Estimating sample size for epidemiologic studies: the impact of ignoring exposure measurement uncertainty

1998 ◽  
Vol 17 (12) ◽  
pp. 1375-1389 ◽  
Author(s):  
Owen J. Devine ◽  
James M. Smith
1996 ◽  
Vol 115 (5) ◽  
pp. 422-428
Author(s):  
Roy E. Shore

A number of topics are discussed related to the potential for and pitfalls in undertaking epidemiologic studies of the late effects of nasopharyngeal radium irradiation. The available evidence indicates that linear extrapolation of risk estimates from high-dose studies is a reasonable basis for estimating risk from radium exposure or other situations in which the radiation exposures were fairly low and fractionated. Epidemiologic study of populations given nasopharyngeal radium irradiation is worthwhile scientifically if several criteria can be met. It is very Important that any such study has adequate statistical power, which is a function of the doses to the organs of interest and the radiation risk coefficients for those organs, as wed as the available sample size. If the organ doses are low, a prohibitively large sample size would be required. Other problems with low-dose studies include the likelihood of false-positive results when a number of health end points are evaluated and the impact of dose uncertainties, small biases, and confounding factors that make the interpretation uncertain. Cluster studies or studies of self-selected cohorts of irradiated patients are not recommended because of the potential for severe bias with such study designs. The ability to define subgroups of the population who have heightened genetic susceptibility may become a reality in the next few years as genes conferring susceptibility to brain cancers or other head and neck tumors are identified; this scientific advance would have the potential to alter greatly the prospects and approaches of epidemiologic studies.


2020 ◽  
Author(s):  
Qing Zhao ◽  
Pei Chen ◽  
Yu Zhang ◽  
Haining Liu ◽  
Xianwen Li

BACKGROUND Mobile health application has become an important tool for healthcare systems. One such tool is the delivery of assisting in people with cognitive impairment and their caregivers. OBJECTIVE This scoping review aims to explore and evaluate the existing evidence and challenges on the use of mHealth applications that assisting in people with cognitive impairment and their caregivers. METHODS Nine databases, including PubMed, EMBASE, Cochrane, PsycARTICLES, CINAHL, Web of Science, Applied Science & Technology Source, IEEE Xplore and the ACM Digital Library were searched from inception through June 2020 for the studies of mHealth applications on people with cognitive impairment and their caregivers. Two reviewers independently extracted, checked synthesized data independently. RESULTS Of the 6101 studies retrieved, 64 studies met the inclusion criteria. Three categories emerged from this scoping review. These categories are ‘application functionality’, ‘evaluation strategies’, ‘barriers and challenges’. All the included studies were categorized into 7 groups based on functionality: (1) cognitive assessment; (2) cognitive training; (3) life support; (4) caregiver support; (5) symptom management; (6) reminiscence therapy; (7) exercise intervention. The included studies were broadly categorized into four types: (1) Usability testing; (2) Pilot and feasibility studies; (3) Validation studies; and (4) Efficacy or Effectiveness design. These studies had many defects in research design such as: (1) small sample size; (2) deficiency in active control group; (3) deficiency in analyzing the effectiveness of intervention components; (4) lack of adverse reactions and economic evaluation; (5) lack of consideration about the education level, electronic health literacy and smartphone proficiency of the participants; (6) deficiency in assessment tool; (7) lack of rating the quality of mHealth application. Some progress should be improved in the design of smartphone application functionality, such as: (1) the design of cognitive measurements and training game need to be differentiated; (2) reduce the impact of the learning effect. Besides this, few studies used health behavior theory and performed with standardized reporting. CONCLUSIONS Preliminary results show that mobile technologies facilitate the assistance in people with cognitive impairment and their caregivers. The majority of mHealth application interventions incorporated usability outcome and health outcomes. However, these studies have many defects in research design that limit the extrapolation of research. The content of mHealth application is urgently improved to adapt to demonstrate the real effect. In addition, further research with strong methodological rigor and adequate sample size are needed to examine the feasibility, effectiveness, and cost-effectiveness of mHealth applications for people with cognitive impairment and their caregivers.


1972 ◽  
Vol 31 (2) ◽  
pp. 163-170 ◽  
Author(s):  
H. Tyroler ◽  
Ralph Patrick

With data from the Papago population register and death certificates from the Arizona State Department of Health, vital rates and causes of death were examined for the decade 1950-59. Data were then divided to permit an assessment of the impact of residence in modern and traditional Papago communities on vital rates. Birth and death rates computed for the Papago population were in general agreement with similar data on Arizona Indian and U. S. Indian populations. Because of incompleteness of cause of death coding, mortality analysis was inconclusive. The vital rates for modern versus traditional communities disclosed differences which were the opposite of those predicted. Both birth and death rates were higher in modern than in traditional villages. This reversal may be explained by the inadequacy of the reporting system for vital events during the decade.


2021 ◽  
Vol 66 (18) ◽  
pp. 185012
Author(s):  
Yingtao Fang ◽  
Jiazhou Wang ◽  
Xiaomin Ou ◽  
Hongmei Ying ◽  
Chaosu Hu ◽  
...  

2020 ◽  
Vol 4 (3) ◽  
pp. 107-115
Author(s):  
Safruddin ◽  
Nurlina ◽  
Anel Ariansyah

A depressive disorder is a serious mental problem characterized by feelings of anxiety and sadness. Depressive disorders have increased from year to year, where the total number of people living with depression in the world is 322 million, this is supported by WHO 2017 data. Generally, someone in a depressed state experiences feelings of sadness, anxiety, or emptiness, and the impact that is caused if depression is not treated immediately, it will have an impact on oneself such as low self-esteem, social isolation, and even suicide attempts. Besides that, it will also have an impact on the people around it. The purpose of this study is to know the description of the level of depression in prisoners in Class II A Penitentiary in Bulukumba Regency in 2020. The research design used in this study is a descriptive research design with a cross-sectional approach. The affordable population in this study were inmates with all cases totaling 194 people with a sample size of 85 respondents. The sampling technique using a systematic random sampling method selects a sample from the population systematically. Data were collected using a questionnaire sheet. Based on the results of the research conducted, it was shown that the frequency distribution of the level of depression of the 85 prisoner respondents experienced mild depression as many as 64 respondents (75.3%) then moderate depression was 14 respondents (16.5%) and 7 respondents (8.2%) were not depressed. In all cases, the depression level of prisoners in class II A prisons in Bulukumba district experienced mild depression. Researchers suggest that further the sample size can be added so that data collection is more accurate and can be linked to other variables that can cause depression


Author(s):  
A J Shaw ◽  
T G Harrison ◽  
K L Shallcross ◽  
S J Williams ◽  
D E Shallcross

Analysis of the average number of applicants received from schools that engaged in the Bristol ChemLabS Outreach program prior to a student‟s application with those that did not engage, shows a significant increase in applicants from engaged schools. The significance is weaker when just Post 16 students are considered but this is almost certainly due to a smaller sample size. When this analysis was inspected in terms of the distance of the school from the University of Bristol, there was an increase in the number of applicants from engaged schools irrespective of distance. However, a statistically significant increase was observed for schools within 50 miles of the University from an analysis of just Post 16 students. Students who applied to the department from an engaged school were more likely to accept an offer and also to make the department their firm acceptance. A slightly higher number of applications that were rejected came from engaged schools too. There are two possible reasons; first, the engagement may have encouraged more students who did not have the required entry qualifications. Second, during the period of analysis, the overall entry grades went up by one grade each year. Such a dramatic rise was probably the reason for the slightly elevated numbers.


Author(s):  
Maria Cristina Dijmarescu

Destructive and non-destructive testing of materials present a rapid expansion given by the increase in market demand caused by the desire to obtain an increasingly better quality of products. The continuous increase in quality demands leads directly to the need to implement and modernize the techniques, methods, and equipment used for quality control. Consequently, the need for product testing services has a rapid growth. This paper presents the strength and weaknesses of implementing IT tools for the estimation of the measurement uncertainty in testing laboratories and the impact of these tools on the economic part


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