Shannon J. FitzGerald

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.

Relation of the Number of Metabolic Syndrome Risk Factors With All-Cause and Cardiovascular Mortality

The metabolic syndrome (MS) is a constellation of risk factors associated with diabetes and cardiovascular disease. This syndrome consists of at least 3 parameters assessing central obesity, hypertension, high-density lipoprotein cholesterol, triglycerides, and impaired glucose metabolism. Whether persons with 4 or 5 risk factors are at higher risk than those with 3 risk factors is unclear. Also unclear is whether those without the MS but with 1 or 2 risk factors warrant therapy. We assessed cardiovascular and all-cause mortality as a function of the number of these risk factors. We followed 30,365 men for a median follow-up of 13.6 years. During follow-up, 1,449 participants died, 527 from cardiovascular causes. All of the individual parameters defining the MS were significantly associated with both all-cause and cardiovascular mortality (p <0.001). After adjustment for age and the other MS variables, hypertension was the most potent risk factor whereas central obesity and hypertriglyceridemia remained associated with both all-cause and cardiovascular mortality. A highly significant trend was also noted between both all-cause or cardiovascular mortality and the number of risk factors (p <0.001 for trend). Risk increased incrementally, beginning at 1 risk factor for cardiovascular mortality and at 2 risk factors for all-cause mortality. In conclusion, there is a continuum of risk as the number of metabolic syndrome risk factors increases. These findings add to the growing evidence that central obesity can independently and adversely affect health.

American Adults' Knowledge of Exercise Recommendations

Abstract Physical inactivity is a major risk factor for cardiovascular disease, stroke, hypertension, diabetes, obesity, osteoporosis, and some cancers. Approximately 950,000 Americans die annually from cardiovascular diseases. The purpose of this study was to determine whether American adults know which traditional and lifestyle physical activities affect health and how they should be physically active to achieve a health benefit. Secondary purposes were to determine whether this knowledge is a function of gender, ethnicity, education, or age and if those who are sufficiently active for a health benefit possess different knowledge levels than those not sufficiently active for a health benefit. Items based on the Centers for Disease Control and Prevention/American College of Sports Medicine principles included knowledge of exercise guidelines and traditional and lifestyle physical activities. This information was obtained from 20 questions that were part of a national random telephone survey of 2,002 American households in the 48 contiguous states and the District of Columbia. Respondents were most aware of traditional physical activities (M = 94%) that provide a health benefit and less aware of specific exercise guidelines (M = 68%) and lifestyle physical activities (M = 71%) that can result in a health benefit. Knowledge was not related to physical activity behavior sufficient for a health benefit and only slightly related to ethnicity, education, and age. These data suggest that physical activity knowledge alone is not sufficient to elicit a behavior; however, it provides educators with an understanding of the publics physical activity knowledge that could be helpful in developing health promotion and physical activity interventions.

Associations among physical activity, television watching, and obesity in adult Pima Indians

It has been suggested that television watching and physical activity are related to obesity. This association, however, has been investigated mainly in children. This study provided the opportunity to examine the relationship between television watching, physical activity, and body mass index in adult Pima Indians, a population with a high prevalence of obesity. Hours per day of television watched, past-year physical levels (MET-h/wk; leisure and occupational combined) and BMI (kg.m-2) were measured in 2452 men and women subjects 21-59 yr old. In adults between the ages of 21 and 39 yr, TV and physical activity levels were negatively correlated (r = -0.11 for men and -0.10 for women). Weaker associations were found between TV and BMI (r = 0.08 for men and 0.04 for women). There were no significant relationships among these variables in older adults (49-59 yr), possibly because of low reported levels of physical activity and TV. Multiple linear regression analysis revealed that physical activity and television watching in men and activity in women were significantly related to BMI. These data suggest that increasing activity levels and decreasing the time spent in sedentary behavior such as watching television should both be considered as potential intervention strategies in obesity prevention programs.

Cardiorespiratory fitness, adiposity, and all-cause mortality in women.

PURPOSE To determine the prospective associations among cardiorespiratory fitness (CRF), different measures of adiposity, and all-cause mortality in women. METHODS A total of 11,335 women completed a comprehensive baseline examination between 1970 and 2005. Clinical measures included body mass index (BMI), waist circumference (WC), waist-to-height ratio (W/HT), waist-to-hip ratio (W/Hip), percent body fat (%BF), and CRF quantified as duration of a maximal exercise test. Participants were classified by CRF as low (lowest 20%), moderate (middle 40%), and high (highest 40%) as well as by standard clinical cut points for adiposity measures. Hazard ratios (HR) were computed using Cox regression analysis. RESULTS During a mean follow-up of 12.3 ± 8.2 yr, 292 deaths occurred. HR for all-cause mortality were 1.0, 0.60, and 0.54 for low, moderate, and high fit groups, respectively (P for trend G0.01). Adjusted death rates of overweight/obese women within each adiposity exposure were somewhat higher compared with normal-weight women and approached statistical significance for BMI, %BF, and W/HT (P = 0.08, P = 0.08, and P = 0.07, respectively). When grouped for joint analyses into categories of fit and unfit (upper 80% and lower 20% of CRF distribution, respectively), HR were significantly higher in unfit women within each stratum of BMI compared with fit–normal BMI women. Fit women with high %BF (HR = 1.0), high WC (HR = 0.9), and high W/HT (HR = 1.2) had no greater risk of death compared with fit–normal-weight women (referent). CONCLUSIONS Low CRF in women was a significant independent predictor of all-cause mortality. Higher CRF was associated with lower mortality within each category of each adiposity exposure. Using adiposity measures as predictors of all-cause mortality in women may be misleading unless CRF is also considered.

Relation of a Coronary Artery Calcium Score Higher Than 400 to Coronary Stenoses Detected Using Multidetector Computed Tomography and to Traditional Cardiovascular Risk Factors

Coronary artery calcium (CAC) is an excellent surrogate for atherosclerosis. However, this calcium is nonspecific for obstructive heart disease. This study sought to determine (1) the frequency of significant computed tomographic (CT) angiographic stenoses as a function of CAC scores, and (2) whether high CAC scores were associated with these stenoses independent of traditional risk factors. Subjects (n = 664) underwent Agatston CAC scoring and multidetector CT angiography using current 64-slice technology. Significant stenoses were defined as >60% diameter compromise. Self-reported risk factors and frequency of stenoses were analyzed as a function of CAC scores. The prevalence of risk factors increased significantly as CAC scores increased. Significant univariate associations included age (p <0.001), male gender (p <0.001), hypertension (p <0.001), and hyperlipidemia (p <0.001). There was also a significant association between CAC scores and the frequency of significant CT angiographic stenoses (p <0.001 for trend). The frequency of CT angiographic stenoses increased as CAC scores increased, with 7.9%, 8.3%, 14.5%, and 27.2% prevalences of significant stenoses in those with CAC scores of 1 to 100, 101 to 400, 401 to 1,000, and >1,000, respectively. Conversely, no significant lesions were found in those with no CAC. Multivariable logistic regression analysis controlling for traditional risk factors showed odds ratios for CAC score of 401 to 1,000 and >1,000 for having significant stenoses of 3.1 (95% confidence interval 1.6 to 6.0) and 6.9 (95% confidence interval 3.5 to 13.5), respectively. In conclusion, a CAC score >400 was significantly associated with multidetector CT angiographic stenoses independently of traditional risk factors.

Construct Validity Evidence for Single-Response Items to Estimate Physical Activity Levels in Large Sample Studies

Valid measurement of physical activity is important for studying the risks for morbidity and mortality. The purpose of this study was to examine evidence of construct validity of two similar single-response items assessing physical activity via self-report. Both items are based on the stages of change model. The sample was 687 participants (men = 504, women = 183) who completed an 8-response (PA8) or 5-response (PA5) single-response item about current level of physical activity. Responses were categorized as meeting or not meeting guidelines for sufficient physical activity to achieve a health benefit. Maximal cardiorespiratory fitness (CRF) and health markers were obtained during a clinical examination. Partial correlation, multivariate analysis of covariance, and logistic regression were used to identify the relations between self-reported physical activity, CRF, and health markers when controlling for gender and age. Single-response items were compared to a detailed measure of physical activity. Single-response items correlated significantly with CRF determined with a maximal exercise test on a treadmill (PA8 = .53; PA5 = .57). Differences in percentage of body fat and cholesterol were in the desired direction, with those self-reporting sufficient physical activity for a health benefit having the lower values. The single-response items demonstrated evidence of construct validity and may provide feasible, cost-effective, and efficient methods to assess physical activity in large-scale studies.

A controlled analysis of the transjugular intrahepatic portosystemic shunt in liver transplant recipients

BACKGROUND The transjugular intrahepatic portosystemic shunt (TIPS) is an important treatment for complications of portal hypertension. As some authors have suggested that TIPS may facilitate liver transplantation technically, the objective of this study was to determine the impact of TIPS on the liver transplant operation and its outcome. METHODS The analysis was designed as a retrospective cohort study using a multicenter database. Fifty-five patients with TIPS were matched with 55 controls on the basis of 10 pretransplant laboratory, clinical, and demographic features. TIPS patients and control patients were compared with regard to duration of surgery, intraoperative blood product usage, liver and renal function, volume of ascites, survival, and hospital stay. For confirmatory purposes, a parallel analysis using linear regression methods was performed. RESULTS By matched analysis, TIPS patients had less ascites at surgery (mean 0.9+/-0.20 vs. 2.2+/-0.37 L, P=0.005) and a slightly shorter time from incision to cross-clamp (mean 2.1+/-0.10 vs. 2.5+/-0.15 hr, P=0.03). However, there were not significant differences for total operative time (mean 6.0+/-0.17 vs. 6.3+/-0.25 hr, P=1.00), blood product usage, or any other outcome variable. Regression analysis confirmed these results. CONCLUSIONS TIPS does not significantly impact the course of liver transplantation surgery. Therefore, preoperative portal decompression solely to facilitate liver transplantation is not an appropriate indication for TIPS.

Comparative Relation of General, Central, and Visceral Adiposity Measures for Coronary Artery Calcium in Subjects Without Previous Coronary Events

It is unclear whether visceral obesity is largely responsible for an increased risk of coronary artery disease. In the present study, 1,054 men underwent coronary artery calcium (CAC) scoring and abdominal computed tomography. Risk factor information, body mass index, waist circumference, and waist-to-hip ratio were collected for all participants. The total fat, visceral fat, and subcutaneous fat areas were also quantified at the level of the umbilicus using computed tomography. We then investigated the association of these obesity parameters with the CAC score. Participants with a CAC score >10 had a larger waist circumference (97 +/- 12 vs 95 +/- 12 cm, p <0.001), a larger total fat area (434 cm(2), interquartile range 339 to 565, vs 415 cm(2), interquartile range 315 to 521; p = 0.005), a larger visceral fat area (200 cm(2), interquartile range 143 to 256, vs 175 cm(2), interquartile range 124 to 225; p <0.001), and a greater waist-to-hip ratio (0.93 +/- 0.07 vs 0.91 +/- 0.07, p <0.001) than those with a CAC score of < or =10. Those with a CAC score >10 also tended to have a greater body mass index and larger subcutaneous fat area. After adjusting for traditional cardiovascular risk factors, however, only a large waist circumference (odds ratio 1.5, 95% confidence interval 1.04 to 2.0), a high total fat area (odds ratio 1.5, 95% confidence interval 1.1 to 2.1), and a high waist-to-hip ratio (odds ratio 1.6, 95% confidence interval 1.2 to 2.3) remained significantly associated with a CAC score >10. In conclusion, the measures of central obesity were more strongly associated with the CAC score than either the parameters assessing overall obesity or other more direct measures of visceral adiposity. These findings suggest that the total amount of central obesity is more important than the relative distribution of visceral versus subcutaneous fat.

Relationships among Body Composition Measures in Community‐dwelling Older Women

Objective: To examine whether simple anthropometric measures provide a good estimate of total and visceral fat in 146 community‐dwelling, older white women (mean age, 74.0 ± 4.1 years).