Cancer, immune function, and physical activity

Baseline physical activity and the risk of severe illness and mortality from COVID-19: A dose-response meta-analysis

To provide a scientific basis for improved exercise-based immunity, a meta-analysis was used to explore the dose-response relationship between physical activity (PA) and the risk of severe illness and mortality related to COVID-19 (coronavirus disease 2019). To this end, we searched PubMed, Web of Science databases from January 2020 through April 2022. 14 observational studies met the criteria for inclusion in the meta-analysis, including 2840 cases of severe illness and death from COVID-19. Categorical dose-relationship analysis showed that the risks of severe illness and mortality from COVID-19 were, respectively, 46% (risk ratio (RR): 0.54; confidence intervals (CIs): 0.41-0.68) and 59% (RR = 0.41; 95%CI: 0.23-0.58) lower for the highest dose of PA compared with the lowest dose of PA. The results of the continuous dose-response analysis show an inverse nonlinear relationship (P_{non-linearity} < 0.05) between PA and both the risk of severe illness and mortality from COVID-19. For PA below 10 MET-h/week (MET-h/week: metabolic equivalent of task-hours/week), an increase of 4 MET-h/week (1 h of moderate-intensity or 0.5 h of high-intensity PA) was associated with 8% and 11% reductions in the risk of severe illness and mortality from COVID-19. PA above 10 MET-h/week lowered the risk of severe illness and mortality from COVID-19 by 7% and 9%, respectively, for each 4 MET-h/week increase. Doses of WHO-recommended PA levels (10 MET-h/week) may be required for more substantial reductions in the risk of severe illness and mortality from COVID-19.

Leisure time physical activity and risk of pneumonia mortality: a dose-response meta-analysis

INTRODUCTION

This meta-analysis of cohort studies aimed to examine the doseresponse relationships between LPTA (Leisure time physical activity) and pneumonia mortality to provide some suggestions for the prevention of respiratory disease mortality.

EVIDENCE ACQUISITION

PubMed、WOS database was systematically searched for eligible studies until Nov.1, 2020. The prospective cohort study on the relationship between LPTA and pneumonia mortality was collected. The Meta-analysis was performed using Stata 14 software to calculate the combined effect size (HR) of pneumonia mortality and its 95% CI in a categorical dose-response relationship. The restrictive cubic spline model was used to fit the continuous dose-response relationship.

EVIDENCE SYNTHESIS

Eight cohort studies included 370045 subjects who met the inclusion criteria. The categorical dose-relational analysis revealed that the highest dose compared to the lowest LTPA dose reduced the risk of pneumonia mortality by 32%(HR=0.68.95% CI：0.64-0.73). The continuous dose-response relationship results showed a negative nonlinear relationship between LTPA and the risk of pneumonia mortality (PNon-linearity<0.05). The risk of pneumonia death HR decreased by 16%(p<0.01, HR=0.84.95%CI:0.82-0.86) for each additional 5 MET-h/week when LTPA below 20 MET-h/week. When LTPA was higher than 20 MET-h/week, the risk of pneumonia death HR decreased by 6% for each additional 5 MET-h/week(p<0.01, HR=0.94,95%CI:0.93-0.94).

CONCLUSIONS

All doses of LTPA are protective factors of pneumonia mortality risk and the protective effect on pneumonia mortality is enhanced if LTPA increases. The degree of enhancement is weakened when LTPA is higher than 20 MET-h/week.

What Do Primary Healthcare Providers and Complementary and Alternative Medicine Practitioners in Palestine Need to Know about Exercise for Cancer Patients and Survivors: A Consensual Study Using the Delphi Technique

Background

Exercise has physiologic and psychological benefits for cancer patients and survivors. Today, various exercises are recommended as adjunct to therapies for cancer patients and survivors. This study was conducted to develop a consensual core list of important knowledge items that primary healthcare providers and complementary and alternative medicine (CAM) practitioners need to know on the role of exercises and physical activities in stimulating anticancer immunity.

Methods

Knowledge items were collected following interviews with key contact experts (4 oncologists, 3 exercise and medicine specialists, 2 researchers, 2 cancer patients, and 3 survivors) and extensive literature review. The collected knowledge items were rated by 9 researchers who conducted research on exercise and cancer. A modified two-iterative Delphi technique was employed among a panel (n = 65) of healthcare providers and CAM practitioners to develop the consensual core list of knowledge items.

Results

Of the 49 knowledge items, consensus was achieved on 45 (91.8%) items in 6 categories. Of those, 9 (20.0%) were general items on recommending moderate to vigorous habitual exercises and physical activities. The rest of items were related to the effects of habitual exercises and physical activities on the functions of immune system and exposure to carcinogens 16 (35.6%), anticancer therapies 12 (26.7%), metastasis of cancer 3 (6.7%), metabolism within tumors 3 (6.7%), and myokines release 2 (4.4%).

Conclusion

Formal consensus was achieved for the first time on a core list of knowledge items on how exercises and physical activities might stimulate anticancer immunity. This core list might be considered at the time of developing training/educational interventions and/or continuing education for primary healthcare providers and CAM practitioners. Future studies are still needed to investigate if such consensual lists might improve congruence in cancer care continuum and improve survival rates and wellbeing of cancer patients and survivors.

Associations of Daily Walking Time With Pneumonia Mortality Among Elderly Individuals With or Without a Medical History of Myocardial Infarction or Stroke: Findings From the Japan Collaborative Cohort Study

Background

The association between daily walking and pneumonia mortality, stratified by the presence of disease conditions, such as myocardial infarction (MI) or stroke, was investigated.

Methods

The study participants were 22,280 Japanese individuals (9,067 men and 13,213 women) aged 65–79 years. Inverse propensity weighted competing risk model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for pneumonia mortality.

Results

After a median of 11.9 years of follow-up, 1,203 participants died of pneumonia. Participants who did not have a history of MI or stroke and who walked for 1 hour/day or more were less likely to die from pneumonia (HR 0.90; 95% CI, 0.82–0.98) than those walked for 0.5 hours/day. A similar inverse association of pneumonia and walking (0.5 hours/day) was observed among participants with a history of MI (HR 0.66; 95% CI, 0.48–0.90). Among the participants with a history of stroke, those who walked for 0.6–0.9 hours/day were less likely to die because of pneumonia (HR 0.65; 95% CI, 0.43–0.98).

Conclusions

Regular walking for ≥1 hour/day may reduce the risk of pneumonia mortality in elderly individuals with or without cardiovascular disease history.

Cancer Cell Membrane-Coated Adjuvant Nanoparticles with Mannose Modification for Effective Anticancer Vaccination

Tumor vaccines for cancer prevention and treatment have attracted tremendous interests in the area of cancer immunotherapy in recent years. In this work, we present a strategy to construct cancer vaccines by encapsulating immune-adjuvant nanoparticles with cancer cell membranes modified by mannose. Poly(d,l-lactide- co-glycolide) nanoparticles are first loaded with toll-like receptor 7 agonist, imiquimod (R837). Those adjuvant nanoparticles (NP-R) are then coated with cancer cell membranes (NP-R@M), whose surface proteins could act as tumor-specific antigens. With further modification with mannose moiety (NP-R@M-M), the obtained nanovaccine shows enhanced uptake by antigen presenting cells such as dendritic cells, which would then be stimulated to the maturation status to trigger antitumor immune responses. With great efficacy to delay tumor development as a prevention vaccine, vaccination with such NP-R@M-M in combination with checkpoint-blockade therapy further demonstrates outstanding therapeutic efficacy to treat established tumors. Therefore, our work presents an innovative way to fabricate cancer nanovaccines, which in principle may be applied for a wide range of tumor types.

Physical Activity and Prostate Cancer: An Updated Review

Prostate cancer affects a major proportion of older men, and effective preventive measures are few. Earlier suggestions of 10-30% risk reduction from vigorous physical activity thus merit further analysis. This narrative review updates information on associations between physical activity and prostate cancer, seeking activity patterns associated with maximal risk reduction. Systematic searches of Ovid/MEDLINE and PubMed databases from 1996 to June 2016 have linked the terms prostate neoplasms/prostate cancer with occupation, occupational title, sedentary job or heavy work, exercise, physical activity, sports, athletes, physical education/training or aerobic fitness. Combining these searches with findings from earlier reviews, 85 analyses were captured, although three were repeat analyses of the same data set. Seven analyses reported increased risk, and a further 31 showed no clear relationship. However, 24 analyses found a trend to diminished risk, and 21 a significant decrease (10-30% or more) in at least some subject subsets. Benefit was seen more consistently in occupational than in leisure studies, usually with adolescence or the early 20 s as the optimal age for preventive activity. In general, benefit showed a dose-response relationship, with vigorous activity required for maximal effect. Furthermore, several recent observational studies have indicated that physical activity is beneficial in preventing disease recurrence and improving survival following the diagnosis and treatment of prostate cancer. Despite continued research, conclusive proof of an association between regular physical activity and a low risk of prostate cancer remains elusive. However, reports that exercise exacerbates risk are few, and despite issues around controls, covariates, and co-morbidities, an impressive number of studies have now found significant benefit, suggesting that regular physical activity is important in terms of disease development, progression, and therapy. Given also the many other health benefits of an active lifestyle, it can be recommended as a potentially useful measure in the prevention of prostate cancer.

Effects of aquatic exercise on health-related physical fitness, blood fat, and immune functions of children with disabilities

The purpose of this study is to verify the effects of aquatic exercise on the health-related physical fitness, blood fat, and immune functions of children with disabilities. To achieve the aforementioned purpose, the researchers studied 10 children with grade 1 or grade 2 disabilities who do not exercise regularly. The researchers used SPSS 21.0 to calculate the averages and standard deviations of the data and performed a paired t-test to verify the differences in averages before and after an exercise. The study showed significant differences in lean body weight, muscular strength, cardiovascular endurance, flexibility, and muscular endurance. The researchers found statistically significant differences in triglyceride as well as in immunoglobulin G. The findings suggest that aquatic exercise affects the health-related physical fitness, blood fat, and immune functions of children with disabilities.

Latest Evidence on the Impact of Smoking, Sports, and Sexual Activity as Modifiable Lifestyle Risk Factors for Prostate Cancer Incidence, Recurrence, and Progression: A Systematic Review of the Literature by the European Association of Urology Section of Oncological Urology (ESOU)

CONTEXT

Smoking, sexual activity, and physical activity (PA) are discussed as modifiable lifestyle factors associated with prostate cancer (PCa) development and progression.

OBJECTIVE

To evaluate the available evidence concerning the association of smoking, sexual activity, and sports and exercise on PCa risk, treatment outcome, progression, and cancer-specific mortality.

EVIDENCE ACQUISITION

A systematic review of studies published between 2007 and 2017 using MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement criteria was conducted.

EVIDENCE SYNTHESIS

While data concerning the impact of smoking on PCa development remain conflicting, there is robust evidence that smoking is associated with aggressive tumor features and worse cancer-related outcome, which seems to be maintained for 10 yr after smoking cessation. Less convincing and limited evidence exists for the association of sexual activity with PCa risk. The findings related to PA and PCa support the inference that exercise might be a useful factor in the prevention of PCa and tumor progression, while it is not finally proved under which specific conditions PA might be protective against disease development.

CONCLUSIONS

Smoking is associated with aggressive tumor features and worse cancer-related prognosis; as this negative impact seems to be maintained for 10yr after smoking cessation, urologists should advise men to quit smoking latest at PCa diagnosis to improve their prognosis. As several studies indicate a positive impact of exercise on tumor development, progression, and treatment outcome, it is certainly reasonable to advocate an active lifestyle. Least convincing evidence is available for the interaction of sexual activity and PCa, and well-conducted and longitudinal studies are clearly necessary to evaluate whether the suggested associations between PCa risk and sexual behavior are real or spurious.

PATIENT SUMMARY

In this systematic review, we looked at the impact of smoking, sexual activity, and sports and exercise on prostate cancer risk and outcome after treatment. While the evidence for sexual activity is not overall clear, we found that smoking might lead to more aggressive cancers and result in worse treatment outcome. Physical activity might prevent prostate cancer and improve cancer-related outcomes as well. Hence, it is certainly reasonable to advocate an active lifestyle and advise men to quit smoking.

Physical activity among cancer survivors-what is their perception and experience?

PURPOSE

Physical activity (PA) plays an important role relating to cancer. The aim of this study was to investigate the attitude to and experience with the subject of PA in cancer in a large group of tumour patients.

METHODS

A standardised questionnaire was carried out and distributed to patients online and in printed form.

RESULTS

Nine hundred five patients answered the questionnaire. Most tumour patients (60%) received information about PA after their cancer therapy. The Internet was often rated to be inadequate as a source of information. One in two tumour patients were recommended PA by a therapist. During the acute phase, the majority (57% of the 776) did not receive a sport-therapeutic exercise programme. Two thirds (68%) of the 898 patients indicated regularly engaging in PA at least 3 or 5 days per week. In most cases (30% of the 787), 2 to 4 h per week were dedicated to PA. In addition to a desire to increase well-being, enjoyment played a large role. Weakness and lack of willpower are among the most common barriers. Most tumour patients confirmed that PA improved their body awareness (58%) or gave them the feeling that they could do something to better cope with the disease (61%) or feel better (68%).

CONCLUSION

On the one hand, the information requirements of tumour patients with respect to PA have not been adequately taken into account by practitioners. On the other hand, there are still subjective inhibitions on the part of the patients, which keep them from engaging in PA.

Does physical activity moderate the association between alcohol drinking and all-cause, cancer and cardiovascular diseases mortality? A pooled analysis of eight British population cohorts

OBJECTIVE

To examine whether physical activity (PA) moderates the association between alcohol intake and all-cause mortality, cancer mortality and cardiovascular diseases (CVDs) mortality.

DESIGN

Prospective study using 8 British population-based surveys, each linked to cause-specific mortality: Health Survey for England (1994, 1998, 1999, 2003, 2004 and 2006) and Scottish Health Survey (1998 and 2003).

PARTICIPANTS

36 370 men and women aged 40 years and over were included with a corresponding 5735 deaths and a mean of 353 049 person-years of follow-up.

EXPOSURES

6 sex-specific categories of alcohol intake (UK units/week) were defined: (1) never drunk; (2) ex-drinkers; (3) occasional drinkers; (4) within guidelines (<14 (women); <21 (men)); (5) hazardous (14-35 (women); 21-49 (men)) and (6) harmful (>35 (women) >49 (men)). PA was categorised as inactive (≤7 MET-hour/week), active at the lower (>7.5 MET-hour/week) and upper (>15 MET-hour/week) of recommended levels.

MAIN OUTCOMES AND MEASURES

Cox proportional-hazard models were used to examine associations between alcohol consumption and all-cause, cancer and CVD mortality risk after adjusting for several confounders. Stratified analyses were performed to evaluate mortality risks within each PA stratum.

RESULTS

We found a direct association between alcohol consumption and cancer mortality risk starting from drinking within guidelines (HR (95% CI) hazardous drinking: 1.40 (1.11 to 1.78)). Stratified analyses showed that the association between alcohol intake and mortality risk was attenuated (all-cause) or nearly nullified (cancer) among individuals who met the PA recommendations (HR (95% CI)).

CONCLUSIONS

Meeting the current PA public health recommendations offsets some of the cancer and all-cause mortality risk associated with alcohol drinking.

Leisure-time physical activity and lung cancer risk: A systematic review and meta-analysis

OBJECTIVES

We conducted a systematic review and meta-analysis of the association between recreational physical activity and lung cancer risk to update previous analyses and to examine population subgroups of interest defined by smoking status and histology.

MATERIALS AND METHODS

We searched the PubMed database for studies up to May 2015. Individual study characteristics were abstracted including study design, number of cases, assessment of recreational physical activity and type and level of adjustment for confounding factors. Combined effect estimates were calculated for the overall associations and across subgroups of interest.

RESULTS

We identified 28 studies that were eligible for inclusion in the meta-analysis. The overall analysis indicated an inverse association between recreational physical activity and lung cancer risk (Relative Risk (RR), 0.76; 95% Confidence Interval (CI), 0.69-0.85, p-value: <0.001). Similar inverse associations with risk were also noted for all evaluated histological subtypes, including adenocarcinoma (RR, 0.80; 95% CI, 0.72-0.88), squamous (RR, 0.80; 95% CI, 0.71-0.90) and small cell (RR, 0.79; 95% CI, 0.66-0.94). When we examined effects by smoking status, inverse associations between recreational physical activity and lung cancer risk were observed among former (RR, 0.77; 95% CI, 0.69-0.85) and current smokers (RR, 0.77; 95% CI, 0.72-0.83), but not among never smokers (RR, 0.96; 95% CI, 0.79-1.18).

CONCLUSION

Results from this meta-analysis suggest that regular recreational physical activity may be associated with reduced risk of lung cancer. Only four studies examining never smokers were identified, suggesting the need for additional research in this population.

Mild obesity, physical activity, calorie intake, and the risks of cervical intraepithelial neoplasia and cervical cancer

Objective

We investigated whether obesity, physical activity, and calorie intake are associated with the risks of cervical intraepithelial neoplasia (CIN) and cervical cancer.

Methods

We enrolled 1125 women (age, 18–65 years) into a human papillomavirus cohort study established from 2006 to 2012. Multinomial logistic regression models were used to estimate crude and multivariate odds ratios (ORs) and the corresponding 95% confidence intervals (95% CIs), and to assess whether body mass index (BMI), height, weight, total calorie intake, and physical activity were associated with the risks of CIN and cervical cancer.

Results

Cervical cancer risk was positively associated with BMI and inversely associated with physical activity. When compared with women with a normal BMI (18.5–23 kg/m²), the multivariate ORs (95% CIs) for those overweight (23–25 kg/m²) and mild obesity (≥25 kg/m²) were 1.25 (0.79–2.00) and 1.70 (1.10–2.63), respectively. When compared with women with the lowest tertile of physical activity (<38.5 MET-hours/week), the ORs (95% CIs) for cervical cancer were 0.95 (0.61–1.48) and 0.61 (0.38–0.98) for women with medium physical activity (38.5–71.9 MET-hours/week) and those with high physical activity (72 MET-hours/week), respectively (p for linear trend  = 0.03). The CIN2/3 risk was inversely associated with physical activity after adjustment for confounders. Compared with women with low physical activity (< 38.5 MET-hours/week), the ORs (95% CIs) for CIN2/3 were 0.64 (0.40–1.01) and 0.58 (0.36–0.93) for the medium and high physical activity groups, respectively (p for linear trend  = 0.02). Total calorie intake was not statistically associated with the risks of CIN and cervical cancer after adjustment for confounders.

Conclusion

Our results indicate that in addition to screening for and treatment of CIN, recommendations on the maintenance of an appropriate BMI with an emphasis on physical activity could be an important preventive strategy against the development of cervical cancer.

Physical activity and cancer prevention: a systematic review of clinical trials

BACKGROUND

Physically active individuals have lower rates of many cancers and improved cancer outcomes. Controlled exercise trials measuring putative biomarkers of cancer risk are being conducted to further understand the role of exercise in cancer etiology and progression. We aimed to systematically review the effect of exercise on various biomarkers.

METHODS

A comprehensive search strategy identified 353 publications from January 1980 to August 2010. We included those clinical trials of exercise measuring biomarkers following minimum 4-week intervention among cancer survivors or people with one or more cancer risk factors. Two reviewers abstracted data and assessed quality independently. Effect sizes and 95% confidence intervals were estimated.

RESULTS

Four primary prevention and five tertiary prevention trials were included. Exercise had a small to moderate effect on improving concentrations of several blood biomarkers implicated in breast and colon cancer pathways including insulin, leptin, estrogens, and apoptosis regulation. In breast cancer survivors, exercise had a small to moderate effect on improving some biomarkers associated with prognosis including various insulin-like growth factor axis proteins, insulin, and inflammation; and a large effect on enhancing immune function.

CONCLUSION

Data are few, but there is some evidence to support the role of exercise in modulating various cancer pathways.

The association between graded physical activity in postmenopausal British women, and the prevalence and incidence of hip and wrist fractures

BACKGROUND

physical activity is promoted for older women as a means of maintaining health and avoiding falls and fractures. Findings relating physical activity of older women to risk of falls and fracture are contradictory. The association between level of physical activity and prevalent and incident hip and wrist fractures was examined in a large representative sample of postmenopausal British women.

METHODS

data from the British Women's Heart and Health Study, a cohort study of 4286 postmenopausal women aged 60-79, from 23 UK towns were used. Information on physical activity, anthropometry, falls and hip and wrist fractures from baseline examination and questionnaire (1999-2001) and follow-up questionnaire (2007) were available. Cross-sectional baseline prevalence data were analysed using logistic regression and cohort incidence data using a Cox proportional hazards model examining the association of physical activity with fracture outcomes.

RESULTS

3003 (70%) women, with complete baseline data, were studied. 13.6% had previously fractured a wrist and 1.3% a hip. Analyses unadjusted for confounders showed moderate protective associations between activity and fracture risk. After adjustment for confounders there was a weak trend towards fewer hip fractures (adjusted OR 0.13 [0.01, 1.18]) and more wrist fractures (adjusted OR 1.35 [0.76, 2.48]), amongst most active compared with inactive women. The crude incidence rate of wrist and/or hip fracture was 7.0 [5.9, 8.2] per 1000 person-years. No evidence was found for an association between physical activity and combined incident hip and/or wrist fracture (adjusted rate ratio inactive versus most active 1.69 [0.67, 4.24]).

CONCLUSION

no clear associations between graded physical activity and hip/wrist fractures were seen but estimates were imprecise. Physical activities are heterogeneous and individual fracture types and mechanisms differ. Very large prospective observational studies are required to disentangle the precise effects of different activity patterns on different fracture types.

Physical activity and hematologic cancer prevention

This chapter presents the epidemiologic evidence on the association between physical activity and hematologic cancers and related hypothesized biologic mechanisms. Some preliminary indications of a protective role for physical activity for non-Hodgkin's lymphoma, leukemia, multiple myeloma, and Hodgkin's lymphoma exist, but the level of epidemiologic evidence is still insufficient to make any definitive conclusions regarding the nature of these associations. Several plausible biologic mechanisms underlying the possible associations between physical activity and hematologic cancers have been proposed, including enhancement of immune function, reduction in obesity, improvement of antioxidant defense systems, impact on metabolic hormones, and anti-inflammatory effects. Future studies should improve the estimation of physical activity by using more reliable, valid, and comprehensive measurement tools, assessing all components of physical activity (type, intensity, and time period), and conducting intervention studies to evaluate the effect of physical activity on various biomarkers of cancer in order to provide further insight into plausible biologic mechanisms underlying the possible association between physical activity and hematologic cancers.

Physical activity and lung cancer prevention

Since lung cancer is among the cancers with the highest incidence and has the highest mortality rate of cancer worldwide, the means of reducing its impact are urgently needed. Emerging evidence shows that physical activity plays an etiological role in lung cancer risk reduction. The majority of studies support the fact that total and recreational physical activity reduces lung cancer risk by 20-30% for women and 20-50% for men, and there is evidence of a dose-response effect. The biological mechanisms operating between physical activity and lung cancer are likely complex and influenced by many factors including inherited or acquired susceptibility genes, gender, smoking, and other environmental factors. Several plausible biological factors and mechanisms have been hypothesized linking physical activity to reduced lung cancer risk including: improved pulmonary function, reduced concentrations of carcinogenic agents in the lungs, enhanced immune function, reduced inflammation, enhanced DNA repair capacity, changes in growth factor levels and possible gene-physical activity interactions. Future research should target the possible subgroup effects and the biologic mechanisms that may be involved.

Prospective study of physical activity and lung cancer by histologic type in current, former, and never smokers

Increased physical activity has been associated with decreased lung cancer risk. However, no previous investigation has examined physical activity in relation to lung cancer histologic types by smoking status. The authors investigated these relations in the National Institutes of Health-AARP Diet and Health Study among 501,148 men and women aged 50-71 years at baseline in 1995-1996. During follow-up to 2003, 6,745 lung carcinomas occurred (14.8% small cell, 40.3% adenocarcinoma, 19.7% squamous cell, 6.1% undifferentiated large cell, 7.2% non-small cell not otherwise specified, and 11.8% carcinoma not otherwise specified). Among former smokers, the multivariate relative risks of small cell, adenocarcinoma, squamous cell, and undifferentiated large cell carcinomas comparing the highest with the lowest activity level (> or =5 times/week vs. inactive) were 0.93 (95% confidence interval (CI): 0.67, 1.28), 0.79 (95% CI: 0.67, 0.94), 0.73 (95% CI: 0.57, 0.93), and 0.61 (95% CI: 0.38, 0.98), respectively. Among current smokers, corresponding values were 0.77 (95% CI: 0.58, 1.02), 0.76 (95% CI: 0.61, 0.95), 0.85 (95% CI: 0.65, 1.11), and 1.10 (95% CI: 0.69, 1.78). In contrast, physical activity was unrelated to lung carcinoma among never smokers (P(interaction) between physical activity and smoking for total lung carcinomas = 0.002). The inverse findings among former and current smokers in combination with the null results for physical activity among never smokers may point toward residual confounding by cigarette smoking as an explanation for the relations observed.

Daily total physical activity level and total cancer risk in men and women: results from a large-scale population-based cohort study in Japan

The impact of total physical activity level on cancer risk has not been fully clarified, particularly in non-Western, relatively lean populations. The authors prospectively examined the association between daily total physical activity (using a metabolic equivalents/day score) and subsequent cancer risk in the Japan Public Health Center-based Prospective Study. A total of 79,771 general-population Japanese men and women aged 45-74 years who responded to a questionnaire in 1995-1999 were followed for total cancer incidence (4,334 cases) through 2004. Compared with subjects in the lowest quartile, increased daily physical activity was associated with a significantly decreased risk of cancer in both sexes. In men, hazard ratios for the second, third, and highest quartiles were 1.00 (95% confidence interval (CI): 0.90, 1.11), 0.96 (95% CI: 0.86, 1.07), and 0.87 (95% CI: 0.78, 0.96), respectively (p for trend = 0.005); in women, hazard ratios were 0.93 (95% CI: 0.82, 1.05), 0.84 (95% CI: 0.73, 0.96), and 0.84 (95% CI: 0.73, 0.97), respectively (p for trend = 0.007). The decreased risk was more clearly observed in women than in men, especially among the elderly and those who regularly engaged in leisure-time sports or physical exercise. By site, decreased risks were observed for cancers of the colon, liver, and pancreas in men and for cancer of the stomach in women. Increased daily physical activity may be beneficial in preventing cancer in a relatively lean population.

Recreational physical activity and epithelial ovarian cancer: a case-control study, systematic review, and meta-analysis

It remains unclear whether physical activity is associated with epithelial ovarian cancer risk. We therefore examined the association between recreational physical activity and risk of ovarian cancer in a national population-based case-control study in Australia. We also systematically reviewed all the available evidence linking physical activity with ovarian cancer to provide the best summary estimate of the association. The case-control study included women ages 18 to 79 years with a new diagnosis of invasive (n=1,269) or borderline (n=311) epithelial ovarian cancer identified through a network of clinics, physicians, and state cancer registries throughout Australia. Controls (n=1,509) were randomly selected from the national electoral roll and were frequency matched to cases by age and state. For the systematic review, we identified eligible studies using Medline, the ISI Science Citation Index, and manual review of retrieved references, and included all case-control or cohort studies that permitted assessment of an association between physical activity (recreational/occupational/sedentary behavior) and histologically confirmed ovarian cancer. Meta-analysis was restricted to the subset of these studies that reported on recreational physical activity. In our case-control study, we observed weakly inverse or null associations between recreational physical activity and risk of epithelial ovarian cancer overall. There was no evidence that the effects varied by tumor behavior or histologic subtype. Twelve studies were included in the meta-analysis, which gave summary estimates of 0.79 (95% confidence interval, 0.70-0.85) for case-control studies and 0.81 (95% confidence interval, 0.57-1.17) for cohort studies for the risk of ovarian cancer associated with highest versus lowest levels of recreational physical activity. Thus, pooled results from observational studies suggest that a modest inverse association exists between level of recreational physical activity and the risk of ovarian cancer.

Effect of a high-intensity exercise training on the metabolism and function of macrophages and lymphocytes of walker 256 tumor bearing rats

Epidemiologic studies suggest that moderately intense training promotes augmented immune function, whereas strenuous exercise can cause immunosupression. Because the combat of cancer requires high immune function, high-intensity exercise could negatively affect the host organism; however, despite the epidemiologic data, there is a lack of experimental evidence to show that high-intensity training is harmful to the immune system. Therefore, we tested the influence of high-intensity treadmill training (10 weeks, 5 days/week, 30 mins/day, 85% VO(2)max) on immune system function and tumor development in Walker 256 tumor-bearing Wistar rats. The metabolism of glucose and glutamine in lymphocytes and macrophages was assessed, in addition to some functional parameters such as hydrogen peroxide production, phagocytosis, and lymphocyte proliferative responses. The metabolism of Walker 256 cells was also investigated. Results demonstrated that high-intensity training increased the life span of tumor-bearing rats, promoted a reduction in tumor mass, and prevented indicators of cachexia. Several changes, such as a reduction in body weight and food intake and activation of glutamine metabolism in macrophages and lymphocytes induced by the presence of Walker 256 tumor, were prevented by high intensity training. The reduction in tumor growth was associated with an impairment of tumor cell glucose and glutamine metabolism. These data suggest that high-intensity exercise training may be a viable strategy against tumors.

Voluntary exercise produces antidepressant and anxiolytic behavioral effects in mice

Reports of beneficial effects of exercise on psychological health in humans are increasingly supported by basic research studies. Exercise is hypothesized to regulate antidepressant-related mechanisms and we therefore characterized the effects of chronic exercise in mouse behavioral paradigms relevant to antidepressant actions. Mice given free access to running wheels showed antidepressant-like behavior in learned helplessness, forced-swim (FST) and tail suspension paradigms. These responses were similar to responses of antidepressant drug-treated animals. When tested under conditions where locomotor activity was not altered, exercising mice also showed reduced anxiety compared to sedentary control mice. In situ hybridization analysis showed that BDNF mRNA was increased in specific subfields of hippocampus after wheel running. We chose one paradigm, the FST, in which to investigate a functional role for brain-derived neurotrophic factor (BDNF) in the behavioral response to exercise. We tested mice heterozygous for a deletion of the BDNF gene in the FST after wheel-running. Exercising wild-type mice showed the expected antidepressant-like behavioral response in the FST but exercise was ineffective in improving FST performance in heterozygous BDNF knockout mice. A possible functional contribution of a BDNF signaling pathway to FST performance in exercising mice was investigated using the specific MEK inhibitor PD184161 to block the MAPK signaling pathway. Subchronic administration of PD184161 to exercising mice blocked the antidepressant-like behavioral response seen in vehicle-treated exercising mice in the FST. In summary, chronic wheel-running exercise in mice results in antidepressant-like behavioral changes that may involve a BDNF related mechanism similar to that hypothesized for antidepressant drug treatment.

Colon Cancer and Physical Activity: A Content Analysis of Reciprocal Relationship

Background

Colon cancer is among the leading causes of cancer mortality and its incidence is increasing worldwide. This is true in spite of broad basic research into colon cancer while, concurrently, physical activity has been shown to offer significant preventive potential. This background led to the formulation of the following research questions: • Why is physical activity so effective in decreasing the incidence of colon cancer? • Is there a common denominator to colon cancer and physical activity, which has a reciprocal function? • Knowing the potential for public health impact of physical activity on colon cancer, has physical activity-colon cancer relationship been in the forefront of research efforts?

Methods

Content analysis of archival literature has been carried out on census of 32,822 message units, extracted from the National Library of Medicine and its PubMed database. The following search terms were used: colon cancer, physical activity, melatonin, age/genetics, diet (obesity, vitamin D, calcium), immunity/inflammation, and bioactive substances incorporating insulin-like growth factor 1, interleukins, and prostaglandins. The research timeframe for each category began with the first article published and ended with the last one printed in 2005.

Results/Conclusions

The effectiveness of physical activity in decreasing the incidence of colon cancer is likely the result of its biologic activity within not one or two but all of the major known colon cancer etiologies, demonstrating a powerful reciprocal relationship. Melatonin is identified as a plausible common denominator of colon cancer and physical activity. The greatest volume of publications deals with colon cancer and genetics. A significant societal health care impact could be achieved by adopting physical activity as a major cancer control strategy.

The role of exercise on the innate immunity of the elderly

The increased life span in human population has shown that some diseases, as infections, cancer and autoimmune phenomena, occur more frequently in the elderly than in the younger. We describe the ageing process involving the innate immune system and the improvement given by moderate physical activity. In addition, we discuss the altered neutrophil granulocytes function, the role of macrophages and natural killer cells, besides the influence of cytokines and secretory IgA. The acquired information help us to explain how these changes could favor the onset of diseases in the elderly and how they may boost their immune function.

Exercise and biomarkers for cancer prevention studies

The International Agency for Research on Cancer estimates that 25% of cancer cases worldwide are caused by overweight or obesity and a sedentary lifestyle. These lifestyle patterns may increase cancer risk by several mechanisms including increased estrogens and testosterone, hyperinsulinemia and insulin resistance, increased inflammation, and depressed immune function. Several randomized clinical trials have shown that physical activity and diet interventions can change biomarkers of cancer risk. In a controlled physical activity trial, we found decreases in serum estrogen, testosterone, and insulin in overweight, sedentary postmenopausal women with a 1-y exercise program consisting of moderate-intensity aerobic exercise, 45 min/d, 5 d/wk. In another controlled trial in middle-aged to older persons, we found that a 1-y exercise intervention of 60 min/d, 6 d/wk, reduced colon crypt cell proliferation in men who adhered closely to the program. Only 1 trial, the Women's Health Initiative Dietary Modification Trial, has published results of a dietary intervention on breast cancer incidence and reported a statistically nonsignificant 9% reduction in invasive breast cancer incidence in postmenopausal women following a low-fat dietary pattern for 8-12 y. Other trials under way are testing effects of weight loss, physical activity, and dietary patterns on other cancer biomarkers. The NCI-funded Transdisciplinary Research on Energetics and Cancer centers are exploring novel research into mechanisms linking energy balance with cancer risk and prevention. The worldwide trends toward increasing overweight and obesity and decreasing physical activity may lead to an increased incidence of several cancers unless other means of risk reduction counteract these effects. Thus, adoption of lifestyle changes by individuals and populations may have a large impact on the future incidence of cancer.

Physical activity, obesity, energy intake, and the risk of non-Hodgkin's lymphoma: a population-based case-control study

The authors conducted a population-based case-control study of 1,030 cases with histologically confirmed, incident non-Hodgkin's lymphoma (NHL) and 3,106 controls to assess the impact of recreational physical activity, obesity, and energy intake on NHL risk in Canada from 1994 to 1997. Compared with those for subjects in the lowest quartiles of total recreational physical activity, multivariable-adjusted odds ratios for subjects in the highest quartile were 0.79 (95% confidence interval (CI): 0.59, 1.05) for men and 0.59 (95% CI: 0.42, 0.81) for women. Obesity (body mass index > or = 30 kg/m2) was associated with odds ratios of 1.59 (95% CI: 1.18, 2.12) for men and 1.36 (95% CI: 1.00, 1.84) for women. For men and women with a lifetime maximum body mass index of > or = 30 kg/m2, respective odds ratios were 1.55 (95% CI: 1.16, 2.06) and 1.10 (95% CI: 0.83, 1.46). For men and women in the highest quartiles of calorie intake, respective odds ratios were 1.95 (95% CI: 1.45, 2.62) and 1.13 (95% CI: 0.84, 1.52). Some differences were found between histologic subtypes of NHL for these associations. This study suggests that recreational physical activity decreases NHL risk, while obesity and excess calorie intake increase it. More studies are needed to confirm these results, especially the differences between histologic subtypes.

Chronic Resistance Exercise Training Improves Natural Killer Cell Activity in Older Women

BACKGROUND

Regular exercise has been reported to slow the age-associated declines in natural killer cell activity (NKCA). To evaluate this response, we recruited older, postmenopausal women (65-85 years old) to fill one of two groups: training (10 weeks of resistance exercise; TR) or control.

METHODS

Blood samples were collected from an arm vein in the TR group at rest (PRE), immediately following (POST), and 2 hours (2H) following an acute bout of resistance exercise both before (BEFORE) and after (AFTER) training. Leukocytes and NKCA were determined by flow cytometry and a whole blood (51)Cr release assay, respectively.

RESULTS

Acute exercise increased total leukocyte (p < .05), CD8 (p < .05), CD4 (p < .05), and CD56 counts (p < .05), but there was no effect of training. NKCA was greater TR-AFTER-PRE (136%), -POST (80%), and -2H (127%) compared to similar values from TR-BEFORE (p < .05).

CONCLUSION

Increased resting NKCA after chronic resistance training suggests that immunity has been improved.

Natural killer cells and exercise training in the elderly: a review

Consistent reports of the positive relationship between regular physical activity and immunosenescence have generated much excitement in the field of exercise immunology. It is generally accepted that natural killer (NK) cell activity per NK cell decreases with age; decreases in NKCA have been associated with infection and death in the aged. The effects of exercise and training on natural killer cells, components of the innate immune system, have been studied extensively in young people. However, the published research on the elderly population is limited. Generally it has been found that training increases or does not change natural killer cell activity or counts in the elderly. The clinical relevance of these results is yet to be fully explored. In addition, the limitations of these studies on immune function have been many, and studies are often difficult to compare due to differences in their methods and presentation of results.

Moderate physical activity and prostate cancer risk: A case?control study in china

A case-control study was conducted to investigate the association between physical activity and prostate cancer risk in China. A total of 130 recent histopathologically confirmed cancer cases and 274 controls were interviewed. Information collected included type, intensity and duration of various physical activities. The adjusted odds ratios of prostate cancer risk for physical activity variables were obtained from multivariate logistic regression models. Results showed that moderate physical activity was inversely related to the prostate cancer risk, with adjusted odds ratio being 0.20 (95% confidence interval 0.07-0.62) for the upper vs. the lower quartiles of weekly metabolic equivalent task-hours. The dose-response relationship was also significant (p = 0.015). The findings suggest that moderate physical activity may be protective against prostate cancer for Chinese men.

Physical activity and colorectal cancer

Physical activity has been shown to reduce risk of colon cancer. Some studies have shown site-specific associations while others have not. The inverse association between physical activity and colon cancer is consistent although only 7 of 13 studies that have collected both colon and rectal cancer data in the same manner report reduced risk for rectal cancer; four of these studies detected statistically significant inverse associations. The frequency, duration and intensity of activity are important components of a public health message to reduce risk of colon cancer through performance of physical activity. However, difficulties in estimating the exact amount of activity needed and frequency and intensity of activity result in only crude estimates of dose needed for a protective effect. Much of the literature suggest that more intense activity is needed to reduce colon cancer risk and that somewhere between 3.5 and 4 hours of vigorous activity per week may be needed to optimise protection. Several biological mechanisms have been proposed to explain the association between physical activity and colon cancer; many of these mechanisms also support the observation that intense activities are most protective. Biological mechanisms include: physical activity increasing gut motility; enhancing the immune system; decreasing insulin and insulin-like growth factor levels; decreasing obesity; enhancing free radical scavenger systems; and influencing prostaglandin levels. The evidence taken together provides strong support for lack of physical activity being causally related to colon cancer. It has been estimated that 12-14% of colon cancer could be attributed to lack of frequent involvement in vigorous physical activity.

Physical activity and breast cancer risk among female physical education and language teachers: a 34-year follow-up

The cohort consisted of 1,489 Finnish female physical education and 8,560 language teachers born after 1920 and alive in 1967. The 2 study populations were similar in social class and way of living and clearly discordant in physical activity both during their university studies and later in life. The incidence of breast cancer among these teachers up to the year 2000 was assessed through a record linkage with the Finnish Cancer Registry. The number of breast cancer cases among physical education teachers was 61 in 32,862 person-years and among language teachers was 404 in 177,188 person-years. In Poisson-regression analysis, the incidence rate ratio--adjusted for age, calendar time, number of children and age at first birth--for physical education vs. language teachers was overall 0.83 (95% confidence interval 0.63-1.09). This relative rate was 0.79 (0.46-1.36) in ages <50 years and 0.86 (0.62-1.18) in ages > or =50 years. Our study is concordant with the hypothesis that life-long physical activity may reduce the risk of breast cancer.

Comparison of accelerometry and oxymetry for measuring daily physical activity

To assess the validity of accelerometry in measuring daily physical activity, the energy consumption calculated by accelerometry, with respiratory gas analysis as a reference, was evaluated in 45 non-athletes during various exercise tests. Subjects were required to (1) walk on a treadmill ergometer at various speeds, (2) walk on a treadmill ergometer at a fixed speed and with a stride of 20% more or 20% less than that when walking freely, (3) walk on a treadmill ergometer at a fixed speed wearing either sneakers or leather-soled shoes, and (4) cycle on a bicycle ergometer. There were strong linear relationships between the measurements during the progressively graded treadmill test, with an overall Pearson correlation coefficient of 0.97. The mean estimated difference ranged from -0.77 to 0.27 kcal/min and the coefficients of variation from 13.2% to 22.2%. However, the difference between the methods was not negligible for individual subjects. Accelerometry overestimated energy expenditure during short-step walking, and underestimated it during long-step walking. No significant difference in energy expenditure was found according to the type of shoes worn. Cycling activity was not recorded by accelerometry. Accelerometry is a reasonably accurate and feasible method for evaluating the physical activities of non-athletes, and could be a common tool for epidemiological research and health promotion despite its limitations.

Physical activity and colon cancer: confounding or interaction?

PURPOSE

Although physical activity has been consistently inversely associated with colon cancer incidence, the association of physical activity with other diet and lifestyle factors that may influence this association is less well understood. Confounding and effect modification are examined to better understand the physical activity and colon cancer association.

METHODS

Based on hypothesized biological mechanisms whereby physical activity may alter risk of colon cancer, we evaluated confounding and effect modification using data collected as part of a case-control study of colon cancer (N = 1993 cases and 2410 controls). We examined associations between total energy intake, fiber, calcium, fruit and vegetables, red meat, whole grains as well as dietary patterns along with cigarette smoking, alcohol consumption, BMI, and use of aspirin and/or NSAIDs and physical activity.

RESULTS

No confounding was observed for the physical activity and colon cancer association. However, differences in effects of diet and lifestyle factors were identified depending on level of physical activity. Most striking were statistically significant interactions between physical activity and high-risk dietary pattern and vegetable intake, in that the relative importance of diet was dependent on level of physical activity. The predictive model of colon cancer risk was improved by using an interaction term for physical activity and other variables, including BMI, cigarette smoking, energy intake, dietary fiber, dietary calcium, glycemic index, lutein, folate, vegetable intake, and high-risk diet rather than using models that included these variables as independent predictors with physical activity. In populations where activity levels are high, the estimate of risk associated with high vegetable intake was 0.9 (95% CI 0.6-1.3), whereas in more sedentary populations the estimate of risk associated with high vegetable intake was 0.6 (95% CI 0.5-0.9).

CONCLUSIONS

Physical activity plays an important role in the etiology of colon cancer. Its significance is seen by its consistent association as an independent predictor of colon cancer as well as by its impact on the odds ratios associated with other factors. Given these observations, it is most probable that physical activity operates through multiple biological mechanisms that influence the carcinogenic process.

Occupational physical activity and risk for prostate cancer in a nationwide cohort study in Sweden

We investigated effects of occupational physical activity on relative risk for prostate cancer. From Swedish nationwide censuses in 1960 and 1970, we defined two cohorts of men whose occupational titles allowed classification of physical activity levels at work in 1960 (n=1,348,971) and in 1970 (n=1,377,629). A third cohort included only men whose jobs required a similar level of physical activity in both 1960 and 1970 (n=673,443). The incidence of prostate cancer between 1971 and 1989 was ascertained through record linkage to the Swedish Cancer Register. A total of 43,836, 28,702, and 19,670 prostate cancers, respectively, occurred in the three cohorts. In all three cohorts, the relative risk for prostate cancer increased with decreasing level of occupational physical activity (P<0.001), using Poisson regression. Among men with the same physical activity levels in 1960 and 1970, the rate ratio was 1.11 for men with sedentary jobs as compared with those whose jobs had very high/high activity levels after adjustment for age at follow-up, calendar year of follow-up and place of residence (95% CI 1.05-1.17; P for trend <0.001). There was no association between occupational activity and prostate cancer mortality. Since we had no data on other potential risk factors the observed associations for both incidence and mortality might have been confounded. Further studies are needed to better understand the potential role of physical activity for prostate cancer.

Sepsis and mechanisms of inflammatory response: is exercise a good model?

OBJECTIVES

The immune changes induced by a bout of prolonged and vigorous exercise have been suggested to be a useful experimental model of sepsis and the inflammatory response. Available literature was reviewed to evaluate this hypothesis.

METHODS

Literature describing the immune response to various patterns of exercise was compared with data on the immune changes observed during sepsis and inflammation.

RESULTS

Although there are qualitative similarities between the immune responses to exercise and sepsis, the magnitude of the changes induced by most forms of exercise remains much smaller than in a typical inflammatory response. Indeed, the exercise induced changes in some key elements such as plasma cytokine concentrations are too small to be detected reliably by current technology.

CONCLUSIONS

If exercise is to provide a valid model of sepsis and the inflammatory response, it will be necessary to focus on subjects who are willing to exercise extremely hard, to use the pattern of exercise that has the greatest effect on the immune system, and to combine this stimulus with other psychological, environmental, or nutritional stressors.

Special feature for the Olympics: effects of exercise on the immune system: overview of the epidemiology of exercise immunology

The application of epidemiological methods to exercise immunology is reviewed briefly, with particular reference to the possible influences of physical activity, exercise and training on susceptibility to upper respiratory infections. Available reports are arbitrarily rated in terms of limiting factors: the quality of the assessment of physical activity, the precision of diagnosis of upper respiratory infection and overall methodology. The pattern of physical activity has often been clearly established but, in part because of the problems associated with the competitive environment, assessments of infection and overall methodology have often been less than optimal. Although there is some evidence that susceptibility to infection is increased by either a single bout of very heavy activity or a period of heavy training, reports are far from unanimous, and in certain respects fail to meet the classical epidemiological criteria of a causal relationship. The issue is important to both the health and the success of the international competitor, and merits definitive investigation, using optimal methods to assess both activity patterns and infection.

Exercise therapy effect on natural killer cell cytotoxic activity in stomach cancer patients after curative surgery

OBJECTIVE

To evaluate the effect of early exercise therapy on the natural killer cell cytotoxic activity (NKCA) of patients who had undergone curative resection of stomach cancer.

DESIGN

Prospective study.

PATIENTS

Thirty-five stomach cancer patients who had undergone curative surgery were randomly divided into an exercise group (n = 17) and a control group (n = 18).

INTERVENTION

From postoperative day 2, moderated exercise using arm and bicycle ergometers performed twice a day, 5 times a week, for 14 days. The intensity of exercise was 60% of maximal heart rate. Venous blood samples were obtained on postoperative days 1, 7, and 14.

MAIN OUTCOME MEASURE

Mean sequential change of NKCA.

RESULTS

The mean sequential change of NKCA decreased until postoperative day 7 and then increased. Mean NKCA of day 7 decreased in both groups, compared with that at postoperative day 1. At day 14, the mean NKCA of the exercise group demonstrated a significant increase compared with that of the control group (p < .05).

CONCLUSION

This study suggests that early moderate exercise has a beneficial effect on the function of in vitro NK cells in stomach cancer patients after curative surgery.

Breast cancer among former college athletes compared to non-athletes: a 15-year follow-up

A growing body of evidence indicates that physical activity is protective against breast cancer. In 1996-97, we conducted a 15-year follow-up of 5398 college alumnae comprised of former college athletes with their non-athletic classmates. Participants completed a detailed mailed questionnaire on their health history from 1981-82 to the present. Excluding women who had died and non-deliverable questionnaires, 84.7% (n = 3940) of the participants in our earlier study responded to the questionnaire; the response rate for former athletes was 86.6% (n = 1945), for non-athletes, 83.0% (n = 1995). Results confirmed our earlier findings. Based on self-reports, former college athletes had a significantly lower risk of breast cancer than the non-athletes. The OR for the 15-year incidence of breast cancer is 0.605 with 95% confidence interval (CI) (0.438-0.835); the 15-year incident breast cancers were 64 among the athletes and 111 among the non-athletes. Among women under 45 the protective effect of physical activity on the risk of breast cancer is considerably greater; odds ratio (OR) = 0.164, 95% CI (0.042-0.636). Athletic activity during the college and pre-college years is protective against breast cancer throughout the life span, and more markedly among women under 45. These results confirm our earlier findings and the findings of other investigators.

Alternative therapies used by women with breast cancer in four ethnic populations

BACKGROUND

Interest in alternative therapies is growing rapidly in the United States. We studied the types and prevalence of conventional and alternative therapies used by women in four ethnic groups (Latino, white, black, and Chinese) diagnosed with breast cancer from 1990 through 1992 in San Francisco, CA, and explored factors influencing the choices of their therapies.

METHODS

Subjects (n = 379) completed a 30-minute telephone interview in their preferred language. Logistic regression models assessed factors associated with the use of alternative therapies after a diagnosis of breast cancer.

RESULTS

About one half of the women used at least one type of alternative therapy, and about one third used two types; most therapies were used for a duration of less than 6 months. Both the alternative therapies used and factors influencing the choice of therapy varied by ethnicity. Blacks most often used spiritual healing (36%), Chinese most often used herbal remedies (22%), and Latino women most often used dietary therapies (30%) and spiritual healing (26%). Among whites, 35% used dietary methods and 21% used physical methods, such as massage and acupuncture. In general, women who had a higher educational level or income, were of younger age, had private insurance, and exercised or attended support groups were more likely to use alternative therapies. About half of the women using alternative therapies reported discussing this use with their physicians. More than 90% of the subjects found the therapies helpful and would recommend them to their friends.

CONCLUSIONS

Given the high prevalence of alternative therapies used in San Francisco by the four ethnic groups and the relatively poor communication between patients and doctors, physicians who treat patients with breast cancer should initiate dialogues on this topic to better understand patients' choices with regard to treatment options.

Occupational physical activity and renal cell cancer: a nationwide cohort study in Sweden

The causes of renal cell cancer remain incompletely understood. In one previous retrospective case-control study, high occupational physical activity has been associated with a decreased risk among men, but not among women. Our aim was to investigate the association between occupational physical activity and renal cell cancer in a large cohort in Sweden. A cohort of Swedish men and women was identified in the nationwide censuses in 1960 and 1970, and the reported occupations were classified into 4 levels of physical demands. Follow-up from 1971 through 1989 was accomplished through record linkages to the Swedish Cancer Registry. Multivariate Poisson regression models were used to estimate relative risk (RR) and 95% confidence intervals (CI). We found a monotonic increase in risk of renal cell cancer with decreasing level of occupational physical activity among men (p for trend <0.001). After adjustment for socio-economic status, place of residence, and calendar year of follow-up, men with long-term sedentary jobs had a 25% (RR = 1.25, 95% CI 1.02-1.53) increased risk compared to men with physically demanding occupations. Among women there was no association, the dose-risk trend was not significant (p for trend >0.50). Occupational physical activity was inversely associated with renal cell cancer among men. The absence of association among women might be due to smaller range of exposure, confounding by household work or reproductive factors, or to a difference in biological response to physical activity in men and women.