we explored the benefits of hypothetical intervention strategies compared with the natural course that a) set the simulated exposure value at each follow-up year to a threshold value if exposure was above the threshold (8.8μg/m3, 7.04μg/m3, 5μg/m3, and 4μg/m3), and b) reduced the simulated exposure value by a percentage (5% and 10%) at each follow-up year. We used the 3-y average PM2.5 concentration with 1-y lag at the postal code of respondents’ annual mailing addresses as their long-term exposure to PM2.5. We considered baseline and time-varying confounders, including demographics, behavior characteristics, income level, and neighborhood socioeconomic status. We also included the R syntax for reproducibility and replication.

RESULTS: All hypothetical intervention strategies explored led to lower 11-y cumulative mortality risks than the estimated value under the natural course without intervention, with the smallest reduction of 0.20 per 1,000 participants (95% CI: 0.06, 0.34) under the threshold of 8.8μg/m3, and the largest reduction of 3.40 per 1,000 participants (95% CI: 0.23, 7.03) under the relative reduction of 10% per interval. The reductions in cumulative risk, or numbers of deaths that would have been prevented if the intervention was employed instead of maintaining the status quo, increased over time but flattened toward the end of the follow-up period. Estimates among those 65 years of age were greater with a similar pattern. Our estimates were robust to different model specifications.

DISCUSSION: We found evidence that any intervention further reducing the long-term exposure to PM2.5 would reduce the cumulative mortality risk, with greater benefits in the older population, even in a population already exposed to low levels of ambient PM2.5. The parametric g-computation used in this study provides flexibilities in simulating real-world interventions, accommodates time-varying exposure and confounders, and estimates adjusted survival curves with clearer interpretation and more information than a single hazard ratio, making it a valuable analytical alternative in air pollution epidemiological research. https://doi.org/10.1289/EHP11095.

PMID:36920446 | DOI:10.1289/EHP11095

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Nevin Manimala Statistics

Using a Multi-isotope Approach and Isotope Mixing Models to Trace and Quantify Phosphorus Sources in the Tuojiang River, Southwest China

Environ Sci Technol. 2023 Mar 15. doi: 10.1021/acs.est.2c07216. Online ahead of print.

ABSTRACT

Identifying phosphorus (P) sources is critical for solving eutrophication and controlling P in aquatic environments. Phosphate oxygen isotopes (δ18Op) have been used to trace P sources. However, the application of this method has been greatly restricted due to δ18OP values from the potential source having wide and overlapping ranges. In this research, P sources were traced by combining δ18Op with multiple stable isotopes of nitrogen (δ15N), hydrogen (δD), and dissolved inorganic carbon (δ13C). Then, a Bayesian-based Stable Isotope Analysis in R (SIAR) model and IsoSource model were used to estimate the proportional contributions of the potential sources in the Tuojiang River. δ18Op was not in equilibrium with ambient water, and statistically significant differences in the δ18Op values were found between the potential sources, indicating that δ18Op can be used to trace the P sources. δ15N, δD, and δ13C could assist δ18Op in identifying the main sources of P. The SIAR and IsoSource models suggested that industrial and domestic sewage was the largest contributor, followed by phosphate rock and phosphogypsum and agricultural sewage. The uncertainty of the calculation results of the SIAR model was lower than that of the IsoSource model. These findings provide new insights into tracing P sources using multiple stable isotopes in watersheds.

PMID:36920429 | DOI:10.1021/acs.est.2c07216

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Association between GPC2 polymorphisms and neuroblastoma risk in Chinese children

J Clin Lab Anal. 2023 Mar 15:e24866. doi: 10.1002/jcla.24866. Online ahead of print.

ABSTRACT

BACKGROUND: The cell surface glycoprotein glypican 2 (GPC2) has been shown to increase susceptibility to neuroblastoma, which is the most common malignancy in children. However, associations between single nucleotide polymorphism(s) of GPC2 and neuroblastoma risk remain unclarified.

METHODS: We conducted a case-control study to investigate two GPC2 polymorphisms (rs1918353 G>A and rs7799441 C>T) in 473 healthy controls and 402 pediatric patients with neuroblastoma. Single nucleotide polymorphism (SNP) genotyping was conducted on the samples by the TaqMan technique, and the data were subsequently analyzed by the t test, chi-squared test, and logistic regression model. In addition, we further performed stratification analysis by age, sex, tumor site of origin, or clinical stage to control confounding factors.

RESULTS: According to the data of dominant models (GA/AA vs. GG: adjusted OR = 0.99, 95% CI = 0.76-1.29, p = 0.943; CT/TT vs. CC: adjusted OR = 0.91, 95% CI = 0.70-1.19, p = 0.498) or other comparisons, as well as the conjoint analysis (adjusted OR = 1.22, 95% CI = 0.93-1.59, p = 0.152), we unfortunately proved that the analysis of single or multiple loci did not support any significant association of GPC2 polymorphisms with susceptibility to neuroblastoma.

CONCLUSION: GPC2 polymorphisms (rs1918353 G>A and rs7799441 C>T) are unable to statistically affect neuroblastoma risk in Chinese children. Therefore, more samples, especially from patients of various ethnic backgrounds, are required to increase the sample size and verify the effect of GPC2 polymorphisms on neuroblastoma risk in the presence of ethnic factor.

PMID:36920409 | DOI:10.1002/jcla.24866

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Effect of nano-ceramic coating on surface property and microbial adhesion to poly(methyl methacrylate)

J Biomed Mater Res B Appl Biomater. 2023 Mar 15. doi: 10.1002/jbm.b.35247. Online ahead of print.

ABSTRACT

To improve surface properties of poly(methyl methacrylate) (PMMA) using nano-ceramic coatings and assess microbial adherence after long-term use of a chemical cleanser. Thirty-six PMMA samples were fabricated, polished and coated with a nano-thin TiO2 or mixed TiO2 /ZrO2 , with uncoated samples as controls. Six samples in each group (n = 12) were soaked in Polident denture cleaner 180 times for 30 min, while six were soaked in deionized water. Surface roughness of PMMA before and after being soaked in Polident was assessed. All samples were subsequently exposed to Candida albicans for 6 h and the adherent cells were determined by viable colony count. Two-way analysis of variance was performed for statistical analysis. No significant difference in surface roughness was noted between the uncoated and coated PMMA before soaking. After soaking, surface roughness of the uncoated PMMA increased from 0.164 to 0.532 μm (p < .05). No significant change was observed for TiO2 -coated (0.105-0.143 μm) or TiO2 /ZrO2 -coated PMMA (0.104-0.141 μm). Attachment of C. albicans to PMMA soaked in water showed significantly less attachment to both TiO2 -coated (1.4 × 103 cfu/ml) and TiO2 /ZrO2 -coated PMMA (1.6 × 103 cfu/ml) than to the uncoated PMMA (2.6 × 103 cfu/ml). After soaking in Polident, the uncoated PMMA had significantly less C. albicans attachment than coated samples. Less attachment was noted on the TiO2 /ZrO2 -coated PMMA then the TiO2 -coated samples (p < .05). Nano-ceramic TiO22 /ZrO2 coating of PMMA denture base material alters surface properties thus reduces oral microbial adhesion. It represents a promising alternative to the chemical disinfection for PMMA denture materials.

PMID:36920405 | DOI:10.1002/jbm.b.35247

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Nevin Manimala Statistics

Associations Between Natural Language Processing-Enriched Social Determinants of Health and Suicide Death Among US Veterans

JAMA Netw Open. 2023 Mar 1;6(3):e233079. doi: 10.1001/jamanetworkopen.2023.3079.

ABSTRACT

IMPORTANCE: Social determinants of health (SDOHs) are known to be associated with increased risk of suicidal behaviors, but few studies use SDOHs from unstructured electronic health record notes.

OBJECTIVE: To investigate associations between veterans’ death by suicide and recent SDOHs, identified using structured and unstructured data.

DESIGN, SETTING, AND PARTICIPANTS: This nested case-control study included veterans who received care under the US Veterans Health Administration from October 1, 2010, to September 30, 2015. A natural language processing (NLP) system was developed to extract SDOHs from unstructured clinical notes. Structured data yielded 6 SDOHs (ie, social or familial problems, employment or financial problems, housing instability, legal problems, violence, and nonspecific psychosocial needs), NLP on unstructured data yielded 8 SDOHs (social isolation, job or financial insecurity, housing instability, legal problems, barriers to care, violence, transition of care, and food insecurity), and combining them yielded 9 SDOHs. Data were analyzed in May 2022.

EXPOSURES: Occurrence of SDOHs over a maximum span of 2 years compared with no occurrence of SDOH.

MAIN OUTCOMES AND MEASURES: Cases of suicide death were matched with 4 controls on birth year, cohort entry date, sex, and duration of follow-up. Suicide was ascertained by National Death Index, and patients were followed up for up to 2 years after cohort entry with a study end date of September 30, 2015. Adjusted odds ratios (aORs) and 95% CIs were estimated using conditional logistic regression.

RESULTS: Of 6 122 785 veterans, 8821 committed suicide during 23 725 382 person-years of follow-up (incidence rate 37.18 per 100 000 person-years). These 8821 veterans were matched with 35 284 control participants. The cohort was mostly male (42 540 [96.45%]) and White (34 930 [79.20%]), with 6227 (14.12%) Black veterans. The mean (SD) age was 58.64 (17.41) years. Across the 5 common SDOHs, NLP-extracted SDOH, on average, retained 49.92% of structured SDOHs and covered 80.03% of all SDOH occurrences. SDOHs, obtained by structured data and/or NLP, were significantly associated with increased risk of suicide. The 3 SDOHs with the largest effect sizes were legal problems (aOR, 2.66; 95% CI, 2.46-2.89), violence (aOR, 2.12; 95% CI, 1.98-2.27), and nonspecific psychosocial needs (aOR, 2.07; 95% CI, 1.92-2.23), when obtained by combining structured data and NLP.

CONCLUSIONS AND RELEVANCE: In this study, NLP-extracted SDOHs, with and without structured SDOHs, were associated with increased risk of suicide among veterans, suggesting the potential utility of NLP in public health studies.

PMID:36920391 | DOI:10.1001/jamanetworkopen.2023.3079

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Nevin Manimala Statistics

Perceptual history biases in serial ensemble representation

J Vis. 2023 Mar 1;23(3):7. doi: 10.1167/jov.23.3.7.

ABSTRACT

Ensemble perception refers to the visual system’s ability to efficiently represent groups of similar objects as a unified percept using their summary statistical information. Most studies focused on extraction of current trial averages, giving little attention to prior experience effects, although a few recent studies found that ensemble mean estimations contract toward previously presented stimuli, with most of these focusing on explicit perceptual averaging of simultaneously presented item ensembles. Yet, the time element is crucial in real dynamic environments, where we encounter ensemble items over time, aggregating information until reaching summary representations. Moreover, statistical information of objects and scenes is learned over time and often implicitly and then used for predictions that shape perception, promoting environmental stability. Therefore, we now focus on temporal aspects of ensemble statistics and test whether prior information, beyond the current trial, biases implicit perceptual decisions. We designed methods to separate current trial biases from those of previously seen trial ensembles. In each trial, six circles of different sizes were presented serially, followed by two test items. Participants were asked to choose which was present in the sequence. Participants unconsciously rely on ensemble statistics, choosing stimuli closer to the ensemble mean. To isolate the influence of earlier trials, the two test items were sometimes equidistant from the current trial mean. Results showed membership judgment biases toward current trial mean, when informative (largest effect). On equidistant trials, judgments were biased toward previously experienced stimulus statistics. Comparison of similar conditions with a shifted stimulus distribution ruled out a bias toward an earlier, presession, prototypical diameter. We conclude that ensemble perception, even for temporally experienced ensembles, is influenced not only by current trial mean but also by means of recently seen ensembles and that these influences are somewhat correlated on a participant-by-participant basis.

PMID:36920389 | DOI:10.1167/jov.23.3.7

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Distribution of bacterial species and resistance patterns in surgical site infection after prior administration of vancomycin and tobramycin intrawound powdered antibiotic prophylaxis

J Orthop Trauma. 2023 Mar 6. doi: 10.1097/BOT.0000000000002595. Online ahead of print.

ABSTRACT

OBJECTIVE: Evaluate the species distribution and resistance patterns of bacterial pathogens causing surgical site infection (SSI) after operative fracture repair, with and without the use of intrawound powdered antibiotic (IPA) prophylaxis during the index surgery.

DESIGN: Retrospective cohort study.

SETTING: Academic, level 1 trauma center, 2018-2020.Patients/Participants: 59 deep SSIs were identified in a sample of 734 patients with 846 fractures (IPA [n=320], control [n=526]; open [n=157], closed fractures [n=689]) who underwent orthopaedic fracture care. Among SSIs, 28 (48%) patients received IPA prophylaxis and 25 (42%) of the fractures were open.

INTERVENTION: Intrawound powdered vancomycin and tobramycin.

MAIN OUTCOME MEASUREMENTS: Distribution of bacterial species and resistance patterns causing deep surgical site infections requiring operative debridement.

RESULTS: Zero patients developed infections caused by resistant strains of streptococci, enterococci, gram-negative enterics, Pseudomonas, or Cutibacterium species. The only resistant strains isolated were MRSA (19%) and oxacillin-resistant coagulase-negative staphylococci (16%). There was no associated statistical difference in the proportion of bacterial species isolated, their resistance profiles, or rate of polymicrobial infections between the IPA and control group. The vast majority (93%) of cases using IPAs included both vancomycin and tobramycin powders. There were 59 SSIs; 28 (9%) in the IPA cohort and 31 (6%) in the control cohort (p=0.13).

CONCLUSION: The use of local antibiotic prophylaxis resulted in no measurable increase in the proportion of infections caused by resistant bacterial pathogens after operative treatment of fractures. However, the small sample size and limited time frame of these preliminary data require continued investigation into their role as an adjunct to SSI prophylaxis.

PMID:36920373 | DOI:10.1097/BOT.0000000000002595

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Differences in Merkel Cell Carcinoma Presentation and Outcomes Among Racial and Ethnic Groups

JAMA Dermatol. 2023 Mar 15. doi: 10.1001/jamadermatol.2023.0061. Online ahead of print.

ABSTRACT

IMPORTANCE: Racial and ethnic differences in skin cancer outcomes are understudied. Delineating these differences in Merkel cell carcinoma (MCC) is needed to better understand this rare disease.

OBJECTIVE: To determine how MCC presentation and outcomes differ across racial and ethnic groups.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included patients diagnosed with MCC and followed up from 2000 through 2018 in the 18 population-based cancer registries of the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. Patients without follow-up data were excluded. Data analysis occurred from March 12 to November 30, 2022.

MAIN OUTCOMES AND MEASURES: A Cox proportional hazards regression was conducted to determine associations between demographic variables (race and ethnicity, age, sex, and income) and clinical variables (stage at diagnosis, primary site, and diagnosis year) with MCC-specific survival.

RESULTS: Of the 9557 patients with MCC identified (6758 [70.7%] aged ≥70 years; 6008 [62.9%] male), 222 (2.3%) were Asian American or Pacific Islander, 146 (1.5%) Black, 541 (5.7%) Hispanic, and 8590 (89.9%) White. Hispanic patients had improved MCC-specific survival compared with White patients (hazard ratio, 0.82; 95% CI, 0.67-0.99; P = .04). Black patients had the lowest MCC-specific survival, but it was not statistically different from White patients (hazard ratio, 1.19; 95% CI, 0.86-1.60; P = .28). Hispanic and Black patients were less likely to present with a primary site of the head and neck than White patients (183 of 541 [33.8%] Hispanic patients and 45 of 146 [30.8%] Black patients vs 3736 of 8590 [43.5%] White patients; P < .001 and P = .002, respectively). Black patients presented more often than White patients with advanced disease at diagnosis (59 of 146 [40.4%] vs 2510 of 8590 [29.2%]; P = .004).

CONCLUSIONS AND RELEVANCE: In this cohort study, there were differences between racial and ethnic groups in observed MCC outcomes and disease characteristics. Further investigations are warranted into the findings that, compared with White patients, Hispanic patients with MCC had improved outcomes and Black patients did not have worse outcomes despite presenting with more advanced disease.

PMID:36920369 | DOI:10.1001/jamadermatol.2023.0061

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Respiratory aspiration during treatment with clozapine and other antipsychotics: a literature search and a pharmacovigilance study in VigiBase

Expert Opin Drug Metab Toxicol. 2023 Mar 15. doi: 10.1080/17425255.2023.2192401. Online ahead of print.

ABSTRACT

INTRODUCTION: Antipsychotics (APs), during treatment or overdose, may be associated with respiratory aspiration.

AREAS COVERED: A PubMed search on September 30, 2022, provided 3 cases of respiratory aspiration during clozapine therapy and 1 case during an AP overdose. VigiBase records of respiratory aspiration associated with APs from inception until September 5, 2021, were reviewed. VigiBase, the World Health Organization’s global pharmacovigilance database, uses a statistical signal for associations called the information component (IC).

EXPERT OPINION: The ICs (and IC025) were 2.1 (and 2.0) for APs, 3.2 (and 3.0) for clozapine, 2.6 (and 2.4) for quetiapine, and 2.5 (and 2.2) for olanzapine. Cases of respiratory aspiration associated with APs included: 137 overdose/suicide cases (64 fatal) and 609 cases during treatment (385 fatal) including 333 taking clozapine (238 fatal). In logistic regression models of fatal outcomes, the odds ratios, OR, and (95% confidence intervals, CI) of significant independent variables were: a) 2.3 – 2.6 for clozapine in 3 samples of AP treatment of varying size, b) 1.9 (CI 1.0 to 3.5) for geriatric age in 284 patients on clozapine treatment, and c) 1.8 (CI 1.1 – 3.2) for antidepressant co-medication in 276 patients on non-clozapine APs. Multiple AP pharmacological mechanisms may explain respiratory aspiration.

PMID:36920343 | DOI:10.1080/17425255.2023.2192401