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PubMed2007

Physical activity and stomach cancer risk: the influence of intensity and timing during the lifetime.

Physical inactivity is linked to risk for cancers of the colon, breast, lung and endometrium, but few data exist on this association with stomach cancer. We evaluated the association between recreational physical activity and incident stomach cancer in a case-control study. The data yielded odds ratios suggestive of approximately 20-40% reduced risk of stomach cancer when comparing more frequent (3+ times/week) to less frequent (<1/month) strenuous activities. The magnitudes of the associations for strenuous physical activities were consistent across the teens, early 30s, and early 50s. Compared to the least active quartile, the second, third, and fourth quartiles of average lifetime strenuous physical activity yielded odds ratios of 0.82, 0.69, and 0.58 (95% CI, 0.41-0.83), respectively. Odds ratios for moderate activity generally suggested a modest, but not statistically significant, inverse association. Increased strenuous physical activity, throughout the lifespan, was associated with decreased risk of incident stomach cancer.

Adult↗
PubMed1996

The use and interpretation of the Friedman test in the analysis of ordinal-scale data in repeated measures designs.

The purpose of this paper is to review the use and interpretation of the Friedman two-way analysis of variance by ranks test for ordinal-level data in repeated measurement designs. Physical therapists frequently make three or more repeated measurements of the same individual to compare different treatments, or to assess the effect of a single treatment over time. When the measurements are ordinal-scaled, such as some ratings of functional status and muscle strength, statistical significance may be determined by the Friedman test. We illustrate the use of the Friedman test and a post hoc multiple comparison test with data from 27 subjects whose performance on a lifting task was rated on three occasions by use of an ordinal scale. We discuss the interpretation of ordinal-level data and recommend that therapists understand the limitations a measurement scale imposes on the inferences that can be made from these tests.

Analysis of Variance↗
PubMed1997

Physical and biological predictors of changes in whole-lung function following thoracic irradiation.

PURPOSE: To develop methods of predicting the pulmonary consequences of thoracic irradiation (RT) by prospectively studying changes in pulmonary function following RT. METHODS AND MATERIALS: 100 patients receiving incidental partial-lung irradiation during treatment of tumors in or adjacent to the thorax had whole-lung function assessed via symptoms and pulmonary function tests (PFTs: FEV1-forced expiratory volume 1 s; DLCO-diffusion capacity) before and repeatedly 6-48 months following RT. All had computed tomography-based three-dimensional (3D) dose calculations with lung density heterogeneity corrections for dose-volume histogram (DVH) and normal tissue complication probability (NTCP) calculations. Functional DVHs (DVfH) based on SPECT (single photon emission computed tomography) lung perfusion scans, and serial transforming growth factor-beta (TGF-beta1) levels were available in 50 and 48 patients, respectively. The incidence and severity of changes in whole-lung function were correlated with clinical, physical, and biological factors. Exploratory statistical analyses were performed using chi-square, Pearson correlations, logistic regression, and multiple linear regression. RESULTS: RT-induced symptoms developed in 21 patients. In the overall group, the single best predictor for the development of symptoms was the NTCP (p < 0.05). Pre-RT PFTs alone were less predictive (p = 0.1 for FEV1, p = 0.08 for DLCO). A multivariate model based on pre-RT DLCO and CT-based NTCP was strongly predictive for the development of symptoms (p < 0.001). NTCPs based on SPECT-derived DVf Hs and TGF-beta1 levels did not appear to provide additional predictive value. The presence or absence of pulmonary symptoms was correlated with the decline in PFT 6 months following RT (p < 0.05). In the overall group, the degree of decline in PFTs was not well correlated with any of the dose-volume variables considered. In patients with "good" pre-RT PFTs, there was a relationship between the percent reduction in PFT and dose-volume parameters such as the percent of lung volume receiving > 30 Gy (p < 0.05). CONCLUSION: The extent of alteration in whole-lung function (symptoms or PFT changes) appears to be related to both dose-volume and pre-RT PFT parameters. The data suggest that no one variable is likely to be an adequate predictor and that multivariate predictive models will be needed. Additional studies are underway to develop better predictive models that consider physical factors such as the DVH and regional perfusion, as well as biological/clinical factors such as pre-RT PFTs and TGF-beta1.

Adult↗
PubMed1994

A fast random cost algorithm for physical mapping.

Ordering clones from a genomic library into physical maps of whole chromosomes presents a central computational/statistical problem in genetics. Here we present a physical mapping algorithm for creating ordered genomic libraries or contig maps by using a random cost approach [Berg, A. (1993) Nature (London) 361, 708-710]. This random cost algorithm is 5-10 times faster than existing physical mapping algorithms and has optimization performance comparable to existing procedures. The speedup in the algorithm makes practical the widespread use of bootstrap resampling to assess the statistical reliability of links in the physical map as well as the use of more elaborate physical mapping criteria to improve map quality. The random cost algorithm is illustrated by its application in assembling a physical map of chromosome IV from the filamentous fungus Aspergillus nidulans.

Aspergillus nidulans↗
PubMed1993

The multidimensional structure of physical fitness: invariance over gender and age.

This investigation extends the factor analytic approach pioneered by Fleishman (1964) by incorporating subsequent developments in the application of confirmatory factor analysis and the physical fitness literature. Specifically, it tests the ability of an a priori factor structure of physical fitness to fit (i.e., account for) data based on 25 indicators of fitness (field exercises, technical measures, and laboratory measures) for 2,817 boys and girls aged 9, 12, and 15. An eight-factor (Cardiovascular Endurance, Explosive/Dynamic Strength, Static Strength, Flexibility/Joint Mobility, Blood Pressure, Lung Function, Body Girth, and Skinfold) model derived from previous research fit the data well for each of the six age/gender groups, considered separately. Based on tests of factorial invariance, factor loadings and factor correlations were reasonably invariant across the six groups. This important finding indicates that all 25 indicators are equally valid for boys and girls aged 9, 12, and 15 and that the multidimensional structure of physical fitness generalizes over gender and age.

Adolescent↗
PubMed1998

A survey of physics and dosimetry practice of permanent prostate brachytherapy in the United States.

PURPOSE: To obtain data with regard to current physics and dosimetry practice in transperineal interstitial permanent prostate brachytherapy (TIPPB) in the U.S. by conducting a survey of institutions performing this procedure with the greatest frequency. METHODS AND MATERIALS: Seventy brachytherapists with the greatest volume of TIPPB cases in 1995 in the U.S. were surveyed. The four-page comprehensive questionnaire included questions on both clinical and physics and dosimetry practice. Individuals not responding initially were sent additional mailings and telephoned. Physics and dosimetry practice summary statistics are reported. Clinical practice data is reported separately. RESULTS: Thirty-five (50%) surveys were returned. Participants included 29 (83%) from the private sector and 6 (17%) from academic programs. Among responding clinicians, 125I (89%) is used with greater frequency than 103Pd (83%). Many use both (71%). Most brachytherapists perform preplans (86%), predominately employing ultrasound imaging (85%). Commercial treatment planning systems are used more frequently (75%) than in-house systems (25%). Preplans take 2.5 h (avg.) to perform and are most commonly performed by a physicist (69%). A wide range of apparent activities (mCi) is used for both 125I (0.16-1.00, avg. 0.41) and 103Pd (0.50-1.90, avg. 1.32). Of those assaying sources (71%), the range in number assayed (1 to all) and maximum accepted difference from vendor stated activity (2-20%) varies greatly. Most respondents feel that the manufacturers criteria for source activity are sufficiently stringent (88%); however, some report that vendors do not always meet their criteria (44%). Most postimplant dosimetry imaging occurs on day 1 (41%) and consists of conventional x-rays (83%), CT (63%), or both (46%). Postimplant dosimetry is usually performed by a physicist (72%), taking 2 h (avg.) to complete. Calculational formalisms and parameters vary substantially. At the time of the survey, few institutions have adopted AAPM TG-43 recommendations (21%). Only half (50%) of those not using TG-43 indicated an intent to do so in the future. Calculated doses at 1 cm from a single 1 mCi apparent activity source permanently implanted varied significantly. For 125I, doses calculated ranged from 13.08-40.00 Gy and for 103Pd, from 3.10 to 8.70 Gy. CONCLUSION: While several areas of current physics and dosimetry practice are consistent among institutions, treatment planning and dose calculation techniques vary considerably. These data demonstrate a relative lack of consensus with regard to these practices. Furthermore, the wide variety of calculational techniques and benchmark data lead to calculated doses which vary by clinically significant amounts. It is apparent that the lack of standardization with regard to treatment planning and dose calculation practice in TIPPB must be addressed prior to performing any meaningful comparison of clinical results between institutions.

Brachytherapy↗
PubMed2000

The effect of aerobic exercise training on the lipid-lipoprotein profile of children and adolescents.

Longitudinal paediatric population studies have provided evidence that the risk factor theory may be extended to children and adolescents. These studies could assist in identifying individuals at increased coronary risk. Numerous studies have focused on the effects of regular exercise on the paediatric lipoprotein profile, a recognised primary risk factor, with equivocal results. Cross-sectional comparisons of dichotomised groups provide the strongest evidence of an exercise effect. 'Trained' or 'active' children and adolescents demonstrate 'favourable' levels of high density lipoprotein-cholesterol (HDL-C), triacylglycerol, total cholesterol (TC)/HDL-C and low density lipoprotein-cholesterol (LDL-C)/HDL-C, whilst TC is generally unaffected. The evidence regarding LDL-C in these studies is equivocal. A possible self-selection bias means that a cause-effect relationship between exercise and the lipoprotein profile cannot be readily established from this design. Correlational studies are difficult to interpret because of differences in participant characteristics, methods employed to assess peak oxygen uptake and habitual physical activity (HPA), and the statistical techniques used to analyse multivariate data. Directly measured cardiorespiratory fitness does not appear to be related to lipoprotein profiles in the children and adolescents studied to date, although there are data to the contrary. The relationship with HPA is more difficult to decipher. The evidence suggests that a 'favourable' lipoprotein profile may be related to higher levels of HPA, although differences in assessment methods preclude a definitive answer. While few prospective studies exist, the majority of these longitudinal investigations suggest that imposed regular exercise has little, if any, influence on the lipoprotein levels of children and adolescents. However, most prospective studies have several serious methodological design weaknesses, including low sample size, inadequate exercise training volume and a lack of control individuals. Recent studies have suggested that increases in HDL-C and reductions in LDL-C may be possible with regular exercise. The identification of a dose-response relationship between exercise training and the lipoprotein profile during the paediatric years remains elusive.

Adolescent↗
PubMed2005

The role of the MR-fluoroscopy in the diagnosis and staging of the pelvic organ prolapse.

INTRODUCTION: The aim of the study is to investigate the efficacy of the magnetic resonance fluoroscopy in the diagnosis and staging of the pelvic prolapse. MATERIALS AND METHODS: The study consisted of 46 patients who were known to have pelvic prolapses from their vaginal examination. Thirty women who underwent vaginal exam and shown not have pelvic prolapse were selected as a control group. Firstly, pelvic sagittal FSE T2 weighted images of all the women were acquired in 0.3 T open MR equipment than sagittal MR-fluoroscopic images using spoiled gradient echo sequences were obtained during pelvic strain. Physical examination and MR-fluoroscopic findings were compared. The relationship between the stages of prolapse established by both of the methods was evaluated statistically with Pearson's correlation analysis. RESULTS: Physical examination and MR findings were very concordant in the diagnosis of pelvic prolapse and statistical correlations in the stages of prolapse were established between both of the methods (P<0.01 for anterior and middle comportment, P<0.05 for posterior comportment). CONCLUSION: We conclude that MR-fluoroscopy is a non-invasive, easily applied, dynamic useful method without contrast agent in the diagnosis and staging of pelvic organ prolapse.

Adult↗
PubMed2005

Health-related quality of life in older adults with symptomatic hip and knee osteoarthritis: a comparison with matched healthy controls.

BACKGROUND AND AIMS: Health-related quality of life (HRQOL) assessment is receiving increasing attention as an outcome measure in osteoarthritis (OA). The aims of this study were to compare HRQOL among older adults aged 55 to 78 years with hip and/or knee OA with those without OA, and to assess the influence of selected variables (sex, body mass index, radiographic OA severity, educational level, comorbidities) on HRQOL. METHODS: The generic Medical Outcome Study Short Form-36 item health status questionnaire (SF-36) was administered to a cohort of 264 OA patients (105 with hip OA alone, 108 with knee OA alone, and 51 with both hip and knee OA) and 112 healthy controls. RESULTS: Compared with the healthy controls, OA of the lower extremities has a detrimental effect on the eight-scale profile score, as well as on physical and mental summary measures of the SF-36. The most striking impact was seen in the physical measures "physical functioning", "physical role" and "pain" (p<0.0001). No statistically significant differences in SF-36 scores were found among the three groups of OA patients. The physical and mental summary scales of the SF-36 were closely correlated (p<0.0001). One hundred and forty-five patients (54.9%) reported at least one chronic coexisting disease. There was a significant inverse association with measures of comorbidity (number of comorbidities and comorbidity index score) and both physical and mental summary scores of the SF-36 questionnaire. In patients with OA of the knee alone (but not in hip OA alone or hip and knee OA), the SF-36 pain score was inversely correlated with years of formal education (p=0.016). In addition, the impact of hip and knee SF-36 dimensions was not influenced by the degree of radiographic severity. CONCLUSIONS: Older adults with OA of the lower extremities undergo a significant impact on multiple dimensions of HRQOL, compared with healthy controls. The use of a generic measure of HRQOL such as the SF-36, in studies of OA where comorbidity is common, should be useful in characterizing the global burden of this disease.

Adult↗
PubMed2001

Educational level and decreases in leisure time physical activity: predictors from the longitudinal GLOBE study.

STUDY OBJECTIVE: This study describes educational differences in decreases in leisure time physical activity among an adult, physically active population and additionally attempts to identify predictors of these differences from information on health status and individual and environmental factors. DESIGN: Prospective population based study. Baseline measurement were carried out in 1991 and follow up in 1997. SETTING: South eastern part of the Netherlands. PARTICIPANTS: The study included 3793 subjects who were physically active in 1991 and who participated in the follow up. METHODS: Potential predictors of decreasing physical activity were measured in 1991. Logistic regression analyses were carried out for two age groups (< 45 years; > or = 45 years) separately. MAIN RESULTS: Lower educated respondents experienced statistically significant higher odds to decrease physical activity during follow up, compared with respondents with higher vocational schooling or a university degree. Perceived control was the main predictor of educational differences in decreasing physical activity in both age groups. In the older group, material problems and a poor perceived health experienced by lower educated people additionally predicted educational differences in decreases in physical activity during leisure time. CONCLUSIONS: These findings have important implications for health promotion practice and policy to prevent socioeconomic differences in physical inactivity and health. There is a need for evidence-based interventions that improve perceived control and reduce material problems in lower educated groups.

Adolescent↗
PubMed1999

Discrimination of the native from misfolded protein models with an energy function including implicit solvation.

An essential requirement for theoretical protein structure prediction is an energy function that can discriminate the native from non-native protein conformations. To date most of the energy functions used for this purpose have been extracted from a statistical analysis of the protein structure database, without explicit reference to the physical interactions responsible for protein stability. The use of the statistical functions has been supported by the widespread belief that they are superior for such discrimination to physics-based energy functions. An effective energy function which combined the CHARMM vacuum potential with a Gaussian model for the solvation free energy is tested for its ability to discriminate the native structure of a protein from misfolded conformations; the results are compared with those obtained with the vacuum CHARMM potential. The test is performed on several sets of misfolded structures prepared by others, including sets of about 650 good decoys for six proteins, as well as on misfolded structures of chymotrypsin inhibitor 2. The vacuum CHARMM potential is successful in most cases when energy minimized conformations are considered, but fails when applied to structures relaxed by molecular dynamics. With the effective energy function the native state is always more stable than grossly misfolded conformations both in energy minimized and molecular dynamics-relaxed structures. The present results suggest that molecular mechanics (physics-based) energy functions, complemented by a simple model for the solvation free energy, should be tested for use in the inverse folding problem, and supports their use in studies of the effective energy surface of proteins in solution. Moreover, the study suggests that the belief in the superiority of statistical functions for these purposes may be ill founded.

Models, Molecular↗
PubMedDate not supplied

Effect of physical exercise upon nystagmus and locomotor dysequilibrium after labyrinthectomy in experimental primates.

Spontaneous nystagmus and locomotor equilibrium function were repeatedly tested before and after unilateral labyrinthectomy in 12 squirrel monkeys in order to study the effect of physical exercise on the vestibulo-oculomotor and vestibulo-locomotor compensation. Post-operatively, 6 of the monkeys received forced physical exercise in the rotating cage, while the other 6 did not. The provocation of post-operative spontaneous nystagmus was less in the exercise group. The statistical studies showed a certain contribution of physical exercise toward the oculomotor balance compensation and maintenance, probably at the level of the brain stem. Statistical comparison of the locomotor equilibrium performance did not depict a significant difference between the exercise and non-exercise groups; however, there was a possibility that the present testing maneuver which involves physically advanced tasks might have concealed the effect of the physical exercise.

Animals↗
PubMed2004

Association of normative beliefs and anger with aggression and antisocial behavior in Russian male juvenile offenders and high school students.

Examined the association of anger experience and two types of normative beliefs with physical aggression and nonaggressive antisocial behavior in 361 juvenile offenders and 206 high school students in Russia. All participants were male and ranged in age from 14 to 18 years. Higher frequency of aggressive acts was significantly associated with higher levels of anger and stronger beliefs that physical aggression is an appropriate course of action in conflicts. After statistically controlling for nonaggressive antisocial behavior, the relationship between physical aggression and antisocial beliefs was not significant. Similarly, with physical aggression controlled, nonaggressive antisocial behavior was uniquely associated with approval of deviancy, but not with anger or beliefs legitimizing aggression. Juvenile offenders reported higher levels of anger experience and higher frequency of aggression and antisocial behavior compared to high school students. There were no differences in normative beliefs between these two groups. This specificity of association of social-cognitive and emotion-regulation processes to aggressive and nonaggressive forms of antisocial behavior may be relevant to understanding the mechanisms of cognitive-behavioral therapy for conduct disorder and antisocial behavior.

Adolescent↗
PubMed1983

The effect of physical conditioning on serum lipids and lipoproteins in white male adolescents.

This study was designed to measure the effect of physical conditioning on the serum lipid and lipoprotein levels of white male adolescents. Fifty white males, ages 11-17 yr, underwent pre-test evaluations including physical measurements, physical activity levels, nutritional intake, physical working capacity, and fasting serum lipid and lipoprotein levels. Each subject was randomly assigned to a physical conditioning group or to a control group. There were no statistically significant differences in pre-test measurements. The physical conditioning group participated in an 8-wk progressive aerobic exercise program 30 min/d for 4 d each wk. The pre-test measurements were then repeated for both groups. Based on Student's t-test, the physical conditioning group had a significantly higher physical working capacity on the post-test than the control group. An analysis of covariance test showed no differences between the groups in the post-test serum lipid and lipoprotein levels. The results suggested that although the exercise program was strenuous enough to increase significantly the physical working capacity of the exercise group, it did not alter their serum lipid and lipoprotein levels during the 8-wk period.

Adolescent↗
PubMed1992

Relationship of glucose intolerance and hyperinsulinaemia to body fat pattern in south Asians and Europeans.

Type 2 (non-insulin-dependent) diabetes mellitus and insulin resistance are associated with centrally-distributed obesity. These disturbances are especially prevalent in people of South Asian (Indian, Pakistani and Bangladeshi) descent. We examined the relationship of glucose intolerance to body fat pattern in a population survey of 2936 men and 537 women of South Asian and European origin living in London, UK. In both groups glucose intolerance (defined as diabetes or impaired glucose tolerance) was more strongly associated with waist-hip girth ratio than with skinfolds or body mass index. The associations between body mass index and glucose intolerance were fully accounted for by waist-hip ratio. In European men with normal glucose tolerance fasting insulin levels were more strongly correlated with body mass index than with waist-hip ratio. Physical activity scores were lower in South Asians than in Europeans but no statistically significant associations between glucose intolerance and low physical activity were detectable. Leisure-time physical activity scores were inversely correlated with 2 h insulin levels in both groups. In contrast with other studies these results suggest that a specific effect of intra-abdominal fat deposition underlies the association between glucose intolerance and obesity. The association between hyperinsulinaemia and obesity is less specific for centrally-distributed fat. When measured appropriately waist-hip ratio is the most valid anthropometric index for identifying individuals whose obesity predisposes them to glucose intolerance.

Adipose Tissue↗
PubMedDate not supplied

Risk factors of stroke mortality: a 40-year follow-up of the Corfu cohort from the Seven-Countries Study.

The present work evaluates several risk factors for stroke mortality based on a 40-year follow-up of the Corfu cohort from the Seven-Countries Study. The population studied in this analysis consisted of 529 rural men (49.7 +/- 5.7 years old) enrolled at 1961. The death rate at the end of follow-up was 87.1% (i.e. 461 deaths out of 529 participants). Of 529 cardiovascular-disease-free men at entry, 74 (14%) died because of hemorrhagic or thrombotic stroke. Age (HR=1.11/year, p<0.001), pulse pressure (HR=1.16/5 mm Hg, p<0.001), total serum cholesterol levels (HR=0.81/10 mg/dl, p<0.01) and presence of physical activity (HR=0.59, p<0.05), showed a statistically significant association with fatal stroke events. In conclusion, age, pulse pressure levels, physical activity (protective) and total serum cholesterol levels (protective) were significantly related with 40-year stroke mortality.

Adult↗