Category: Statistics

Health Rep. 2021 May 19;32(5):3-14. doi: 10.25318/82-003-x202100500001-eng.

ABSTRACT

BACKGROUND: Residential greenness has been associated with health benefits, such as lower risk of mortality, cardiovascular disease, obesity, adverse birth outcomes and asthma and better psychological health. However, the variation in greenness across socioeconomic and demographic characteristics in urban areas of Canada has not been well documented.

DATA AND METHODS: Respondents to the 2016 Census long-form questionnaire were assigned estimates of exposure to residential greenness based on the mean Normalized Difference Vegetation Index (NDVI) (from 2012 or the most recent year available) within a 500 m buffer around their home, based on postal code. Census weights were used to determine differences in average exposure to greenness according to selected demographic and socioeconomic characteristics.

RESULTS: Mean residential greenness among the 5.3 million census respondents in urban Canada was 0.44 units of the NDVI (standard deviation = 0.18 units). Greenness was lower among immigrants (particularly recent immigrants), some groups designated as visible minorities (particularly people of Filipino ancestry), lower-income households and tenants (i.e., NDVI values ranging from 0.40 to 0.43 units). Greenness values were highest among White non-immigrants and higher-income households (i.e., NDVI values ranging from 0.46 to 0.47 units).

DISCUSSION: Given the potentially multifaceted role that greenness plays in health outcomes, the inequalities in residential greenness described here may contribute to producing or exacerbating existing health inequalities in the Canadian population.

PMID:34008928 | DOI:10.25318/82-003-x202100500001-eng

Photobiomodul Photomed Laser Surg. 2021 May 18. doi: 10.1089/photob.2020.4944. Online ahead of print.

ABSTRACT

Objective: Laser irradiation is being used for treatment of peri-implantitis. Therefore, this study aimed to assess the heat transfer from laser irradiation on an implant-supported, metal-ceramic fixed prosthesis in vitro. Materials and methods: Two titanium implants were placed in artificial type I bone, and after abutment connection, a bridge was fabricated and cemented. A peri-implant 3-wall defect was created around one of the implants. Thermocouples were placed at coronal (T1/T2) and apical (T3/T4) positions of both implants, and the T5 thermocouple was placed in the pontic. An identical setup was created in the type IV artificial bone. Diode laser irradiation (2 W, noninitiated tips, 320-μm fiber, and noncontact) was performed for 60 sec on each experimental model. This experiment was performed separately with 810- and 980-nm lasers for pulsed and continuous modes. ΔT based on the baseline was recorded during irradiation. Statistical analysis was performed with repeated analysis of variance. Results: Across all experimental models, the recorded ΔT (°) values in T2, T4, and T5 at 10, 30, and 60 sec were significantly less than 10°C (p < 0.001) for both types of bones. For both types of bones, there was a statistically significant ΔT greater than 10°C (p < 0.001) for continuous and pulsed 980-nm irradiation and continuous 810-nm diode laser irradiation after 60 sec. For both 810- and 980-nm lasers, there was a statistically significant ΔT greater than 10°C (p < 0.001) for type I and IV bones under irradiation and only for the type I bone model under pulsed irradiation after 60 sec. Conclusions: Within the limitations of this study, 810- and 980-nm lasers on splinted implants placed in vitro may increase the temperature on adjacent splinted implants due to material conductivity and splinting. Clinicians are advised to keep the temperature lower than the critical threshold following recommended power settings to avoid excessive heat and control complications due to overheating.

PMID:34009027 | DOI:10.1089/photob.2020.4944

J Adv Nurs. 2021 May 19. doi: 10.1111/jan.14889. Online ahead of print.

ABSTRACT

AIM: To investigate the associations between demographic characteristics, perceived threat, perceived stress, coping responses and adherence to COVID-19 prevention measures in Chinese Healthcare students.

DESIGN: A cross-sectional survey collecting data in Hong Kong and Fujian Province of China in April 2020.

METHODS: A convenience and snowball sample of 2706 students aged 18 years or older and studying a healthcare programme were recruited in tertiary education institutions/universities in Hong Kong and Putian. The participants completed the questionnaire with six scales: Social Distancing Scale; Personal Hygiene Scale; Empathic Responding Scale; Wishful Thinking Scale; Perceived Stress Scale and Perceived Threat Scale. Path analysis was performed to identify factors associated with the preventive measures outcomes. p value < .05 was considered as statistical significance.

RESULTS: The participants reported high compliances to both social distancing (SoD) and personal hygiene measures (PHM). Confidence to manage the current situation, wishful thinking and empathetic responding directly predicted compliance with SoD and PHM. The final model constructed demonstrated a very good fit to the data.

CONCLUSION: The findings suggest that students who are male, habituate in Hong Kong, have more clinical experience and weak confidence to manage the threat tend to have lower compliance with the COVID-19 preventive measures.

IMPACT: The predictive model constructed is the first one to explore factors associating with the compliance with infection control measures in healthcare students amid the COVID-19 outbreak. As the infection control behaviours of healthcare students, whom are still under training and are the high-risk group of being infected and infecting others in the community, are rarely reported in literature, this study has provided empirical evidence to nurses and other healthcare professionals to identify students susceptible to poor compliance and provide early monitoring and education to suppress the COVID-19 transmission.

PMID:34008883 | DOI:10.1111/jan.14889

J Biomech Eng. 2021 May 19. doi: 10.1115/1.4051230. Online ahead of print.

ABSTRACT

Rotator cuff (RC) tears cause pain and functional disability of the shoulder. Despite advances in suture anchors, there are still reports about the incidence of surgical-related injuries to RC mainly associated with sutures. The purpose of this study was to design and evaluate the mechanical behavior of sutureless implants to repair RC tears. We hypothesized that the implants present mechanical characteristics suitable for the surgical treatment of RC tears as suture anchors. Three different implants (T1,T2,T3) were designed and fabricated with titanium: T1 has two rods and rectangular head; T2 has two rods with a small opening and enlarged rectangular head and T3 has three rods and a circular head. The implants were fixed in rigid polyurethane foam blocks by a series of blows, and the applied mechanical loads along with the number of blows were quantified. Pullout tests using tapes fixed between the implant head and testing machine grip were conducted until implant failure. The maximum pullout strength and displacement of the implant relative to the rigid foam block were computed. Statistical significance was set at p < 0.05. Owing to its geometric configuration, implant T2 presented the best characteristics related to stability, strength, and ease of insertion. Implant T2 confirms our hypothesis that its mechanical behavior is compatible with that of suture anchors which could lead to the reduction of RC repair failures and simplify the arthroscopic procedure.

PMID:34008848 | DOI:10.1115/1.4051230

Mol Ecol. 2021 May 19. doi: 10.1111/mec.15991. Online ahead of print.

ABSTRACT

The continued endemicity of foot and mouth disease virus (FMDV) in East Africa has significant implications for livestock production and poverty reduction, yet its complex epidemiology in endemic settings remains poorly understood. Identifying FMDV dispersal routes and drivers of transmission is key to improved control strategies. Environmental heterogeneity and anthropogenic drivers (e.g. demand for animal products) can impact viral spread by influencing host movements. Here, we utilized FMDV serotype O VP1 genetic sequences and corresponding spatiotemporal data in order to (1) infer the recent dispersal history and (2) investigate the impact of external factors (cattle density, human population density, proximity to livestock markets, and drought) on dispersal velocity, location, and direction of FMDV serotype O in East Africa. We identified statistical evidence of long-distance transmission events, and we found that FMDV serotype O tends to remain circulating in areas of high cattle density, high human population density, and in close proximity to livestock markets. The latter two findings highlight the influence of anthropogenic factors on FMDV serotype O spread in this region. These findings contribute to the understanding of FMDV epidemiology in East Africa and can help guide improved control measures.

PMID:34008868 | DOI:10.1111/mec.15991

Genet Epidemiol. 2021 May 19. doi: 10.1002/gepi.22385. Online ahead of print.

ABSTRACT

Recently, Mendelian Randomization (MR) has gained in popularity as a concept to assess the causal relationship between phenotypes in genetic association studies. An extension of standard MR methodology, the MR Steiger approach, has recently been developed to infer the causal direction between two phenotypes in prospective studies. Through simulation studies, we examined and quantified the ability of the MR Steiger approach to determine the causal direction between two phenotypes (i.e., effect direction). Through simulation studies, our results show that the MR Steiger approach may fail to correctly identify the direction of causality. This is true, especially in the presence of pleiotropy. We also applied the MR Steiger method to the COPDGene study, a case-control study of chronic obstructive pulmonary disease (COPD) in current and former smokers, to examine the role of smoking on lung function. We have created an R package on Github called reverseDirection which runs simulations for user-specified scenarios to examine when the MR Steiger approach can correctly determine the causal direction between two phenotypes in any user specified scenario. In summary, our results emphasize the importance of caution when the MR Steiger approach is used in to infer the direction of causality.

PMID:34008876 | DOI:10.1002/gepi.22385

Arq Bras Cardiol. 2021 May;116(5):959-967. doi: 10.36660/abc.20200115.

ABSTRACT

BACKGROUND: For patients with ST-segment elevation myocardial infarction (STEMI) that are suffering from subsequent coronary microvascular functional and structural obstruction (CMVO), no specific and definitive therapeutic approaches of attenuation have been proven valid in up-to-date large-scale tests, which highlights the urge to address its early recognition.

OBJECTIVES: This study aimed to compare the performance of two clinical risk scores with an objective measurement of CMVO during percutaneous coronary intervention (PCI) with STEMI.

METHODS: The Index of Microcirculatory Resistance (IMR) measurement was conducted and the baseline clinical and angiographic parameters were also recorded. The patients were divided into MO (Microvascular obstruction) or NMO (Non-microvascular obstruction) groups according to the post-procedure IMR value. The CMVO risk was evaluated for all participants by SAK and ATI predictive scores, respectively. Each system was calculated by summing the scores of all variables. The receiver operator characteristic (ROC) curves and the area under the curve (AUC) of two risk models were used to evaluate the discriminatory performance. An echocardiography was performed seven days after the procedure to evaluate left ventricular ejection fraction (LVEF). A two-sided P-value of <0.05 was considered statistically significant.

RESULTS: Among the 65 eligible STEMI patients, 48 patients were allocated in the NMO group and 17 in the MO group, with a CMVO incidence of 26.15%. There was no significant difference in the AUC between both scores. The LVEF evaluated for the NMO group was higher than that of MO group.

CONCLUSION: Both SAK and ATI scores performed well in estimating CMVO risk after primary PCI for STEMI patients.

PMID:34008822 | DOI:10.36660/abc.20200115

J Biomech Eng. 2021 May 19. doi: 10.1115/1.4051213. Online ahead of print.

ABSTRACT

The relationship between three-dimensional shape and patellofemoral mechanics is complicated. The Wiberg patella classification is a method of distinguishing shape differences in the axial plane of the patella that can be used to connect shape differences to observed mechanics. This study uses a statistical shape model to relate the Wiberg patella classification to patella height and investigates its role in force distribution within the patellofemoral joint. The Wiberg Type I patella is shortest and has a more symmetrical medial and lateral facet while the Type III patella is longest with a larger lateral facet compared to medial. We generated patellofemoral morphologies from the statistical shape model and integrated them into a musculoskeletal model with a twelve degrees-of-freedom knee. We simulated an overground walking trial with these morphologies and recorded patellofemoral mechanics and ligament forces. An increase in patellar ligament force corresponded with an increase in patella height. Wiberg Type III patellas had a sharper patella apex which related to lower ratios of quadriceps tendon forces to patellar ligament forces. The change in pivot point of the patella affects the ratio of forces as well as the patellofemoral reaction force. This study provides a better understating of how patella morphology affects fundamental patella mechanics which may help identify at-risk populations for pathology development.

PMID:34008841 | DOI:10.1115/1.4051213

Arq Bras Cardiol. 2021 May;116(5):928-937. doi: 10.36660/abc.20190356.

ABSTRACT

BACKGROUND: Although non-ischemic troponin elevation is frequently seen in patients admitted to the emergency department (ED), consensus regarding its management is lacking.

OBJECTIVES: This study aimed to characterize patients admitted to the ED with non-ischemic troponin elevation and to identify potential mortality predictors in this population.

METHODS: This retrospective observational study included ED patients with a positive troponin test result between June and July of 2015. Patients with a clinical diagnosis of acute coronary syndrome (ACS) were excluded. Data on patient demographics and clinical and laboratory variables were extracted from medical records. Follow-up data were obtained for 16 months or until death occurred. The statistical significance level was 5%.

RESULTS: Troponin elevation without ACS was found in 153 ED patients. The median (IQR) patient age was 78 (19) years, 80 (52.3%) were female and 59(38.6%) died during follow-up. The median (IQR) follow-up period was 477(316) days. Survivors were significantly younger 76 (24) vs. 84 (13) years; p=0.004) and featured a higher proportion of isolated troponin elevation (without creatine kinase or myoglobin elevation) in two consecutive evaluations: 48 (53.9%) vs. 8 (17.4%), p<0.001. Survivors also presented a lower rate of antiplatelet treatment and same-day hospitalization. In the multivariate logistic regression with adjustment for significant variables in the univariate analysis, isolated troponin elevation in two consecutive evaluations showed a hazard ratio= 0.43 (95%CI 0.17-0.96, p=0.039); hospitalization, previous antiplatelet treatment and age remained independently associated with mortality.

CONCLUSIONS: Isolated troponin elevation in two consecutive measurements was a strong predictor of survival in ED patients with troponin elevation but without ACS.

PMID:34008817 | DOI:10.36660/abc.20190356

Arq Bras Cardiol. 2021 May;116(5):879-886. doi: 10.36660/abc.20200231.

ABSTRACT

BACKGROUND: Body mass index (BMI) is the most commonly used index to categorize a person as obese or non-obese, which is subject to important limitations.

OBJECTIVE: To evaluate the direct effect of BMI on cardiovascular outcomes among participants without central obesity.

METHODS: This analysis included 14,983 males and females aged 45-75 years from the Atherosclerosis Risk in Communities Study (ARIC). BMI was measured as general obesity, and waist circumference (WC), waist-to-hip ratio (WHR) and hip circumference as central obesity. Targeted maximum likelihood estimation (TMLE) was used to estimate the total effects (TEs) and the controlled direct effects (CDEs). The proportion of TE that would be eliminated if all participants were non-obese regarding central obesity was computed using the proportion eliminated (PE) index. P <0.05 was considered statistically significant. Analyses were performed in the TMLE R package.

RESULTS: The risk of cardiovascular outcomes attributed to BMI was significantly reversed by eliminating WHR obesity (p<0.001). The proportion eliminated of BMI effects was more tangible for non-obese participants regarding WC (PE=127%; 95%CI (126,128)) and WHR (PE=97%; 95%CI (96,98)) for coronary heart disease (CHD), and WHR (PE=92%; 95%CI (91,94)) for stroke, respectively. With respect to sex, the proportion eliminated of BMI effects was more tangible for non-obese participants regarding WHR (PE=428%; 95%CI (408,439)) for CHD in males, and WC (PE=99%; 95%CI (89,111)) for stroke in females, respectively.

CONCLUSION: These results indicate different potential effects of eliminating central obesity on the association between BMI and cardiovascular outcomes for males and females. (Arq Bras Cardiol. 2021; 116(5):879-886).

PMID:34008807 | DOI:10.36660/abc.20200231