Biomedical subjects

Kiang Liu

Publications and source records attributed to Kiang Liu.

90 records · Page 5Linked to original sources

PubMed2003

Influence of systolic blood pressure and body mass index on left ventricular structure in healthy African-American and white young adults: the CARDIA study.

OBJECTIVES: In the Coronary Artery Risk Development in Young Adults (CARDIA) Study comprised of a generally healthy, biracial cohort of 28- to 40-year-old adults, we sought to characterize the distribution of left ventricular (LV) mass and LV geometry and the relationship of systolic blood pressure (SBP), body mass index (BMI), and fasting insulin to LV mass and geometry. BACKGROUND: Left ventricular mass is a risk factor for cardiovascular morbidity and mortality. METHODS: Two-dimensionally guided M-mode echocardiograms were used to calculate LV mass index (g/height(2.7)) and geometry. RESULTS: Black men had highest LV mass index followed by white men, black women, and white women. Blacks had higher LV wall thickness/diameter ratios than whites. Left ventricular hypertrophy was present in 2% of the cohort. Going from highest to lowest quartile for LV mass index and LV wall thickness/diameter ratio, SBP and BMI were highest in those with the highest LV mass index and LV wall thickness/diameter ratio. Increasing BMI and SBP over a 10-year interval was also strongly related to LV structure in most race/gender groups. CONCLUSIONS: In a generally healthy young adult cohort, LV structure as defined by LV mass and geometry is associated with SBP and BMI at levels generally considered normal.

Adult↗

PubMed2003

Statin use and leg functioning in patients with and without lower-extremity peripheral arterial disease.

BACKGROUND: We determined whether statin use (versus nonuse) is associated with superior lower-extremity functioning independently of cholesterol levels and other confounders in patients with and without peripheral arterial disease. METHODS AND RESULTS: Participants included 392 men and women with an ankle brachial index (ABI) <0.90 and 249 with ABI 0.90 to 1.50. Functional outcomes included 6-minute walk distance and 4-meter walking velocity. A summary performance score combined performance in walking speed, standing balance, and time for 5 repeated chair rises into an ordinal score ranging from 0 to 12 (12=best). Adjusting for age, sex, ABI, comorbidities, education level, medical insurance status, cholesterol, and other confounders, participants taking statins had better 6-minute walk performance (1276 versus 1218 feet, P=0.045), faster walking velocity (0.93 versus 0.89 m/s, P=0.006), and a higher summary performance score (10.2 versus 9.4, P<0.001) than participants not taking statins. Positive associations were attenuated slightly after additional adjustment for C-reactive protein level but remained statistically significant for walking velocity and the summary performance score. We did not find significant associations between lower-extremity functioning and aspirin, ACE inhibitors, vasodilators, or beta-blockers. CONCLUSIONS: Statin use is associated with superior leg functioning compared with no statin use, independent of cholesterol levels and other potential confounders. These data suggest that non-cholesterol-lowering properties of statins may favorably influence functioning in persons with and without peripheral arterial disease.

Adrenergic beta-Antagonists↗

PubMed2003

Depressive symptoms and lower extremity functioning in men and women with peripheral arterial disease.

OBJECTIVE: Factors associated with impaired functioning in patients with lower extremity peripheral arterial disease (PAD) are not fully understood. The purpose of this study was to determine the relationship between depressive symptoms and objective measures of lower extremity functioning in persons with PAD. DESIGN: Cross-sectional. PATIENTS/PARTICIPANTS: Four hundred twenty-three men and women with PAD identified from 3 Chicago area medical centers. MEASUREMENTS AND MAIN RESULTS: PAD was defined as ankle brachial index (ABI) <0.90. The Geriatric Depression Scale short form (GDS-S) (0-15 scale, 15 = worst) was completed by all participants. A clinically significant number of depressive symptoms was defined as a GDS-S score >or=6. Six-minute walk distance and usual-and fast-pace walking velocity were determined for all participants. A GDS-S score >or=6 was present in 21.7% of participants with PAD. Adjusting for age, increasing numbers of depressive symptoms were associated with an increasing prevalence of leg pain on exertion and rest (P =.004). Adjusting for age, sex, race, ABI, number of comorbidities, current smoking, and antidepressant medications, increasing numbers of depressive symptoms were associated with shorter 6-minute walk distance (P <.001), slower usual-pace walking velocity (P =.005), and slower fast-pace walking velocity (P =.005). These relationships were attenuated slightly after additional adjustment for presence versus absence of leg pain on exertion and rest and severity of exertional leg symptoms. CONCLUSIONS: Among men and women with PAD, the prevalence of a clinically significant number of depressive symptoms is high. Greater numbers of depressive symptoms are associated with greater impairment in lower extremity functioning. Further study is needed to determine whether identifying and treating depressive symptoms in PAD is associated with improved lower extremity functioning.

Aged↗

PubMed2003

Sex differences in peripheral arterial disease: leg symptoms and physical functioning.

OBJECTIVES: To compare lower extremity functioning and leg symptoms between women and men with peripheral arterial disease (PAD). DESIGN: Cross-sectional. SETTING: Three Chicago-area medical centers. PARTICIPANTS: One hundred eighty-seven women and 273 men with PAD identified consecutively in patients in the noninvasive vascular laboratories and a general medicine practice at the three medical centers. MEASUREMENTS: Walking speed, 6-minute walk, accelerometer-measured 7-day physical activity, and a summary performance score. The summary performance score combines data on walking velocity, time for five repeated chair rises, and standing balance to achieve a score on a 0 to 12 scale (12 = best). RESULTS: Women with PAD were older and had a lower prevalence of prior leg revascularization, a higher prevalence of spinal stenosis, and a lower prevalence of other cardiovascular disease than men with PAD. Mean ankle brachial index (ABI) values +/- standard deviation were similar in women and men with PAD (0.64 +/- 0.15 vs 0.66 +/- 0.14, P =.15). Women with PAD were significantly more likely than men with PAD to have exertional leg pain that sometimes begins at rest (27.8% vs 13.2%, P <.001). Women with PAD had slower walking speed (0.81 vs 0.92 m/s, P <.001), shorter 6-minute walk distance (1,047 vs 1,182 feet, P <.001), and a poorer summary performance score (8.9 vs 9.8, P <.001) than men with PAD, adjusting for age, race, height, comorbid disease, and leg symptoms. After adjusting for leg strength, sex differences in 6-minute walk performance and summary performance score were attenuated modestly (1,089 vs 1,177 feet for 6-minute walk, P =.022 and 9.2 vs 9.8 for summary performance score, P =.027). CONCLUSION: Women with PAD had a higher prevalence of leg pain on exertion and rest, poorer functioning, and greater walking impairment from leg symptoms than men with PAD. A higher prevalence of spinal stenosis in women may explain the observed sex differences in leg symptoms. Poorer leg strength in women may contribute to poorer lower extremity functioning in women with PAD than in men with PAD.

Aged↗

PubMed2003

Influence of autonomic nervous system dysfunction on the development of type 2 diabetes: the CARDIA study.

OBJECTIVE: We investigated whether autonomic nervous system dysfunction, estimated by slow heart rate recovery (HRR) following cessation of an exercise treadmill test, was associated with increases in insulin and glucose over time and the development of type 2 diabetes. RESEARCH DESIGN AND METHODS: Maximal exercise tests were performed by 3295 healthy adults aged 18-30 years in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Repeat measurements of insulin and glucose collected at 7-, 10-, and 15-year examinations were compared by quartiles of HRR (maximum heart rate minus heart rate 2 min after cessation of the test). Incident diabetes was identified at any follow-up examination as glucose >or=7 mmol/l or the use of diabetes control medication. RESULTS: Among participants who did not develop diabetes, fasting insulin concentrations increased from baseline to year 15. Following adjustment (for age, race, sex, smoking status, and BMI), participants with the slowest HRR (quartile 1) had higher fasting insulin at each examination than participants with faster HRR (e.g., year 15 examination: 88.1 vs. 81.3 pmol/l for quartile 1 vs. quartile 4, respectively, P = 0.05). Glucose did not differ by quartile of HRR at any examination. Among participants with poor fitness, the risk of developing diabetes (n = 98) was 3.4-fold greater (95% CI 1.5-8.0) when HRR was <42 vs. >42 bpm. This persisted following adjustment for baseline insulin. CONCLUSIONS: Autonomic dysfunction, in combination with poor physical fitness, may be a mechanism associated with early glucose dysmetabolism and the development of diabetes.

Adult↗

PubMed2003

Positional change in blood pressure and 8-year risk of hypertension: the CARDIA Study.

OBJECTIVE: To assess the relationship between positional blood pressure change and 8-year incidence of hypertension in a biracial cohort of young adults. SUBJECTS AND METHODS: Participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study with complete data from year 2 (1987-1988), year 5 (1990-1991), year 7 (1992-1993), and year 10 (1995-1996) examinations were included (N = 2781). Participants were classified into 3 groups based on their year 2 systolic blood pressure response to standing: drop, a decrease in systolic blood pressure of more than 5 mm Hg; same, a change of between -5 and +5 mm Hg; and rise, more than 5-mm Hg increase. RESULTS: The number of participants in each group was as follows: drop, 741; same, 1590; and rise, 450. The 8-year incidence of hypertension was 8.4% in the drop group, 6.8% in the same group, and 12.4% in the rise group (P < .001). Adjusted odds ratios for developing hypertension during the follow-up period in the rise group vs the same group were as follows: in black men, 2.85 (95% confidence interval [CI], 1.43-5.69), in black women, 2.47 (95% CI, 1.19-5.11), in white men, 2.17 (95% CI, 1.00-4.73), and in white women, 4.74 (95% CI, 1.11-20.30). CONCLUSIONS: A greater than 5-mm Hg increase in blood pressure on standing identified a group of young adults at increased risk of developing hypertension within 8 years. These findings support a physiologic link between sympathetic nervous system reactivity and risk of hypertension in young adults.

Adolescent↗

PubMed2002

Multi-Ethnic Study of Atherosclerosis: objectives and design.

The Multi-Ethnic Study of Atherosclerosis was initiated in July 2000 to investigate the prevalence, correlates, and progression of subclinical cardiovascular disease (CVD) in a population-based sample of 6,500 men and women aged 45-84 years. The cohort will be selected from six US field centers. Approximately 38% of the cohort will be White, 28% African-American, 23% Hispanic, and 11% Asian (of Chinese descent). Baseline measurements will include measurement of coronary calcium using computed tomography; measurement of ventricular mass and function using cardiac magnetic resonance imaging; measurement of flow-mediated brachial artery endothelial vasodilation, carotid intimal-medial wall thickness, and distensibility of the carotid arteries using ultrasonography; measurement of peripheral vascular disease using ankle and brachial blood pressures; electrocardiography; and assessments of microalbuminuria, standard CVD risk factors, sociodemographic factors, life habits, and psychosocial factors. Blood samples will be assayed for putative biochemical risk factors and stored for use in nested case-control studies. DNA will be extracted and lymphocytes will be immortalized for genetic studies. Measurement of selected subclinical disease indicators and risk factors will be repeated for the study of progression over 7 years. Participants will be followed through 2008 for identification and characterization of CVD events, including acute myocardial infarction and other coronary heart disease, stroke, peripheral vascular disease, and congestive heart failure; therapeutic interventions for CVD; and mortality.

Aged↗

PubMed2002

Decline in physical activity in black girls and white girls during adolescence.

BACKGROUND: Physical activity declines during adolescence, but the underlying reasons remain unknown. METHODS: We prospectively followed 1213 black girls and 1166 white girls enrolled in the National Heart, Lung, and Blood Institute Growth and Health Study from the ages of 9 or 10 to the ages of 18 or 19 years. We used a validated questionnaire to measure leisure-time physical activity on the basis of metabolic equivalents (MET) for reported activities and their frequency in MET-times per week; a higher score indicated greater activity. RESULTS: The respective median activity scores for black girls and white girls were 27.3 and 30.8 MET-times per week at base line and declined to 0 and 11.0 by year 10 of the study (a 100 percent decline for black girls and a 64 percent decline for white girls, P<0.001). By the age of 16 or 17 years, 56 percent of the black girls and 31 percent of the white girls reported no habitual leisure-time activity. Lower levels of parental education were associated with greater decline in activity for white girls at both younger ages (P<0.001) and older ages (P=0.005); for black girls, this association was seen only at the older ages (P=0.04). Pregnancy was associated with decline in activity among black girls (P<0.001) but not among white girls, whereas cigarette smoking was associated with decline in activity among white girls (P<0.001). A higher body-mass index was associated with greater decline in activity among girls of both races (P< or =0.05). CONCLUSIONS: Substantial declines in physical activity occur during adolescence in girls and are greater in black girls than in white girls. Some determinants of this decline, such as higher body-mass index, pregnancy, and smoking, may be modifiable.

Adolescent↗

PubMed2002

The ankle brachial index is associated with leg function and physical activity: the Walking and Leg Circulation Study.

BACKGROUND: The ankle brachial index (ABI) is a noninvasive, reliable measure of lower-extremity ischemia. However, the relationship between ABI and lower-extremity function has not been well studied. OBJECTIVE: To describe the association between the ABI and lower-extremity function. DESIGN: Cross-sectional study. SETTING: 3 academic medical centers in the Chicago area. PARTICIPANTS: 740 men and women (460 with peripheral arterial disease). MEASUREMENTS: Accelerometer-measured physical activity over 7 days, 6-minute walk, 4-m walking velocity, standing balance, and ABI. RESULTS: 33% of participants with peripheral arterial disease had intermittent claudication. Fewer than 40% of participants with an ABI less than 0.40 walked continuously for 6 minutes compared with more than 95% of participants with an ABI between 1.00 and 1.50. Compared with an ABI of 1.10 to 1.50, an ABI less than 0.50 was associated with shorter distance walked in 6 minutes (beta-regression coefficient = -523 ft [95% CI, -592 to -454 ft]; P < 0.001), less physical activity (beta = -514.8 activity units [CI, -657 to -373 activity units]; P < 0.001), slower 4-m walking velocity (beta = -0.21 m/s [CI, -0.27 to -0.15 m/s]; P < 0.001), and less likelihood of maintaining a tandem stand for 10 seconds (odds ratio, 0.37 [CI, 0.18 to 0.76]; P = 0.007), after adjustment for typical confounders. Associations between ABI and function were stronger than associations between leg symptoms and function. CONCLUSIONS: The ABI, a noninvasive test that can be performed in a medical office, is more closely associated with leg function in persons with peripheral arterial disease than is intermittent claudication or other leg symptoms. These data support the use of the ABI to identify abnormal lower-extremity function.

Aged↗

PubMed2002

Socioeconomic trajectories and incident hypertension in a biracial cohort of young adults.

We assessed the impact of initial socioeconomic status and change in socioeconomic status across 10 years, ie, status trajectories, on the development of essential hypertension among black and white young men and women. Three thousand eight hundred twenty-seven normotensive individuals ages 18 to 30 years at study entry were followed for 10 years, with blood pressure, body mass index, and socioeconomic status characteristics measured at years 0, 2, 5, 7, and 10. Socioeconomic status trajectory measures were a new educational degree earned by year 10; difficulties paying for basics during years 2 to 10; and change in income category from year 5 to 10, defined in relation to year 0 status. Hypertension was defined as systolic blood pressure > or =140, diastolic blood pressure > or =90, or antihypertensive medication use at year 10. Reporting difficulties paying for basics at study entry (odds ratio=1.45, 95% confidence interval, 1.05 to 2.02) and continued difficulties during year 2 to 10 follow-up (odds ratio=1.62, 95% confidence interval, 1.04 to 2.53) were independently associated with incident hypertension, adjusted for race-gender group, body mass index, site, age, and initial systolic blood pressure. Decline in income from year 5 to 10 tended to be associated with hypertension, P=0.07, but a new educational degree after study onset was not. Socioeconomic trajectories are independently associated with incidence of hypertension. A dynamic index of socioeconomic status may be a useful concept in understanding the effects of socioeconomic status on the natural history of hypertension.

Adolescent↗

PubMed2002

Relation of cigarette smoking to 25-year mortality in middle-aged men with low baseline serum cholesterol: the Chicago Heart Association Detection Project in Industry.

It has been suggested that smoking does not influence risk of cardiovascular diseases in populations with low serum cholesterol levels. To determine whether cigarette smoking is an independent risk factor among men with low levels of serum cholesterol, data on 25-year coronary, cardiovascular, and all-cause mortality for 8,816 middle-aged men screened between 1967 and 1973 by the Chicago Heart Association Detection Project in Industry were examined. With Cox multivariate proportional hazards regression, relative risks of coronary heart disease and cardiovascular disease mortality associated with smoking for the two subcohorts with favorable levels of serum total cholesterol, that is, less than 180 and 180-199 mg/dl, were of the same magnitude as those for men with elevated serum cholesterol, that is, 200-239 and 240 mg/dl. In the two lower strata of cholesterol, the absolute risk and absolute excess risk of mortality for current smokers at baseline were substantially higher compared with men who never smoked, with all-cause death rates of 423.0 and 428.0 per 1,000 and absolute excess rates of 209.8 and 225.7 per 1,000. These translate to estimated shorter life expectancies of 5.3 and 5.7 years, respectively. Adverse effects of smoking on risk of coronary, cardiovascular, and all-cause mortality prevail for men with lower as well as higher serum cholesterol levels.

Adult↗

PubMed2002

Lower extremity performance is associated with daily life physical activity in individuals with and without peripheral arterial disease.

OBJECTIVES: To determine whether persons with poorer lower extremity functioning have reduced physical activity levels. DESIGN: Cross-sectional. SETTING: Three Chicago-area medical centers. PARTICIPANTS: Two hundred twenty-five people with lower extremity peripheral arterial disease (PAD) and 121 individuals without PAD. MEASUREMENTS: The summary performance score (SPS) was determined for all participants. The SPS combines data on walking velocity, time for five repeated chair rises, and standing balance. Each test is scored on a 0 to 4 scale (4 = best). Scores are summed to create the SPS (0-12 scale, 12 = best). All participants wore a vertical accelerometer for 7 days to measure physical activity. RESULTS: The SPS was associated linearly with 7-day physical activity levels of participants with (P< .0001) and without PAD (P< .0001). This relationship was maintained even after restricting analyses to subsets of participants who reported that they could walk a quarter of a mile and up and down stairs without difficulty (P< .001) and were able to walk for 6-minutes without stopping (P< .001). In multiple linear regression analyses, the SPS was associated with physical activity in participants with (P< .01) and without PAD (P< .001), adjusting for age, sex, race, comorbidities, ankle brachial index, neuropathy, and leg symptoms. CONCLUSION: In people with and without PAD who have impaired lower extremity performance, reduced physical activity levels may contribute to subsequent disability. Future study is needed to determine whether interventions to increase physical activity can prevent functional decline in persons with a low SPS.

Activities of Daily Living↗

PubMed2002

Eight-year blood pressure change in middle-aged men: relationship to multiple nutrients.

Relationships of nutrients, alcohol intake, and change in weight to change in blood pressure over 8 years in 1714 employed middle-aged men from the Chicago Western Electric Study were explored. At first and second annual examinations, 2 in-depth interviews were performed to assess usual intake of foods and beverages during the preceding 28 days. Annual follow-up data through examination year 9 were used to determine change in weight and blood pressure. Averages of nutrients from 2 interviews were related to annual blood pressure change from baseline by use of the Generalized Estimating Equation, with control for confounders. In analyses of dietary variables considered individually, total and animal protein; total, saturated, monounsaturated, and polyunsaturated fatty acids; cholesterol; Keys dietary lipid score; calcium; alcohol; and average annual change in weight were positively and significantly related to average annual change in systolic pressure; vegetable protein, total carbohydrate, beta-carotene, and an antioxidant vitamin score based on vitamin C and beta-carotene were inversely and significantly related to average annual change in systolic pressure. In analyses of combinations of dietary factors, cholesterol, Keys score, and alcohol were positively related to change in systolic pressure (eg, Z-scores 2.21, 2.05, and 2.50); vegetable protein and antioxidant index were inversely related to change in systolic and diastolic pressure. Change in weight was directly related to change in systolic and diastolic pressure. These findings support the concept that multiple macro- and micronutrients, alcohol intake, and calorie imbalance relate prospectively to blood pressure change.

Adult↗

PubMed2002

Peripheral artery disease, diabetes, and reduced lower extremity functioning.

OBJECTIVE: To characterize lower extremity function and dysfunction in peripheral artery disease (PAD) patients with and without diabetes. RESEARCH DESIGN AND METHODS: In this cross-sectional study, 460 men and women with PAD (147 with diabetes) were recruited from three academic medical centers. Assessments included ankle brachial index (ABI), neuropathy score, 6-min walk distance, 4-m walking velocity, Walking Impairment Questionnaire (0-100 scale, 100 = best), and summary performance score (SPS) (0-12 scale, 12 = best). RESULTS: The mean ABI was similar in PAD patients with and without diabetes. PAD patients with diabetes were younger, had a higher BMI, had a worse neuropathy score, and had a greater number of cardiovascular comorbidities compared with those without diabetes. Participants with diabetes were less likely to report classical symptoms of intermittent claudication and more likely to report exertional leg pain, which sometimes started at rest. After adjusting for age, those with diabetes had a shorter mean 6-min walk distance (1,040 vs. 1,168 feet, P < 0.001), slower fast-pace 4-m walk velocity (0.83 vs. 0.90 m/sec, P < 0.001), and a lower SPS (7.3 vs. 8.6, P < 0.001) than those without diabetes. Patients with diet-controlled diabetes performed better than those on diabetes medications. Differences in lower extremity functioning between patients with and without diabetes were largely attenuated but not abolished for SPS and fast-pace 4-m walk velocity after adjustment for type of exertional leg pain, neuropathy score, and number of cardiovascular comorbidities. CONCLUSIONS: Subjects with PAD and diabetes have poorer lower extremity function than those with PAD alone. This difference in functioning appears to be largely explained by diabetes-associated neuropathy, differences in exertional leg symptoms, and greater cardiovascular disease in patients with diabetes.

Arterial Occlusive Diseases↗

PubMed2002

Colorectal cancer mortality and factors related to the insulin resistance syndrome.

It has been proposed that hyperinsulinemia is involved in colon carcinogenesis. An association between post-load plasma glucose (PLG) levels and risk of colorectal cancer mortality would be consistent with this hypothesis. We used data from the Chicago Heart Association Detection Project in Industry to examine the associations of nonfasting PLG and other variables related to the insulin resistance syndrome (i.e., systolic blood pressure, body mass index, uric acid, and resting heart rate) with colorectal cancer mortality. After excluding participants reporting a history of diabetes, 191 and 126 colorectal cancer deaths occurred among 20,433 men and 15,149 women, respectively. In multivariate Cox regression analysis, there was a positive relationship between PLG levels and colorectal cancer mortality for women (P for trend = 0.08) but not for men. When men and women were combined, a trend (P = 0.05) for PLG remained. Examination of clustering of insulin resistance syndrome-related risk factors revealed that men with at least 3 of 4 risk factors (i.e., in the highest quartile of the sex-specific distribution for PLG, systolic blood pressure, body mass index, or resting heart rate) had a relative risk (RR) of 1.67 [95% confidence interval (CI), 1.04-2.70] as compared with men who were not in the upper quartile for any of these factors. For women, the RR was 1.29 (95% CI, 0.70-2.37). For men and women combined, the RR was 1.50 (95% CI, 1.03-2.19). These findings provide evidence for a modest association of PLG and insulin resistance syndrome with colorectal cancer mortality and support the insulin hypothesis.

Adult↗

PubMed2002

Serum androgen concentrations in young men: a longitudinal analysis of associations with age, obesity, and race. The CARDIA male hormone study.

Serum testosterone concentration appears to be higher in black men than white men, particularly at younger ages. The higher incidence of prostate cancer in blacks has been attributed, at least in part, to this difference. Other factors associated with androgen levels in men include age and obesity. However, most of the studies of adult androgen levels are limited by their cross-sectional design. We conducted longitudinal analyses (Generalized Estimating Equation) of the associations of age, body mass index (BMI), and waist circumference with total and free testosterone and sex hormone-binding globulin (SHBG) concentrations during an 8-year period and compared these hormonal factors between black (n = 483) and white (n = 695) male participants of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. For men ages 24 years and older at the time of the first hormone measurement, increasing age was associated with a statistically significant decrease in serum total and free testosterone and an increase in SHBG (P < 0.05). BMI and waist circumference were inversely associated with total testosterone and SHBG, but only BMI was inversely associated with free testosterone. After adjustment for age and BMI, total testosterone was higher in blacks (0.21 ng/ml; P = 0.028) than whites, an approximately 3% difference. However, after further adjustment for waist circumference, there was no black-white difference (0.05 ng/ml; P = 0.62). These results indicate that the age-associated decrease in circulating testosterone and increase in SHBG begin during the 3rd decade of life, and that increasing obesity, particularly central obesity, is associated with decreasing total testosterone and SHBG. Results also suggest that the previously observed difference in total testosterone between black and white men could be attributed, for the most part, to racial differences in abdominal obesity.

Adolescent↗

PubMedDate not supplied

Relation between the changes in physical activity and body-mass index during adolescence: a multicentre longitudinal study.

BACKGROUND: The role of physical activity in preventing obesity during adolescence remains unknown. We examined changes in activity in relation to changes in body-mass index (BMI) and adiposity in a cohort of 1152 black and 1135 white girls from the USA, who were followed up prospectively from ages 9 or 10 to 18 or 19 years. METHODS: BMI and sum of skinfold thickness were assessed annually, whereas habitual activity was assessed at years 1 (baseline), 3, 5, and 7-10. Each girls' overall activity status was categorised as active, moderately active, or inactive. Longitudinal regression models examined associations between changes in activity and in overall activity status with changes in BMI and in sum of skinfold thickness. FINDINGS: Each decline in activity of 10 metabolic equivalent [MET]-times per week was associated with an increase in BMI of 0.14 kg/m2 (SE 0.03) and in sum of skinfold thickness of 0.62 mm (0.17) for black girls, and of 0.09 kg/m2 (0.02) and 0.63 mm (0.13) for white girls. At ages 18 or 19 years, BMI differences between active and inactive girls were 2.98 kg/m2 (p<0.0001) for black girls and 2.10 kg/m2 (p<0.0001) for white girls. Similar results were apparent for sum of skinfold thickness. For moderately active girls, changes in BMI and sum of skinfold thickness were about midway between those for active and inactive girls. INTERPRETATION: Changes in activity levels of US girls during adolescence significantly affected changes in BMI and adiposity. Thus, preventing the steep decline in activity during adolescence is an important method to reduce obesity.

Adolescent↗

PubMedDate not supplied

A pilot exercise intervention to improve lower extremity functioning in peripheral arterial disease unaccompanied by intermittent claudication.

PURPOSE: A pilot study was conducted to test the feasibility of supervised treadmill exercise training to improve functioning in study participants with peripheral arterial disease who did not have classical symptoms of intermittent claudication. METHODS: For this study, 32 men and women with peripheral arterial disease but no symptoms of claudication were randomized to exercise training or usual care. The intervention was a 12-week supervised treadmill walking program. Outcomes included 6-minute walk distance, maximum treadmill walking distance, and 4-meter walking velocity. Participant-reported community walking ability was measured with the Walking Impairment Questionnaire (WIQ). Inflammatory blood factor levels also were measured. RESULTS: Altogether, 25 participants who completed follow-up testing were included in intention-to-treat analyses. Of 24 participants (58%) randomized to exercise, 14 completed the entire exercise training program. The participants randomized to the intervention showed greater improvement in their WIQ walking speed score than the control subjects (P =.05). The participants randomized to the intervention showed improvements in their 6-minute walk distance (1134 +/- 347 vs 1266 +/- 295 feet; P =.03), maximal treadmill walking distance (389 +/- 248 vs 585 +/- 293 feet; P <.001), WIQ distance score (52.3 +/- 29.1 vs 63.1 +/- 25.1; P =.002), and WIQ speed score (48.7 +/- 26.8 vs 59.7 +/- 22.7; P =.008). The participants randomized to the control condition showed improvements in maximal treadmill walking distance (362 +/- 180 vs 513 +/- 237 feet; P =.014). There were no significant changes in the inflammatory blood factors after exercise. CONCLUSIONS: This pilot study demonstrated that a supervised treadmill walking program may be feasible and may improve functioning for individuals with peripheral arterial disease who do not have classical symptoms of intermittent claudication. Further study is needed with a larger sample to identify optimal exercise methods that improve lower extremity functioning in men and women with peripheral arterial disease who do not have intermittent claudication.

Aged↗