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Results for “Effect Modifier, Epidemiologic”

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PubMed2000

Effects on mortality of getting the basic health examination under the Health Services for the Elderly Act and modification of the effects by health status among elderly persons in a rural community.

This longitudinal study examines the effect on mortality of regular use of the basic health examination under the Health Services for the Elderly Act and heterogeneity of the effect according to levels of physical and mental health status among community dwelling elderly persons. Of persons aged 65 and older who lived in Otsuki town, Kochi prefecture, and completed a questionnaire survey about health in February 1991, 1,470 survivors on the anniversary of the baseline survey were followed by the end of March 1996. Regularity of getting the examination was determined by the history of use of the examination in 1990 and 1991. Mortality reduction associated with annual use of the examination was observed in both the 65-74 and the 75 and older age groups and the benefit got smaller with advancing in age. In the 75 and older age group, the benefit from annual use of the examination was restricted to persons having no impairment in physical activities of daily living and those having favorable mental health. Biennial use of the examination was associated with the same amount of mortality reduction as annual use among persons having chronic conditions under treatment in the 65-74 age group. Regular use of the basic health examination at old ages is effective and the effectiveness varies by age range and level of functional health status.

Aged↗
PubMed2004

A measure of effect size for experimental designs with heterogeneous variances.

A recent trend in the psychological literature has been to include measures of effect size when reporting probability values. The several measures of effect size associated with the Student t test for two independent samples are appropriate only when the variances are homogeneous. In this paper, commonly used measures of effect size are considered and compared, using four data sets. A chance-corrected measure of effect size is provided for two or more treatment groups characterized by either homogeneous or heterogeneous variances.

Effect Modifier, Epidemiologic↗
PubMed2004

The power of tests for bioequivalence in feed experiments with poultry.

Several studies have compared the feeding of genetically modified (GM) grains and conventional grains to poultry. The general conclusion has been that there were no significant differences detected in the biological performance of the birds (i.e., the grains were bioequivalent). However, the question has been posed whether the experimental designs used in the studies had sufficient statistical power to detect treatment differences. The power of tests can be used to determine the ability of an experimental design to detect treatment differences. The definition of statistical power is the probability of rejecting the null hypothesis when it is false and should be rejected. The complement of statistical power is the Type II error (beta). That is, accepting the null hypothesis that there is no difference in treatments when there is one. A priori power analysis can indicate the probability at which the sampling regimen or experiment can actually detect an effect if a difference exists. Post hoc power analysis indicates the sufficiency or the sample size needed for an experiment that has already been conducted. In the current study, the power of tests for experiments published in the literature where significant and nonsignificant differences were reported between control birds and birds fed new feed grains was examined. With some exceptions, the power of tests is rarely formally considered or mentioned in poultry research. The results of the survey of the literature showed, in general, low power of statistical tests for feeding experiments involving non-GM grains or in those cases when GM and non-GM grains were compared in poultry feeding experiments. These results suggest that care needs to be taken when designing experiments for bioequivalence of grains fed to poultry.

Animal Feed↗
PubMedDate not supplied

Meta-analysis of the effects of nonnutritive sucking on heart rate and peripheral oxygenation: research from the past 30 years.

A meta-analysis of the effects of nonnutritive sucking (NNS) on heart rate and transcutaneous oxygen tension (TcPaO2) was performed. Four studies of NNS on heart rate without stimulations, three studies on heart rate during painful stimulations, and three studies on TcPaO2--all conducted over the past 30 years--were found through a computer search. Using the Fisher combined test, NNS significantly decreased heart rate without stimulations (p = .002) and during painful stimulations (p = .0001), and significantly increased TcPaO2 (p = .0001). The total weighted effect size for heart rate without stimulations was small (0.17); however, it was large for heart rate during painful stimulations (1.05) and TcPaO2 (0.69). Larger effects were noticed for preterm infants than for term infants and for longer NNS. More studies of NNS effects with independent treatment and control groups, using the physiological outcome variables of heart rate and oxygenation for different age groups of preterm infants, are needed to examine the fundamental mechanisms of NNS effects. Clinically, a low-risk intervention such as NNS can be more broadly used during any painful procedures to decrease infant distress.

Age Factors↗
PubMed2000

Statistical power for the two-factor repeated measures ANOVA.

Determining a priori power for univariate repeated measures (RM) ANOVA designs with two or more within-subjects factors that have different correlational patterns between the factors is currently difficult due to the unavailability of accurate methods to estimate the error variances used in power calculations. The main objective of this study was to determine the effect of the correlation between the levels in one RM factor on the power of the other RM factor. Monte Carlo simulation procedures were used to estimate power for the A, B, and AB tests of a 2 x 3, a 2 x 6, a 2 x 9, a 3 x 3, a 3 x 6, and a 3 x 9 design under varying experimental conditions of effect size (small, medium, and large), average correlation (.4 and .8), alpha (.01 and .05), and sample size (n = 5, 10, 15, 20, 25, and 30). Results indicated that the greater the magnitude of the differences between the average correlation among the levels of Factor A and the average correlation in the AB matrix, the lower the power for Factor B (and vice versa). Equations for estimating the error variance of each test of the two-way model were constructed by examining power and mean square error trends across different correlation matrices. Support for the accuracy of these formulae is given, thus allowing for direct analytic power calculations in future studies.

Analysis of Variance↗
PubMed1990

Clinical evaluation of the rocker bottom crutch.

One hundred fifty hospitalized patients referred to a physical therapy department for crutch walking instruction were evaluated in a randomized, controlled crossover study with "rocker bottom" and conventional axillary crutches. A large training effect was observed with each crutch, but no significant differences (all P greater than .05) of gait speed, stride length, heart rate, stability, or feeling of security were noted between the groups. Thus, rocker bottom crutches, despite potential stability and energy conservation benefits, were found to be no more effective than conventional axillary crutches in this hospital setting.

Aged↗
PubMed1995

Evaluating teaching effectiveness.

Major reform in nursing education is underway, with increased emphasis being placed on the importance of the teacher-student relationship. An instrument for evaluation of teaching effectiveness, developed at the Oregon Health Sciences University School of Nursing, attempts to capture the student's perception of the quality of the teacher-student relationship as well as other salient aspects of teaching practices. The evaluation tool contains 26 items evaluating teaching effectiveness and 14 items that evaluate the course. The teaching effectiveness items yield five scales including: knowledge and expertise, facilitative teaching methods, communication style, use of own experiences, and feedback. Psychometric testing has been completed and there is evidence of construct validity in relation to teaching effectiveness and internal consistency reliability for the five scales.

Analysis of Variance↗
PubMed2002

Critical ethnographic methodology in nursing research: issues and solutions.

Five methodological issues were encountered in a study using critical ethnography to investigate nurses' attitudes, knowledge and practices towards patients with alcohol and drug related problems in a general hospital. These issues related to the recording of field notes, over-identification with participants, the role of being a researcher, the effect of the researcher's presence - the Hawthorne effect, and cultural differences. The latter issue was viewed from the personal perspective as an international student from Denmark conducting the research in an Australian setting. This paper discusses the issues in turn and concludes with recommendations on how they might be effectivley addressed by other researchers considering to use critical ethnography.

Alcoholism↗
PubMed2006

The "Hawthorne effect" is a myth, but what keeps the story going?

The Hawthorne studies became famous because of the discovery of the "Hawthorne effect": "a marked increase in production related only to special social position and social treatment". They mark the beginning of the Human Relations School. This article demonstrates that the Hawthorne research does not pass a methodological quality test. Even if methodological shortcomings were waived, there is no proof of a Hawthorne effect in the original data. The following five myths are debunked: (i) scientific worth, (ii) continuous improvement, (iii) social factors prevailing over physical factors and pay, (iv) wholehearted cooperation, and (v) the neurotic worker. The following five factors are held responsible for the creation and survival of the Hawthorne myth: (i) a story too good to be untrue, (ii) bias and selective accounts by original researchers and "laziness" among later scientists, (iii) social factors do matter, and (iv) a story that fits the cognitive world and interests of psychologists, and (v) management.

Effect Modifier, Epidemiologic↗
PubMed2000

Respondent bias in the collection of alcohol and tobacco data in American Indians: the Strong Heart Study.

This study addresses the impact of assessment method (interviewer-administered questionnaire vs. self-administered questionnaire) and interviewers demographic characteristics (gender, ethnicity, and residency) on responses to alcohol and tobacco questions. The study population included 1,522 men and women aged 45 to 74 from the Dakota Center of the Strong Heart Study (SHS), a multi-center study of cardiovascular disease in American Indians. Assessment method effects were greater for alcohol than tobacco but did not differ by interviewer characteristics.

Adult↗
PubMed2005

Non-participant observation: using video tapes to collect data in nursing research.

Observation is a highly valued and effective research method, as well as being an essential part of nursing practice. The authors explore the way in which non-participant observation as a research method might be enhanced by the use of video recording. The utility, ethical considerations and constraints of video recording as a data collection tool are discussed, with examples from a research study. The authors argue that the use of videos can enhance the credibility of non-participant observation studies through the minimisation of selectivity and bias and the opportunity to employ more rigorous strategies for ensuring reliability.

Attitude of Health Personnel↗
PubMed2005

Noise levels in PICU: an evaluative study.

High levels of noise in the hospital environment can have an impact on patients and staff increasing both recovery time and stress respectively. When our seven-bedded paediatric intensive care unit (PICU) is full, noise levels seem to increase significantly. This study measured noise levels at various times and places within a PICU using Tenma sound level meter which simulates the subjective response of a human ear. Noise levels were often excessive, exceeding international guidelines. Staff conversation was responsible for most of the noise produced; medical equipment, patient interventions, telephones, doorbell and the air shoot system were also responsible for causing high levels of noise. More can be done to reduce noise and its effects on patients and staff.

Causality↗
PubMed1999

Is residual impairment after alcohol an effect of repeated performance?

BACKGROUND: The study examines the residual impairment of performance due to alcohol on the descending limb of the blood alcohol curve. The occurrence of residual impairment at low or zero levels of blood alcohol is well established but its cause is uncertain. It is hypothesized that residual impairment may be due in part to the methodological procedure of repeated performance testing in the post-ingestion period. METHODS: There were 80 volunteers randomly allocated to one of four treatment conditions: a) alcohol and repeated performance (A-R) where psychomotor tasks were performed at 20-min interval for 2 h post ingestion; b) alcohol and double performance (A-D) where tasks were performed only at 1 h and 2 h from ingestion; c) placebo and repeated performance (P-R); and d) placebo and double performance (P-D). Alcohol was administered as vodka to achieve a peak blood-alcohol concentration (BAC) of approximately 80 mg per 100 ml. Performance effects were assessed by a dual task of primary pursuit tracking and secondary visual reaction time, and a visual sustained attention task. RESULTS: Alcohol caused significant impairment of secondary reaction time, the effect being greatest at peak BAC. Sustained attention was also impaired by alcohol but the effect just missed significance. Repeated performance conditions were associated with significantly greater impairment of secondary reaction time and sustained attention when compared with double performance conditions. The factor of performance condition did not, however, interact with that of alcohol. CONCLUSIONS: The monotony and boredom that may be associated with repeated performance do not contribute to residual alcohol impairment.

Adolescent↗
PubMed1999

Mortality rates after cataract extraction.

Senile cataract may be a marker of generalized tissue aging. We examined this hypothesis using population-based linked health data. We hypothesized that any such association would diminish with increased use of cataract surgery. Mortality rates of those 50-95 years of age undergoing cataract surgery in British Columbia during either 1985 or 1989 were compared with the provincial population of comparable age who did not undergo cataract surgery during the study period. The 1985 cohort included 8,262 patients undergoing surgery and a comparison population of 804,303, and the 1989 cohort included 11,952 patients and a comparison population of 839,393. Using Cox regression, for the 1985 cohort, the hazard ratios for dying during follow-up were 3.2 for males 50-54.9 years of age [95% confidence limits (CL) = 2.0, 5.0] and 3.3 for females (95% CL = 1.9, 5.7). Hazard ratios for older age groups decreased with age. We also fit an additive risk model that produced excess mortalities that were less age dependent. In the 1985 analysis, these ranged from +7.1 per 1,000 (95% CL = +0.44, +13.76) to +20.3 (95% CL = +13.24, +27.36) for males and -17.5 (95% CL = -28.28, -6.72) to +2.0 (95% CL = -2.12, +6.12) for females. Findings for the 1989 analyses were similar, indicating that the association between cataracts and generalized aging remained constant despite a large increase in the use of cataract surgery.

Age Distribution↗
PubMed1999

Antenatal steroids to prevent respiratory distress syndrome: multiple gestation as an effect modifier.

BACKGROUND: To determine the effect of antenatal steroids on the incidence of respiratory distress syndrome and the need for surfactant in low-birth-weight infants (501-1500 grams). METHODS: A 6 year cohort of 946 infants (396 received complete steroids and 550 received no steroids) was studied for the occurrence of respiratory distress syndrome and the need for surfactant following antenatal steroid therapy. A stratified analysis identified confounding baseline characteristics or effect modifiers. The covariates used were multiple birth, maternal race, sex, mode of delivery, Apgar score <7 at 5 minutes, birth weight and gestational age. A multivariate logistic regression model was used to adjust odds ratios simultaneously for all statistically significant covariates. RESULTS: Multiple gestation and race were effect modifiers. The reduction in RDS was greatest among singleton infants of black mothers with no significant reduction for multiple gestation white infants. The need for surfactant following steroids was reduced only in the group of singletons of other race (not black or white). CONCLUSION: In this retrospective analysis of cohort data collected prospectively antenatal steroid therapy did not reduce the incidence of RDS in multiple gestation white infants.

Betamethasone↗
PubMed1998

Cycle counting: a quality assurance process.

Accurate inventory records result from careful tracking of in and out transactions. Regardless of how these transactions are done--by computer (backflush) or manually--they must be done correctly if accurate inventory records are to be the result. Cycle counting plays an important role in assuring that there is a sufficient inventory-tracking process in place to achieve accuracy. The purpose of this article is to explain how to use cycle counting to establish an effective process for keeping records accurate and how to ensure that it remains in place.

Effect Modifier, Epidemiologic↗