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Lisa H Colbert

Publications and source records attributed to Lisa H Colbert.

At least 19 recordsLinked to original sources
PubMed2007

Intestinal microbiota: a potential diet-responsive prevention target in ApcMin mice.

We previously reported that two dietary regimens, calorie restriction (CR) and a high olive oil-containing diet supplemented with a freeze-dried fruit and vegetable extract (OFV), reduced the development of intestinal adenomas in Apc(Min) mice by 57% and 33%, respectively, compared to control mice fed a defined diet ad libitum. The OFV diet was designed to have a strong effect on the composition of the intestinal microbiota through its high content of fiber, which represents a major source of fermentable substrate for the gut bacteria. We hypothesized that some of the observed effects of diet on intestinal carcinogenesis might be mediated by diet-related changes in the bacterial species that thrive in the gut. Therefore, we determined by fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) how the dietary interventions affected the composition of the intestinal microbiota, and we characterized specific microbiota changes that were associated with diet and reduced intestinal carcinogenesis. The OFV diet changed the overall composition of the intestinal microbiota, smaller changes were observed for the CR diet. Furthermore, we detected a 16S rDNA fragment associated with mice that did not develop polyps. Sequence analysis suggested that hitherto unidentified bacteria belonging to the family Lachnospiraceae (order Clostridiales) were its source. Thus, these bacteria may be an indicator of intestinal conditions associated with reduced intestinal carcinogenesis in Apc(Min) mice.

Adenoma↗
PubMed2006

Physical activity and the risk of colon cancer among women: a prospective cohort study (United States).

Physical activity has frequently been reported to decrease the risk of colon cancer in men, but data on the relation of physical activity to colon cancer risk in women have generally been less consistent. To further investigate the relationship of physical activity with colon cancer risk in women, we studied a cohort of 31,783 US women participating in the Breast Cancer Detection Demonstration Project Follow-up Study. Information on daily physical activity over the past year was ascertained using a self-administered questionnaire at study baseline. The Cox proportional hazards model was used to estimate relative risks (RRs) relating physical activity to the risk of incident colon cancer. During 270,325 person-years of follow-up, 243 colon cancer cases were identified. No association was observed between physical activity and the subsequent risk of colon cancer. The multivariable RRs of colon cancer across increasing quintiles of total physical activity were 1.0, 1.45, 1.16, 1.27 and 1.15 (95% CI: 0.76, 1.75; p(trend) = 0.77). The multivariable RRs comparing women at the extremes of moderate and vigorous physical activity, respectively, were 1.07 (95% CI: 0.70, 1.62) and 1.10 (95% CI: 0.78, 1.55). The relationship between physical activity and colon cancer risk did not vary by anatomic subsite or across subgroups defined by age, body mass, dietary fiber intake, menopausal status, menopausal hormone use or aspirin use. The results of this large prospective cohort study among women do not support the hypothesis that physical activity is related to a lower incidence of colon cancer.

Adult↗
PubMed2006

Daily activity energy expenditure and mortality among older adults.

CONTEXT: Exercise is associated with mortality benefits but simply expending energy through any activity in an individual's free-living environment may confer survival advantages. OBJECTIVE: To determine whether free-living activity energy expenditure is associated with all-cause mortality among older adults. DESIGN, SETTING, AND PARTICIPANTS: Free-living activity energy expenditure was assessed in 302 high-functioning, community-dwelling older adults (aged 70-82 years). Total energy expenditure was assessed over 2 weeks using doubly labeled water. Resting metabolic rate was measured using indirect calorimetry and the thermic effect of meals was estimated at 10% of total energy expenditure. Free-living activity energy expenditure was calculated as: (total energy expenditure x 0.90) - resting metabolic rate. Participants were followed up over a mean of 6.15 years (1998-2006). MAIN OUTCOME MEASURES: Free-living activity energy expenditure (3 tertiles: low, <521 kcal/d; middle, 521-770 kcal/d; high, >770 kcal/d) and all-cause mortality. RESULTS: Fifty-five participants (18.2%) died during follow-up. As a continuous risk factor, an SD increase in free-living activity energy expenditure (287 kcal/d) was associated with a 32% lower risk of mortality after adjusting for age, sex, race, study site, weight, height, percentage of body fat, and sleep duration (hazard ratio, 0.68; 95% confidence interval, 0.48-0.96). Using the same adjustments, individuals in the highest tertile of free-living activity energy expenditure were at a significantly lower mortality risk compared with the lowest tertile (hazard ratio, 0.31; 95% confidence interval, 0.14-0.69). Absolute risk of death was 12.1% in the highest tertile of activity energy expenditure vs 24.7% in the lowest tertile; absolute risks were similar to these for tertiles of physical activity level. The effect of free-living activity energy expenditure changed little after further adjustment for self-rated health, education, prevalent health conditions, and smoking behavior. According to self-reports, individuals expending higher levels of free-living activity energy were more likely to work for pay (P = .004) and climb stairs (P = .01) but self-reported high-intensity exercise, walking for exercise, walking other than for exercise, volunteering, and caregiving did not differ significantly across the activity energy expenditure tertiles. CONCLUSIONS: Objectively measured free-living activity energy expenditure was strongly associated with lower risk of mortality in healthy older adults. Simply expending energy through any activity may influence survival in older adults.

Activities of Daily Living↗
PubMed2006

Association between infant birth weight and maternal cardiovascular risk factors in the health, aging, and body composition study.

PURPOSE: Mothers who deliver a low-birth-weight (LBW) infant may themselves be at excess risk for cardiovascular disease. We investigated whether older women who bore LBW infants had higher blood pressure, lipid, glucose, insulin, interleukin 6 (IL-6), and C-reactive protein concentrations, and pulse wave velocity compared to women with normal-weight births. METHODS: Participants were 446 women with a mean age of 80 years and 47% black. Women reported birth weight and complications for each pregnancy. Analysis was limited to first births not complicated by hypertension or preeclampsia. RESULTS: Women who had delivered a first-birth infant weighing less than 2500 g had a lower body mass index (BMI) compared with women with a normal-weight (>or=2500 g) infant (26.7 versus 28.4 kg/m2; p=0.02), but they had a larger abdominal circumference for BMI (97.9 versus 95.5 cm; p=0.05). They also were marginally more likely to be administered antihypertensive medication (p=0.06). After adjustment for BMI, race, and age, women with a history of a small infant had elevations in systolic blood pressure (p=0.05) and greater IL-6 levels (p=0.02) and were more insulin resistant (p=0.05) compared with women with a normal-weight infant. CONCLUSIONS: These findings suggest that a history of LBW delivery identifies women with elevated cardiovascular risk factors.

Black or African American↗
PubMed2006

Negative energy balance induced by voluntary wheel running inhibits polyp development in APCMin mice.

Treadmill running of approximately 0.9 km/day has had inconsistent effects on spontaneous intestinal polyp development in C57BL/6J-Apc(Min)/J (Min) mice; the amount of energy expenditure and/or a lack of hormonal changes could account for this variability. The purpose of this study was to examine the effects of a negative energy balance induced by voluntary wheel running on polyps, insulin-like growth factor-1 (IGF-1) and corticosterone in Min mice. Seven-week-old male Min mice were randomly assigned to control (CON, n = 23) or wheel running (EX, n = 24) conditions for a 10-week study period. All mice had water and AIN-76A diet ad libitum for the first approximately 3 weeks on study, after which the EX group was pair-fed to the CON group to maintain a negative energy balance due to the exercise. EX mice voluntarily ran 3.8 km/day (2.7-6.0 km/day) (median, interquartile range) and weighed less than CON mice throughout the study. More CON mice died before the end of the study versus EX mice (26 versus 0%, P < 0.01). CON mice had significantly more polyps versus EX mice (21.6 +/- 1.5 versus 16.9 +/- 2.0, P < 0.01; mean +/- SE), and daily running distance in EX was inversely correlated with total polyp number (r = -0.70, P < 0.01). Urinary corticosterone output (P < 0.01) and serum IGF-1 were significantly higher in EX than CON (P < 0.001); however, total polyp number was unrelated to corticosterone (r = 0.05, P = 0.84) and IGF-1 (r = -0.01, P = 0.93). In this study, a negative energy balance produced by wheel running exercise and restricted feeding decreased polyp burden in male Min mice and appeared to have a dose-response effect on polyp number. Although EX affected IGF-1 and corticosterone, neither marker was related to total polyp number.

Animals↗
PubMed2006

Influence of marital status on physical activity levels among older adults.

PURPOSE: The purpose of these analyses was to describe the levels and types of activity in relationship to current marital status among older adults and determine if the physical activity level of the husband was related to the physical activity level of his wife. METHODS: Participants included 3075 well-functioning white and black men and women aged 70-79 yr with further examination of 345 spousal pairs. Marital status was self-reported and participants were grouped as married versus not married. Based on responses to a leisure-time questionnaire, total physical activity was calculated and participants were classified as low or high active. Descriptive statistics were used to describe level and proportions of type of activity by marital status. Logistic regression was used to determine if marital status was an important determinant of physical activity participation. Regression models were adjusted for demographics, body mass index (BMI), and chronic disease conditions. RESULTS: When compared with their single counterparts, married men reported higher median levels of exercise participation (P = 0.008) and married women reported higher levels of total (P < 0.0001) and nonexercise activity (P < 0.0001) with a trend toward higher exercise participation (P = 0.05). In spousal pairs, compared with men in the low active group, highly active men were almost three times as likely (OR = 2.97; 95% CI = 1.73, 5.10) to have a similarly active spouse. The model only modestly attenuated when adjusted for age, BMI, and health status of the husband [OR = 2.49 (1.41, 4.42)]. CONCLUSIONS: Marital status and spousal physical activity (PA) levels are important determinants for PA participation among older adults.

Aged↗
PubMed2006

Diabetes, hyperglycemia, and inflammation in older individuals: the health, aging and body composition study.

OBJECTIVE: The objective of this study was to assess the association of inflammation with hyperglycemia (impaired fasting glucose [IFG]/impaired glucose tolerance [IGT]) and diabetes in older individuals. RESEARCH DESIGN AND METHODS: Baseline data from the Health, Aging and Body Composition study included 3,075 well-functioning black and white participants, aged 70-79 years. RESULTS: Of the participants, 24% had diabetes and 29% had IFG/IGT at baseline. C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels (P < 0.001) were significantly higher among diabetic participants and those with IFG/IGT. Odds of elevated IL-6 and TNF-alpha (>75th percentile) were, respectively, 1.95 (95% CI 1.56-2.44) and 1.88 (1.51-2.35) for diabetic participants and 1.51 (1.21-1.87) and 1.14 (0.92-1.42) for those with IFG/IGT after adjustment for age, sex, race, smoking, alcohol intake, education, and study site. Odds ratios for elevated CRP were 2.90 (2.13-3.95) and 1.45 (1.03-2.04) for diabetic women and men and 1.33 (1.07-1.69) for those with IFG/IGT regardless of sex. After adjustment for obesity, fat distribution, and inflammation-related conditions, IL-6 remained significantly related to both diabetes and IFG/IGT. CRP in women and TNF-alpha in both sexes were significantly related to diabetes, respectively, whereas risk estimates for IFG/IGT were decreased by adjustment for adiposity. Among diabetic participants, higher levels of HbA(1c) were associated with higher levels of all three markers of inflammation, but only CRP remained significant after full adjustment. CONCLUSIONS: Our findings show that dysglycemia is associated with inflammation, and this relationship, although consistent in diabetic individuals, also extends to those with IFG/IGT.

Aged↗
PubMed2005

Angiotensin-converting enzyme insertion/deletion genotype, exercise, and physical decline.

CONTEXT: Physical performance in response to exercise appears to be influenced by the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) genotype in young adults, but whether this relationship could help explain variation in older individuals' response to exercise has not been well studied. OBJECTIVE: To determine whether the ACE genotype interacts with significant physical activity to affect the incidence of mobility limitation in well-functioning older adults. DESIGN, SETTING, AND PARTICIPANTS: The Health Aging and Body Composition (Health ABC) Cohort Study, conducted in the metropolitan areas of Memphis, Tenn, and Pittsburgh, Pa. A total of 3075 well-functioning community-dwelling adults aged 70 through 79 years were enrolled from 1997 to 1998 and had a mean of 4.1 years of follow-up. MAIN OUTCOME MEASURE: Incident mobility limitation defined as the report of difficulty walking a quarter of a mile (0.4 km) or walking up 10 steps on 2 consecutive semiannual interviews (n = 1204). RESULTS: Physically active participants (those reporting expending > or =1000 kcal/wk in exercise, walking, and stair climbing) were less likely to develop mobility limitation regardless of genotype. However, activity level interacted significantly with the ACE genotype (P = .002). In the inactive group, the ACE genotype was not associated with limitation (P = .46). In the active group, those with the II genotype were more likely to develop mobility limitation after adjusting for potential confounders compared with those with ID/DD genotypes (adjusted rate ratio, 1.45, 95% confidence interval, 1.08-1.94). The gene association was especially strong among participants reporting weightlifting. Exploration of possible physiological correlates revealed that among active participants, those with the II genotype had higher percentage of body fat (P = .02) and more intermuscular thigh fat (P = .02) but had similar quadriceps strength as those with ID/DD. CONCLUSIONS: Among older individuals who exercised, those with the ACE DD or ID genotypes were less likely to develop mobility limitation than those with the II genotype. Regardless of genotype, individuals who exercised were less likely to develop mobility limitation than those who did not exercise.

Aged↗
PubMed2005

Type and intensity of activity and risk of mobility limitation: the mediating role of muscle parameters.

OBJECTIVES: To investigate the association between different types of physical activity behavior and incident mobility limitation in older men and women and to examine whether muscle parameters mediate these associations. DESIGN: Cohort study with 4.5-year follow-up. SETTING: Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. A random sample of white Medicare beneficiaries and all age-eligible blacks. PARTICIPANTS: Three thousand seventy-five black and white men and women aged 70 to 79 with no self-reported difficulty walking one-quarter of a mile or climbing 10 steps, enrolled in the Health, Aging and Body Composition (Health ABC) Study. MEASUREMENTS: Participants were classified as exercisers (reporting > or = 1,000 kcal/wk of exercise activity), lifestyle active (reporting < 1,000 kcal/wk of exercise activity and > or = 2,719 kcal/wk of total physical activity), or inactive (reporting < 1,000 kcal/wk of exercise activity and < 2,719 kcal/wk of total physical activity). The study outcome, incident mobility limitation, was defined as two consecutive, semiannual self-reports of any difficulty walking one quarter of a mile or climbing 10 steps. Thigh muscle area, thigh muscle attenuation (a marker of fat infiltration in muscle), appendicular lean soft tissue mass, and isokinetic knee extensor strength were examined as potential mediators. RESULTS: Over 4.5 years, 34.3% of men and 47.4% of women developed mobility limitation. Inactive persons had twice the risk of incident mobility limitation as exercisers (hazard ratio (HR)=2.08, 95% confidence interval (CI)=1.60-2.70, for men, HR=1.98, 95% CI=1.51-2.60, for women). Lifestyle-active men and women had an intermediate risk (HR=1.47 and 1.44, respectively). For the lifestyle active and inactive, absence of walking activity conferred an additional risk of mobility limitation. Muscle parameters did not mediate the relationship between physical activity and mobility limitation, except for knee extensor strength in men. CONCLUSION: Exercise and an active lifestyle that includes walking protect against mobility loss in older men and women. Activity effects on muscle parameters do not explain this association.

Activities of Daily Living↗
PubMed2005

Circulating levels of inflammatory markers and cancer risk in the health aging and body composition cohort.

BACKGROUND: Chronic inflammation is associated with processes that contribute to the onset or progression of cancer. This study examined the relationships between circulating levels of the inflammatory markers interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-alpha) and total as well as site-specific cancer incidence. METHODS: Study subjects (n = 2,438) were older adults (ages 70-79 years) participating in the Health Aging and Body Composition study, who did not report a previous cancer diagnosis (except for nonmelanoma skin cancer) at baseline. Incident cancer events (n = 296) were ascertained during an average follow-up of 5.5 years. Inflammatory markers were measured in stored baseline fasting blood samples. RESULTS: The adjusted hazard ratios (95% confidence intervals) for incident cancer associated with a 1-unit increase on the natural log-scale were 1.13 (0.94-1.37), 1.25 (1.09-1.43), and 1.28 (0.96-1.70) for IL-6, CRP, and TNF-alpha, respectively. Markers were more strongly associated with cancer death: hazard ratios were 1.63 (1.19-2.23) for IL-6, 1.64 (1.20-2.24) for CRP, and 1.82 (1.14-2.92) for TNF-alpha. Although precision was low for site-specific analyses, our results suggest that all three markers were associated with lung cancer, that IL-6 and CRP were associated with colorectal cancer, and that CRP was associated with breast cancer. Prostate cancer was not associated with any of these markers. CONCLUSIONS: These findings suggest that (a) the associations between IL-6, CRP, and TNF-alpha and the risk of cancer may be site specific and (b) increased levels of inflammatory markers are more strongly associated with the risk of cancer death than cancer incidence.

Aged↗
PubMed2005

Estrogen replacement, muscle composition, and physical function: The Health ABC Study.

PURPOSE: Although the beneficial effects of estrogen use on cardiovascular and cognitive function in postmenopausal women have been recently discredited, controversy remains regarding its usefulness for maintaining skeletal muscle mass or strength. Therefore, the purpose of this study was to determine whether estrogen use is associated with enhanced muscle composition and, if so, whether this translates into improved strength and physical function. METHODS: Cross-sectional analysis of 840 well-functioning community-dwelling white women (current estrogen replacement therapy (ERT) users = 259, nonusers = 581) aged 70-79 yr participating in the Health, Aging and Body Composition Study. Muscle composition of the midthigh by computed tomography included cross-sectional area (CSA) of the quadriceps, hamstrings, intermuscular fat and subcutaneous fat, and muscle attenuation in Hounsfield units (HU) as a measure of muscle density. Isometric hand grip and isokinetic knee extensor strength were assessed by dynamometry. Physical function was assessed using a summary scale that included usual 6-m walk and narrow walk speed, repeated chair stands, and standing balance. RESULTS: In analyses of covariance adjusted for relevant confounders, quadriceps muscle CSA and HU were greater in current ERT than non-ERT women (P < 0.05). Grip strength was also greater (P < 0.05) in women taking ERT while knee extensor strength approached significance (P < 0.10). However, differences in muscle composition and strength were modest at < or =3.3%. There was no difference by ERT status for the hamstring muscles, fat CSA, or for physical function. CONCLUSION: The associations between ERT and muscle composition and strength were minor and did not translate into improved physical function. Initiation of ERT for preservation of muscle composition and function may not be indicated.

Aged↗
PubMed2004

Physical activity, exercise, and inflammatory markers in older adults: findings from the Health, Aging and Body Composition Study.

OBJECTIVES: To examine the association between physical activity and inflammatory markers, with consideration for body fatness and antioxidant use. DESIGN: Cross-sectional study, using baseline data from the Health, Aging and Body Composition Study. SETTING: Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Black and white, well-functioning men and women (N=3,075), aged 70 to 79. MEASUREMENTS: Interviewer-administered questionnaires of previous-week household, walking, exercise, and occupational/volunteer physical activities. Analysis of covariance was used to examine the association between activity level and serum C-reactive protein (CRP), interleukin-6 (IL-6), and plasma tumor necrosis factor alpha (TNFalpha) with covariate adjustment. Antioxidant supplement use (multivitamin, vitamins E or C, beta carotene) was evaluated as an effect modifier of the association. RESULTS: Higher levels of exercise were associated with lower levels of CRP (P<.01), IL-6 (P<.001), and TNFalpha (P=.02) (e.g., CRP=1.95 mg/L for no exercise and 1.72 for >180 min/wk). Adjustment for body fatness attenuated the associations somewhat. Use of antioxidant supplements modified the CRP (P(interaction)=.01) and IL-6 (P(interaction)=.08) associations such that concentrations were low in those taking supplements (e.g., CRP=1.79-1.84 across exercise levels) and higher in nonsupplement users who did no exercise (2.03) than in those who did the most (1.72). Among nonexercisers, higher levels of other physical activity were related to lower levels of CRP (P<.01) and IL-6 (P=.02) but not TNFalpha (P=.36), even after accounting for body fat. CONCLUSION: Inflammatory markers are lower in older adults with higher levels of exercise and nonexercise activity and in antioxidant supplement users regardless of exercise level.

Aged↗
PubMed2004

Physical activity and risk of ovarian cancer: a prospective cohort study in the United States.

Increased physical activity may lower the risk of ovarian cancer by reducing the frequency of ovulation, decreasing body fat, or diminishing chronic inflammation. Previous epidemiological studies examining the association between physical activity and risk of ovarian cancer have been inconsistent. We investigated the association of physical activity with ovarian cancer in a prospective cohort of 27,365 individuals from the Breast Cancer Detection Demonstration Project. During 227,045 person-years of follow-up, 121 cases of ovarian cancer were ascertained. Usual physical activity during the past year was assessed by a self-administered questionnaire. After adjusting for potential risk factors for ovarian cancer, the relative risks (95% confidence intervals) across increasing quintiles of total physical activity were 1.0, 0.73 (0.43-1.25), 0.84 (0.50-1.40), 0.56 (0.31-1.00), and 0.70 (0.41-1.21), respectively (P for trend = 0.13). In this prospective cohort study among U.S. women, we found no overall significant association between physical activity and risk of ovarian cancer, although the results are suggestive of an inverse association.

Adult↗
PubMed2003

Association of high coronary heart disease risk status with circulating oxidized LDL in the well-functioning elderly: findings from the Health, Aging, and Body Composition study.

OBJECTIVE: Although circulating oxidized LDL (oxLDL) is elevated in persons with coronary heart disease (CHD), whether oxLDL is elevated in persons with high CHD risk before any events is unknown. Therefore, we studied the association between high, predicted CHD risk and oxLDL in the Health ABC cohort. METHODS AND RESULTS: This cohort included 385 persons with CHD and 1183 persons at high risk; the latter were all persons with CHD risk equivalents: noncoronary forms of clinical atherosclerotic disease, diabetes, and a 10-year risk for CHD >20% by Framingham scoring. The remaining 1535 participants were at low risk. Levels of oxLDL were 1.18+/-0.61 mg/dL for low-risk persons, 1.50+/-0.81 mg/dL for high-risk persons without diagnosed CHD, and 1.32+/-0.83 mg/dL for persons with CHD (P<0.001). The odds ratio for high CHD risk in the highest quintile of oxLDL, compared with the lowest quintile and after adjusting for age, sex, race, LDL cholesterol, smoking status, and C-reactive protein, was 2.79 (P<0.001). CONCLUSIONS: The odds ratio for elevated oxLDL among persons with high CHD risk before any CHD events was higher than that among persons with established CHD. A likely explanation is that once CHD is diagnosed, individuals are frequently treated with a statin, which is associated with lowering of LDL cholesterol and oxLDL levels.

Aged↗
PubMed2003

Calorie restriction and diet composition modulate spontaneous intestinal tumorigenesis in Apc(Min) mice through different mechanisms.

We evaluated the effects of diet on intestinal tumorigenesis in male Apc(Min) mice by comparing AIN-76A diet fed ad libitum (CON); calorie intake restricted by 40% of the CON (CR); diet high in olive oil and supplemented with freeze-dried fruit and vegetable extracts (OFV); and diet high in total fat (HF). Compared with CON, the frequency of intestinal polyps was reduced by 57% by CR (P < 0.001) and by 33% OFV diet (P = 0.04). Both effective interventions reduced total body weight, lean mass, and fat mass and increased daily urinary corticosterone output, but only CR reduced serum insulin-like growth factor I and leptin. We conclude that dietary interventions can partially offset genetic susceptibility to intestinal carcinogenesis.

Animals↗
PubMed2003

Physical activity and risk of endometrial cancer in a prospective cohort study (United States).

OBJECTIVE: To examine the physical activity and endometrial cancer relationship in a prospective study of US women enrolled in the Breast Cancer Detection Demonstration Project (BCDDP) Follow-up Study. METHODS: We assessed past-year physical activity of all types in 23,369 women who returned the baseline questionnaire (1987-1989) and had no prior hysterectomy and/or endometrial cancer. Cox proportional hazards models were used to estimate age, education, and parity-adjusted rate ratios (RR) and 95% confidence intervals (CI) for the 253 confirmed endometrial cancer cases identified during an average 8.2 years of follow-up (ending 1995-1998). RESULTS: There were no dose-response relationships with either total or vigorous physical activity; however, compared to the lowest total activity quartile, the higher four quartiles had a non-significantly lower risk (RR = 0.8, CI = 0.6-1.0). The association with moderate activity varied with follow-up time: RRs (CI) for a 1 h increase in daily moderate activity within 2-year intervals of follow-up (< or = 2, 2.1-4.9, 5.0-8.0, > 8 years) were 1.1 (1.0, 1.2), 1.0 (0.9, 1.1), 1.0 (0.9, 1.1), 1.0 (0.9, 1.1), and 0.8 (0.7, 1.0), respectively. CONCLUSION: These data suggest that recent physical activity is not strongly related to the risk of endometrial cancer, and that prolonged exposure and longer follow-up may be necessary.

Aged↗
PubMed2003

Exercise and intestinal polyp development in APCMin mice.

PURPOSE: Epidemiological evidence suggests that physical activity protects against colon cancer. We previously used a mouse predisposed to intestinal polyps (APCMin) to evaluate this association and found the suggestion of fewer polyps in exercised males but not females. The present study was designed to further explore the potential exercise x sex interaction on polyp development and to begin to look at potential mechanisms. METHODS: Six-week-old APCMin mice (N = 60 males; 60 females) were randomly assigned to one of two groups by sex: treadmill running at 20 m.min-1, 5% grade, 45 min.d-1, 5 d.wk-1 (EX) or nonrunning controls (CON) (N = 30 per group). EX mice ran in running wheels while in quarantine (weeks 0-3), followed by treadmill running weeks 3-8. Body weights were measured weekly. Urine was collected at 5 wk and fasting blood at 7.5 wk. Body composition was measured, serum was frozen, and polyp number and size were measured at sacrifice. RESULTS: EX resulted in lower body weights (P < 0.01) and reduced fat mass (P < 0.01). Fasting glucose was lower in EX (P < 0.01), and leptin was lower in EX (P = 0.05) compared with CON. EX did not affect serum insulin-like growth factor-1 or urinary corticosterone. Total polyp number and size were not statistically different between groups; however, there were fewer jejunal polyps in EX (3.6 +/- 0.7, mean +/- SE) versus CON males (5.2 +/- 0.8; P = 0.04) and an even larger difference when only the consistent runners were kept in the analysis (2.7 +/- 0.5 in EX; P = 0.01). CONCLUSION: Despite favorable changes in body composition, blood glucose, and leptin, 8 wk of running resulted in only minor changes related to polyp development in male but not female APCMin mice.

Animals↗