The variable parity as a risk factor in the Cuban perinatal survey.
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Adult↗
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Performance of Gem Premier blood gas/electrolyte analyzer evaluated.
We evaluated a new analyzer designed for point-of-care testing of blood gases, sodium, potassium, ionized calcium, and hematocrit. The Gem Premier (Mallinckrodt) system has two components: the analyzer and a disposable cartridge. Analysis takes place in the cartridge, which contains the electrochemical sensors, the calibrants, the reagents, the sampling stylus, and the waste container. The system was evaluated for imprecision and accuracy. With aqueous control materials, total imprecision (CV) was: pH, 0.10-0.18%; PCO2, 3.16-5.78%; PO2, 2.92-4.85%; sodium, 0.82-1.44%; potassium, 1.35-1.48%; ionized calcium, 0.75-1.45%; and hematocrit, 1.13-1.83%. Accuracy of the system was assessed by split-sample comparison with the Radiometer ABL 330 blood gas analyzer for pH and blood gases, the Nova Stat Profile 5 for whole-blood electrolyte and hematocrit analysis, and the IL Phoenix for plasma electrolyte analysis. After outlier correction, regression statistics were excellent for all analytes except sodium, which demonstrated Sy[x values between 1.80 and 2.30 mmol/L and 0.85 < or = r < 0.90.
Blood Gas Analysis↗
Risk factors for childhood obesity in a transitional society in Thailand.
OBJECTIVE: To identify factors associated with childhood obesity among the population of Hat Yai municipality, a transitional society in Thailand. DESIGN: Cross-sectional study. SUBJECTS: 2161 primary schoolchildren, aged 6-13 completed years. MEASUREMENTS: Weight-for-height of children by measurement, parental weight and height, parental income, family history of disease and children's activities by questionnaire. RESULTS: Prevalence of obesity was 14.1%. Using polytomous logistic regression, statistically significant associations with obesity were found for family history of obesity (relative rate ratio, RRR = 3.1), low exercise level (RRR = 2.6 vs normal), obesity in mother and father (RRR = 1.9 and 2.2, respectively vs normal weight status). Significant trends of increased risk were associated with higher family income and smaller family size. The highest population attributable fraction was that for family history of obesity (34%), followed by those for low exercise level (12%) and an obese or overweight mother (10%). CONCLUSION: As the parental and family factors identified in this study cannot be readily modified, increasing exercise may be the most appropriate intervention to prevent obesity in childhood.
Adolescent↗
Male-female differences in the relationship between obesity and lipids/lipoproteins.
OBJECTIVE: To examine the effect of gender on the relationship between obesity measures and lipids/lipoproteins. DESIGN: Cross-sectional, matched observational study of adult men and women. SUBJECTS: 225 spousal pairs from Cincinnati, Ohio (age range, 28-66 years; mean +/- SD (yr), 44.0 +/- 6.7 (men), 42.1 +/- 5.9 (women). MEASUREMENTS: Body mass measures, lipids, lipoproteins, apolipoproteins, physical activity levels, cigarette use and dietary variables. RESULTS: Correlations between the lipids/lipoproteins and body mass index (BMI) were stronger in women than in men for cholesterol (r = 0.24 vs 0.10), LDL-c (r = 0.27 vs 0.12), triglycerides (TG) (r = 0.48 vs 0.23) and the ratio cholesterol/HDL-c (r = 0.47 vs 0.28). Utilizing statistical regression models which included potentially confounding environmental factors, BMI and WHR both contributed significant information to describe cholesterol, HDL-c, TG and cholesterol/HDL-c values in women, whereas WHR alone provided information for these lipids/lipoproteins in men. CONCLUSION: The association between BMI and lipids/lipoproteins appears to be stronger in women than in men. In women, in contrast to men, BMI and WHR, measures which are easily attainable in the clinical setting, provide separate, independent information in the explanation of these lipid/lipoprotein levels.
Adult↗
Prediction of radiation doses from therapy using tracer studies with iodine-131-labeled antibodies.
UNLABELLED: Tracer pharmacokinetic studies are often used in treatment planning for radionuclide therapy including radioimmunotherapy. This study evaluates the validity of using tracer studies to predict radiation doses from therapy with the same radiolabeled antibody. METHODS: Quantitative imaging and blood radioactivity were used to obtain the pharmacokinetics and radiation doses that were delivered to the total body, blood, marrow, lungs, liver, kidneys, thyroid, spleen and tumors. Tracer and therapy data for eight patients with lymphoma and one patient with breast cancer were compared using linear regression statistics. Doses of 131I-labeled antibody for the tracer studies ranged from 0.1 to 0.4 GBq (2 to 10 mCi), and therapy doses ranged from 0.7 to 5.6 GBq (20 to 150 mCi). RESULTS: Radiation doses to tissues and, in particular, the bone marrow and tumors were reliably predicted from tracer studies. In this group of patients, median dose to marrow from marrow targeting, total body and blood was 9.2 cGy/GBq for tracer studies and 7.6 cGy/GBq for therapy studies with a median difference of 0.5 cGy/GBq. Median dose to tumors was 81.1 cGy/GBq for tracer studies and 70.3 cGy/GBq for therapy studies with a median difference of 5.9 cGy/GBq. CONCLUSION: In these patients, tracer studies were predictive of the radiation doses from therapy for total body, major organs and tumors. The radiation doses to marrow and tumors, which are the usual determinants of the therapeutic index, correlated well between tracer and therapy studies (r > or = 0.95).
Antibodies, Monoclonal↗
Factors associated with back pain in nursing staff: a survey in Athens, Greece.
Factors associated with self-reported back pain were investigated using questionnaire data on 407 female nurses from a large hospital in Athens, Greece. Factor analysis was used to construct indices of pain and its impact on normal life, and also to summarize work load descriptions. Pain factors were examined in relation to work load and personal characteristics by logistic regression. Statistically significant items, in relation both to pain and impact, were the existence of previous back injury, self-reported headaches and the 'carrying and lifting' factor of work load which principally included moving equipment. Age, height and weight were not associated with back pain. Compared to a similar study by Harber and colleagues in California, United States of America, the factors associated with back pain were quite similar in this study even though the prevalence of back pain was much higher among Greek nurses and their work load was physically much more demanding.
Back Pain↗
[Use of subjective perception of exertion in the evaluation of the tolerance to repetitive lifting: a pilot study].
This preliminary study was conducted to validate subjective perception of effort as indicator of the tolerable workload for prolonged lifting tasks. Three healthy male subjects underwent endurance and incremental lifting tests. Cardiorespiratory parameters (HR, VO2) were monitored with a portable telemetric oxygen uptake analyzer, mechanical parameters were calculated from a lift dynamometer. Rating of perceived exertion was given on Borg's CR-10 scale. Individual fitness profiles for lifting tasks were obtained from the individual relationships between oxygen consumption and heart rate at different lifting frequencies. Physiological responses to repetitive lifting were matched with subjective perceptions. The relationship between perception of exertion and time was described by power functions, Y = a.Xn, in which 0 < n < 1. A single-variable statistical regression for power functions was performed to obtain the individual "iso-perception" curves. The iso-perception curve corresponding to a "moderate effort" (CR3) identified the individual tolerable threshold for prolonged lifting tasks. The individually tolerable power output over time for lifting tasks was calculated.
Adult↗
Tolerability to prolonged lifting tasks. A validation of the recommended limits.
Prolonged physical exertion is subjectively regulated by the perception of effort. This preliminary study was conducted to validate the use of subjective perceptions of effort in assessing objectively tolerable workloads for prolonged lifting tasks. Ten healthy male subjects tested their maximal lifting capacity (MLC) on a lift dynamometer (LidoLift, Loredan Biomed., West Sacramento, CA) and underwent incremental and 30-minute endurance lifting tests. Cardiorespiratory parameters were monitored with an oxygen uptake analyzer, mechanical parameters were calculated using a computerized dynamometer. Ratings of perceived exertion were given on Borg's 10-point scale. Physiological responses to repetitive lifting were matched with subjective perceptions. A single-variable statistical regression for power functions was performed to obtain the individual "iso-perception" curves as functions of the mechanical work exerted. We found that the "iso-perception" curve corresponding to a "moderate" perception of effort may represent the individual "tolerance threshold" for prolonged lifting tasks, since physiological responses at this level of intensity did not change significantly and the respiratory exchange ratio was less than one. The individually tolerable weight for lifting tasks lasting 30 min has been expressed as a percentage of the isoinertial MLC value and compared with the currently recommended limits for prolonged lifting tasks (Italian legislation D.L. 626/94). On the basis of our preliminary results a "tolerance threshold" of 20% MLC has been proposed for prolonged lifting tasks.
Adult↗
Comparison of quantitative variables between patients with relatively normal and gastritis-altered mucosae.
OBJECTIVE: To develop a statistical (regression) analysis of quantitative patterns of human epithelial nuclear and cellular profiles from chronic atrophic and hypertrophic gastritis, excluding Menetrier's gastropathy. STUDY DESIGN: The study group consisted of 30 patients with chronic gastritis with or without intestinal metaplasia, including gastric dysplasia. The control group consisted of 25 patients with relatively normal mucosae. Both groups were compared with respect to changes in quantitative morphometric variables as well as nuclear DNA quantities. RESULTS: Specific interdependences between minor (BN) and major (LN) nuclear axis length and cellular caliper diameters (Bc) and (Lc) were stipulated; thus, the corresponding area features were determined by regression equations. The value of the L2 norm as differences between corresponding linear functions involved in the regression equations were also examined. Higher nuclear DNA content values were obtained from patients with chronic gastritis. CONCLUSION: Chronic gastritis appears to be an intermediate and crucial moment in the process of gastric mucosal malignant progression. The pentaploid (5C) region was found to be an intermediate and critical feature of chronic gastritis since values in the ploidy range higher than pentaploid have been found to potentially indicate a malignancy.
Cell Nucleus↗
Statistical issues of regression analysis on development of an age-predictive equation.
Several statistical information criteria and other statistical issues such as residual examinations and multi-collinearity in regression analysis were argued to establish the predictive equation of age from physical fitness measurements. These independent variables of physical fitness, body composition, two blood pressures, and bone strength were taken from 31 Japanese males (48 +/- 11.9 years old) living in rural areas. The following equation was selected as the optimal one according to Akaike's information criterion: ŷ = 90.0 -1.294 * SITUP - 0.467 * MAP - 0.094 * BALANCE (R = 0.837). When all ten variables were included in the initial equation, R was 0.864, and the highest R* (R adjusted for d.f.) was observed at the fifth step.
Adult↗
Sparse modeling using orthogonal forward regression with PRESS statistic and regularization.
The paper introduces an efficient construction algorithm for obtaining sparse linear-in-the-weights regression models based on an approach of directly optimizing model generalization capability. This is achieved by utilizing the delete-1 cross validation concept and the associated leave-one-out test error also known as the predicted residual sums of squares (PRESS) statistic, without resorting to any other validation data set for model evaluation in the model construction process. Computational efficiency is ensured using an orthogonal forward regression, but the algorithm incrementally minimizes the PRESS statistic instead of the usual sum of the squared training errors. A local regularization method can naturally be incorporated into the model selection procedure to further enforce model sparsity. The proposed algorithm is fully automatic, and the user is not required to specify any criterion to terminate the model construction procedure. Comparisons with some of the existing state-of-art modeling methods are given, and several examples are included to demonstrate the ability of the proposed algorithm to effectively construct sparse models that generalize well.
Journal Article↗
Imagination inflation: a statistical artifact of regression toward the mean.
In the imagination inflation procedure of Garry, Manning, Loftus, and Sherman (1996), subjects rated a list of events in terms of how likely each was to have occurred in their childhood. Two weeks later, some of the events were imagined; control events were not. The subjects then rated the likelihood of occurrence for each event a second time. Garry et al. (1996) reported that the act of imagining the target events led to increased ratings of likelihood. This finding has been interpreted as indicating that false events can be suggestively planted in memory by simply having people imagine them. The present study tests and confirms the hypothesis that the results that have been attributed to imagination inflation are simply a statistical artifact of regression toward the mean. The experiment of Garry et al. (1996) was reproduced (with some procedural changes), using younger and older adults. The results of Garry et al. (1996) were replicated; likelihood ratings for events initially rated low in likelihood did increase from Time 1 to Time 2. However, ratings for events initially rated high in likelihood decreased under the same conditions, and these results were consistent with the imagined target events, the target events not imagined, and the nontarget events.
Adolescent↗
Statistical methods in regression and calibration analysis of chromosome aberration data.
The method of iteratively reweighted least squares for the regression analysis of Poisson distributed chromosome aberration data is reviewed in the context of other fit procedures used in the cytogenetic literature. As an application of the resulting regression curves methods for calculating confidence intervals on dose from aberration yield are described and compared, and, for the linear quadratic model lambda = beta 0 + beta 1 chi + beta 2 chi 2 a confidence interval for the ratio beta 1/ beta 2 is given. Emphasis is placed on the rationale, interpretation and the limitations of various methods from a statistical point of view.
Chromosome Aberrations↗
A review of goodness of fit statistics for use in the development of logistic regression models.
Several statistics have recently been proposed for the purpose of assessing the goodness of fit of an estimated logistic regression model. These statistics are reviewed and compared to other, less formal, procedures in the context of applications in epidemiologic research. One statistic is recommended for use and its computation is illustrated using data from a recent study of mortality of intensive care unit patients.
Humans↗
Predicting the probability of malignancy of the neck mass with logistic regression model: a statistical analysis of excisional biopsy of neck masses.
One hundred and fifty-six patients with neck lesions were selected into this retrospective study between January, 1989 and December, 1990. All the patients visited OPD with the chief complaint of neck mass without other apparent symptoms and signs after initial work-up. They can be divided into 5 types according to the pathological reports: type a) metastatic lesion, type b) malignant lymphoma, type c) TB lymphadenitis, type d) miscellaneous benign lesion, and type e) inadequate specimen. They represent 24.4%, 12.8%, 9.6%, 52.6%, and 0.6% of the patients respectively. Type a) and type b) were classified as group of malignancy and the other three types were group of benignancy. Chi-square test and t-test were then used to evaluate the significant level of difference in each semiological factor between both groups. Several parameters were found to reach significant level, including tumor fixation, age of the patients, tenderness, location and size of the tumor, and history of cancer. Stepwise logistic regression was utilized to obtain a regression equation to predict the probability of malignancy in OPD patients with neck masses. The accuracy rate of prediction is 83.3%, if the cutpoint value is 0.5. A clinician can therefore avoid untimely excisional biopsy and delay in treatment planning.
Adolescent↗
An empirical study of population density gradients and their determinants.
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Asia↗
[Studies on background of gamma-GTP abnormality in human multiphasic screening. (Part 3): Multiple regression analysis by SAS statistic package for computer analysis].
Multiple regression analysis in 1493 cases (1256 male cases, 237 female cases) who were examined in the short-term human dry dock managed by the Fukuoka University Hospital, was done with gamma-GTP as the dependent variable and other parameters as the independent variables. As the result, 16 variables including LAP, alcohol, GPT, triglyceride, HDL and obesity rate were selected as the variables explaining gamma-GTP by stepwise methods in men. The standard regression coefficient of alcohol is shown to be greater than that of obesity on gamma-GTP. On the contrary, neither alcohol nor the obesity rate was included in this regression formula in women.
Adult↗
[Massive penicillin therapy in single series preceded by 3 injections of mercuric cyanide in primary & secondary syphilis; status of the statistics after maximum regression of 9 1/2 years].
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Chancre↗