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The significance of routine radiographic findings with respect to subsequent racing performance and longevity in standardbred trotters.

A retrospective cohort study was made of the racing performance of trotters which had been subjected routinely to radiography before they started training and racing. Sixty-one per cent (148) of the 243 horses, foaled in 3 consecutive years, had one or more abnormal findings categorised into 5 relevant groups based on radiography, of which osteochondrosis (OCD) was the most specific diagnosis. Parameters used to reflect racing performance were: proportion of horses starting in races, number of starts per year, earnings per year, earnings per start and racing longevity. No significant association between the presence or type of radiological abnormalities and the subsequent performance and longevity could be found. Horses with multiple lesions, however, had a tendency to lower earnings and poorer survival than horses with single lesions.

Animals↗

Metabolic responses to submaximal field exercise tests and relationships with racing performance in pacing Standardbreds.

This study was undertaken to invesigate the application of submaximal field tests in assessment of performance. A submaximal field exercise test consisting of 2 bouts of pacing for 1600 m, with 5 min rest or walking between runs was performed on Standardbred racehorses at 2 training centres (A and B). Performance indices were compiled for each horse: number of race starts, number of race wins, number of race placings (1, 2 or 3), and lifetime earnings. Regression analysis was conducted to describe the relationship between plasma lactate concentrations and speed for tests one, 2 and pooled results. Using the regression equation, observed (measured) minus expected (predicted) (O-E) lactate concentrations for tests were calculated and plotted against performance indices to determine their relationship. For stables A and B the association between lactate and velocity for the 2 runs was best described by the exponential equations: y = 0.0014(e07306x) (r2 = 0.54, P<0.001) and y = 0.002(e06812x) (r2 = 0.42, P<0.001), respectively, where y is lactate concentration (mmol/l) and x is speed (m/s). For the pooled results for heat 1 and heat 2 for stables A and B the relationship between lactate and velocity was best described by an exponential equation y = 0.0016(e07117x) (r2 = 0.47, P<0.001). This study found no relationship between (O-E) and performance indices (number of race wins, number of race placings, lifetime earnings and average $/start) at stables A or B for test run 1, 2 or pooled lactates. At stable A, there was a significant association between V(La4) and log lifetime earnings (r = 0.51, P = 0.053) and log average $/start (r = 0.54, P = 0.036). There were no significant correlations at stable B. In conclusion a 2-step determination method of V(La4) is a possible means for studying limits to performance in pacing Standardbred racehorses.

Animals↗

Case study of training, fitness, and nourishment of a dog driver during the Iditarod 1049-mile dogsled race.

The purpose of the present case study was threefold: (a) to estimate intake and expenditure of a dog driver (musher) while participating in the Iditarod, (b) to determine the hydration status of the musher at the completion of the event, and (c) to evaluate training related changes in aerobic capacity and body composition of a long-distance dog sled driver in preparation for and following completion of a 1049-mile (1692-km) sled dog race. Actual energy intake during the Iditarod Sled Dog Race was estimated at 8,921 kilojoules (kJ) per day. Nutrient intake expressed as percentage kJ of total energy (14%, 44% and 42% for protein, carbohydrates, and fat, respectively). Weight loss of .72 kg of body weight indicated an energy deficit of 1819 kJ per day during the race. Total energy needs per day were calculated to be 10,740 kJ/day. An increase in hematocrit and hemoglobin during the race may indicate dehydration during the event. There was an improvement in aerobic fitness during on-snow training as determined by ventilatory threshold and VO2peak data. Fat-free mass was maintained during training (46.4 kg), with a concomitant decrease in fat (2.4 kg). Fat-free mass was also maintained during the 12-day race.

Alaska↗

Left ventricular chamber size predicts the race time of Japanese participants in a 100 km ultramarathon.

OBJECTIVE: As a subanalysis of an echocardiographic study performed on 291 Japanese participants in a 100 km ultramarathon, to estimate predictors of race time. METHODS: A total of 247 male participants in a 100 km ultramarathon (age 20-73 years) were examined by echocardiography. Correlations between age, body surface area, monthly running distance, or echocardiographic variables and the race time were examined. RESULTS: According to simple regression analysis, age (r = 0.299, p < 0.0001), monthly running distance (r = -0.388, p < 0.0001), left ventricular end diastolic diameter (r = -0.300, p < 0.0001), and left ventricular end systolic diameter (r = -0.325, p < 0.0001) correlated significantly with the race time. When multiple regression analysis was performed, age (f = 2.364), monthly running distance (f = -0.113), and left ventricular end systolic diameter (f = -2.361) remained significant predictors of the race time. CONCLUSION: Left ventricular diameter predicts the race time for a 100 km ultramarathon, in addition to age and amount of training.

Adult↗

Marathon finishers and pre-race drop-outs.

The purpose of this longitudinal questionnaire study was to investigate the effects of participation or non participation in a marathon race on future running behaviour. The majority (70 per cent) of the participants who intended to run a future marathon actually did so and only 11 per cent stopped running altogether. Fewer of the pre-race drop-outs (31 per cent) who indicated their intention to run a future marathon actually did so (P less than 0.001) and more of them (24 per cent) stopped running altogether (P less than 0.001) compared with the runners in the finishers' sample. These results suggest that the experience of running in a marathon does not negatively influence future running habits. However, failure to run in a race for which an entry has been made may lead to a reduced involvement in running. The present study also examined the reasons for pre-race drop-out. Injury (36 per cent), lack of training (31 per cent) and illness (12 per cent) were the most frequently given reasons for drop-out. Few differences were found between the pre-race drop-outs and the finishers, but the drop-outs did feel that running was less important (P less than 0.001), reported a greater number of longer term injuries (P less than 0.001) and did significantly less training (P less than 0.001) than the finishers.

Adult↗

Prediction of drafted-triathlon race time from submaximal laboratory testing in elite triathletes.

PURPOSE AND METHODS: To determine which physiological variables accurately predict the race time of an Olympic-distance International Triathlon undertaken in drafted conditions, 8 elite triathletes underwent both maximal and submaximal laboratory and field physiological testing: a 400-m maximal swim test; an incremental treadmill test; an incremental cycling test; 30 min of cycling followed by 20 min of running (C-R); and 20 min of control running (R) at the exact same speed variations as in running in C-R. Blood samples were drawn to measure venous lactate concentration after the 400-m swim and the cycle and run segments of C-R. During the maximal cycling and running exercises, data were collected using an automated breath-by-breath system. RESULTS: The only parameters correlated with the overall drafted-triathlon time were lactate concentration noted at the end of the cycle segment (r = 0.83, p < 0. 05) and the distance covered during the running part of the submaximal C-R test (r = 0.92, p < 0. 01). Stepwise multiple regression analysis revealed a highly significant (r = 0.96, p < 0.02) relationship between predicted race time (from laboratory measures) and actual race time, using the following calculation: Predicted Triathlon Time (s) = 1.128 (distance covered during R of C-R [m]) + 38.8 ([lactate] at the end of C in C-R) + 13,338. The high R2 value of 0.93 indicated that, taken together, these two laboratory measures could account for 93% of the variance in race times during a drafted triathlon. CONCLUSION: Complementing previous studies, this study demonstrates that different parameters seem to be reliable for predicting performance in drafted vs. nondrafted Olympic-triathlon races. It also demonstrates that, for elite triathletes competing in a drafted Olympic-distance triathlon, performance is accurately predicted from the results of submaximal laboratory measures.

Adult↗

Immune alterations, lipid peroxidation, and muscle damage following a hill race.

Hill races usually include large downhill running sections, which can induce significant degrees of muscle damage in a field setting. This study examined the link between muscle damage, oxidative stress, and immune perturbations following a 7-km mountainous hill race with 457 m of ascent and 457 m of descent. Venous blood samples were taken from 7 club level runners before, immediately after, and 48 hrs postrace. Samples were analysed for total and differential leukocyte counts, markers of muscle damage (CK), lipid peroxidation (MDA), and acute phase proteins (CRP; fibrinogen; alpha-1-ACT). The total antioxidant status (TEAC) and plasma levels of the proinflammatory cytokines IL-6, IL-8, and TNF-alpha were also determined. Subjective pain reports, and plasma activities of CK, MDA, and circulatory monocytes reached peak values at 48 hrs postrace (p < 0.05). TEAC and the cytokine IL-8 increased immediately after the race (p < 0.05). Plasma TNF-alpha remained unchanged (p > 0.05). Despite the reports of muscle damage and soreness, no evidence of an acute phase response was observed (p > 0.05), which may be explained by the failure of the race to induce a plasma TNF-alpha response. Future studies should examine the link between muscle damage, oxidative stress, and the acute phase response following hill races of longer duration with larger eccentric components.

Acute-Phase Proteins↗

Examining population stratification via individual ancestry estimates versus self-reported race.

Population stratification has the potential to affect the results of genetic marker studies. Estimating individual ancestry provides a continuous measure to assess population structure in case-control studies of complex disease, instead of using self-reported racial groups. We estimate individual ancestry using the Federal Bureau of Investigation CODIS Core short tandem repeat set of 13 loci using two different analysis methods in a case-control study of early-onset lung cancer. Individual ancestry proportions were estimated for "European" and "West African" groups using published allele frequencies. The majority of Caucasian, non-Hispanics had >50% European ancestry, whereas the majority of African Americans had <20% European ancestry, regardless of ancestry estimation method, although significant overlap by self-reported race and ancestry also existed. When we further investigated the effect of ancestry and self-reported race on the frequency of a lung cancer risk genotype, we found that the frequency of the GSTM1 null genotype varies by individual European ancestry and case-control status within self-reported race (particularly for African Americans). Genetic risk models showed that adjusting for individual European ancestry provided a better fit to the data compared with the model with no group adjustment or adjustment for self-reported race. This study suggests that significant population substructure differences exist that self-reported race alone does not capture and that individual ancestry may be confounded with disease status and/or a candidate gene risk genotype.

Black People↗

Influence of age, anatomic site and race on skin roughness and scaliness.

BACKGROUND: Variations in skin roughness and scaliness between age groups, anatomic sites and race have been assumed but minimally quantified. OBJECTIVE: We quantitatively investigated skin roughness, scaliness and stratum corneum hydration as a function of age, anatomic site and race (white and black). METHODS: Skin roughness, scaliness and stratum corneum hydration were determined in vivo by noninvasive bioengineering and image analysis techniques in 22 female subjects grouped according to age (young and aged) and race (white and black). RESULTS: Skin roughness, scaliness and stratum corneum hydration varied significantly in different anatomic areas and age groups. There was no racial variation in skin hydration between any anatomic site, nor significant differences in roughness and scaliness between races, except for the preauricular area. Skin roughness was significantly increased in the aged, compared to the young at the preauricle, volar forearm, lower back, thigh and lower leg. Older women demonstrated significantly more scaling at the preauricle than younger women. Stratum corneum hydration correlated with scaliness. No significant correlation between stratum corneum hydration and skin roughness was observed. CONCLUSION: Age and anatomic site but not race demonstrated a significant influence on skin roughness and scaliness. The desquamation index appears a good indicator of the status of stratum corneum hydration.

Adult↗

Fission or fusion? Mitochondrial DNA phylogenetics of the chromosome races of Hemideina crassidens (Orthoptera: Anostostomatidae).

The weta Hemideina crassidens has two chromosomal races that differ by two centric fusions or fissions. The mitochondrial DNA of weta from both chromosomal races and a sister species were sequenced for a 750-bp region of the gene coding for cytochrome oxidase I. The average pairwise genetic distance among the 15 (XO)-chromosome race weta was almost four times greater than the average distance among the 19 (XO)-chromosome race weta. The weta from the 19-chromosome race formed a well-supported monophyletic clade in all shortest maximum parsimony trees. Maximum likelihood and neighbor-joining trees suggested that the 15-chromosome karyotype was paraphyletic with respect to the 19-chromosome karyotype, but this was not supported by maximum parsimony analyses. Although phylogenetic analysis could not exclude chromosome fusion as the rearrangement responsible for the karyotype differentiation, the level of sequence variation and pattern of distribution appear to implicate fission as the more likely event.

Animals↗

Race and cardiovascular reactivity. A neglected relationship.

The magnitude of the cardiovascular response to stress has been implicated in the pathogenesis of cardiovascular disease. Psychological stress procedures have received increased usage as an alternative to expensive physical (exercise) stress procedures. In the present investigation, 213 healthy, black or white, male or female children between the ages of 6 and 18 years were exposed to the psychological stress of a video game. The video game challenge was administered by a black or a white experimenter and was played under three levels of increasing stress, 1) personal challenge, 2) experimenter's challenge, and 3) experimenter's challenge accompanied by a financial incentive, while blood pressure and heart rate were monitored. Results indicated that the video games provoked significant and incremental cardiovascular reactivity across the games. Black children demonstrated significantly greater reactivity than white children; the racial difference was more reliably observed for systolic and diastolic blood pressure than for heart rate. Furthermore, the race of the experimenter exerted a significant effect and often interacted with the race of the child, such that greater reactivity occurred in same-race pairings than in mixed-race pairings. These results suggest that reactivity is affected by an individual's race and social milieu and that reactivity may be one mechanism responsible for the greater prevalence of hypertension among blacks.

Adolescent↗

Race-ethnic disparities in the impact of stroke risk factors: the northern Manhattan stroke study.

BACKGROUND AND PURPOSE: Stroke risk factors have been determined in large part through epidemiological studies in white cohorts; as a result, race-ethnic disparities in stroke incidence and mortality rates remained unexplained. The aim in the present study was to compare the prevalence, OR, and etiological fraction (EF) of stroke risk factors among white, blacks, and Caribbean Hispanics living in the same urban community of northern Manhattan. METHODS: In this population-based incident case-control study, cases (n=688) of first ischemic stroke were prospectively matched 1:2 by age, sex, and race-ethnicity with community controls (n=1156). Risk factors were determined through in-person assessment. Conditional logistic regression was used to calculate adjusted ORs in each race-ethnic group. Prevalence and multivariate EFs were determined in each race-ethnic group. RESULTS: Hypertension was an independent risk factor for whites (OR 1.8, EF 25%), blacks (OR 2.0, EF 37%), and Caribbean Hispanics (OR 2.1, EF 32%), but greater prevalence led to elevated EFs among blacks and Caribbean Hispanics. Greater prevalence rates of diabetes increased stroke risk in blacks (OR 1.8, EF 14%) and Caribbean Hispanics (OR 2.1 P<0.05, EF 10%) compared with whites (OR 1.0, EF 0%), whereas atrial fibrillation had a greater prevalence and EF for whites (OR 4.4, EF 20%) compared with blacks (OR 1.7, EF 3%) and Caribbean Hispanics (OR 3.0, EF 2%). Coronary artery disease was most important for whites (OR 1.3, EF 16%), followed by Caribbean Hispanics (OR 1.5, EF 6%) and then blacks (OR 1.1, EF 2%). Prevalence of physical inactivity was greater in Caribbean Hispanics, but an elevated EF was found in all groups. CONCLUSIONS: The prevalence, OR, and EF for stroke risk factors vary by race-ethnicity. These differences are crucial to the etiology of stroke, as well as to the design and implementation of stroke prevention programs.

Aged↗

Effects of race and hypertension on flow-mediated and nitroglycerin-mediated dilation of the brachial artery.

Black Americans have increased morbidity and mortality rates from cardiovascular disease, greater prevalence of hypertension, and altered responses to vasodilator medications compared with those of white Americans. Hypertension and black race have been linked to impaired vascular function in the microcirculation. To examine these effects and their interaction in the conduit vasculature, we examined vasomotor responses of the brachial artery by using high-resolution vascular ultrasound in 228 subjects (48% hypertensive, 54% black). Subjects had no history of diabetes mellitus and were matched for age and gender. Flow-mediated dilation (8.5+/-5.3% versus 11.7+/-6.3%, P<0.001) and nitroglycerin-mediated vasodilation (14.9+/-6.0 versus 18.5+/-7.8, P=0.003) were both impaired in hypertensive compared with normotensive individuals. Multivariate analysis identified higher systolic blood pressure (P=0.003) and larger baseline vessel (P<0.001) size as independent predictors of lower flow-mediated dilation. Race did not significantly influence flow-mediated dilation. In contrast, blacks had a greater vasodilator response to nitroglycerin compared with whites (17.7+/-7.5% versus 15.0+/-6.2%, respectively; P=0.02). By multivariate analysis, black race (P=0.004), smaller vessel size (P=0.001), lower serum glucose (P=0.02), lower systolic blood pressure (P=0.02), and lower serum total cholesterol (P=0.04) were independent predictors of higher nitroglycerin-mediated dilation. Thus, hypertension is associated with impaired NO-mediated vasodilation in the conduit brachial artery. Overall, race did not influence flow-mediated dilation, but black race was associated with an enhanced response to sublingual nitroglycerin. This later observation provides further evidence of racial differences in the responses to medical therapy that may be relevant to the treatment of patients with cardiovascular disease.

Adult↗

Failure of an ointment based on IR3535 (ethyl butylacetylaminopropionate) to prevent an outbreak of cercarial dermatitis during swimming races across Lake Annecy, France.

Cercarial dermatitis, a re-emerging disease world-wide, may affect those engaged in water sports. Many of those who swim in the annual cross-lake races at Annecy in France, for example, develop such dermatitis. In an attempt to see whether ethyl butylacetylaminopropionate (IR3535) would protect swimmers from the dermatitis, the exposed skin on the right side of each of 78 participants in the cross-lake races of 2001 was treated with IR3535-based ointment. When contacted by telephone during the week following the races, 64 (82%) of the subjects reported that they had developed cercarial dermatitis. Subjects with a past history of cercarial dermatitis were more likely to report an attack in 2001 than those who said that they had never had such dermatitis prior to 2001 (P=0.001). The skin lesions were scattered all over the body in 89% of the cases and limited to the left side of the body in 11%. Of the 63 cases who reported time of onset, 32 (51%) had noticed lesions within an hour of the race. The mean duration of clinical manifestations was 4.8 days (range=30 min-18 days). The clinical manifestations were significantly more severe in the subjects aged >16 years than in the younger subjects, although these two age-groups swam in separate races. Thirty-one of the affected subjects attempted to cure their dermatitis, using any of five different treatments. Overall, the results were disappointing, with the IR3535-based ointment, which had initially been developed as an insect repellent, appearing to offer little, if any, protection against cercarial dermatitis.

Adolescent↗

Infiltrating ductal carcinoma of the breast: the survival impact of race.

PURPOSE: Breast cancer has a poorer prognosis among black women than among white women. This review was conducted to determine whether this disparity reflects the direct impact of race on likelihood of cure or on time to death from breast cancer or stems from the interaction of race with tumor stage and patient age. PATIENTS AND METHODS: We analyzed data from 115,838 patients with localized (node-negative) and regionally metastatic (node-positive) breast cancer from the Surveillance, Epidemiology, and End-Results (SEER) Program of the National Cancer Institute. Parametric analysis was used to determine the independent prognostic value of age, stage, and race. Linear regression and distribution analyses were also used to examine the interaction of these covariates. RESULTS: The prevalence of regionally metastatic disease, relative to localized disease, declined with increased age among white patients and those classified as "other," but remained relatively constant among black patients. Parametric analysis showed a smaller cured fraction and shorter time to death when patients with regional disease were compared with those with localized disease. A similar disparity was found when black patients were compared with those classified as white or other. CONCLUSION: Age and race have a significant association with tumor stage. In addition, our data show that race has an independent impact on the clinical course of breast cancer and diminishes both the likelihood of cure and time to death among uncured patients.

Adult↗

The biological concept of race and its application to public health and epidemiology.

The category of race is widely used in public health. Although its significance may be clear-cut in some practical situations, an adequate theoretical construct for the concept of race does not exist. Public health appears to lag far behind the other biological sciences in the effort to grapple with the idea of race and its implications for the nature-nurture question. This paper outlines the current anthropological and social perspective on race, and applies this view to problems of disease epidemiology. It is proposed that uncritical use of the traditional biological concept of race has distorted etiological thinking in public health and has proven an obstacle in the development of effective intervention strategies. The pragmatism of medicine and its isolation from social science may account for much of this backwardness.

Cultural Characteristics↗

Effect of race and musculoskeletal development on the accuracy of air plethysmography.

PURPOSE: The purpose of this study was to determine the effect of race and musculoskeletal development on the accuracy of estimates of body fatness (%fat) via air displacement plethysmography (AP). METHODS: Estimates of %fat were made via AP, hydrostatic weighing (HW), dual-energy x-ray absorptiometry (DXA), and the criterion, a four-component model (4C) in 64 black (B) and white (W) men, who were either resistance trained (RT) or served as controls (C). RESULTS: Based on a three-way ANOVA, there were no statistically significant three-way or race x musculoskeletal development interactions. There was no main effect of race on the validity of estimating %fat by AP; the mean bias between %FatAP and %Fat4C was similar for B (3.6% body fat) and W (3.7%). In addition, the density of the fat-free mass (Dffm) for B (1.098 +/- 0.002 g x mL) was not different than 1.10 g x mL. There was a significant effect of musculoskeletal development on the validity of the estimation of %fat from AP; the mean difference in %fat between %FatAP and %Fat4C was less in RT (1.5% body fat) than in C (5.3%), but a large SEE of 5.5% was observed for RT. A significant (P < 0.05) correlation was found between the mean bias between methods and body volume (-0.44) and mesomorphy (-0.55). CONCLUSIONS: Race does not affect the accuracy of estimating %fat by AP. Race-specific equations estimating %fat via densitometry (e.g., AP, HW) such as the Schutte are not justified, because Dffm is not greater than 1.10 g x mL. Estimation of %fat via AP is more accurate in larger individuals with high musculoskeletal development as a group, but individual results are highly variable.

Absorptiometry, Photon↗

Race and sex effects on the association between muscle strength, soft tissue, and bone mineral density in healthy elders: the Health, Aging, and Body Composition Study.

Two factors generally reported to influence bone density are body composition and muscle strength. However, it is unclear if these relationships are consistent across race and sex, especially in older persons. If differences do exist by race and/or sex, then strategies to maintain bone mass or minimize bone loss in older adults may need to be modified accordingly. Therefore, we examined the independent effects of bone mineral-free lean mass (LM), fat mass (FM), and muscle strength on regional and whole body bone mineral density (BMD) in a cohort of 2,619 well-functioning older adults participating in the Health, Aging, and Body Composition (Health ABC) Study with complete measures. Participants included 738 white women, 599 black women, 827 white men, and 455 black men aged 70-79 years. BMD (g/cm2) of the femoral neck, whole body, upper and lower limb, and whole body and upper limb bone mineral-free LM and FM was assessed by dual-energy X-ray absorptiometry (DXA). Handgrip strength and knee extensor torque were determined by dynamometry. In analyses stratified by race and sex and adjusted for a number of confounders, LM was a significant (p < 0.001) determinant of BMD, except in white women for the lower limb and whole body. In women, FM also was an independent contributor to BMD at the femoral neck, and both FM and muscle strength contributed to limb BMD. The following were the respective beta-weights (regression coefficients for standardized data, Std beta) and percent difference in BMD per unit (7.5 kg) LM: femoral neck, 0.202-0.386 and 4.7-5.9%; lower limb, 0.209-0.357 and 2.9-3.5%; whole body, 0.239-0.484 and 3.0-4.7%; and upper limb (unit = 0.5 kg), 0.231-0.407 and 3.1-3.4%. Adjusting for bone size (bone mineral apparent density [BMAD]) or body size BMD/height) diminished the importance of LM, and the contributory effect of FM became more pronounced. These results indicate that LM and FM were associated with bone mineral depending on the bone site and bone index used. Where differences did occur, they were primarily by sex not race. To preserve BMD, maintaining or increasing LM in the elderly would appear to be an appropriate strategy, regardless of race or sex.

Absorptiometry, Photon↗