Greater male variability in daily energy expenditure develops through puberty.

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages.

Patterns of sedentary behavior and physical function in older adults.

BACKGROUND/AIMS: The purposes of this study were to examine the relationship between various objectively measured sedentary behavior (SB) variables and physical function in older adults, examine the measurement properties of an SB questionnaire, and describe the domains of SB in our sample. METHODS: Forty-four older adults (70 ± 8 years, 64 % female) had their SB measured via activPAL activity monitor and SB questionnaire for 1 week followed by performance-based tests of physical function. RESULTS: The pattern of SB was more important than total SB time. Where a gender by SB interaction was found, increasing time in SB and fewer breaks were associated with worse function in the males only. The SB questionnaire had acceptable test-retest reliability but poor validity compared to activPAL-measured SB. The majority of SB time was spent watching television, using the computer and reading. DISCUSSION/CONCLUSIONS: This study provides further evidence for the association between SB and physical function and describes where older adults are spending their sedentary time. This information can be used in the design of future intervention to reduce sedentary time and improve function in older adults.

Dose-response relationships between sedentary behaviour and the metabolic syndrome and its components.

AIMS/HYPOTHESIS: The aim of this study was to examine the relationship among sedentary behaviour (SB) and the metabolic syndrome and its components by age, moderate-to-vigorous physical activity (MVPA) and sex. METHODS: A cross-sectional analysis was performed on 2003-2006 National Health and Nutrition Examination Survey data from 5,076 adults aged ≥18 years (mean ± SD = 43.8 ± 19.5). SB was measured using ActiGraph accelerometers worn for 1 week and defined as <100 counts/min. Metabolic syndrome was defined using the Adult Treatment Panel III criteria. Natural cubic spline logistic regression models were used to estimate the odds of meeting criteria for the metabolic syndrome and its components by total daily SB time and breaks in SB. Statistical interactions between SB and age, sex and MVPA were explored. RESULTS: The prevalence of the metabolic syndrome was 19% and the average daily SB time was 8.1 ± 2.8 h, with 90 ± 25 breaks/day. The relationship between daily SB time and the metabolic syndrome was linear and characterised by an OR of 1.09 (95% CI 1.01, 1.18) for each hour of SB. Total SB was associated with the following components: high triacylglycerol, low HDL-cholesterol and high fasting glucose. All three associations were modified by MVPA level. No relationship between breaks in SB and the metabolic syndrome was found. CONCLUSIONS/INTERPRETATION: There appears to be no SB threshold at which the risk of the metabolic syndrome is elevated. Therefore, an effort should be made to maintain low levels of total time spent in SB and so lessen the risk of the metabolic syndrome.

Smokers' physical activity and weight gain one year after a successful versus unsuccessful quit attempt.

OBJECTIVE: To examine whether smokers' physical activity is related to weight change following a quit attempt. METHOD: Data were analyzed for participants (n=683) of a randomized controlled trial comparing the efficacy of different smoking cessation pharmacotherapies (Wisconsin, 2005-2008). Activity (assessed via pedometry) and body weight were measured in the days surrounding the quit day and again one year later, at which time 7-day point-prevalence abstinence from smoking was assessed. We examined the effects of quitting, physical activity, and their interaction, on a one-year weight change with relevant covariate adjustment. RESULTS: Participants were predominantly female (57%), 46 ± 11 years of age (mean ± SD), and took 7544 ± 3606 steps/day at baseline. Of those who quit, 87% gained weight. A main effect was found for quitting (p<0.001), but not physical activity (p=0.06). When pattern of activity was examined across the 1-year study period, quitters who decreased their physical activity had significantly greater weight gain than quitters who increased their physical activity (p<0.01) or maintained a high level of activity (p=0.02). CONCLUSION: Physical activity is associated with an attenuation of the weight gain that often occurs after quitting smoking.

Executive dysfunction is independently associated with reduced functional independence in heart failure.

AIMS AND OBJECTIVES: To examine the independent association between executive function with instrumental activities of daily living and health behaviours in older adults with heart failure. BACKGROUND: Executive function is an important contributor to functional independence as it consists of cognitive processes needed for decision-making, planning, organising and behavioural monitoring. Impairment in this domain is common in heart failure patients and associated with reduced performance of instrumental activities of daily living in many medical and neurological populations. However, the contribution of executive functions to functional independence and healthy lifestyle choices in heart failure patients has not been fully examined. DESIGN: Cross-sectional analyses. METHODS: One hundred and seventy-five heart failure patients completed a neuropsychological battery and echocardiogram. Participants also completed the Lawton-Brody Instrumental Activities of Daily Living Scale and reported current cigarette use. RESULTS: Hierarchical regressions revealed that reduced executive function was independently associated with worse instrumental activity of daily living performance with a specific association for decreased ability to manage medications. Partial correlations showed that executive dysfunction was associated with current cigarette use. CONCLUSIONS: Our findings suggest that executive dysfunction is associated with poorer functional independence and contributes to unhealthy behaviours in heart failure. Future studies should examine whether heart failure patients benefit from formal organisation schema (i.e. pill organisers) to maintain independence. RELEVANCE TO CLINICAL PRACTICE: Screening of executive function in heart failure patients may provide key insight into their ability to perform daily tasks, including the management of treatment recommendations.

Intensity of physical activity in the energy expenditure of older adults.

This study examined the intensity of activity contributing to physical activity energy expenditure in older adults. In 57 men and women aged ≥ 65, total energy expenditure (TEE) was measured using doubly labeled water and resting metabolic rate was measured using indirect calorimetry to calculate a physical activity index (PAI). Sedentary time and physical activity of light and moderate to vigorous (mod/vig) intensity was measured using an accelerometer. The subjects were 75 ± 7 yrs (mean ± SD) of age and 79% female. Subjects spent 66 ± 8, 25 ± 5, and 9 ± 4% of monitor wear time in sedentary, light, and mod/vig activity per day, respectively. In a mixture regression model, both light (ß = 29.6 [15.6-43.6, 95% CI]), p < .001) and mod/vig intensity activity (ß = 28.7 [7.4-50.0, 95% CI]), p = .01) were strongly associated with PAI, suggesting that both light and mod/vig intensity activities are major determinants of their physical activity energy expenditure.

Cognitive function and treatment adherence in older adults with heart failure.

OBJECTIVE: Treatment recommendation and guidelines for patients with heart failure (HF) can be complex, and past work has shown that patients with HF demonstrate low rates of adherence to recommended health behaviors. Although previous work has identified several medical, demographic, and psychosocial predictors of the capacity to adhere to treatment recommendations of persons with HF, little is known about the contribution of cognitive impairment to reported treatment adherence in this population. METHODS: A total of 149 persons with HF (mean [standard deviation] = 68.08 [10.74] years) completed a brief fitness assessment and neuropsychological testing. Treatment adherence was assessed using the Heart Failure Compliance Questionnaire, a brief measure that asks participants to report their adherence to a variety of recommended health behaviors (i.e., medication management, diet, and exercise, among others). RESULTS: The percentage of participants who reported poor overall adherence was 16.1%, with particularly high rates of nonadherence to dietary and exercise recommendations. Hierarchical regression analyses adjusting for possible confounds revealed that reduced performance on attention (ß = .26, p = .01), executive function (ß = .18, p = .04), and language (ß = .22, p = .01) was associated with poorer overall adherence. Follow-up analyses showed that these cognitive domains were associated with behaviors such as keeping doctor appointments, medication management, and dietary recommendations (p < .05 for all). CONCLUSIONS: The current findings demonstrate that cognitive function is an independent contributor to adherence in older adults with HF. Prospective studies that objectively measure treatment adherence are needed to clarify these findings and identify possible strategies to improve outcomes in this population. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00871897.

The 2-minute step test is independently associated with cognitive function in older adults with heart failure.

BACKGROUND AND AIMS: Cognitive impairment is common in persons with heart failure (HF), and measures like the 6-minute walk test (6MWT) are known to correspond to level of impairment. The 2- minute step test (2MST) has been suggested as a more practical alternative to the 6MWT, though no study has examined whether it is associated with cognitive impairment in persons with HF. This study examined whether the 2MST is associated with cognitive function in older adults with HF. METHODS: Older adults with HF (n=145; 68.97±9.31 yrs) completed the 2MST and a neuropsychological test battery that assessed function in multiple cognitive domains. RESULTS: Consistent with past work, HF patients exhibited high rates of cognitive impairment. Hierarchical regression analyses adjusting for demographic and medical characteristics found that the 2MST accounted for unique variance in global cognitive function (ΔR²=0.09, p<0.001), executive function (ΔR²=0.03, p<0.05), and language (ΔR²=0.10, p<0.001). A trend emerged for attention (ΔR²=0.02, p=0.09). Follow-up tests indicated that better 2MST performance was significantly correlated with better global cognitive function, attention, executive, and language test performance. CONCLUSION: The current results indicate that the 2MST is associated with cognitive function in older adults with HF. Further work is needed to clarify underlying mechanisms for this association and the value of implementing the 2MST during routine visits.

Cognitive impairment is independently associated with reduced instrumental activities of daily living in persons with heart failure.

BACKGROUND: Heart failure (HF) is a disabling disease that often affects instrumental activities of daily living (instrumental ADLs). Despite high rates of disability in this population, little is known about the effects of cognitive impairment on instrumental ADLs in this population. OBJECTIVE: The current study examined whether cognitive functioning predicts instrumental ADL performance in persons with HF. METHODS: Persons with HF (N = 122; 68.49 [SD, 9.43] years; 35.2% female) completed neuropsychological testing, fitness assessment, and self-reported instrumental and basic ADL function as part of a larger protocol. Neuropsychological tests included the Mini-Mental State Examination and Trail Making Tests A and B. The 2-minute step test estimated fitness. Instrumental and basic ADL function was based on self-report on the Lawton-Brody Activities of Daily Living Scale. Hierarchical regression analyses were used to determine the independent contribution of cognitive function to ADLs in HF. RESULTS: Heart failure patients reported high rates of impairments in instrumental ADLs, but indicated requiring little or no assistance with basic ADLs. Cognitive function showed incremental predictive validity for driving (R(2) change = .07, P = .03) and medication management (R(2) change = .14, P < .001). In each case, poorer neuropsychological test performance was associated with poorer instrumental ADL function. CONCLUSION: In persons with HF, cognitive performance is an independent predictor of independence in driving and medication management. Strategies to maintain or improve cognitive functioning in HF may help patients remain functionally independent in their daily living.

Activity energy expenditure and mobility limitation in older adults: differential associations by sex.

In this study, the authors aimed to determine whether higher activity energy expenditure, assessed by using doubly labeled water, was associated with a reduced decline in mobility limitation among 248 older community-dwelling US adults aged 70-82 years enrolled in 1998-1999. Activity energy expenditure was calculated as total energy expenditure (assessed over 2 weeks by using doubly labeled water) minus resting metabolic rate (measured with indirect calorimetry), with adjustment for the thermic effect of food. Across sex-specific tertiles of activity energy expenditure, men in the lowest activity group experienced twice the rate of mobility limitation as men in the highest activity group (41% (n = 18) vs. 18% (n = 8)). Conversely, women in the lowest and highest activity groups exhibited similarly high rates of mobility limitation (40% (n = 16) vs. 38% (n = 15)). After adjustment for potential confounders, men with higher activity energy expenditure levels continued to show reduced risk of mobility limitation (per standard deviation (284 kcal/day): hazard ratio = 0.61, 95% confidence interval: 0.41, 0.92). Women showed no association (per standard deviation (226 kcal/day): hazard ratio = 1.34, 95% confidence interval: 0.98, 1.85). Greater energy expenditure from any and all physical activity was significantly associated with reduced risk of developing mobility limitation among men, but not among women.

Physical activity and function in older, long-term colorectal cancer survivors.

OBJECTIVE: Increasing age and cancer history are related to impaired physical function. Since physical activity has been shown to ameliorate age-related functional declines, we evaluated the association between physical activity and function in older, long-term colorectal cancer survivors. METHODS: In 2006-2007, mailed surveys were sent to colorectal cancer survivors, aged > or = 65 years when diagnosed during 1995-2000, and identified through a state cancer registry. Information on physical activity, physical function, and relevant covariates was obtained and matched to registry data. Analysis of covariance and linear regression were used to compare means and trends in physical function across levels of activity in the final analytic sample of 843 cases. RESULTS: A direct, dose-dependent association between physical activity and function was observed (p(trend) < .001), with higher SF-36 physical function subscores in those reporting high versus low activity levels (65.0 +/- 1.7 vs. 42.7 +/- 1.7 (mean +/- standard error)). Walking, gardening, housework, and exercise activities were all independently related to better physical function. Moderate-vigorous intensity activity (p(trend) < .001) was associated with function, but light activity (p(trend) = 0.39) was not. CONCLUSION: Results from this cross-sectional study indicate significant associations between physical activity and physical function in older, long-term colorectal cancer survivors.

Physical activity during pregnancy and age at menarche of the daughter.

In utero exposures have been proposed as possible determinants of later disease risk. Given that a later age at menarche is a breast cancer risk factor, and that higher childhood physical activity has been associated with a later menarcheal age, it is possible that a pregnant mother's activity may also influence this outcome. The purpose of this study was to determine if a mother's physical activity during pregnancy is related to their daughter's menarcheal age. Participants of the Nurses' Health Study II reported their age at menarche to the nearest year, whereas their mothers (n=33,016) completed surveys regarding their health and lifestyle habits during their pregnancy with their daughters. Mothers reported their home, occupational, and leisure-time physical activities, as well as the activity of their daughters at ages 5 to 10 years. Using multiple linear regression analysis with adjustment for specific covariates including daughter's childhood body size, neither home nor occupational activity alone were associated with age at menarche of the daughter, but there was a direct association with leisure-time physical activity (P(trend)<0.001). Compared with women inactive in their leisure-time, women who were highly active had daughters with menarche 1.1 (95% confidence interval, 0.3-1.9) months later. Using a composite variable of both home and leisure-time activity, daughters of women who were highly active at home and in their leisure-time had daughters with menarche 3.1 (95% confidence interval, 0.4-5.9) months later than those who were highly inactive in both. Physical activity during pregnancy may be associated with a modest delay in menarcheal age in offspring.

Physical activity and cancer prevention : pathways and targets for intervention.

The prevalence of obesity, an established epidemiological risk factor for many cancers, has risen steadily for the past several decades in the US and many other countries. Particularly alarming are the increasing rates of obesity among children, portending continuing increases in the rates of obesity and obesity-related cancers for many years to come. Modulation of energy balance, via increased physical activity, has been shown in numerous comprehensive epidemiological reviews to reduce cancer risk. Unfortunately, the effects and mechanistic targets of physical activity interventions on the carcinogenesis process have not been thoroughly characterized. Studies to date suggest that exercise can exert its cancer-preventive effects at many stages during the process of carcinogenesis, including both tumour initiation and progression. As discussed in this review, exercise may be altering tumour initiation events by modifying carcinogen activation, specifically by enhancing the cytochrome P450 system and by enhancing selective enzymes in the carcinogen detoxification pathway, including, but not limited to, glutathione-S-transferases. Furthermore, exercise may reduce oxidative damage by increasing a variety of anti-oxidant enzymes, enhancing DNA repair systems and improving intracellular protein repair systems. In addition to altering processes related to tumour initiation, exercise may also exert a cancer-preventive effect by dampening the processes involved in the promotion and progression stages of carcinogenesis, including scavenging reactive oxygen species (ROS); altering cell proliferation, apoptosis and differentiation; decreasing inflammation; enhancing immune function; and suppressing angiogenesis. A paucity of data exists as to whether exercise may be working as an anti-promotion strategy via altering ROS in initiated or preneoplastic models; therefore, no conclusions can be made about this possible mechanism. The studies directly examining cell proliferation and apoptosis have shown that exercise can enhance both processes, which is difficult to interpret in the context of carcinogenesis. Studies examining the relationship between exercise and chronic inflammation suggest that exercise may reduce pro-inflammatory mediators and reduce the state of low-grade, chronic inflammation. Additionally, exercise has been shown to enhance components of the innate immune response (i.e. macrophage and natural killer cell function). Finally, only a limited number of studies have explored the relationship between exercise and angiogenesis; therefore, no conclusions can be made currently about the role of exercise in the angiogenesis process as it relates to tumour progression. In summary, exercise can alter biological processes that contribute to both anti-initiation and anti-progression events in the carcinogenesis process. However, more sophisticated, detailed studies are needed to examine each of the potential mechanisms contributing to an exercise-induced decrease in carcinogenesis in order to determine the minimum dose, duration and frequency of exercise needed to yield significant cancer-preventive effects, and whether exercise can be used prescriptively to reverse the obesity-induced physiological changes that increase cancer risk.

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.

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.

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.

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.

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.

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.

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.