On the use of statistical models of within-person variation in long-term studies of healthy individuals.

Harris, Eugene K.; Cooil, Bruce; Shakarji, George; Williams, G

doi:10.1093/clinchem/26.3.383

Cited by 30 publications

(2 citation statements)

References 8 publications

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“…assessing the T/EpiT intra-individual (within-subject) variability is useful in determining whether an o¡ence has occurred. The application of T/EpiT intraindividual pro¢ling was ¢rst discussed by Donike et al 182 In a subsequent article, 183 the statistical test proposed by Harris 184,185 was applied for biochemical analyses to assess the suitability of using such data. This statistical test evaluates whether it is appropriate to use an intra-individual (subject-based) reference range, as opposed to an inter-individual (populationbased) reference range, for assessing changes in biochemical status.…”

Section: Intra-individual Pro Ling Of T/epit Ratiosmentioning

confidence: 99%

Anabolic steroids in sport: biochemical, clinical and analytical perspectives

2003

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International Olympic Committee accredited laboratories play a key role in upholding the principle of fair play and innate ability, as desired by the majority of sports competitors and spectators. Not only does doping damage the image of sport, but it can also be harmful to the individual. The great majority of samples test negative but, when an adverse nding is declared, the analytical data must be of a suf ciently high standard to withstand legal challenges by third parties. The most widely misused performance-enhancing drugs are the anabolic-androgenic steroids, commonly referred to as 'anabolic steroids'. This review attempts to address the complex issues concerning anabolic steroids in sport by considering the clinical, biochemical and analytical perspectives. Fifty years of anabolic steroids and sport: an overviewThe discovery of a process for synthesizing the steroid testosterone (T) from cholesterol in 1935 1 greatly accelerated scienti¢c investigations into the e¡ects of this endogenous androgen. T rapidly became noted for its anabolic properties in increasing muscle size and strength and in its androgenic properties of increasing virilization and aggression. In a comprehensive review of the history of the use of anabolic steroids in sport, Todd 2 noted that, as early as 1945, the science writer Paul de Kreuf had speculated that`it would be interesting to watch the productive power of [a] . . . professional group [of athletes] that would try a systematic supercharge with testosterone . . .'.In the early 1950s, the ¢rst suspicion that T was actually being administered to improve sporting performance came with the allegation that Soviet weightlifters were administering T to gain strength. 2 Also, around that time, pharmaceutical companies were developing synthetic analogues of T with the aim of treating patients in a`catabolic state', the objective being to enhance the anabolic e¡ects of T and to dissociate the unwanted androgenic e¡ects (particularly to minimize the viriliz ing e¡ects). Nandrolone (19-nortestosterone) was the ¢rst synthetic analogue of T to show enough anabolic-androgenic dissociation in animal experiments 3 to justify its introduction as a therapeutic agent. 4 Subsequently, numerous analogues of T [and also its 5a-reduced metabolite, 5a-dihydrotestosterone (DHT)] were developed (see Fig. 1), such as methandienone (methandrostenolone), oxymesterone and stanozolol (for dates of patent awards see Ref. 5). With the growing availability of these licensed compounds, competitors began to experiment with them in an attempt to gain improvements in sporting performance without imparting the full androgenic e¡ects associated with T. During the 1960s, a number of deaths occurred in sports competitors from the use of stimulants and, as a result, in 1967 the International Olympic Committee (IOC) reestablished a medical commission (an IOC Medical Commission was rst established in Athens in 1961; see Ref. 6) which banned the practice of doping in sport, the banned classes including stimula...

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Section: Intra-individual Pro Ling Of T/epit Ratiosmentioning

confidence: 99%

Anabolic steroids in sport: biochemical, clinical and analytical perspectives

2003

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“…For calculation on categorical data, χ 2 or Fisher's exact test was used. Within-person correlations were calculated using ANCOVA as recommended [16,17]. For between-person correlation, we performed a between-investigation correlation in which a correlation between 2 variables was calculated to investigate if high (or low) values in 1 variable correlated to high (or low) values in the other at a group level.…”

Section: Statisticsmentioning

confidence: 99%

Body Weight Changes in Hyperthyroidism: Timing and Possible Explanations during a One Year Repeated Measurement Study

2020

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Background: Weight gain during treatment of hyperthyroidism is a frequent and for many patients unwanted outcome. With this repeated measurement study, we explored the timing of weight changes during the first year of antithyroid drug (ATD) treatment and assessed the correlation between body weight changes and changes in thyroid hormones, resting energy expenditure (REE), physical activity level, and energy efficiency. Methods: Patients with new onset hyperthyroidism were investigated every second month during the first year of ATD treatment. At each investigation, the following were measured: body weight, thyroid hormone concentrations, physical activity level, and daily number of steps, REE, and exercise performance. Results: Two men and eleven women, all sedentary, mean age 49(SD: 9.3) years were included. Significant changes after 1 year occurred for body weight (68.9–74.1 kg), thyroid hormones (free T3 [fT3] 17.5 to 4.42 pmol/L), REE (1,630–1,484 kcal/24 h), and energy efficiency at lower (50 W) workloads (16.0–17.6%). In individual patients, only REE and fT3 correlated to changes in body weight. Physical activity level did not change during treatment. Conclusion: In this study, treatment of hyperthyroidism was associated with marked increase in body weight in the patients. This increase correlated to a decrease in REE and only to a negligible extent to changes in energy efficiency and not at all to changes in physical activity level of daily living.

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The Teaching of Statistics in the Biological, Medical and Health Sciences: Some Comments and a Selected Bibliography

1990

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IntroductionSince 1975 when a committee of the American Statistical Amciat.ion (ASA) published guidelines for a core curriculum in medical and health sciences (American Statistical Association, 1975), there has been a renewed surge of interest in the teaching of statistics in medical and health sciences. For example, the 1975 and 1977 surveys on the teaching of biostatistics in medical schools showed that only two thirds of the U.S. and Canadian schools required some biostatistical instruction (we COLTON, 1975; REED, 1977). A n earlier survey by HO~KINS (1958) had revealed that nearly 70 percent of the medical schools required biostatistical instruction. In contraat, the results of a recent survey show that 90 percent of the responding medical schools are currently imparting biostatistical instruction, though there is a wide variation in the topics being covered (see DAWSON-SAWN- DERS et al., 1987).In the decade since the ASA committee report and the subsequent curriculum surveys, when a major purpose for teaching biostatistics was identified as developing shlls necessary to evaluate the medical literature critically, there has been renewed attention and greater emphasis on teaching statistical and adjunct skills necessary to manage and evaluate information, make decisions under uncertainty, and read the medical literature critically. For example, at an international conference, jointly sponsored by World Health Organization and Pakistan, several new guidelines were developed for teaching of statistics in the medical and health sciences in order to achieve the aforementioned goals (Bee LOWE, 1980). Furthermore, a recent panel report on the general professional education of the physicians (GPEP) made recommendations for an educational process providing ski& which assist students to be independent problem solvers and self-learners rather than imparting purely factual information. The report further emphasized that instruction in the basic sciences and clinical hsciplines be integrated in order to aid and enhance learning of scientific principles and their applications (MULLER, 1984).From the recent articles in the literature one can also discern new trends and MULVIHILL et al., 1980; and KRAtL et al., 1983). In addition, many more schools are now offering some instruction in medical decision analysis and the use of computers (see, e.g., ELSTEM, A. A. et al., 1985 ; Organization of Student Affairs, 1985). In many European countries some form of formal statistical teaching and education for medical students and physicians was initjated in the fifties. Presently, biostatistics, biomathematics, or medical statistics is a required discipline for all medical students in most of the European universities, including Austria, Federal Republic of Germany, and German Democratic Republic. However, there is a trend toward more medicine specific teaching in statistics; and in postgraduate medical teaching and training, many special topics in biostatistics play an important role in different didactic forms. In addition, m...

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On the use of statistical models of within-person variation in long-term studies of healthy individuals.

Cited by 30 publications

References 8 publications

Anabolic steroids in sport: biochemical, clinical and analytical perspectives

Anabolic steroids in sport: biochemical, clinical and analytical perspectives

Body Weight Changes in Hyperthyroidism: Timing and Possible Explanations during a One Year Repeated Measurement Study

The Teaching of Statistics in the Biological, Medical and Health Sciences: Some Comments and a Selected Bibliography

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