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Left ventricle systolic volume in vasovagal syncope patients.

One of the hypotheses put forward concerning the mechanism of vasovagal syncope is that the vagal afferent fibres are activated during vigorous contractions against a partly empty left ventricle. The aim of the study was to confirm this hypothesis by using 2D echocardiography during a head-up tilt test. The study was carried out on 39 patients (17 male, 22 female, age range 21-64 years), all with a history of recurrent syncope. The patients were examined using a 2D echo to measure the end-diastolic and end-systolic volume before the head-up tilt test after the Westminster protocol (45 min/60 grade) and every five minutes after tilting. T patients during head-up tilt test had a positive response and 32 proved negative. A reduction of both the end-diastolic and end-systolic volumes of the left ventricle was noticed. There was no significant difference in the degree of ejection fraction reduction. The difference in ejection fraction reduction between the two groups was similarly non-significant. It was also noticed that the patients with a positive response had more vigorous contractions than those with a negative test. The decision was therefore taken to use a different parameter for the left ventricle contraction, namely the LV posterior wall slope. As this parameter is partly dependent on time, its use in confirming the extremely vigorous nature of the contractions was considered appropriate. Only 6 patients were tested using this parameter. A tendency towards greater left ventricle posterior wall slope values, both before and during tilting was noticed in the group of patients with vasovagal reaction. Our data shows that vigorous contraction is probably less responsible for vasovagal syncope release than left ventricle volume reduction.

Adult↗

Prediction of activity energy expenditure using accelerometers in children.

PURPOSE: To validate two accelerometer-based activity monitors as measures of children's physical activity using energy expenditure as the criterion measure. METHODS: Actiwatch (AW) and Actical (AC) activity monitors were validated against continuous 4-h measurements of energy expenditure (EE) in a respiratory room calorimeter and 1-h measurements in an exercise laboratory using a portable calorimeter and treadmill in 32 children, ages 7-18 yr. The children performed structured activities including basal metabolic rate (BMR), playing Nintendo, using a computer, cleaning, aerobic exercise, ball toss, treadmill walking, and running. Equations were developed to predict activity energy expenditure (AEE = EE - BMR), and physical activity ratio (PAR = EE/BMR) from a power function of AW or AC, and age, sex, weight, and height. Thresholds were determined to categorize sedentary, light, moderate, and vigorous levels of physical activity. RESULTS: Activity counts accounted for the majority of the variability in AEE and PAR, with small contributions of age, sex, weight, and height. Overall, AW equations accounted for 76-79% and AC equations accounted for 81% of the variability in AEE and PAR. Relatively wide 95% prediction intervals suggest the accelerometers are best applied to groups rather than individuals. Sensitivities were higher for the vigorous threshold (97%) than the other thresholds (86-92%). Specificities were on the order of 66-73%. The positive predictive values for sedentary, light, moderate, and vigorous categories were 80, 66, 69, and 74% for AW, respectively, and 81, 68, 72, 74% for AC, respectively. CONCLUSION: Both accelerometer-based activity monitors provided valid measures of children's AEE and PAR, and can be used to discriminate sedentary, light, moderate, and vigorous levels of physical activity but require further development to accurately predict AEE and PAR of individuals.

Adolescent↗

[Relationship between physical activity and metabolic syndrome].

OBJECTIVE: To investigate the relationship between physical activity and metabolic syndrome (MS). METHODS: A multi-stage stratified cluster sampling was conducted in 132 sampling 218,920 residents, aged 44.3 +/- 15.3 (15 - 96), in the 31 provinces, autonomous regions, and municipalities of the mainland China according to the program of the National Nutrition and Health Survey. Questionnaire survey, interview, physical examination, measurement of biochemical indices, and dietary investigation were done. Information of physical activity and measurement of fasting glucose and/or glucose 2 hours after meal, blood pressure, triglycerides, high-density lipoprotein cholesterol were obtained in 50,494 participants. Metabolic syndrome was defined according to the Chinese Medical Association's definition. The intensity of physical activity was divided into 3 categories according to the Center for Disease Control and Prevention of US/American College of Sports Medicine criteria. RESULTS: 50,495 subjects, 23,932 males (47.4%) and 26,562 females (52.6%), were diagnosed as with MS. The MS incidence of those with high intensity of physical activity was lower by 60% in comparison with those with low intensity of physical activity (odds ratio 0.60, 95% CI: 0.362 - 0.443) adjusted for age, sex, smoking, and alcohol intake. The risk of MS in those with moderate intensity of physical activity of 151 - 300 minutes/week was slightly decreased compared to those with moderate intensity of physical activity of 90 - 150 minutes/week, (odds ratio 0.935, 95% CI: 0.685 - 1.277), however, the risk of MS in those with the moderate intensity of physical activity over 300 minutes/week increased slightly (OR = 1.269, 95% CI: 0.923 - 1.745). The risk of MS in those with low-level physical activity of 301 - 420 minutes/week was lower by 35% in comparison with those with the low-level physical activity of 90 - 150 minutes/week (95% CI: 0.451 - 0.933), however, the risk of MS in those with the low-level physical activity over 420 minutes/week was 0.871, not significantly different from that of the subjects with the low-level physical activity of other intensity (odd ratio = 0.871, 95% CI: 0.643 - 1.181). The risk of MS of those with the vigorous physical activity odds rations for having MS of vigorous activity over 150 minutes/week was 0.757, lower by 25% in comparison with those with the vigorous physical activity of 10 - 60 minutes/week (95% CI: 0.603 - 0.951), adjusted for sex, age, smoking, alcohol intake and BMI. CONCLUSION: MS risk can be decreased by low level physical activity of 300 - 420 minutes/week, moderate physical activity of 90 - 300 minutes/week and vigorous physical activity of over 150 minutes/week.

Adolescent↗

The Behavioral Risk Factor Surveys: IV. The descriptive epidemiology of exercise.

Telephone interview data from aggregated state surveys showed that about 21 percent of the U.S. adult population expends greater than or equal to 3 kcal/kg-day in vigorous leisure-time exercise. Three kilocalories per kilogram-day is equivalent to the amount commonly recommended to maximally reduce the incidence of coronary heart disease. Approximately 36 percent of the U.S. population reported no vigorous leisure-time exercise. Men, younger persons, and the more highly educated were most likely to expend greater than or equal to 3 kcal/kg-day, but for no subgroup did the rate exceed 30 percent. People who did not smoke, were not obese, and who did wear seat belts are also more likely to expend energy in vigorous leisure-time exercise. The prevalence of alcohol misuse is similar for all exercise categories. The proportion of people who expend greater than or equal to 3 kcal/kg-day is unrelated to self-reported occupational physical effort. Given the established and presumed benefits of physical activity, a substantial portion of the U.S. population would probably benefit from regular, vigorous, leisure-time exercise.

Adolescent↗

Tumoricidal macrophages isolated from liver granulomas of Schistosoma mansoni-infected mice.

In murine schistosomiasis, inflammatory macrophages (M phi) are a major cell type of the granulomata that encase eggs of the tropical helminth Schistosoma mansoni as they are deposited in the liver by adult worm pairs. The granulomatous response is vigorous during acute infection (8 wk) and spontaneously undergoes immunomodulation during chronic infection (20 wk). Inflammatory M phi isolated from liver granulomas of 8 and 20-wk schistosome-infected CBA/J mice were assessed for their cytolytic potential. Macrophages from vigorous liver granulomas displayed significant cytolytic activity against 3 mammary tumor lines of strain BALB/cfC3H origin, while leaving untransformed embryo fibroblasts relatively unharmed. The cytolytic activity of inflammatory M phi from immunomodulated lesions was markedly less than that of cells from vigorous lesions at equivalent effector to target (E:T) cell ratios. Granuloma cell preparations depleted of the inflammatory macrophage component were marginally cytolytic at the higher E:T cell ratio; supernatant fluids from cultured inflammatory M phi-enriched cell preparations possessed no tumoricidal activity. The cytolytic potential of the vigorous granuloma M phi was lost subsequent to prolonged in vitro culture. We conclude that inflammatory M phi in S. mansoni egg-elicited granulomas are sufficiently activated to lyse allogeneic tumor cells. The degree of activation appears to correlate directly with the intensity of the granulomatous response.

Acute Disease↗

Physiological and perceptual responses to walking while swinging hand-held towels.

The intent of this investigation was to determine the intensity of cardiovascular exercise produced by walking while swinging hand-held towels and its potential as a training method. Sixteen healthy college students were the volunteer subjects in this experiment. Each subject performed five randomly ordered trials in which they walked with: (1) a normal arm swing (NAS); (2) a vigorous arm swing (VAS); (3) a vigorous arm swing with hand-held towels (VAST); (4) a vigorous arm swing at NAS heart rate (VNH); and (5) a vigorous arm swing with hand-held towels at NAS heart rate (VTNH). Treadmill speed was 89 m.min-1 for VTNH, 103 for VNH, and 119 for NAS, VAS, and VAST trials. Each trial lasted 6 min and was separated by a 2 min walking recovery. Statistical analysis revealed (p < 0.05) that oxygen consumption (VO2), heart rate (HR), and rating of perceived exertion (RPE) were significantly greater for the VAST (27.8 +/- 3.9 ml.kg-1.min-1, 152 +/- 13.8 bpm, 4.2 +/- 1.4 Borg) vs. NAS (21.0 +/- 3.4, 125 +/- 14.7, 2.6 +/- 1.0) and VAS (24.7 +/- 3.7, 139 +/- 14.1, 3.4 +/- 1.1) vs. NAS trials, but were similar for NAS, VNH, and VTNH. Although not statistically significantly different, VO2, HR, and RPE were physiologically greater for the VAST than VAS trial. These results suggest that walking while swinging hand-held towels is a way to: (1) increase oxygen consumption without altering walking speed and (2) slow walking speed yet maintain exercise intensity.

Adult↗

A case of behavioral heterosis in mice: quantitative and qualitative aspects of performance in a water-escape task.

Fourteen hundred and four mice from two inbred strains (Balb/c and C57BL/6), F1, F2, and backcrosses were subjected to four trials in a water-escape task and to a swimming test. Detailed analysis of mice behavior in these situations showed that the "F1 hybrid vigor" affected behavioral characters not directly related to physical vigor but of potential adaptive value. Their superiority was mainly due to more frequent adoption of an efficient behavioral tactic (direct or edge escape paths toward the exit) and more rapid progress with experience in this respect than other generations exhibited. These results clearly show that heterosis is not limited to physical vigor but may extend to behavioral and even psychological characters.

Animals↗

Molecular marker genotypes, heterozygosity and genetic interactions explain heterosis in Arabidopsis thaliana.

The underlying mechanisms for hybrid vigor or heterosis are elusive. Here we report a population of recombinant inbred lines (RILs), derived from the two ecotypes, Col and Ler, which can serve as a permanent resource for studying the molecular basis of hybrid vigor in Arabidopsis. Using a North Carolina mating design III (NCIII), we determined the additive and dominant nature of gene action in this population. We detected heterosis among crosses of RILs with one of the two parents (Col and Ler) and analyzed genotypes and heterozygosities for RILs and test cross families (RILs crossed to Col and Ler) using a total of 446 published molecular markers. The performance of RILs and additive and dominant components in the test cross families were used to analyze QTLs for 16 traits, using QTL cartographer and composite interval mapping with 1,000 permutations for each trait. Our data suggest that locus-specific and/or genome-wide differential heterozygosity, including epistasis, plays an important role in the generation of the observed heterosis. Furthermore, the hybrid vigor occurred between two closely related ecotypes, and provides a general mechanism for novel variation generated between genetically similar materials.

Arabidopsis↗

[The nature of heterosis, methods of its enhancing and fixation in a series of generations without hybridization].

The long-standing studies into the problem of heterosis on the silkworm and other objects are reviewed. Silkworms are divided by sex for hybridization using the genetic marking of the eggs by sex, an improved method of ameiotic parthenogenesis providing all-female progeny, or the method of obtaining all-male progeny as a result of the death of eggs with female embryos under the influence of two non-allele embryonic lethals balances in the Z-chromosome. The experimental data suggest that heterosis is determined by the heterozygosity of lethals and semilethals, rather than depending on the heterozygosity of all gene types. The number of modifier genes that control viability plays a big role in the vigor of heterosis. An effective method is proposed to enhance the vigor of heterosis through the selection of one or two parents of a hybrid for viability, both of which received a strong semilethal. In hybrids, this semilethal is suppressed by the normal allele, and then a more unbalanced complex of modifier genes initiates a heterosis two to three times more vigorous than in standard hybrids. A method is developed to fix heterosis through the backcrosses of females of the high-heterosis hybrids to the absolutely homozygous males of androgenetic origin obtained from these females. These crosses preserve the main genotype of the hybrid and eliminate lethals and semilethals, and, as a result, heterosis is not damped during standard intrahybrid reproduction.

Alleles↗

The efficacy of exercise as an aid for smoking cessation in women: a randomized controlled trial.

BACKGROUND: Smoking prevalence rates among women are declining at a slower rate than among men. OBJECTIVE: To determine if exercise, a healthful alternative to smoking, enhances the achievement and maintenance of smoking cessation. METHODS: Two hundred eighty-one healthy, sedentary female smokers were randomly assigned to either a cognitive-behavioral smoking cessation program with vigorous exercise (exercise) or to the same program with equal staff contact time (control). Subjects participated in a 12-session, group-based smoking cessation program. Additionally, exercise subjects were required to attend 3 supervised exercise sessions per week and control subjects were required to participate in 3 supervised health education lectures per week. Abstinence from smoking was based on self-report, was verified by saliva cotinine level, and was measured at 1 week after quit day (week 5), end of treatment (week 12), and 3 and 12 months later (20 and 60 weeks after quit day, respectively). RESULTS: Compared with control subjects (n = 147), exercise subjects (n = 134) achieved significantly higher levels of continuous abstinence at the end of treatment (19.4% vs 10.2%, P = .03) and 3 months (16.4% vs 8.2%, P=.03) and 12 months (11.9% vs 5.4%, P=.05) following treatment. Exercise subjects had significantly increased functional capacity (estimated VO2 peak, 25+/-6 to 28+/-6, P<.01) and had gained less weight by the end of treatment (3.05 vs 5.40 kg, P = .03). CONCLUSIONS: Vigorous exercise facilitates short- and longer-term smoking cessation in women when combined with a cognitive-behavioral smoking cessation program. Vigorous exercise improves exercise capacity and delays weight gain following smoking cessation.

Adult↗

A prospective study of physical activity and incident and fatal prostate cancer.

BACKGROUND: Whether physical activity has benefits against prostate cancer incidence or progression is unclear. Therefore, we assessed physical activity in relation to prostate cancer incidence, mortality, and Gleason histologic grade. METHODS: We used data from the Health Professionals Follow-up Study, a prospective cohort study, to determine the number of cases of incident, advanced (seminal vesicle invasion, metastasis, or fatal), fatal, and high-grade prostate cancer in a cohort of 47,620 US male health professionals, followed up from February 1, 1986, to January 31, 2000. RESULTS: During 14 years of follow-up, we documented 2892 new cases of prostate cancer, including 482 advanced cases (280 of which were fatal). For total prostate cancer, no association was observed for total, vigorous, and nonvigorous physical activity. In men 65 years or older, we observed a lower risk in the highest category of vigorous activity for advanced (multivariable relative risk, 0.33; 95% confidence interval, 0.17-0.62, for more than 29 vs 0 metabolic equivalent hours) and for fatal (relative risk, 0.26; 95% confidence interval, 0.11-0.66) prostate cancer. No associations were observed in younger men. Differential screening by prostate-specific antigen or a reduction in physical activity due to undiagnosed prostate cancer did not appear to account for the results. Among cases, men with high levels of physical activity were less likely to be diagnosed with poorly differentiated cancers (Gleason grade > or = 7). CONCLUSION: Although the mechanisms are not yet understood, these findings suggest that regular vigorous activity could slow the progression of prostate cancer and might be recommended to reduce mortality from prostate cancer, particularly given the many other documented benefits of exercise.

Adult↗

No-touch technique for intraocular malignant melanomas.

Large variations in intraocular pressure occur during enucleation, scleral depression, 32P testing, and vigorous rubbing of an eye. Data from animal studies show that during a critical phase of an intraocular malignant melanoma, ocular massage significantly decreased longevity due to increased metastastic disease. We report "no-touch" technique to prevent tumor spread from occurring secondary to ocular manipulation during enucleation. This technique avoids IOP elevations above 50 mm Hg before freezing completely around the tumor, thereby preventing flow of fluid and blood to or from the tumor prior to the manipulation necessary for enucleation. Theoretically, the patient with an ocular tumor should be warned against vigorous rubbing of his eyes and hard lid squeezes or diagnostic techniques that elevate IOP. The ophthalmologist should perform enucleation with gentieness and avoid pressure on the globe. Patients who are being followed up with a suspected ocular tumor should be warned not to rub or vigorously squeeze their eyelids.

Animals↗

A multicomponent program for nutrition and physical activity change in primary care: PACE+ for adolescents.

BACKGROUND: Most adolescents do not meet national recommendations for nutrition and physical activity. However, no studies of physical activity and nutrition interventions for adolescents conducted in health care settings have been published. The present study was an initial evaluation of the PACE+ (Patient-centered Assessment and Counseling for Exercise plus Nutrition) program, delivered in primary care settings. PARTICIPANTS: Adolescents aged 11 to 18 years (N = 117) were recruited from 4 pediatric and adolescent medicine outpatient clinics. Participants' mean (SD) age was 14.1 (2.0) years, 37% were girls, and 43% were ethnic minorities. INTERVENTION: Behavioral targets were moderate physical activity, vigorous physical activity, fat intake, and fruit and vegetable intake. All patients completed a computerized assessment, created tailored action plans to change behavior, and discussed the plans with their health care provider. Patients were then randomly assigned to receive no further contact or 1 of 3 extended interventions: mail only, infrequent telephone and mail, or frequent telephone and mail. MEASURES: Brief, validated, self-report measures of target behaviors were collected at baseline and 4 months later. RESULTS: All outcomes except vigorous physical activity improved over time, but adolescents who received the extended interventions did not have better 4-month outcomes than those who received only the computer and provider counseling components. Adolescents who targeted a behavior tended to improve more than those who did not target the behavior, except for those who targeted vigorous physical activity. CONCLUSIONS: A primary care-based interactive health communication intervention to improve physical activity and dietary behaviors among adolescents is feasible. Controlled experimental research is needed to determine whether this intervention is efficacious in changing behaviors in the short- and long-term.

Adolescent↗

Factors associated with changes in physical activity: a cohort study of inactive adolescent girls.

OBJECTIVE: To identify factors associated with changes in physical activity in adolescent girls at risk for sedentary lifestyles and obesity. DESIGN: A cohort study was performed with 201 high school girls recruited to participate in an evaluation study of a school-based obesity prevention physical education program. Three assessments were performed during an 8-month period. MAIN OUTCOME MEASURES: Associations between physical activity and a range of personal factors (self-acceptance, self-worth, athletic competence, body image, depressive mood, perceived benefits, enjoyment of physical activity, self-efficacy, and body mass index), behavioral factors (watching television and time constraints), and socioenvironmental factors (social support and costs/resources) were assessed. RESULTS: The 2 strongest and most consistent factors associated with change in physical activity were time constraints and support for physical activity from peers, parents, and teachers. Measures assessing self-perceptions, global (ie, self-worth) and specific to physical activity (ie, self-efficacy to be physically active), were also associated with change in physical activity. For example, a decrease of 2.0 U for an adolescent's perceived time constraints (possible range, 3.0-12.0 U) would be expected to lead to an increase of 53 minutes of moderate to vigorous physical activity per week (95% confidence interval, 33-72 minutes). An increase of 2.0 U in perceived support for physical activity (possible range, 3.0-12.0 U) would be expected to lead to an increase of 35 minutes of moderate to vigorous physical activity per week (95% confidence interval, 13-56 minutes). An increase of 3.0 U on the self-worth scale (possible range, 5.0-20.0 U) might be expected to lead to an increase of 19 minutes of moderate to vigorous physical activity per week (95% confidence interval, 0-40 minutes). CONCLUSION: The effectiveness of interventions aimed at increasing physical activity among adolescent girls might be enhanced by engaging support from friends, family, and caring adults; addressing real and perceived time constraints; and helping adolescent girls feel more confident about themselves and their ability to engage in physical activity.

Adolescent↗

Objectively measured physical activity in sixth-grade girls.

OBJECTIVES: To describe the objectively measured physical activity characteristics of a diverse sample of sixth-grade girls, to examine influences on physical activity, and to report compliance with physical activity guidelines. DESIGN: Cross-sectional study. SETTING: Six locations across the United States. PARTICIPANTS: A total of 1578 sixth-grade girls. Accelerometers were worn for 7 days, and data for 6 days were included in the analyses. Main Exposures Race/ethnicity, free or reduced-price lunch, and geographic region. MAIN OUTCOME MEASURES: Six operational definitions of adequate activity (60 or 30 minutes of daily moderate to vigorous physical activity at or above 4.6, 3.8, or 3.0 metabolic equivalents) were used to examine whether girls met physical activity guidelines. RESULTS: Average times spent in sedentary, light, moderate, and vigorous activities were 460, 342, 18, and 6 min/d, respectively. White girls were more active than girls in other race/ethnic groups, and girls who did not receive free or reduced-price lunch were more active than girls who did. Girls in western states were most active. Percentages of girls in compliance with the 6 thresholds for adequate activity varied widely and ranged from 0.6% to 100.0%. CONCLUSIONS: When physical activity is measured objectively and a 4.6-metabolic equivalents cut point for moderate to vigorous physical activity is used, most sixth-grade girls do not meet guidelines for adequate physical activity. One notable finding was the effect of different accelerometer scoring protocols on estimates of compliance. Conceptual and empirical work is needed to define appropriate physical activity for youth using objective physical activity measures.

Child↗

Outcomes of a field trial to improve children's dietary patterns and physical activity. The Child and Adolescent Trial for Cardiovascular Health. CATCH collaborative group.

OBJECTIVE: To assess the outcomes of health behavior interventions, focusing on the elementary school environment, classroom curricula, and home programs, for the primary prevention of cardiovascular disease. DESIGN: A randomized, controlled field trial at four sites with 56 intervention and 40 control elementary schools. Outcomes were assessed using prerandomization measures (fall 1991) and follow-up measures (spring 1994). PARTICIPANTS: A total of 5106 initially third-grade students from ethnically diverse backgrounds in public schools located in California, Louisiana, Minnesota, and Texas. INTERVENTION: Twenty-eight schools participated in a third-grade through fifth-grade intervention including school food service modifications, enhanced physical education (PE), and classroom health curricula. Twenty-eight additional schools received these components plus family education. MAIN OUTCOME MEASURES: At the school level, two primary end points were changes in the fat content of food service lunch offerings and the amount of moderate-to-vigorous physical activity in the PE programs. At the level of the individual student, serum cholesterol change was the primary end point and was used for power calculations for the study. Individual level secondary end points included psychological factors, recall measures of eating and physical activity patterns, and other physiologic measures. RESULTS: In intervention school lunches, the percentage of energy intake from fat fell significantly more (from 38.7% to 31.9%) than in control lunches (from 38.9% to 36.2%)(P<.001). The intensity of physical activity in PE classes during the Child and Adolescent Trial for Cardiovascular Health (CATCH) intervention increased significantly in the intervention schools compared with the control schools (P<.02). Self-reported daily energy intake from fat among students in the intervention schools was significantly reduced (from 32.7% to 30.3%) compared with that among students in the control schools (from 32.6% to 32.2%)(P<.001). Intervention students reported significantly more daily vigorous activity than controls (58.6 minutes vs 46.5 minutes; P<.003). Blood pressure, body size, and cholesterol measures did not differ significantly between treatment groups. No evidence of deleterious effects of this intervention on growth or development was observed. CONCLUSION: The CATCH intervention was able to modify the fat content of school lunches, increase moderate-to-vigorous physical activity in PE, and improve eating and physical activity behaviors in children during 3 school years.

Analysis of Variance↗

Physical activity and coronary heart disease in women: is "no pain, no gain" passé?

CONTEXT: Physically active women have lower coronary heart disease (CHD) rates than inactive women. However, whether the association differs by intensity of activity or in women at high risk for CHD is unclear. OBJECTIVE: To examine the relation between physical activity, specifically investigating walking (a light-to-moderate activity depending on pace), and CHD among women, including those at high risk for CHD. DESIGN, SETTING, AND PARTICIPANTS: Cohort study of 39 372 healthy female health professionals aged 45 years or older, enrolled throughout the United States between September 1992 and May 1995, with follow-up to March 1999. Recreational activities, including walking and stair climbing, were reported at study entry. MAIN OUTCOME MEASURE: Correlation of CHD with energy expended on all activities, vigorous activities, and walking. RESULTS: A total of 244 cases of CHD occurred. Adjusting for potential confounders, the relative risks (RRs) of CHD for less than 200, 200-599, 600-1499, and 1500 or more kcal/wk expended on all activities were 1.00 (referent), 0.79 (95% confidence interval [CI], 0.56-1.12), 0.55 (95% CI, 0.37-0.82), and 0.75 (95% CI, 0.50-1.12), respectively (P for linear trend =.03). Vigorous activities were associated with lower risk (RR, 0.63; 95% CI, 0.38-1.04 comparing highest and lowest categories). Walking also predicted lower risk among women without vigorous activities. Among these women, the multivariate RRs for walking 1 to 59 min/wk, 1.0 to 1.5 h/wk, and 2 or more h/wk, compared with no regular walking, were 0.86 (95% CI, 0.57-1.29), 0.49 (95% CI, 0.28-0.86), and 0.48 (95% CI, 0.29-0.78), respectively. For walking paces of less than 3.2 km/h (2.0 mph), 3.2 to 4.7 km/h (2.0-2.9 mph), and 4.8 km/h (3.0 mph) or more, compared with no regular walking, RRs were 0.56 (95% CI, 0.32-0.97), 0.71 (95% CI, 0.47-1.05), and 0.52 (95% CI, 0.30-0.90), respectively. When analyzed simultaneously, time spent walking (P for linear trend =.01) but not walking pace (P for linear trend =.55) predicted lower risk. The inverse association between physical activity and CHD risk did not differ by weight or cholesterol levels (P for interaction =.95 and.71, respectively), but there were significant interactions by smoking and hypertension status. Physical activity was inversely related to risk in current smokers but not hypertensive women (P for interaction =.01 and.001, respectively). CONCLUSIONS: These data indicate that even light-to-moderate activity is associated with lower CHD rates in women. At least 1 hour of walking per week predicted lower risk. The inverse association with physical activity was also present in women at high risk for CHD, including those who were overweight, had increased cholesterol levels, or were smokers.

Cohort Studies↗

Risk of cardiovascular events associated with selective COX-2 inhibitors.

Atherosclerosis is a process with inflammatory features and selective cyclooxygenase 2 (COX-2) inhibitors may potentially have antiatherogenic effects by virtue of inhibiting inflammation. However, by decreasing vasodilatory and antiaggregatory prostacyclin production, COX-2 antagonists may lead to increased prothrombotic activity. To define the cardiovascular effects of COX-2 inhibitors when used for arthritis and musculoskeletal pain in patients without coronary artery disease, we performed a MEDLINE search to identify all English-language articles on use of COX-2 inhibitors published between 1998 and February 2001. We also reviewed relevant submissions to the US Food and Drug Administration by pharmaceutical companies. Our search yielded 2 major randomized trials, the Vioxx Gastrointestinal Outcomes Research Study (VIGOR; 8076 patients) and the Celecoxib Long-term Arthritis Safety Study (CLASS; 8059 patients), as well as 2 smaller trials with approximately 1000 patients each. The results from VIGOR showed that the relative risk of developing a confirmed adjudicated thrombotic cardiovascular event (myocardial infarction, unstable angina, cardiac thrombus, resuscitated cardiac arrest, sudden or unexplained death, ischemic stroke, and transient ischemic attacks) with rofecoxib treatment compared with naproxen was 2.38 (95% confidence interval, 1.39-4.00; P =.002). There was no significant difference in cardiovascular event (myocardial infarction, stroke, and death) rates between celecoxib and nonsteroidal anti-inflammatory agents in CLASS. The annualized myocardial infarction rates for COX-2 inhibitors in both VIGOR and CLASS were significantly higher than that in the placebo group of a recent meta-analysis of 23 407 patients in primary prevention trials (0.52%): 0.74% with rofecoxib (P =.04 compared with the placebo group of the meta-analysis) and 0.80% with celecoxib (P =.02 compared with the placebo group of the meta-analysis). The available data raise a cautionary flag about the risk of cardiovascular events with COX-2 inhibitors. Further prospective trial evaluation may characterize and determine the magnitude of the risk.

Anti-Inflammatory Agents, Non-Steroidal↗