Assessment of ability to recall physical activity of several years ago

The associations between social support change and physical activity trajectory from late adolescence to young adulthood

BACKGROUND

Previous research examined the associations between social support and physical activity. However, little is known about the associations between social support change and trajectories of physical activity during the transition from late adolescence to young adulthood.

METHODS

The current study sought to examine these issues among 434 Chinese college students (Mage = 19.15, SDage = 0.61; 46.1% male), who completed questionnaires regarding demographics, physical activity, family support change, and peer support change across three waves (the data from one of the waves was retrospective).

RESULTS

After controlling for covariates, the findings revealed that: (a) there was an increase in overall physical activity and duration, but a decrease in frequency during the transition from late adolescence (the second year of high school) to young adulthood (the third year of college); (b) family support change did not contribute to trajectories of physical activity, while peer support change significantly predicted the trajectory of overall physical activity, duration, and frequency.

CONCLUSIONS

The findings extend the literature on physical activity from a developmental perspective by revealing different trends among physical activity duration and frequency, and unpacking different effects of family and peer support change on trajectories of physical activity.

The Relationship of Neighborhood Walking Behavior to Duration of Aging in Place-A Retrospective Cohort Study

The benefits of physical activity on health are widely known. However, the impact of physical activity on aging-in-place at home for older adults is unclear. Focusing on older adults who recently moved from home to a senior-living facility, this research explored the impact of walking on the ability to age-in-place. Data were collected through a questionnaire survey completed by residents in 12 assisted-living facilities in Houston, Texas. Controlling for significant personal factors, ANOVAs were applied. Non-Hispanic White older adults (N = 124) who used canes or no aids and engaged in 30 min to 1 h of walking per occurrence were able to remain in their homes for an average of 17.84 years after age 65, 1.85 years longer than their counterparts who walked less than 30 min per occurrence. Those who walked for more than an hour per occurrence remained at home for 22.71 years on average, 6.72 years longer than their counterparts (p ≤ 0.05). Engaging in neighborhood walking may help older adults maintain more years of aging-in-place at home. The findings have a direct impact on both public health programs and community design and planning strategies promoting aging-in-place.

Analysis of Association between Adolescents' Food Habits and Body Mass Change in a Population-Based Sample: Diet and Activity of Youth during COVID-19 (DAY-19) Study

The COVID-19 pandemic may have contributed to food habit changes, including some negative ones that may increase the risk of overweight and obesity. The aim of the study was to analyze the association between adolescents' food habits, body mass change, as well as physical activity level in a population-based sample within the Diet and Activity of Youth during COVID-19 (DAY-19) Study. The DAY-19 Study was conducted in a cohort of 1333 students (aged 10-16 years) recruited in schools after stratified random quota sampling of primary schools (sampling counties within voivodeships and schools within counties) in June 2020. The food habits were assessed for the period of the COVID-19 pandemic and the period before the COVID-19 pandemic while using Adolescent Food Habits Checklist (AFHC). The body mass changes were assessed based on body weight and height for the period of the COVID-19 pandemic and the period before the COVID-19 pandemic while using Polish growth reference values. The physical activity changes were assessed based on the subjective assessment of adolescents. It was stated that for female adolescents declaring body mass gain during the COVID-19 pandemic the highest AFHC purchase scores (healthy purchase habits) (p < 0.0001) were accompanied by the lowest AFHC consumption score (unhealthy consumption habits) (p < 0.0001), as well as for female adolescents declaring physical activity decrease during the COVID-19 pandemic the highest AFHC purchase scores (healthy purchase habits) were observed (p = 0.0333). It was stated that for male adolescents declaring physical activity increased during the COVID-19 pandemic, the highest AFHC consumption scores (healthy consumption habits) were observed (p = 0.0003). In the case of a majority of participants, the general food habits were unchanged, which was observed mainly for food habits associated with food preparation. More food habits changes associated with the COVID-19 pandemic resulting in body mass changes were observed in females than in male adolescents. Body mass gain during the COVID-19 pandemic in adolescents may have resulted from unhealthy consumption habits, accompanied by decreased physical activity, in spite of the fact that this sub-group presented healthy purchase habits, which was observed especially for female adolescents.

Exercise and colorectal cancer: prevention and molecular mechanisms

Exercise and physical activity have been shown to be strongly associated with a decreased incidence rate of various chronic diseases especially numerous human malignancies. A huge number of clinical trials and meta-analysis have demonstrated that exercise is significantly effective in lowering the risk of colorectal cancer. In addition, it is suggested as an effective therapeutic modality against this cancer type. Therefore, in this review, we will review comprehensibly the effects of exercise in preventing, treating, and alleviating the adverse effects of conventional therapeutic options in colorectal cancer. Moreover, the possible mechanisms underlying the positive effects of exercise and physical activity in colorectal cancer, including regulation of inflammation, apoptosis, growth factor axis, immunity, epigenetic, etc. will be also discussed.

Exercise is an effective post-treatment management program in colorectal cancer survivals

Exercise improves muscle strength, cardiorespiratory fitness, emotional distress, physical activity, fatigue, and sleep quality in colorectal patients undergoing chemotherapy

Targeting and modulating insulin-like growth factor (IGF) system, inflammation, apoptosis, immunity, epigenetic, Leptin and Ghrelin, and signaling pathways are major underlying mechanisms for preventive effects of exercise in colorectal cancer

Metamemory mediates the protective effect of cognitive reserve on episodic memory during aging

The present study investigated the impact of cognitive reserve on episodic memory and metamemory control during aging using a multidimensional index of cognitive reserve and a measure of metamemory control abilities. We tested the hypotheses that cognitive reserve may play a protective role against age-related differences in episodic memory and metamemory control and that metamemory control may mediate the effect of cognitive reserve on episodic memory during aging. Young and older adults carried out a readiness-recall task in which task difficulty was manipulated through a variation of the nature of the cue-target pair link (weak vs. strong semantic associates). Episodic memory was assessed through recall performance, and metamemory by a task difficulty index reflecting the ability to adjust study time to task difficulty. Results confirmed that older adults recall fewer words, indicating an age-related deficit in episodic memory, and that older adults adjust less to task difficulty, suggesting impaired metamemory control. Findings also showed that metamemory control moderates the age-related decline in episodic memory and that cognitive reserve plays a protective role against age-related deficits in episodic memory and metamemory control. In addition, metamemory abilities mediated the beneficial effect of cognitive reserve on episodic memory performance during aging. Hence, this study sheds new light on the mechanisms underlying the impact of cognitive reserve on cognitive aging, highlighting the role of metacognitive processes.

Impact of Activity Monitoring on Physical Activity, Sedentary Behavior, and Body Weight during the COVID-19 Pandemic

Decreases in individuals' physical activity and increases in sedentary behavior and bodyweight have been reported during the COVID-19 pandemic. The present study assessed the ability of physical activity monitoring, which may promote physical activity and discourage sedentary behavior, to mitigate these negative outcomes. An evaluation of university samples (N = 404, 40.5 ± 15.4 years) of self-reported physical activity, sedentary behavior, and bodyweight prior to the closure of campus due to the pandemic in March of 2020 and again at the time of the survey administration (May-June 2020) during pandemic-related restrictions was performed. Participants also reported whether they did (n = 172) or did not (n = 232) regularly use physical activity monitoring technology. While physical activity was unchanged during the pandemic (p ≥ 0.15), participants significantly increased sitting by 67.8 ± 156.6 min/day and gained 0.64 ± 3.5 kg from pre-campus to post-campus closure (p < 0.001). However, the use of activity monitoring did not moderate these changes. In conclusion, while physical activity was not affected, participants reported significant increases in sedentary behavior and bodyweight during the COVID-19 pandemic. These changes occurred regardless of whether participants regularly used physical activity monitoring or not.

Population-Based Study of the Influence of the COVID-19 Pandemic on Hand Hygiene Behaviors—Polish Adolescents’ COVID-19 Experience (PLACE-19) Study

Due to the COVID-19 pandemic, the World Health Organization and other major authorities recommend frequent hand washing and applying proper hand hygiene procedures as one of the cheapest, easiest, and most important ways to prevent the spread of a virus. For adolescents it is especially important as it should become for them a lifelong habit. The aim of the study was to assess the hand hygiene behaviors during the COVID-19 pandemic in a national Polish sample of secondary school adolescents and to verify the influence of the COVID-19 pandemic on those behaviors. The study was conducted in April 2020 in a national sample of 2323 secondary school students recruited based on secondary school sampling procedure (random quota sampling with quotas for voivodeships). The hand hygiene behaviors that were assessed included: frequency of washing hands, reasons for not washing hands, circumstances of washing hands, and procedure of handwashing. Participants were asked each question twice—for the current period of the COVID-19 pandemic and for the period before the COVID-19 issue. The declared frequency of washing hands during the COVID-19 pandemic was significantly higher than before (p < 0.0001), as the majority of respondents declared doing it 6–15 times a day (58.4%) while before the pandemic, it was 3–10 times a day (68.1%). The share of respondents declaring washing their hands always while it would be needed was significantly higher for the period during the COVID-19 pandemic (54.8%) than it was for the period before (35.6%; p < 0.0001), and there was a lower share of respondents declaring various reasons for not washing hands. For the majority of circumstances of washing hands, including those associated with meals, personal hygiene, leaving home, socializing, health, and household chores, the share of respondents declaring always washing their hands was significantly higher for the period during the COVID-19 pandemic than for the period before (p < 0.0001). For the majority of steps of handwashing procedure, the share of respondents declaring including them always was significantly higher for the period during the COVID-19 pandemic than for the period before (p < 0.0001), but a higher share declared not wearing a watch and bracelet (p = 0.0006), and rings (p = 0.0129). It was concluded that during the COVID-19 pandemic all the assessed hand hygiene behaviors of Polish adolescents were improved, compared with those before, but hand hygiene education is still necessary.

Trajectories of physical activity, from young adulthood to older adulthood, and pancreatic cancer risk; a population-based case-control study in Ontario, Canada

Background

There is inconsistent evidence on the association between physical activity and pancreatic cancer risk and few studies have investigated early life or life-course physical activity. The objective of this study was to evaluate the association between trajectories of physical activity across the life-course and pancreatic cancer risk.

Methods

A population-based case-control study was conducted (2011–2013) using cases (n = 315) from the Ontario Pancreas Cancer Study and controls (n = 1254) from the Ontario Cancer Risk Factor Study. Self-reported recall of moderate and vigorous physical activity was measured at three time points: young adulthood (20s–30s), mid-adulthood (40s–50s) and older-adulthood (1 year prior to questionnaire completion). Physical activity trajectories were identified using latent class analysis. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from multivariable logistic regression adjusted for covariates: age, sex, race, alcohol, smoking, vegetable, fruit and meat consumption, and family history of pancreatic cancer.

Results

Six life-course physical activity trajectories were identified: inactive at all ages (41.2%), low activity at all ages (31.9%), increasingly active (3.6%), high activity in young adulthood with substantial decrease (13.0%), high activity in young adulthood with slight decrease (5.0%), and persistent high activity (5.3%). Compared to the inactive at all ages trajectory, the associations between each trajectory and pancreatic cancer after confounder adjustment were: low activity at all ages (OR: 1.11; 95% CI: 0.75, 1.66), increasingly active (OR: 1.11; 95% CI: 0.56, 2.21), high activity in young adulthood with substantial decrease in older adulthood (OR: 0.76; 95% CI: 0.47, 1.23), high activity in young adulthood with slight decrease in older adulthood (OR: 0.98; 95% CI: 0.62, 1.53), and persistently high activity (OR: 1.50; 95% CI: 0.86, 2.62). When time periods were evaluated separately, the OR for the association between high moderate activity in the 20s–30s and pancreatic cancer was 0.89 (95% CI: 0.64, 1.25) and some sex differences were observed.

Conclusion

Distinct life-course physical activity trajectories were identified, but there was no evidence that any of the trajectories were associated with pancreatic cancer. Future studies with larger sample sizes are needed to understand the associations between physical activity trajectories over the life-course and pancreatic cancer risk.

Curriculum requirements and subsequent civic engagement: is there a difference between 'forced' and 'free' community service?

Despite figures showing the growth of mandatory community service programmes, there is mixed empirical evidence of their effectiveness. This paper addresses the relationship of mandated community service to one of its purported aims: subsequent volunteerism. It compares current volunteerism among four university student cohorts: those doing no service in secondary school, those volunteering with no requirement, those volunteering both before and after the introduction of a requirement, and those introduced to service through a requirement. The analysis indicates that (1) students who were introduced to service through a mandated programme exhibit current levels of engagement no greater than non-volunteers; (2) this relationship stems largely from the different service experiences of our four cohorts and relates to the fact that service satisfaction and duration, as well as background variables account for current levels of civic engagement. The findings suggest that mandatory service programmes might well be failing the very population they seek to target, particularly in weaker, less structured programmes.

Socioeconomic status and lifestyle behaviours in cancer survivors: smoking and physical activity

PURPOSE

Smoking cessation and increased physical activity (pa) have been linked to better outcomes in cancer survivors. We assessed whether socioeconomic factors influence changes in those behaviours after a cancer diagnosis.

METHODS

As part of a cross-sectional study, a diverse group of cancer survivors at the Princess Margaret Cancer Centre (Toronto, ON), completed a questionnaire about past and current lifestyle behaviours and perceptions about the importance of those behaviours with respect to their health. The influence of socioeconomic indicators on smoking status and physical inactivity at 1 year before and after diagnosis were assessed using multivariable logistic regression with adjustment for clinico-demographic factors.

RESULTS

Of 1222 participants, 1192 completed the smoking component. Of those respondents, 15% smoked before diagnosis, and 43% of those smokers continued to smoke after. The proportion of survivors who continued to smoke increased with lower education level (p = 0.03). Of the 1106 participants answering pa questions, 39% reported being physically inactive before diagnosis, of whom 82% remained inactive afterward. Survivors with a lower education level were most likely to remain inactive after diagnosis (p = 0.003). Lower education level, household income, and occupation were associated with the perception that pa had no effect or could worsen fatigue and quality of life (p ≤ 0.0001).

CONCLUSIONS

In cancer survivors, education level was a major modifier of smoking and pa behaviours. Lower socioeconomic status was associated with incorrect perceptions about pa. Targeting at-risk survivors by education level should be evaluated as a strategy in cancer survivorship programs.

Role of a service corridor in ICU noise control, staff stress, and staff satisfaction: environmental research of an academic medical center

OBJECTIVE

To investigate the role of a dedicated service corridor in intensive care unit (ICU) noise control and staff stress and satisfaction.

BACKGROUND

Shared corridors immediately adjacent to patient rooms are generally noisy due to a variety of activities, including service deliveries and pickups. The strategy of providing a dedicated service corridor is thought to reduce noise for patient care, but the extent to which it actually contributes to noise reduction in the patient care environment and in turn improves staff performance has not been previously documented.

METHODS

A before-and-after comparison was conducted in an adult cardiac ICU. The ICU was relocated from a traditional hospital environment to a new addition with a dedicated service corridor. A total of 118 nursing staff participated in the surveys regarding pre-move and post-move environmental comfort, stress, and satisfaction in the previous and new units. Acoustical measures of noise within the new ICU and a control environment of the previous unit were collected during four work days, along with on-site observations of corridor traffic.

RESULTS

Independent and paired sample t-tests of survey data showed that the perceived noise level was lower and staff reported less stress and more satisfaction in the new ICU (p < 0.01). Analyses of acoustical data confirmed that the new ICU was significantly quieter (p < 0.02). Observations revealed how the service corridor impacted patient care services and traffic.

CONCLUSIONS

The addition of a dedicated service corridor works in the new unit for improving noise control and staff stress and satisfaction.

KEYWORDS

Critical care/intensive care, noise, satisfaction, staff, work environment.

Racial differences in physical activity among breast cancer survivors: implications for breast cancer care

BACKGROUND

Physical activity after breast cancer diagnosis is associated with improved survival. The current study examined levels of and changes in physical activity after breast cancer diagnosis, overall and by race.

METHODS

Phase 3 of the Carolina Breast Cancer Study assessed both pre- and postdiagnosis physical activity levels in a cohort of 1735 women aged 20 years to 74 years who were diagnosed with invasive breast cancer between 2008 and 2011 in 44 counties of North Carolina. Logistic regression and analysis of variance were used to examine whether demographic, behavioral, and clinical characteristics were associated with activity levels.

RESULTS

Only 35% of study participants met current physical activity guidelines after diagnosis with breast cancer. A decrease in activity after diagnosis was reported by 59% of patients, with the average study participant reducing their activity by 15 metabolic equivalent task (MET) hours (95% confidence interval [95% CI], 12 MET hours-19 MET hours). After adjustment for potential confounders, when compared with white women, African American women were less likely to meet national physical activity guidelines after diagnosis (odds ratio, 1.38; 95% CI, 1.01-1.88) and reported less weekly postdiagnosis physical activity (12 MET hours vs 14 MET hours; P = .13). In adjusted stratified analyses, receipt of treatment was found to be significantly associated with postdiagnosis activity in African American women (P < 0.01).

CONCLUSIONS

Despite compelling evidence demonstrating the benefits of physical activity after a diagnosis of breast cancer, it is clear that more work needs to be done to promote physical activity in patients with breast cancer, especially among African American women.

Racial differences in physical activity among breast cancer survivors: implications for breast cancer care

BACKGROUND

Physical activity after breast cancer diagnosis is associated with improved survival. The current study examined levels of and changes in physical activity after breast cancer diagnosis, overall and by race.

METHODS

Phase 3 of the Carolina Breast Cancer Study assessed both pre- and postdiagnosis physical activity levels in a cohort of 1735 women aged 20 years to 74 years who were diagnosed with invasive breast cancer between 2008 and 2011 in 44 counties of North Carolina. Logistic regression and analysis of variance were used to examine whether demographic, behavioral, and clinical characteristics were associated with activity levels.

RESULTS

Only 35% of study participants met current physical activity guidelines after diagnosis with breast cancer. A decrease in activity after diagnosis was reported by 59% of patients, with the average study participant reducing their activity by 15 metabolic equivalent task (MET) hours (95% confidence interval [95% CI], 12 MET hours-19 MET hours). After adjustment for potential confounders, when compared with white women, African American women were less likely to meet national physical activity guidelines after diagnosis (odds ratio, 1.38; 95% CI, 1.01-1.88) and reported less weekly postdiagnosis physical activity (12 MET hours vs 14 MET hours; P = .13). In adjusted stratified analyses, receipt of treatment was found to be significantly associated with postdiagnosis activity in African American women (P < 0.01).

CONCLUSIONS

Despite compelling evidence demonstrating the benefits of physical activity after a diagnosis of breast cancer, it is clear that more work needs to be done to promote physical activity in patients with breast cancer, especially among African American women.

TERT's role in colorectal carcinogenesis

Telomerase reverse transcriptase (TERT) is one of the main functional subunits of the telomerase enzyme, which functions to increase telomere length. Studies have suggested that TERT may be important to the etiology of colorectal cancer. In this study we evaluate seven TERT SNPs in 1555 incident colon cancer cases and 1956 matched controls and in 754 incident rectal cancer cases and 959 matched controls. We observed that two TERT SNPs were associated with colon cancer. TERT rs2736118 was associated with increased risk of colon cancer (OR = 1.31, 95% CI 1.02, 1.69) and TERT-CLPTM1L rs2853668 was inversely associated with colon cancer (OR = 0.71, 95% CI 0.55, 0.92). TERT-CLPTM1L rs2853668 also was inversely associated with rectal cancer (OR 0.62, 95% CI 0.43, 0.90). BMI interacted significantly with three TERT SNPs to alter risk of colon cancer. Those with the variant allele and who were obese had the greatest risk of colon cancer. TERT-CLPTM1L rs2853668 interacted significantly with aspirin/NSAID use, where those with the AA genotype had a much lower risk of colon cancer when using aspirin/NSAIDs than those with the other genotypes. Several TERT SNPs were uniquely associated with CIMP+ and MSI tumors. These data confirm earlier reports of the association between TERT-CLPTM1L and colon and rectal cancer. Our detection of a significant interaction with BMI for multiple TERT SNPs and unique associations with CIMP+ tumors enhance our understanding of TERT's role in colon carcinogenesis.

Sport-specific association between exercise loading and the density, geometry, and microstructure of weight-bearing bone in young adult men

In this population-based study of 24-year-old men, we have investigated the association between sport-specific exercise loading and different bone parameters. We reveal that the association between exercise loading and bone parameters is sport-specific, indicating that nonspecific resistance exercise does not impact bone density, geometry, or microstructure in young men.

INTRODUCTION

In this cross-sectional study, the association between nonspecific resistive exercise and areal and volumetric bone density, bone geometry, or bone microstructure was investigated in young adult men.

METHODS

A total of 184 male athletes, 24.0 ± 0.6 years of age (mean ± SD), representing nonspecific resistive exercise and soccer (proportion of recreational athletes, 93.4 and 7.7 %, respectively), and 177 nonathletic age-matched controls were measured with dual-energy X-ray absorptiometry. Radius and tibia were measured by peripheral quantitative computed tomography (pQCT) at the diaphysis and by three-dimensional pQCT at the metaphysis.

RESULTS

Men in the nonspecific resistive exercise group had higher grip strength(9.1 % or 0.4 SD) and higher lean mass(5.6 % or 0.5 SD) than those in the nonathletic group(p < 0.01 and p < 0.001, respectively). However, men who participated in nonspecific resistive exercise did not have higher bone density or a more favorable bone microstructure or geometry than their nonathletic referents. In contrast, men playing soccer had higher areal bone mineral density (aBMD) at the femoral neck (19.5 % or 1.2 SD) and lumbar spine (12.6 % or 1.0 SD), as well as larger cortical cross-sectional area (16.4 % or 1.1 SD) and higher trabecular bone volume fraction (14.5 % or 0.9 SD), as a result of increased trabecular number (8.7 % or 0.6 SD) and thickness (5.7 % or 0.4 SD) at the tibia than men in the nonathletic group(p < 0.001).

CONCLUSIONS

Weight-bearing exercise with impacts from varying directions (playing soccer) is associated with aBMD and volumetric BMD, cortical bone geometry, as well as trabecular microstructure of weight-bearing bone. Nonspecific recreational resistance exercise does not appear to be a strong determinant of bone density, geometry, or microstructure in young adult men.

Reproducibility of physical activity recall over fifteen years: longitudinal evidence from the CARDIA study

Background

To examine the benefits of physical activity (PA) on diseases with a long developmental period, it is important to determine reliability of long-term PA recall.

Methods

We investigated 15-year reproducibility of PA recall. Participants were 3605 White and African-American adults in the Coronary Artery Risk Development in Young Adults study, aged 33–45 at the time of recall assessment. Categorical questions assessed PA before and during high school (HS) and overall PA level at Baseline, with the same timeframes recalled 15 years later. Moderate- and vigorous-intensity scores were calculated from reported months of participation in specific activities.

Results

HS PA recall had higher reproducibility than overall PA recall (weighted kappa = 0.43 vs. 0.21). Correlations between 15-year recall and Baseline reports of PA were r = 0.29 for moderate-intensity scores, and r = 0.50 for vigorous-intensity. Recall of vigorous activities had higher reproducibility than moderate-intensity activities. Regardless of number of months originally reported for specific activities, most participants recalled either no activity or activity during all 12 months.

Conclusion

PA recall from the distant past is moderately reproducible, but poor at the individual level, among young and middle aged adults.

Genetic variation in the transforming growth factor-β-signaling pathway, lifestyle factors, and risk of colon or rectal cancer

BACKGROUND

The transforming growth factor-β-signaling pathway has been identified as being involved in colorectal cancer.

OBJECTIVE

The aim of this study was to determine how diet and lifestyle factors in combination with genetic variation in the transforming growth factor-β-signaling pathway alters colorectal cancer risk.

DESIGN

We used data from 2 population-based case-control studies.

PATIENTS

Participants included patients with colon cancer (n = 1574) and controls (n = 1970) and patients with rectal cancer ( n = 791) and controls (n = 999).

MAIN OUTCOME MEASURES

The primary outcomes measured were newly diagnosed cases of colon or rectal cancer.

RESULTS

Colon and rectal cancer risk increased with the number of at-risk genotypes within the transforming growth factor-β-signaling pathway (OR 3.68, 95% CI 2.74,4.94 for colon cancer; OR 3.89, 95% CI 2.66,5.69 for rectal cancer). A high at-risk lifestyle score also resulted in significant increased risk with number of at-risk lifestyle factors (OR 2.99, 95% CI 2.32,3.85 for colon cancer; OR 3.37, 95% CI 2.24,5.07 for rectal cancer). The combination of high-risk genotype and high-risk lifestyle results in the greatest increase in risk (OR 7.89, 95% CI 4.45,13.96 for colon cancer; OR 8.75, 95% CI 3.66,20.89 for rectal cancer).

LIMITATIONS

The study results need validation in other large studies of colon and rectal cancer.

CONCLUSIONS

In summary, our data suggest that there is increased colon and rectal cancer risk with increasing number of at-risk genotypes and at-risk lifestyle factors. Although the integrity of the pathway can be diminished by a number of high-risk genotypes, this risk can be offset, in part, by maintaining a healthy lifestyle.

Physical Activity and Colon Cancer

Despite the convincing evidence that physical activity reduces the risk of colon cancer, there are some aspects of the association that remain unclear. These include the appropriate timeframe of exposure, whether the intensity of physical activity matters, and whether sedentary behavior is a distinct risk factor. This review summarized the research that has investigated these issues. In terms of timing, physical activity at any age (with the exception of physical activity performed up to and including the late teens) has been shown to be associated with a significantly reduced risk of colon cancer. Physical activity performed between 30 and 50 years of age, as well as long-term or lifetime physical activity, has been most consistently shown to reduce risk. For intensity, research to date suggests that more intense activity (particularly vigorous activity) may be associated with a greater reduction in the risk of colon cancer for males but not for females. Finally, most of the studies that have investigated the effect of sedentary behavior on the risk of colon or colorectal cancer have shown an increased risk, suggesting that sedentary behavior may be a distinct risk factor for colon cancer.

Timing and intensity of recreational physical activity and the risk of subsite-specific colorectal cancer

PURPOSE

Although there is convincing evidence that physical activity reduces colon cancer risk, there are important questions that remain unanswered about the association. These include the timing and intensity of activity required to optimally reduce risk, and whether physical activity has a different effect on cancers at different sites within the colon. We conducted a case-control study to investigate these issues.

METHODS

A case-control study of colorectal cancer was conducted in Western Australia in 2005-2007. Data were collected on various risk factors. The estimated effects of recreational physical activity on the risk of cancers of the distal colon, proximal colon, and rectum were analyzed using multinomial logistic regression. This analysis included 870 cases and 996 controls.

RESULTS

The risk of distal colon cancer was reduced by performing a high level of vigorous-intensity activity between the ages 19 and 34 years (women), 35 and 50 years (men), after the age of 51 years (men and women), and consistently over the adult lifetime (men and women). The risk of rectal cancer was reduced by performing a high level of vigorous activity between the ages 35 and 50 years (men), and consistently over the adult lifetime (men). Proximal colon cancer risk was not associated with physical activity in any of the age periods or over the adult lifetime. Moderate intensity activity did not reduce the risk of colorectal cancer.

CONCLUSION

Physical activity may have a greater effect on the risk of distal colon cancer than proximal colon cancer. Vigorous physical activity is required to reduce colorectal cancer risk.

Validity of a physical activity questionnaire in Shanghai

PURPOSE

In large epidemiologic studies, physical activity (PA) is often assessed using PA questionnaires (PAQ). Because available PAQ may not capture the full range of PA in which urban Chinese adults engage, a PAQ was developed for this purpose. We examined the validity of this PAQ and the 1-yr stability of PA in 545 urban Shanghai adults.

METHODS

The PAQ was interview-administered twice, approximately 1 yr apart, and participants also wore an accelerometer and completed a PA-log for seven consecutive days every 3 months during the same year. The intraclass correlation coefficient (ICC) was used to evaluate the stability of PA across questionnaire administrations, and Spearman correlation coefficients (ρ) and mean differences and 95% limits of agreement were used to examine the validity of the questionnaire compared against accelerometry and the PA-log.

RESULTS

When measured by accelerometry, estimates of time spent in moderate-to-vigorous PA were lower and estimates of time spent sedentary were higher than when self-reported on the PAQ (P < 0.001). Total PA (ICC = 0.65) and PA domains (ICC = 0.45-0.85) showed moderate to high stability across PAQ administrations. Total PA (ρ = 0.30), moderate-to-vigorous activity (ρ = 0.17), light activity (ρ = 0.36), and sedentary behavior (ρ = 0.16) assessed by PAQ and by accelerometry were significantly and positively correlated, and correlations of the PAQ with the PA-log (ρ = 0.36-0.85) were stronger than those observed with accelerometry.

CONCLUSIONS

The PAQ significantly overestimated time spent in moderate-to-vigorous activity and underestimated time spent in light activity and sedentary behavior compared with accelerometry, but it performed well at ranking participants according to PA level.

Physical activity recommendations, exercise intensity, and histological severity of nonalcoholic fatty liver disease

OBJECTIVES

Factors that determine disease severity in nonalcoholic fatty liver disease (NAFLD) are unclear, but exercise is a recommended treatment. We evaluated the association between physical activity intensity and histological severity of NAFLD.

METHODS

We conducted a retrospective analysis of adults with biopsy-proven NAFLD enrolled in the NASH CRN (Nonalcoholic Steatohepatitis Clinical Research Network). Using self-reported time spent in physical activity, we classified participants as inactive or as meeting the US guidelines for either moderate or vigorous exercise. Histology was reviewed by a central pathology committee. Frequency and odds of steatohepatitis (NASH) and advanced fibrosis were compared between subjects who either met or did not meet exercise recommendations, and by the total amount of exercise per week.

RESULTS

A total of 813 adults (males=302, females=511) with NAFLD were included, with a mean age of 48 years. Neither moderate-intensity exercise nor total exercise per week was associated with NASH or stage of fibrosis. Meeting vigorous recommendations was associated with a decreased adjusted odds of having NASH (odds ratio (OR): 0.65 (0.43-0.98)). Doubling the recommended time spent in vigorous exercise, as is suggested for achieving additional health benefits, was associated with a decreased adjusted odds of advanced fibrosis (OR: 0.53 (0.29-0.97)).

CONCLUSIONS

These data support an association of vigorous but not moderate or total exercise with the severity of NAFLD. Optimal doses of exercise by duration and intensity for the prevention or treatment of NASH have not been established; however, intensity may be more important than duration or total volume.

Reliability and validity of an internet-based questionnaire measuring lifetime physical activity

Lifetime exposure to physical activity is an important construct for evaluating associations between physical activity and disease outcomes, given the long induction periods in many chronic diseases. The authors' objective in this study was to evaluate the measurement properties of the Lifetime Physical Activity Questionnaire (L-PAQ), a novel Internet-based, self-administered instrument measuring lifetime physical activity, among Canadian men and women in 2005-2006. Reliability was examined using a test-retest study. Validity was examined in a 2-part study consisting of 1) comparisons with previously validated instruments measuring similar constructs, the Lifetime Total Physical Activity Questionnaire (LT-PAQ) and the Chasan-Taber Physical Activity Questionnaire (CT-PAQ), and 2) a priori hypothesis tests of constructs measured by the L-PAQ. The L-PAQ demonstrated good reliability, with intraclass correlation coefficients ranging from 0.67 (household activity) to 0.89 (sports/recreation). Comparison between the L-PAQ and the LT-PAQ resulted in Spearman correlation coefficients ranging from 0.41 (total activity) to 0.71 (household activity); comparison between the L-PAQ and the CT-PAQ yielded coefficients of 0.58 (sports/recreation), 0.56 (household activity), and 0.50 (total activity). L-PAQ validity was further supported by observed relations between the L-PAQ and sociodemographic variables, consistent with a priori hypotheses. Overall, the L-PAQ is a useful instrument for assessing multiple domains of lifetime physical activity with acceptable reliability and validity.

Calcium, vitamin D, VDR genotypes, and epigenetic and genetic changes in rectal tumors

Calcium, vitamin D, exposure to sunshine, and vitamin D receptor (VDR) genotypes have been associated rectal cancer. We used data from 750 rectal tumors and 1,205 population-based controls examine associations with TP53, KRAS2, and CpG Island methylator phenotype (CIMP) markers. Rectal tumors were associated with high levels of calcium overall and with TP53 tumor mutations specifically (OR = 0.6, 95% CI = 0.42-0.84). High levels of sunshine exposure had a borderline protective effect for TP53 tumor mutations (OR = 0.78, 95% CI = 0.59-1.03). A mutation at codon 248 was significantly associated with dietary calcium intake (OR = 0.26, 95% CI = 0.09-0.77); having the Ff/ff genotypes of the FOK1 VDR polymorphism significantly increased the odds of a mutation at codon 245 (OR = 4.74, 95% CI = 1.05-21.39); high levels of dietary vitamin D (OR = 3.42, 95% CI = 1.15-10.17) and the Ff/ff genotypes of FOK1 (OR = 3.34, 95% CI = 1.11-10.02) and the GA/AA genotypes of the CDX2 VDR polymorphism (OR = 2.85, 95% CI = 1.23-6.58) increased the odds of a TP53 mutation at codon 273. These data support an association between calcium and rectal tumors overall as well as specifically with TP53 mutations. However, given the number of comparisons, findings need to be confirmed in other studies.

Association of physical activity with trabecular microstructure and cortical bone at distal tibia and radius in young adult men

CONTEXT

The relationship between physical activity, trabecular microstructure, and cortical geometry in weight-bearing and non-weight-bearing bone has not previously been studied in men.

OBJECTIVE

The aim of this study was to investigate whether present (type and amount) and previous duration of physical activity were associated with trabecular microstructure and cortical cross-sectional area (CSA) in weight-bearing bone in young men.

DESIGN AND SETTING

This was a cross-sectional, population-based study.

PARTICIPANTS

Participants included a cohort of 829 Swedish men between 22.8 and 25.7 yr old (24.1 +/- 0.6 yr, mean +/- SD).

MAIN OUTCOME MEASURES

Several microstructural trabecular and cortical traits were assessed with high-resolution three-dimensional peripheral quantitative computed tomography at distal tibia and radius. A standardized questionnaire was used to collect information about physical activity amount (hours per year), duration (years), and type (strain score 0-3, based on ground reaction forces).

RESULTS

Men with the highest physical activity strain score had higher tibial trabecular bone volume fraction (13.9Delta%) and trabecular number (12.7%) than men with the lowest strain score (P < 0.001). Men in the group with the longest duration of physical activity had higher tibial cortical CSA (16.1%) than the sedentary men (P < 0.001). Inclusion of all physical activity variables in a linear regression model revealed that strain score independently predicted trabecular bone volume fraction, and trabecular number (P < 0.001) and that duration of previous physical activity independently predicted cortical CSA (P < 0.001) of the tibia.

CONCLUSIONS

In this large cohort of young men, the degree of mechanical loading due to type of physical activity was predominantly associated with trabecular microstructure, whereas duration of previous physical activity was mainly related to parameters reflecting cortical bone size in weight-bearing bone.

Diet, physical activity, and body size associations with rectal tumor mutations and epigenetic changes

Diet and lifestyle factors have been inconsistently associated with rectal tumors. It is possible that evaluation of specific tumor markers with these factors may help clarify these associations. In this study, we examine energy contributing nutrients, dietary fiber, BMI (kg/m2), and long-term physical activity with TP53 mutations, KRAS2 mutations, and CpG Island Methylator Phenotype (CIMP) in 750 population-based cases of rectal cancer compared to healthy controls. We observed that high levels of physical activity reduced the risk of having TP53 and KRAS2 rectal tumor mutations. Dairy products rich in fat were associated with an increased risk of CIMP+ tumors (OR 1.88 95% CI 0.92, 3.84), while low-fat dairy products reduced risk of CIMP+ tumors (OR 0.56 95% CI 0.29, 1.09). Omega-3 fatty acids were associated with a twofold increased risk of a CIMP+ tumor. High levels of vegetable intake reduced risk of both TP53 mutations (OR 0.73 95% CI 0.54, 1.00; p trend 0.02) and KRAS2 mutations (OR 0.60 95% CI 0.40, 0.89; p trend <0.01). High intake of whole grains reduced the likelihood of a TP53 mutation (OR 0.74 95% CI 0.56, 0.99), while high intake of refined grains increased the likelihood of a TP53 mutation (OR 1.41 95% CI 1.02, 1.96). Dietary fiber also was associated with reduced risk of TP53 and KRAS2 rectal tumor mutations. Overall, a prudent dietary pattern significantly reduced the likelihood of a KRAS2 tumor mutation (OR 0.68 95% CI 0.47, 0.98; p linear trend 0.03). These data suggest that diet and lifestyle factors are associated with specific types of rectal tumor mutations and epigenetic changes. Findings need confirmation in other studies.

Physical activity is the strongest predictor of calcaneal peak bone mass in young Swedish men

SUMMARY

In a highly representative sample of young adult Swedish men (n = 2,384), we demonstrate that physical activity during childhood and adolescence was the strongest predictor of calcaneal bone mineral density (BMD), and that peak bone mass was reached at this site at the age of 18 years.

INTRODUCTION

The purpose of the present study was to determine if physical activity during growth is associated with peak calcaneal BMD in a large, highly representative cohort of young Swedish men.

METHODS

In this study, 2,384 men, 18.3 +/- 0.3 (mean +/- SD) years old, were included from a population attending the mandatory tests for selection to compulsory military service in Sweden. BMD (g/cm(2)) of the calcaneus was measured using dual-energy X-ray absorptiometry. Training habits were investigated using a standardized questionnaire.

RESULTS

Regression analysis (with age, height, weight, smoking, and calcium intake as covariates) demonstrated that history of regular physical activity was the strongest predictor and could explain 10.1% of the variation in BMD (standardized beta = 0.31, p < 0.001). A regression model with quadratic age effect revealed maximum BMD at 18.4 years.

CONCLUSIONS

We found that history of physical activity during growth was the strongest predictor of peak calcaneal BMD in young men.

Longitudinal study of recreational physical activity in breast cancer survivors

INTRODUCTION

Few longitudinal studies have examined physical activity (PA) levels in breast cancer survivors and how those levels change following cancer diagnosis and treatment.

METHODS

We conducted a longitudinal cohort study of 315 female residents of Washington State, aged 21-74 years, diagnosed with a first primary invasive breast cancer between 2002 and 2004, and identified by a population-based cancer registry. Recreational PA was assessed for the 2-year period before diagnosis and at three intervals after diagnosis (1-12, 13-18, and 19-30 months). We calculated average metabolic equivalent task (MET) hours/wk of total, low-, moderate-, and vigorous-intensity PA.

RESULTS

Mean PA levels decreased by 50% in the 12 months after diagnosis relative to before diagnosis (from 18.8 to 9.2 MET-hours/wk). At 19-30 months post-diagnosis, overall PA levels had increased from the low levels reported in the first year after diagnosis, but remained approximately 3 MET-hours/wk lower than before diagnosis. Reductions were limited to moderate- and vigorous-intensity activities. Declines in PA differed according to certain characteristics of the study population, with the greatest reductions observed in women <40 years at diagnosis and with a pre-diagnosis body mass index <25 kg/m(2); these women were also more likely to report the greatest activity before diagnosis.

CONCLUSIONS

These results, if replicated in other studies, suggest that effective intervention strategies to increase PA in breast cancer survivors may differ according to patient characteristics.

IMPLICATIONS FOR CANCER SURVIVORS

Younger, normal weight, and relatively active women may benefit most from interventions to minimize the decline in PA following diagnosis, while women who are older, overweight, and relatively inactive at diagnosis may benefit from interventions to increase long-term PA.

Physical activity, diet, and pancreatic cancer: a population-based, case-control study in Minnesota

Although mounting evidence suggests that insulin resistance is involved in pancreatic carcinogenesis, few epidemiologic studies have comprehensively investigated the role of lifestyle factors influencing this metabolic disorder in the etiology of pancreatic cancer. We sought to examine this problem in a case-control study conducted in 1994-1998 in Minnesota. Cases (n = 186), aged 20 yr or older, were ascertained from all hospitals in the metropolitan area of the Twin Cities and the Mayo Clinic; from the latter, only cases residing in the Upper Midwest of the United States were recruited. Controls (n = 554) were randomly selected from the general population and frequency matched to cases by age (within 5 yr) and sex. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression. After adjustment for confounders, physical activity was associated with a reduced risk, but this protective effect was confined to light activity and moderate activity only (OR = 0.55, 95% CI = 0.30-0.97, P(trend) = 0.038 and OR = 0.51, 95% CI = 0.28-0.93, P(trend) = 0.07, for highest vs. lowest quartile, respectively). An increased risk was found for dietary intakes of energy and fat but was statistically significant for saturated and polyunsaturated fat only. Of note, no appreciable difference in the magnitude of the associations existed between saturated, monounsaturated, and polyunsaturated fat. Compared with individuals in the lowest quartile of fiber intake, the risk was approximately halved for those in the third (OR = 0.49, 95% CI = 0.26-0.94) and the highest quartile (OR = 0.52, 95% CI = 0.21-1.30). Our study lends support to the hypothesis that dietary and other lifestyle factors influencing insulin resistance modulate pancreatic cancer risk.

Intensity and timing of physical activity in relation to postmenopausal breast cancer risk: the prospective NIH-AARP diet and health study

BACKGROUND

Despite strong evidence of an inverse association of physical activity with postmenopausal breast cancer risk, whether a certain intensity or time of life of physical activity is most effective for lowering breast cancer risk is not known.

METHODS

In 118,899 postmenopausal women in the prospective NIH-AARP Diet and Health Study, we examined the relations of light and moderate-to-vigorous intensity physical activity during four periods of life ("historical": ages 15-18, 19-29, 35-39 years; "recent": past 10 years) to postmenopausal breast cancer risk. Physical activity was assessed by self-report at baseline, and 4287 incident breast cancers were identified over 6.6 years of follow-up.

RESULTS

In age-adjusted and multivariate Cox regression models, >7 hours/week of moderate-to-vigorous activity during the past 10 years was associated with 16% reduced risk of postmenopausal breast cancer (RR:0.84; 95%CI:0.76,0.93) compared with inactivity. The association remained statistically significant after adjustment for BMI (RR:0.87; 95%CI:0.78,0.96). Neither moderate-to-vigorous activity during other periods of life nor light intensity activity during any period of life was related to breast cancer risk, and associations did not vary by tumor characteristics.

CONCLUSION

A high level of recent, but not historical, physical activity of moderate-to-vigorous intensity is associated with reduced postmenopausal breast cancer risk. More precise recall of recent physical activity than activity in the distant past is one possible explanation for our findings.

Tumor markers and rectal cancer: support for an inflammation-related pathway

Inflammation may be a key element in the etiology of colorectal cancer. In our study, we examine associations between factors related to inflammation and specific rectal cancer mutations. A population-based study of 750 rectal cancer cases with interview and tumor DNA were compared to 1,205 population-based controls. Study participants were from Utah and the Northern California Kaiser Permanente Medical Care Program. Tumor DNA was analyzed for TP53 and KRAS2 mutations and CpG Island methylator phenotype. We assessed how these tumor markers were associated with use of anti-inflammatory drugs, polymorphisms in the IL6 genes (rs1800795 and rs1800796) and dietary antioxidants. Ibuprofen-type drugs, IL6 polymorphisms (rs1800796) and dietary alpha-tocopherol and lycopene significantly altered likelihood of having a TP53 mutation. This was especially true for TP53 transversion mutations and dietary antioxidants (OR for beta-carotene 0.51 95% CI 0.27, 0.97, p trend 0.03; alpha-tocopherol 0.41 95% CI 0.20, 0.84, p trend 0.02) Beta-carotene and ibuprofen significantly altered risk of KRAS2 tumors. The associations between lutein and tocopherol and TP53 and KRAS2 mutations were modified by IL6 genotype. These results suggest that inflammation-related factors may have unique associations with various rectal tumor markers. Many factors involved in an inflammation-related pathway were associated with TP53 mutations and some dietary factors appeared to be modified by IL6 genotype.

Self-reported confidence in recall as a predictor of validity and repeatability of physical activity questionnaire data

BACKGROUND

Self-reported confidence ratings have been used in other research disciplines as a tool to assess data quality, and may be useful in epidemiologic studies.

METHODS

We examined whether self-reported confidence in recall of physical activity was a predictor of the validity and retest reliability of physical activity measures from the European Prospective Investigation into Cancer and Nutrition (EPIC) past-year questionnaire and the International Physical Activity Questionnaire (IPAQ) last-7-day questionnaire.During 2005-2006 in Sydney, Australia, 97 men and 80 women completed both questionnaires at baseline and at 10 months and wore an accelerometer as an objective comparison measure for three 7-day periods during the same timeframe. Participants rated their confidence in recalling physical activity for each question using a 5-point scale and were dichotomized at the median confidence value.

RESULTS

Participants in the high-confidence group had higher validity and repeatability coefficients than those in the low-confidence group for most comparisons. The differences were most apparent for validity of IPAQ moderate activity: Spearman correlation rho = 0.34 (95% confidence interval [CI] = 0.08 to 0.55) and 0.01 (-0.17 to 0.20) for high- and low-confidence groups, respectively; and repeatability of EPIC household activity: rho = 0.81 (0.72 to 0.87) and 0.63 (0.48 to 0.74), respectively, and IPAQ vigorous activity: rho = 0.58 (0.43 to 0.70) and 0.29 (0.07 to 0.49), respectively. Women were less likely than men to report high recall confidence of past-year activity (adjusted odds ratio = 0.38; 0.18 to 0.80).

CONCLUSIONS

Confidence ratings could be useful as indicators of recall accuracy (ie, validity and repeatability) of physical activity measures, and possibly for detecting differential measurement error and identifying questionnaire items that require improvement.

Energy balance, physical activity, and cancer risk

This chapter posits that cancer is a complex and multifactorial process as demonstrated by the expression and production of key endocrine and steroid hormones that intermesh with lifestyle factors (physical activity, body size, and diet) in combination to heighten cancer risk. Excess weight has been associated with increased mortality from all cancers combined and for cancers of several specific sites. The prevalence of obesity has reached epidemic levels in many parts of the world; more than 1 billion adults are overweight with a body mass index (BMI) exceeding 25. Overweight and obesity are clinically defined indicators of a disease process characterized by the accumulation of body fat due to an excess of energy intake (nutritional intake) relative to energy expenditure (physical activity). When energy intake exceeds energy expenditure over a prolonged period of time, the result is a positive energy balance (PEB), which leads to the development of obesity. This physical state is ideal for intervention and can be modulated by changes in energy intake, expenditure, or both. Nutritional intake is a modifiable factor in the energy balance-cancer linkage primarily tested by caloric restriction studies in animals and the effect of energy availability. Restriction of calories by 10 to 40% has been shown to decrease cell proliferation, increasing apoptosis through anti-angiogenic processes. The potent anticancer effect of caloric restriction is clear, but caloric restriction alone is not generally considered to be a feasible strategy for cancer prevention in humans. Identification and development of preventive strategies that "mimic" the anticancer effects of low energy intake are desirable. The independent effect of energy intake on cancer risk has been difficult to estimate because body size and physical activity are strong determinants of total energy expenditure. The mechanisms that account for the inhibitory effects of physical activity on the carcinogenic process are reduction in fat stores, activity related changes in sex-hormone levels, altered immune function, effects in insulin and insulin-like growth factors, reduced free radical generation, and direct effect on the tumor. Epidemiologic evidence posits that the cascade of actions linking overweight and obesity to carcinogenesis are triggered by the endocrine and metabolic system. Perturbations to these systems result in the alterations in the levels of bioavailable growth factors, steroid hormones, and inflammatory markers. Elevated serum concentrations of insulin lead to a state of hyperinsulinemia. This physiological state causes a reduction in insulin-like growth factor-binding proteins and promotes the synthesis and biological activity of insulin-like growth factor (IGF)-I, which regulates cellular growth in response to available energy and nutrients from diet and body reserves. In vitro studies have clearly established that both insulin and IGF-I act as growth factors that promote cell proliferation and inhibit apoptosis. Insulin also affects on the synthesis and biological availability of the male and female sex steroids, including androgens, progesterone, and estrogens. Experimental and clinical evidence also indicates a central role of estrogens and progesterone in regulating cellular differentiation, proliferation, and apoptosis induction. Hyperinsulinemia is also associated with alterations in molecular systems such as endogenous hormones and adipokines that regulate inflammatory responses. Obesity-related dysregulation of adipokines has the ability to contribute to tumorigenesis and tumor invasion via metastatic potential. Given the substantial level of weight gain in industrialized countries in the last two decades, there is great interest in understanding all of the mechanisms by which obesity contributes to the carcinogenic process. Continued focus must be directed to understanding the various relationships between specific nutrients and dietary components and cancer cause and prevention. A reductionist approach is not sufficient for the basic biological mechanisms underlying the effect of diet and physical activity on cancer. The joint association between energy balance and cancer risk are hypothesized to share the same underlying mechanisms, the amplification of chemical mediators that modulate cancer risk depending on the responsiveness to those hormones to the target tissue of interest. Disentangling the connection between obesity, the insulin-IGF axis, endogenous hormones, inflammatory markers, and their molecular interaction is vital.

Previous sport activity during childhood and adolescence is associated with increased cortical bone size in young adult men

Physical activity during growth has been associated with altered cortical bone geometry, but it remains uncertain if the physical activity-induced increments in cortical bone size remain when the level of physical activity is diminished or ceased. The aim of this study was to investigate if physical activity during growth is associated with cortical bone geometry in currently inactive young men. In this study, 1068 men (18.9 +/- 0.6 [SD] yr) were included. Cortical bone geometry at the tibia and radius were measured using pQCT. A standardized questionnaire was used to collect information about current and previous sport activity. Subjects who continued to be active (n = 678) and who had been previously active (n = 285) in sports had a wider cortical bone (periosteal circumference [PC], 4.5% and 3.2%, respectively) with increased cross-sectional area (CSA; 12.5% and 6.9%) of the tibia than the always inactive subjects (n = 82). In the currently inactive men (n = 367), regression analysis (including covariates age, height, weight, calcium intake, smoking, and duration of inactivity) showed that previous sport activity was independently associated with cortical bone size of the tibia (CSA and PC). Amount of previous sport activity explained 7.3% of the total variation in cortical CSA. Subjects, who ceased their sport activity for up to 6.5 yr previously, still had greater cortical PC and CSA of the tibia than always inactive subjects. The results from this study indicate that sport activity during growth confers positive effects on bone geometry even though sport activity is ceased.

Genetic variation in calcium-sensing receptor and risk for colon cancer

BACKGROUND

Experimental and epidemiologic studies have suggested that high calcium intake is associated with decreased colon cancer risk, yet very limited data are available for candidate genes in the calcium-vitamin D pathway and colon cancer risk. To address this, we evaluated whether calcium-sensing receptor (CASR) single-nucleotide polymorphisms are associated with colon cancer risk. We also examined interactions among CASR, calcium, and vitamin D intake and previously genotyped vitamin D-related genes.

METHODS

We conducted a large multicenter population-based case-control study of 1,600 cases and 1,949 controls. Seventeen tagging single-nucleotide polymorphisms for CASR were selected from common single-nucleotide polymorphisms (minor allele frequency, >or=5%) based on resequencing data. Haplotypes were estimated and evaluated using HaploStats.

RESULTS

We did not observe an association between any CASR genotypes or haplotypes and colon cancer risk overall. However, when stratified by anatomic site, statistically significant associations were seen with risk for proximal colon cancer [rs10934578 TT: odds ratio, 1.35; 95% confidence interval (95% CI), 1.01-1.81; rs12485716 AG/AA: odds ratio, 0.84; 95% CI, 0.71-1.00; rs4678174 CT/CC: odds ratio, 0.83; 95% CI, 0.70-0.98; rs2270916 CC: odds ratio, 0.43; 95% CI, 0.19-0.97]. Concordantly, we observed a suggested association for a CASR haplotype (rs4678174, rs2270916) with risk for proximal colon cancer (global P=0.08). We did not observe any meaningful gene-environment (calcium and vitamin D) or gene-gene (CYP24A1, CYP27B1, and VDR) interactions with CASR genotypes and colon cancer risk.

CONCLUSION

Our study does not provide evidence for an overall association between CASR single-nucleotide polymorphisms and colon cancer; however, results suggest a possible role of CASR on proximal colon cancer, and subsite differences are consistent with known calcium biology. Nonetheless, these findings require confirmation.

Physical activity and breast cancer risk among pre- and postmenopausal women in the U.S. Radiologic Technologists cohort

To clarify aspects of the association between physical activity and breast cancer, such as activity intensity required, and possible effect modification by factors such as menopausal hormone therapy (MHT) use. We prospectively examined physical activity in relation to breast cancer risk among 45,631 women participating in the U.S. Radiologic Technologists cohort. Participants provided information at baseline regarding hours spent per week engaging in strenuous activity, walking/hiking for exercise, and walking at home or work. We estimated multivariable relative risks (RR) and 95% confidence intervals (CI) of breast cancer using Cox regression. We identified 864 incident-invasive breast cancers. Greatest risk reduction was observed among women who reported walking/hiking for exercise 10 or more hours per week (RR, 0.57; 95% CI, 0.34-0.95) compared with those reporting no walking/hiking. The association between walking/hiking for exercise and breast cancer was modified by MHT use (p for interaction = 0.039). Postmenopausal women who never used MHT had reduced risks of breast cancer associated with physical activity whereas no relation was observed among ever users of MHT. Our study suggests moderate intensity physical activity, such as walking, may protect against breast cancer. Further, the relation between physical activity and breast cancer may be modified by MHT use.

Colon tumor mutations and epigenetic changes associated with genetic polymorphism: insight into disease pathways

Variation in genes associated with serum levels of proteins may be useful for examining specific disease pathways. Using data from a large study of colon cancer, we examine genetic variants in insulin, inflammation, estrogen, metabolizing enzymes, and energy homeostasis genes to explore associations with microsatellite instability (MSI), CpG Island methylator phenotype (CIMP), mutations of p53 in exons 5 through 8, and mutations in codons 12 and 13 of Ki-ras. Insulin-related genes were associated with CIMP-positive and MSI tumors, with the strongest associations among aspirin users. The Fok1 vitamin D receptor (VDR) polymorphism was associated with CIMP-positive/Ki-ras-mutated tumors; the Poly A and CDX2 VDR polymorphisms were associated only with Ki-ras-mutated tumors. NAT2 was associated with CIMP-positive/Ki-ras-mutated tumors but not with MSI tumors. The TCF7L2 rs7903146 polymorphism was associated with p53 mutated tumors. Most associations varied by recent aspirin/NSAID use: IL6 rs1800796 and rs1800795 polymorphisms were associated inversely with tumor mutations in the presence of aspirin/NSAIDs; POMC significantly reduced risk of Ki-ras-mutated tumors when aspirin/NSAIDs were not used; the TCF7L2 rs7903146 was associated with reduced risk of Ki-ras-mutated tumors in the presence of aspirin and increased risk in the absence of aspirin. These data, although exploratory, identify specific tumor subsets that may be associated with specific exposures/polymorphism combinations. The important modifying effects of aspirin/NSAIDs on associations with genetic polymorphisms reinforce the underlying role of inflammation in the etiology of colon cancer.

Validity and repeatability of the EPIC physical activity questionnaire: a validation study using accelerometers as an objective measure

Background

A primary aim of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study is to examine the association between total physical activity levels (comprising occupational, household and recreational activity) and the incidence of cancer. We examined the validity and long-term repeatability of total physical activity measurements estimated from the past-year recall EPIC questionnaire, using accelerometers as an objective reference measure.

Methods

Participants included 100 men and 82 women aged 50–65 years. Criterion validity was assessed by comparing the physical activity estimates from the EPIC questionnaire with total activity estimated from the average of three separate 7-day accelerometer periods during the same (past-year) period. Long-term repeatability of the EPIC questionnaire was assessed by comparing the responses from the baseline and 10-month administrations. Past-year EPIC estimates were also compared with the Friedenreich Lifetime Total Physical Activity Questionnaire to examine whether recent activity reflected lifetime activity.

Results

Accelerometer total metabolic equivalent (MET)-hours/week were positively associated with a total physical activity index (Spearman rank correlation ρ = 0.29, 95% confidence interval (CI) 0.15, 0.42) and with non-occupational activity estimated in MET-hours/week (ρ = 0.21, 95% CI 0.07, 0.35). Stratified analyses suggested stronger correlations for non-occupational activity for participants who were male, had a lower BMI, were younger, or were not full-time workers, although the differences in correlations between groups were not statistically significant. The weighted kappa coefficient for repeatability of the total physical activity index was 0.62 (95% CI 0.53, 0.71). Spearman correlations for repeatability of components of activity were 0.65 (95% CI 0.55, 0.72) for total non-occupational, 0.58 (95% CI 0.48, 0.67) for recreational and 0.73 (95% CI 0.66, 0.79) for household activity. When past-year activity was compared to lifetime estimates of activity, there was fair agreement for non-occupational (ρ = 0.26) activity, which was greater for household activity (ρ = 0.46) than for recreational activity (ρ = 0.21).

Conclusion

Our findings suggest that the EPIC questionnaire has acceptable measurement characteristics for ranking participants according to their level of total physical activity. The questionnaire should be able to identify the presence or absence of reasonably strong aetiological associations when either recent or long-term activity is the responsible factor.

Physical activity, sedentary behavior, and the risk of colon and rectal cancer in the NIH-AARP Diet and Health Study

OBJECTIVE

In order to prospectively investigate physical activity at varying intensities and sedentary behavior in relation to colorectal cancer.

METHODS

We considered 488,720 participants of the NIH-AARP Diet and Health Study who were aged 50-71 years at baseline in 1995-1996. Through 31 December, 2003, we identified 3,240 and 1,482 colorectal cancers among men and women, respectively. We estimated multivariable relative risks (RR) and 95% confidence intervals (CI) of colorectal cancer using Cox regression.

RESULTS

Engaging in exercise/sports five or more times per week compared to never or rarely exercising was associated with a reduced risk of colon cancer among men (p = 0.001; RR = 0.79, 95% CI = 0.68-0.91) and a suggestive decrease in risk among women (p = 0.376; RR = 0.85, 95% CI = 0.70-1.04). Engaging in exercise/sports was also associated with a decreased risk of rectal cancer in men (P = 0.074; RR comparing extreme categories = 0.76, 95% CI = 0.61-0.94). In men, we observed inverse relations of both low intensity (p = 0.017; RR = 0.81, 95% CI = 0.65-1.00 for > or =7 h/week) and moderate to vigorous intensity activity (p = 0.037; RR = 0.82, 95% CI = 0.67-0.99 for > or =7 h/week) to colon cancer risk. In contrast, sedentary behavior (time spent watching television/videos) was positively associated with colon cancer (p < 0.001; RR = 1.61, 95% CI = 1.14-2.27 for > or =9 h/day) among men. Similar, but less pronounced relations were observed in women.

CONCLUSION

Engaging in physical activity of any intensity is associated with reductions in colon and rectal cancer risk. Conversely, time spent sedentary is associated with increased colon cancer risk.

Physical activity and breast cancer risk among women in the southwestern United States

Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.

Lifetime physical activity and the risk of renal cell cancer

The relation between lifelong physical activity at work and during leisure-time and the risk of renal cell cancer (RCC) was analyzed in a case-control study conducted in Italy between 1992 and 2004. Cases were 767 subjects with incident, histologically confirmed RCC, and controls were 1,534 patients hospitalized for acute nonneoplastic conditions. Odds ratios (OR) and 95% confidence intervals (CI) for RCC were computed by multiple logistic regression models, conditioned on study center, sex and age, and adjusted for main covariates. Compared to the lowest level of occupational physical activity, the multivariate OR of RCC for the highest level were 0.65 (95% CI 0.49-0.87) at age 12 years, 0.67 (95% CI 0.53-0.84) at age 15-19, 0.74 (95% CI 0.59-0.93) at age 30-39 and 0.71 (95% CI 0.55-0.92) at age 50-59 years, with significant inverse trends in risk. The inverse association was consistent in strata of sex, age at diagnosis, body mass index, smoking habit and alcohol drinking. No significant association was found for leisure-time physical activity. The inverse association between occupational physical activity and RCC risk, if real, may be related to the effects of insulin-like growth factors, or lipid peroxidation and about 9% of cases of RCC in Italy could be avoided by increasing physical activity. However the inverse association might involve confounding by indirect mechanisms, such as body composition or other social class correlates.

Diet and lifestyle factor associations with CpG island methylator phenotype and BRAF mutations in colon cancer

It has been proposed that dietary factors such as folate, alcohol and methionine may be associated with colon cancer because of their involvement in DNA methylation processes. Data from a large population-based case-control study of incident colon cancer were used to evaluate whether intake of dietary, obesity, physical activity and nonsteroidal antiinflammatory drugs are associated with a CpG island methylator phenotype (CIMP). The BRAF V600E mutation and 5 CpG island markers (MINT1, MINT2, MINT31, p16 and hMLH1) were assessed in 1154 cases of colon cancer. We hypothesized that dietary factors involved in DNA methylation, cruciferous vegetables and use of aspirin/NSAIDs would be associated with CIMP-high tumors. Dietary folate, vitamins B(6) and B(12), methionine and alcohol were not associated with increased likelihood of colon tumors with the CIMP-high (2 or more markers methylated) phenotype. Dietary fiber, physical activity and aspirin and other nonsteroidal antiinflammatory drugs were inversely associated with both CIMP-low and CIMP-high tumors. Our results also suggested non-CIMP pathways as well. Obese individuals were at 2-fold increased risk of having a CIMP-low tumor. Alcohol was associated with an increased risk of tumors that were MSI+ and CIMP-low. In the presence of smoking 20 or more cigarettes per day, use of NSAIDs did not protect against a BRAF mutation. Our data suggest multiple pathways to colon cancer. They do not support a unique role for dietary folate, alcohol, vitamins B(6) and B(12) and methionine in a CpG island methylator phenotype.

Physical activity and endometrial cancer risk: a review of the current evidence, biologic mechanisms and the quality of physical activity assessment methods

OBJECTIVES

To (1) determine the nature of the association between physical activity and endometrial cancer risk; (2) assess the contribution of variation in the quality of physical activity measurement to inconsistencies in study results; and (3) review the biologic mechanisms that might mediate possible effects of physical activity on risk.

METHODS

We reviewed and summarized all published epidemiologic studies examining physical activity and endometrial cancer risk, and evidence relating to possible biologic mechanisms. We assigned each study a quality score for physical activity measurement.

RESULTS

Fourteen of the 18 studies showed a convincing or possible protective effect of physical activity on endometrial cancer risk, with an average relative risk reduction of around 30%. A dose-response relation was observed in 7 of 13 studies. The quality score was not related to the observed strength of association or the presence of a dose-response relation. There was epidemiologic and biologic evidence that vigorous activity, as well as light and moderate intensity activities, such as housework, gardening or walking for transportation, may reduce risk.

CONCLUSIONS

Physical activity probably has a protective role in endometrial cancer development. More epidemiologic and biologic evidence is needed to make conclusive recommendations on optimal types, characteristics or time periods of physical activity.

Age and temporal trends of total physical activity among Swedish women

PURPOSE

Few epidemiological studies have been conducted among middle-aged women on long-term total and specific physical activity (PA) trends. We studied in a cross-sectional setting the relationship of self-reported total daily PA with age and calendar time.

METHODS

In a population-based cohort of 38,988 women aged 49-83 yr in central Sweden, information was collected on physical activity, such as work or occupation, household work, walking or bicycling, exercise, watching TV or reading, and other lifestyle factors through a self-administered questionnaire. Total and specific daily PA levels at ages 15, 30, and 50 yr were recalled retrospectively and measured as metabolic equivalents (MET.h.d(-1)).

RESULTS

Total PA level linearly decreased with calendar time in all three age groups (slope for 5-yr change in calendar time among those 15 yr of age = -0.82; 95% confidence interval (CI), -0.86 to -0.78; among those 30 yr of age=-0.42; 95% CI, -0.45 to -0.38; and among those 50 yr of age = -0.62; 95% CI, -0.66 to -0.58). High-intensity activities such as walking or bicycling decreased by 0.21 MET.h.d(-1) (95% CI, -0.22 to -0.20) every 5-calendar-year change among adolescents between the 1930s and 1960s. Total activity level decreased in all age groups by an average of approximately 3MET.h(-1).d(-1), corresponding to approximately 45 min of brisk walking.

CONCLUSIONS

Our results suggest that intervention efforts aimed at engaging in healthful amounts of physical activity are needed throughout the life cycle.

Reliability of a measure of prediagnosis physical activity for cancer survivors

PURPOSE

This study was conducted to examine the test-retest reliability of a measure of prediagnosis physical activity participation administered to colorectal cancer survivors recruited from a population-based state cancer registry.

METHODS

A total of 112 participants completed two telephone interviews, 1 month apart, reporting usual weekly physical activity in the year before their cancer diagnosis. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to describe the test-retest reliability of the measure across the sample; the Bland-Altman approach was used to describe reliability at the individual level. The test-retest reliability for categorized total physical activity (active, insufficiently active, sedentary) was assessed using the kappa statistic.

RESULTS

When the complete sample was considered, the ICC ranged from 0.40 (95% CI: 0.24, 0.55) for vigorous gardening to 0.77 (95% CI: 0.68, 0.84) for moderate physical activity. The SEM, however, were large, indicating high measurement error. The Bland-Altman plots indicated that the reproducibility of data decreases as the amount of physical activity reported each week increases. The kappa coefficient for the categorized data was 0.62 (95% CI: 0.48, 0.76).

CONCLUSION

Overall, the results indicated low levels of repeatability for this measure of historical physical activity. Categorizing participants as active, insufficiently active, or sedentary provides a higher level of test-retest reliability.

Lifetime occupational and recreational physical activity and risk of benign prostatic hyperplasia

To investigate the relation between occupational and recreational physical activity (PA) in different periods of life and the risk of benign prostatic hyperplasia (BPH), we conducted a hospital-based, case-control study in Italy. The study included 1,369 histologically confirmed BPH and 1,451 controls, admitted to the same hospitals for acute, nonneoplastic diseases. Odds ratios (ORs) and 95% confidence intervals (CIs) of BPH, according to lifetime PA, were obtained by unconditional multiple logistic regression models, including terms for age, study center and education. Compared to the lowest level of occupational PA, the multivariate ORs for BPH for the heavy/strenuous level were 0.6 (95% CI, 0.4-0.8) at age 15-19, 0.6 (95% CI, 0.4-0.8) at age 30-39 and 0.7 (95% CI, 0.5-0.9) at age 50-59. Moreover, compared to <2 hr/week of recreational PA, the ORs for BPH for the highest level (>or=5 hr/week) were 0.5 (95% CI, 0.4-0.7) at age 15-19, 0.6 (95% CI, 0.5-0.8) at age 30-39, and 0.7 (95% CI, 0.5-0.8) at age 50-59. All inverse trends in risk were significant, and no heterogeneity was found by reason of BPH-diagnosis, age at diagnosis, and body mass index (BMI). The inverse association between PA and BPH risk may be due to favorable hormonal correlates of PA, but residual confounding by socioeconomic covariates cannot be excluded. A moderate PA at any ages may help reducing a sizeable number of BPH.

The association of physical activity and body mass index with the risk of large bowel polyps

PURPOSE AND METHOD

Several studies have suggested that physical inactivity and obesity increase the risk for colorectal neoplasia. In this study, we investigated the association of physical activity and body mass index (BMI) with the risk of different types of large bowel polyps. We did an observational analysis nested within a randomized double-blind placebo-controlled chemoprevention trial among patients with one or more recently resected histologically confirmed colorectal adenoma. Nine hundred thirty patients were randomized to calcium (1,200 mg/d, as carbonate) or placebo. Follow-up colonoscopies were conducted approximately 1 and 4 years after the qualifying examination. At study entry, we obtained each subject's current body weight and height, which we used to calculate BMI. After the second study colonoscopy, we asked subjects questions about their leisure time physical activity. Seven hundred eighty-seven subjects completed at least part of the physical activity questionnaire.

RESULTS

We found no association between measures of physical activity or BMI and tubular adenomas or hyperplastic polyps. However, among men, there were strong inverse associations observed between physical activity and advanced neoplastic polyps. Compared with men whose total daily energy expenditure was in the lowest tertile, those in the highest tertile had a risk ratio of 0.35 (95% confidence interval, 17-0.72); there was no similar reduction observed among women (risk ratio, 1.21; 95% confidence interval, 0.36-4.03; P for interaction = 0.04).

DATA INTERPRETATIONS

We found a significant inverse relationship between several measures of physical activity and risk of advanced colorectal neoplasms, particularly among men. No associations were found between BMI and hyperplastic polyps, tubular adenomas, or advanced neoplastic polyps.

PPARgamma, energy balance, and associations with colon and rectal cancer

Peroxisome proliferator-activated receptor-gamma (PPARgamma) has been hypothesized as being involved in colorectal cancer given its role in adipocyte development and insulin resistance. In this study we evaluated the association between the Pro12Ala (P12A) PPARgamma polymorphism and body mass index (BMI), waist-to-hip ratio (WHR), physical activity level, and energy intake and risk of colorectal cancer using data from a population-based, case-control study of colon cancer (1,577 cases and 1,971 controls) and rectal cancer (794 cases and 1,001 controls). We further evaluated how the P12A PPARgamma polymorphism is associated with obesity and fat pattern in the control population. The odd ratio for PPARgamma PA or AA genotype relative to the PP genotype for colon cancer was 0.9 (95% confidence interval, CI=0.8-1.0) and for rectal cancer was 1.2 (95% CI=1.0-1.5) adjusting for race, age, and sex. P12A PPARgamma did not significantly interact with BMI, WHR, energy intake, and energy expenditure to alter risk of colon or rectal cancer. Furthermore, the P12A PPARgamma polymorphism was not associated with obesity or WHR in the control population; it did not interact with energy intake or energy expenditure to alter risk of obesity or large WHR. These data do not support the hypothesis that the P12A PPARgamma polymorphism is associated with colon or rectal cancer through regulation of energy balance.

Case–control study of lifetime occupational and recreational physical activity and risks of colon and rectal cancer

Important aspects of the inverse relation between physical activity and colon cancer risk are still under discussion. In 2000-2003, 239 incident cases of colorectal cancer confirmed by histopathology and 239 hospital-based controls, matched by age and gender, were enrolled. In standardized interviews, data on occupational and recreational physical activity for ages 20, 30, 40, 50 and 60 years were collected from 98 colon cancer cases, 141 rectal cancer cases, and from 193 controls. Besides lifestyle and sociodemographic characteristics, a detailed food frequency questionnaire was assessed. In multivariate logistic regression for colon cancer, significant risk reductions for the highest quartile of total physical activity were found for almost all ages. For lifetime mean physical activity, the multivariate odds ratio for the highest quartile was 0.37 [95% confidence interval (CI) 0.17, 0.83]. For lifelong constantly high-exercisers compared with lifelong non-exercisers an odds ratio of 0.26 (95% CI 0.08, 0.84) was estimated. For rectal cancer, no consistent association with physical activity was found. No confounding effects were observed but the authors found effect modification with total energy intake. These data support an inverse association of colon cancer risk and physical activity which is most expressed if activity is kept up throughout life.