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Timothy S Church

Publications and source records attributed to Timothy S Church.

At least 37 records · Page 2Linked to original sources
PubMed2005

Reliability of the Lode Excalibur Sport Ergometer and applicability to Computrainer electromagnetically braked cycling training device.

New technology allows cyclists to train via power output (PO) in addition to heart rate (HR). For those athletes undertaking seasonal laboratory testing (e.g., Vo(2), lactate threshold), it is imperative that athletes be able to directly apply this information to their training device. We examined the reliability of a standardized laboratory ergometer (Lode Excalibur Sport) and its applicability to an electromagnetically braked ergometer (Computrainer) in 2 phases. Phase I (n = 12) examined the reliability of the Lode. Phase II (n = 14) compared the Lode to the Computrainer using a randomized, counterbalance assignment. Following warm-up, each trial started at 100 W, progressing 50 W every 3 minutes to exhaustion. Outcomes were time-to-exhaustion (TTE), peak PO (W) (PO(peak)), peak HR (HR(peak)), and ventilatory (VT) and respiratory compensation (RCP) thresholds. We used a repeated measures analysis of variance (ANOVA), Tukey post hoc analysis, regression analysis, Bland-Altman plots, and coefficient of variation (CV) analysis for each variable. During phase I, we found no significant difference for any variable, minimal dispersion of Vo(2) during Bland-Altman analysis, and a low CV at each test stage (</= 5%). During phase II, significant differences and higher CV for most parameters (all data; p < 0.001) were observed for Lode versus Computrainer: TTE (21 minutes, 12 seconds +/- 3 minutes, 12 seconds vs. 19 minutes, 9 seconds +/- 2 minutes, 36 seconds; CV = 16%), PO(peak) (335 +/- 57.8 W vs. 295 +/- 47.1 W, CV = 17%), as well as PO at VT (CV = 51%) and RCP (CV = 24%; p < 0.01). We conclude that coaches and cyclists may need to use some caution when directly transferring results obtained from laboratory testing to the Computrainer training device.

Bicycling↗
PubMed2005

Metabolic syndrome, obesity, and mortality: impact of cardiorespiratory fitness.

OBJECTIVE: To determine in normal weight, overweight, and obese men the risk of all-cause and cardiovascular disease (CVD) mortality associated with the metabolic syndrome (MetS) and the influence of cardiorespiratory fitness (CRF). RESEARCH DESIGN AND METHODS: This observational cohort study included 19,173 men who underwent a clinical examination, including a maximal exercise test. MetS was defined according to National Cholesterol Education Program guidelines. RESULTS: At baseline 19.5% of the men had MetS. The ORs of the metabolic syndrome at baseline were 4.7 (95% CI 4.2-5.3) in overweight and 30.6 (26.7-35.0) in obese men compared with normal weight men. A total of 477 deaths (160 CVD) occurred in 10.2 years of follow-up. The risks of all-cause mortality were 1.11 (0.75-1.17) in normal weight, 1.09 (0.82-1.47) in overweight, and 1.55 (1.14-2.11) in obese men with MetS compared with normal weight healthy men. The corresponding risks for CVD mortality were 2.06 (0.92-4.63) in normal weight, 1.80 (1.10-2.97) in overweight, and 2.83 (1.70-4.72) in obese men with the MetS compared with normal weight healthy men. After the inclusion of CRF in the model, the risks associated with obesity and MetS were no longer significant. CONCLUSIONS: Obesity and MetS are associated with an increased risk of all-cause and CVD mortality; however; these risks were largely explained by CRF.

Adult↗
PubMed2005

Cardiorespiratory fitness attenuates metabolic risk independent of abdominal subcutaneous and visceral fat in men.

OBJECTIVE: Moderate to high levels of cardiorespiratory fitness (CRF) are associated with a lower risk of the metabolic syndrome and all-cause mortality. Unknown is whether CRF attenuates health risk for a given level of abdominal visceral fat, subcutaneous fat, and/or waist circumference. RESEARCH DESIGN AND METHODS: The sample studied comprised 297 apparently healthy men with available computed tomography or magnetic resonance imaging scans of the abdomen, metabolic data, and maximal treadmill exercise test results. Men were categorized into low-CRF (20%, n = 56), moderate-CRF (40%, n = 94), and high-CRF (40%, n = 147) groups based on age and exercise test results. All analyses were adjusted for age. RESULTS: For a given level of waist circumference, visceral fat, or subcutaneous fat, the high-CRF group had lower triglyceride levels (P < 0.05) and higher HDL cholesterol levels than the low- or moderate-CRF groups. There was a significant group interaction (P < 0.01) for blood pressure, indicating that the increase in blood pressure per unit increase in visceral fat or waist circumference was greater in men in the low-CRF group compared with the high-CRF group. The relative risks of having the metabolic syndrome were 1.8 (95% CI 1.0-3.1) and 1.6 (0.9-2.7) times higher in the low- and moderate-CRF groups, respectively, compared with the high-CRF group after adjusting for age, visceral fat, and subcutaneous fat (P for trend = 0.06). CONCLUSIONS: High levels of CRF are associated with a substantial reduction in health risk for a given level of visceral and subcutaneous fat.

Abdomen↗
PubMed2004

Cardiorespiratory fitness attenuates the effects of the metabolic syndrome on all-cause and cardiovascular disease mortality in men.

BACKGROUND: The metabolic syndrome is a prevalent condition that carries with it an increased risk of type 2 diabetes mellitus, cardiovascular disease (CVD), and mortality. OBJECTIVE: To determine the relationship between cardiorespiratory fitness (CRF) and mortality in healthy men and in those with the metabolic syndrome. METHODS: The sample included 19 223 men, aged 20 to 83 years, who received a clinical evaluation between 1979 and 1995 with mortality follow-up through December 31, 1996. There were 15 466 healthy men (80.5%) and 3757 men with the metabolic syndrome (19.5%). RESULTS: A total of 480 deaths (161 due to CVD) occurred during 196 298 man-years of follow-up. After adjustment for age, year of examination, smoking status, alcohol consumption, and parental CVD, the relative risks (RRs) (95% confidence interval) of all-cause and CVD mortality were 1.29 (1.05-1.57) and 1.89 (1.36-2.60), respectively, for men with the metabolic syndrome compared with healthy men. After the inclusion of CRF, the associations were not significant. The RRs comparing unfit with fit men for all-cause mortality were 2.18 (1.66-2.87) in healthy men and 2.01 (1.38-2.93) in men with the metabolic syndrome, whereas the RRs for CVD mortality for unfit vs fit men were 3.21 (2.03-5.07) in healthy men and 2.25 (1.27-3.97) in men with the metabolic syndrome. A significant dose-response relationship between CRF and mortality was also observed in men with the metabolic syndrome. CONCLUSION: In this sample, CRF provided a strong protective effect against all-cause and CVD mortality in healthy men and men with the metabolic syndrome.

Adult↗
PubMed2004

Eight weeks of moderate-intensity exercise training increases heart rate variability in sedentary postmenopausal women.

BACKGROUND: Regular exercise is associated with increased heart rate variability (HRV). However, results from studies examining the effect of exercise training on HRV in postmenopausal women are inconclusive. In addition, the effect of hormone replacement therapy (HRT) on HRV remains a subject of speculation. METHODS: We examined 88 sedentary postmenopausal women in a randomized controlled trial who were assigned to exercise (n = 49) or control (n = 39) groups. The exercising women performed 8 weeks of aerobic exercise training at a heart rate equivalent to 50% of VO2max, consisting on average of 44 minutes per session, 3 to 4 times per week. Resting HRV was measured in each participant at baseline and after 8 weeks of intervention. Ten minutes of resting R-R intervals were analyzed by time (standard deviation of mean R-R intervals, root of mean square successive differences) and frequency domain methods: low-frequency (LF) was defined as 0.04 to 0.15 Hz, high-frequency (HF) as 0.15 to 0.40 Hz, and total spectral power as 0.00 to 0.40 Hz. The LF and HF components in normalized units were also calculated. RESULTS: At baseline, there were no significant differences in HRV between control and exercise groups. Additionally, there were no differences in any HRV variables when women were grouped by HRT use (no HRT, estrogen-only HRT, and progestin-containing HRT). After 8 weeks, women randomly assigned to the exercise group increased all absolute time and frequency domain indexes (all P <.001) and reduced resting heart rate (P =.002) compared with women in the control group. The LF and HF components expressed as normalized units remained unchanged after exercise intervention. Additionally, HRT use did not modify the exercise-induced changes in HRV. CONCLUSIONS: We conclude that moderate aerobic exercise increases HRV in sedentary postmenopausal women. This benefit is not influenced by the use of HRT.

Analysis of Variance↗
PubMed2004

Liver fat is not a marker of metabolic risk in lean premenopausal women.

We examined the independent associations among abdominal adipose tissue (AT) depots, liver fat, cardiorespiratory fitness (CRF), and metabolic risk factors in 86 lean premenopausal women. We measured abdominal AT and liver fat by computed tomography (CT), and CRF by a maximal treadmill exercise test. Liver fat was not related to any abdominal AT depot, metabolic risk factor, or CRF (P > .10). Visceral AT mass (kilograms) remained a significant (P < .05) predictor of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), TC/high-density lipoprotein cholesterol (HDL-C), and LDL-C/HDL-C after statistical adjustment for CRF. Abdominal subcutaneous AT mass was also a significant (P < .05) correlate of TC/HDL-C and LDL-C/HDL-C after control for CRF. Visceral AT remained a significant predictor (P < .05) of TC and LDL-C after control for abdominal subcutaneous AT. Conversely, subcutaneous AT did not remain a significant correlate after control for visceral AT. However, the deep subcutaneous AT depot remained significantly associated with LDL-C, TC/HDL-C, and LDL-C/HDL-C after control for visceral AT. In contrast, visceral AT remained correlated with triglycerides (TG) alone, after control for the deep subcutaneous AT. These observations suggest that liver fat is not a determinant of metabolic risk in lean women. Conversely, both visceral and the deep subcutaneous depot are determinants of metabolic risk in premenopausal woman despite the absence of obesity.

Abdomen↗
PubMed2004

Cardiorespiratory fitness is associated with lower abdominal fat independent of body mass index.

PURPOSE: To determine whether, for a given body mass index (BMI), men with high cardiorespiratory fitness (CRF) have lower waist circumference (WC) and less total abdominal, abdominal subcutaneous, and visceral adipose tissue (AT) compared with men with low CRF. METHODS: Subjects were categorized into HIGH CRF (N = 169) and LOW CRF (N = 124) groups based on age and CRF measured using a maximal treadmill test. Total abdominal, abdominal subcutaneous and visceral AT were measured by computerized tomography. RESULTS: For a given BMI, men in the HIGH CRF group had significantly lower WC (P < 0.001), total abdominal (P < 0.001), visceral AT (P < 0.001), and abdominal subcutaneous AT (P < 0.001) compared with men in the LOW CRF group. CONCLUSION: These findings suggest that the ability of CRF to attenuate the health risks associated with BMI may be partially mediated through a reduction in abdominal AT. Accordingly, our observations reinforce the importance of regular physical activity in the prevention and reduction of obesity-related health risk independent of a corresponding reduction in body weight.

Abdomen↗
PubMed2004

Dose Response to Exercise in Women aged 45-75 yr (DREW): design and rationale.

INTRODUCTION AND PURPOSE: Physical inactivity in postmenopausal women contributes to a rise in atherogenic risk factors associated with the metabolic syndrome. Although regular physical activity positively contributes to health, inactivity progressively increases with age. The Dose Response to Exercise in Women aged 45-75 yr (DREW) study is designed to investigate the effect of different amounts of exercise training on cardiorespiratory fitness and risk factors for cardiovascular disease (CVD) in postmenopausal women at moderately increased risk of CVD. METHODS: DREW will recruit 450 sedentary, healthy, postmenopausal women with a body mass index of 25-40 kg.m-2, resting systolic blood pressure (BP) of 120-159 mm Hg, and a resting diastolic BP of < or = 99 mm Hg. Laboratory and self-report measures completed at baseline and 6 months include maximal oxygen consumption (.VO2max), resting BP, anthropometry, dietary habits, physical activity history, medication use, menstrual history, personal and family medical history, and fasting HDL cholesterol, LDL cholesterol, triglycerides, and glucose. Eligible participants are randomly assigned to a nonexercise group or one of three exercise groups. Participants exercise 3 to 4x wk-1 at a heart rate equivalent to 50% of .VO2max expending 4, 8, or 12 kcal.kg-1.wk-1, depending on group assignment. This study will allow quantification of possible dose-response relations (50%, 100%, and 150% of the consensus physical activity recommendation) between exercise training and study outcomes. CONCLUSION: DREW can make important contributions to our understanding of the effects of physical activity in postmenopausal women and help refine public health and clinical recommendations for this group.

Adaptation, Physiological↗
PubMed2004

Effects of a commercial herbal-based formula on exercise performance in cyclists.

INTRODUCTION/PURPOSE: We examined the effects of a commercially marketed herbal-based formula purported to increase endurance on oxygen consumption (VO2) in 17 competitive category III/IV amateur cyclists [mean (SEM) age: 31.1 (1.8) yr; height: 178.5 (1.8) cm; weight: 77.1 (1.6) kg]. METHODS: Each cyclist participated in two (pre/post) cycling tests progressing 25 W.4 min(-1) starting at 100 W administered in a randomized, placebo-controlled, double-blind fashion. The second trial was performed 14 d after the ingestion of a manufacturer recommended loading phase (4 d x 6 caps.d(-1)) and a maintenance phase (11 d x 3 caps.d(-1)). Three treatment capsules contained 1000 mg of Cordyceps sinensis (CS-4) and 300 mg Rhodiola rosea root extract as the primary ingredients; 800 mg of other ingredients included calcium pyruvate, sodium phosphate, potassium phosphate, ribose, and adenosine and 200 mcg of chromium. RESULTS: Using a 2 x 2 ANOVA, we observed no significant treatment effect for any between or within group variables including peak VO2 [treatment 4.14 (0.2) L.min(-1); placebo 4.10 (0.2) L.min(-1)], time to exhaustion [treatment 38.47 (1.7) min; placebo 36.95 (1.8) min], peak power output (PO) [treatment 300.00 (12.1) W; placebo 290.63 (12.9) W], or peak heart rate. We also observed no differences for any subpeak exercise variable including the PO eliciting 2 mmol.L(-1) blood lactate (BLa) [treatment 201.00 (18.1) W; placebo 167.50 (19.2) W] and 4 mmol.L(-1) BLa [treatment 235.88 (15.8) W; placebo 244.78 (14.9) W], ventilatory threshold, respiratory compensation point, or Vo2 L.min(-1) gross efficiency at each stage. CONCLUSION: A 2-wk ingestion schema of a commercial herbal-based formula is insufficient to elicit positive changes in cycling performance.

Adult↗
PubMed2004

Effects of oral ATP supplementation on anaerobic power and muscular strength.

PURPOSE: We examined 14 d of oral adenosine 5'-triphosphate (ATP) supplementation on indices of anaerobic capacity and muscular strength. METHODS: Twenty-seven healthy males successfully completed the trial, after randomly receiving in a double-blind manner an oral dose of low dose (150 mg) or high dose (225 mg) ATP, or matched placebo. To improve absorption characteristics, the ATP was enterically coated. Total blood ATP (whole blood and plasma ATP) concentrations, two Wingate anaerobic power tests (30 s), and muscular strength (1RM and three sets of repetitions to fatigue at 70% of 1RM) were measured under three conditions: (i) baseline; (ii) acutely (7d later, no prior supplementation and 75 min after ATP ingestion); and (iii) after 14 d of daily ingestion (post). RESULTS: Statistical analyses showed no significant between or within group treatment effects for whole blood ATP or plasma ATP concentrations for any treatment condition. We also did not observe any treatment effects for any Wingate testing parameter including peak PO, total work, average PO for 30 s, or post-Wingate lactate accumulation. Overall, we observed no significant between group treatment effects for any muscular strength parameter. We did observe several within group differences for the group ingesting the high ATP dosage including 1RM (6.6%; P < 0.04) and repetitions to fatigue during set 1 of posttesting (18.5%; P < 0.007) and total lifting volume at post (22%; P < 0.003). CONCLUSIONS: We conclude that enterically coated oral ATP supplementation may provide small ergogenic effects on muscular strength under some treatment conditions.

Adenosine Triphosphate↗
PubMed2004

Longitudinal changes in cardiorespiratory fitness: measurement error or true change?

PURPOSE: This study examined the thesis that the reported Aerobics Center Longitudinal Study (ACLS) mortality reductions associated with improved cardiorespiratory fitness were because of measurement error of serial treadmill tests. We tested the research hypothesis that longitudinal changes in cardiorespiratory fitness of the ACLS cohort were a multivariate function of changes in self-report physical activity (SR-PA), resting heart rate, and body mass index (BMI). METHODS: We used the results of three serial maximal treadmill tests (T1, T2, and T3) to evaluate the serial changes in cardiorespiratory fitness of 4675 men. The mean duration between the three serial tests examined was: T2 - T1, 1.9 yr; T3 - T2, 6.1 yr; and T3 - T1, 8.0 yr. Maximum and resting heart rate, BMI, SR-PA, and maximum Balke treadmill duration were measured on each occasion. RESULTS: General linear models analysis showed that with change in maximum heart rate statistically controlled change in treadmill time performance was a function of independent changes in SR-PA, BMI, and R-HR. These variables accounted for significant (P < 0.001) proportions (7%, 9%, and 12%) of the change in treadmill time variance. Those men who increased their SR-PA and lowered their BMI and resting heart rate gained the most fitness between serial tests. CONCLUSIONS: These results support the research hypothesis tested. Variations in serial ACLS treadmill tests are not just due to measurement error alone, but also to systematic variation linked with changes in lifestyle.

Adult↗
PubMed2004

Associations of muscle strength and fitness with metabolic syndrome in men.

PURPOSE: To examine the associations for muscular strength and cardiorespiratory fitness with the prevalence of metabolic syndrome among men. METHODS: Participants were 8570 men (20-75 yr) for whom an age-specific muscular strength score was computed by combining the body weight adjusted one-repetition maximum measures for the leg press and the bench press. Cardiorespiratory fitness was quantified by age-specific maximal treadmill exercise test time. RESULTS: Separate age and smoking adjusted logistic regression models revealed a graded inverse association for metabolic syndrome prevalence with muscular strength (beta = -0.37, P < 0.0001) and cardiorespiratory fitness (beta = -1.2, P < 0.0001). The association between strength and metabolic syndrome was attenuated (beta = -0.08, P < 0.01) when further adjusted for cardiorespiratory fitness. The association between cardiorespiratory fitness and metabolic syndrome was unchanged (beta = -1.2, P < 0.0001) after adjusting for strength. Muscular strength added to the protective effect of fitness among men with low (P trend = 0.0002) and moderate (P trend < 0.0001) fitness levels. Among normal weight (BMI < 25), overweight (BMI 25-30), and obese (BMI >or= 30) men, respectively, being strong and fit was associated with lower odds (73%, 69%, and 62% respectively, P < 0.0001) of having prevalent metabolic syndrome. CONCLUSIONS: Muscular strength and cardiorespiratory fitness have independent and joint inverse associations with metabolic syndrome prevalence.

Adult↗
PubMed2004

Exercise capacity and body composition as predictors of mortality among men with diabetes.

OBJECTIVE: To quantify the relation of fitness to mortality among men with diabetes, adjusted for BMI and within levels of BMI. RESEARCH DESIGN AND METHODS: In this observational cohort study, we calculated all-cause death rates in men with diabetes across quartiles of fitness and BMI categories. Study participants were 2,196 men with diabetes (average age 49.3 years, SD 9.5) who underwent a medical examination, including a maximal exercise test, during 1970 to 1995, with mortality follow-up to 31 December 1996. RESULTS: We identified 275 deaths during 32,161 person-years of observation. Risk of all-cause mortality was inversely related to fitness. For example, in the fully adjusted model, the risk of mortality was 4.5 (2.6-7.6), 2.8 (1.6-4.7), and 1.6 (0.93-2.76) for the first, second, and third fitness quartiles, respectively, with the fourth quartile (highest fitness level) as the referent (P for trend <0.0001). There was no significant trend across BMI categories for mortality after adjustment for fitness. Similar results were found when the fitness-mortality relation was examined within levels of body composition. In normal-weight men with diabetes, the relative risks of mortality were 6.6 (2.8-15.0), 3.2 (1.4-7.0), and 2.2 (1.1-4.6) for the first, second, and third quartiles of fitness, respectively, as compared with the fourth quartile (P for trend <0.0001). We found similar results in the overweight and obese weight categories. CONCLUSIONS: There was a steep inverse gradient between fitness and mortality in this cohort of men with documented diabetes, and this association was independent of BMI.

Blood Pressure↗
PubMed2003

Reduction of C-reactive protein levels through use of a multivitamin.

PURPOSE: Elevated C-reactive protein levels are associated with the risk of cardiovascular disease and diabetes. We examined whether multivitamins reduce C-reactive protein levels. METHODS: We performed a post hoc subgroup analysis of a 6-month, randomized, double-blind, placebo-controlled trial. Patients (n = 87; mean age, 53 years) for whom frozen plasma samples were available; who did not have an inflammatory condition at baseline; and who were not hospitalized, taking antibiotics, smoking, or starting statin therapy during the study were included. C-reactive protein and plasma vitamin levels were measured at baseline and 6 months. RESULTS: At 6 months, C-reactive protein levels were significantly lower in the multivitamin group than in the placebo group (between-group difference = -0.91 mg/L; 95% confidence interval: -1.52 to -0.30; P= 0.005). The reduction in C-reactive protein levels was most evident in patients who had elevated levels (> or =1.0 mg/L) at baseline. Of the six vitamins measured (C, E, B(6), B(12), folate, and beta carotene), only vitamin B(6) (baseline: r = -0.31, P= 0.003; 6 months: r = -0.29, P= 0.006) and vitamin C (baseline: r = -0.25, P= 0.02) were inversely associated with C-reactive protein level. CONCLUSION: In a post hoc analysis of a randomized, double-blind, placebo-controlled study, multivitamin use was associated with lower C-reactive protein levels. Other similarly formulated multivitamins may yield comparable results.

Adult↗
PubMed2003

Comparison of coronary artery calcium detected by electron beam tomography in patients with to those without symptomatic coronary heart disease.

Although the presence of coronary artery calcium (CAC) has been associated with the prevalence and incidence of coronary heart disease (CHD), it is unclear if this association has a threshold or a continuous relation. The aim of this research was to explore the relation between CAC, as detected by electron beam tomography (EBT), and CHD in a cross-sectional study of women and men who presented to a single center for elective screening with EBT from 1995 to 1998. Of 17,967 participants, patients with CHD had higher CAC levels than those without CHD. Using subjects without CAC as the referent group, the odds ratios for prevalent CHD increased significantly across increasing quartiles of CAC in the overall population and in both genders. In a subset of the population, after adjusting for CHD risk factors, CAC scores in the fourth quartile were associated with an odds ratio of 33.8 (p <0.001) for prevalent CHD. Among patients with and without CHD, men were more likely than women to have detectable CAC (58.1% vs 28.3% and 96.1% vs 68.9% respectively, p <0.001 for each); the prevalence of detectable CAC increased with age and was higher in men than in women. There was an increased risk for prevalent CHD at all levels of CAC >0, with the greatest increase in risk occurring in patients with CAC scores >95. These observations support the potential of EBT as a sensitive test for detection of CHD.

Adult↗
PubMed2003

Visceral fat and liver fat are independent predictors of metabolic risk factors in men.

We examined the independent associations among abdominal adipose tissue (AT), liver fat, cardiorespiratory fitness (CRF), and lipid variables in 161 Caucasian men who had a wide variation in adiposity. We measured AT and liver fat by computed tomography and CRF by a maximal exercise test on a treadmill. Visceral AT remained a significant (P or= 0.05) correlate of any lipid variable after control for visceral AT and CRF. Furthermore, subdivision of subcutaneous AT into deep and superficial depots did not alter these observations. Visceral AT was the strongest correlate of liver fat and remained so after control for abdominal subcutaneous AT, CRF, and alcohol consumption (r = -0.34, P < 0.01). In contrast, abdominal subcutaneous AT and CRF were not significant (P > 0.10) correlates of liver fat after control for visceral AT. Visceral AT remained a significant (P < 0.01) correlate of TG, HDL-C, and TC/HDL-C independent of liver fat. However, liver fat was also a significant correlate (P <or= 0.05) of fasting glucose and TG independent of visceral AT. These observations reinforce the importance of visceral obesity in the pathogenesis of dyslipidemia in men, and they suggest that visceral AT and liver fat carry independent health risk.

Adipose Tissue↗
PubMed2003

Complex multivitamin supplementation improves homocysteine and resistance to LDL-C oxidation.

OBJECTIVE: We previously reported in an open-label pilot trial that a 24-ingredient multivitamin formula favorably influenced homocysteine concentration and LDL-C oxidation indices following 24 weeks of supplementation. Our current aim was to more thoroughly examine this same formula in a randomized, placebo-controlled, clinical study. METHODS: We examined 182 participants for selected plasma vitamin concentrations and clinically relevant variables including homocysteine, lipids and LDL-C oxidation indices at baseline and six months. RESULTS: We found no significant differences between groups for any parameter at baseline. Following six months of vitamin supplementation, we observed elevations in plasma concentrations of vitamin B6 (as pyridoxal 5'-phosphate; PLP), vitamin B12, folate, vitamin C, vitamin E and beta-carotene (p < 0.0001), all of which were significantly greater than respective placebo group changes (p < 0.0001). Homocysteine decreased in the treatment (8.38 +/- 2.9 vs. 6.93 +/- 2.5 micro mol/L; p < 0.0001) and placebo group (8.17 +/- 3.0 vs. 7.42 +/- 2.2 micro mol/L; p < 0.0001) from baseline to six months, respectively, with reductions in the treatment group being greater than placebo (p < 0.008). LDL-C oxidation indices were also improved as LDL-C oxidation rate was decreased (-0.39 micro mol/min/g protein; p < 0.0003) and LDL-C lag time increased (11.3 min; p < 0.003) in supplemented participants. Further analysis also showed that LDL-C oxidation rate was lower (p < 0.0007) and LDL-C lag time longer (p < 0.0001) for the vitamin group than placebo treatment after six months. CONCLUSION: We conclude that a multi-ingredient vitamin formula with antioxidant properties has measurable effects on homocysteine and LDL-C oxidation indices.

Adult↗
PubMed2003

Heart rate recovery following maximal exercise testing as a predictor of cardiovascular disease and all-cause mortality in men with diabetes.

OBJECTIVE: Heart rate recovery (HRR) is an independent prognostic indicator for cardiovascular disease (CVD) and all-cause mortality in healthy men. We examined the association of HRR to CVD-related and all-cause mortality in men with diabetes. RESEARCH DESIGN AND METHODS: In this cohort study we examined 2,333 men with documented diabetes (mean age 49.4 years) that had baseline 5-min HRR measurement following maximal exercise (heart rate(peak) - heart rate(5 min of recovery)) at The Cooper Clinic, Dallas, TX. We identified HRR quartiles as quartile 1 <55, quartile 2 55-66, quartile 3 67-75, and quartile 4 >75 bpm. Hazard ratios (HRs) for cardiovascular and all-cause death were adjusted for age, cardiorespiratory fitness, resting heart rate, fasting blood glucose, BMI, smoking habit, alcohol consumption, total cholesterol, triglyceride, and history of CVD at baseline. RESULTS: During a median of 14.9 years follow-up, there were 142 deaths that were considered CVD related and 287 total deaths. Compared with men in the highest quartile of HRR, adjusted HRs in the first, second, and third quartiles were 2.0 (95% CI 1.1-3.8), 1.5 (0.8-2.7), and 1.5 (0.9-2.8), respectively, for cardiovascular death (P for trend < 0.001). Similarly, for all-cause death, adjusted HRs in the first, second, and third quartiles were 2.0 (1.3-3.2), 1.5 (1.0-2.3), and 1.5 (1.1-2.3) (P for trend < 0.001). CONCLUSIONS: Among men with diabetes, a decreased HRR, even measured as long as 5 min after recovery, was independently predictive of cardiovascular and all-cause death.

Adult↗