Physical activity and the risk of prostate and testicular cancer: a cohort study of 53,000 Norwegian men

The associations between recreational and occupational physical activity and the subsequent risk of prostate and testicular cancer were examined in a population-based cohort study of 53,242 men in Norway. Age at study entry was 19 to 50 years. Information on physical activity was based on questionnaire responses and a brief clinical examination. A total of 220 prostate and 47 testicular cancer cases were recorded in the Cancer Registry of Norway during a mean follow-up time of 16.3 years. We found a nonsignificant, reduced, adjusted relative risk (RR) of prostate cancer with increased level of physical activity at work and among those men with the greatest recreational physical activity. When occupational and recreational physical activity were combined, a reduced adjusted risk of prostate cancer was observed among men who walked during occupational hours and performed either moderate recreational activity (RR-0.61, 95 percent confidence interval [CI]=0.36 to 1.01) or regular recreational training (RR=0.45, CI=0.20 to 1.01) relative to sedentary men (test for trend,P=0.03). Physically active men who were older than 60 years of age at diagnosis showed a reduced adjusted RR of borderline significance, while no association was observed for younger men. No evidence was found for any association between physical activity and testicular cancer regardless of physical activity at work and recreation.This project is funded by the Norwegian Cancer Society.     

Occupational physical activity and risk of cancer of the colon and rectum in New Zealand males

The association between occupational physical activity and risk of colorectal cancer by age and anatomic site was investigated in a study of 2,503 males with colorectal cancer registered with the New Zealand Cancer Registry during 1972–80. Occupational groups that involved high levels of physical activity or were predominantly sedentary were identified prior to analysis of the registry data. Relative to males in high physical activity occupations, males in sedentary occupations had an increased incidence of both cancer of the colon (relative risk [RR]=1.2; 95 percent confidence interval [CI]=1.0–1.4) and rectum (RR=1.3, CI=1.0–1.5). The RRs for sedentary workers were particularly elevated in the 35–44 and 45–54 year age-groups for colon cancer (RR=1.8 and 1.5, respectively) and in the 45–54 year age-group for rectal cancer (RR=1.5), whereas there was no increase in risk for sedentary workers in the 55–64 year age-group for either cancer site. The generalincrease in colon cancer incidence for New Zealand during the study period was reflected in the sedentary group, but there was no change in incidence among men in occupations involving high or intermediate levels of physical activity. There was no obvious pattern for the increased cancer risk for men in sedentary occupations by anatomic site. Current physiologic hypotheses for the effect of physical activity on colon cancer risk do not adequately explain an association of physical activity with risk of rectal cancer.Dr Fraser is affillated with the University of Otago, Medical School, Dunedin, New Zealand. Dr Pearce is with the Wellington School of Medicine, Wellington, New Zealand. Address correspondence to Dr Fraser, Department of Preventive and Social Medicine, University of Otago Medical School, PO Box 913, Dunedin, New Zealand.     

Physical activity and lung cancer risk in the European Prospective Investigation into Cancer and Nutrition Cohort

Research conducted predominantly in male populations on physical activity and lung cancer has yielded inconsistent results. We examined this relationship among 416,277 men and women from the European Prospective Investigation into Cancer and Nutrition (EPIC). Detailed information on recent recreational, household and occupational physical activity, smoking habits and diet was assessed at baseline between 1992 and 2000. Relative risks (RR) were estimated using Cox regression. During 6.3 years of follow-up we identified 607 men and 476 women with incident lung cancer. We did not observe an inverse association between recent occupational, recreational or household physical activity and lung cancer risk in either males or females. However, we found some reduction in lung cancer risk associated with sports in males (adjusted RR = 0.71; 95% confidence interval 0.50-0.98; highest tertile vs. inactive group), cycling (RR = 0.73; 0.54-0.99) in females and non-occupational vigorous physical activity. For occupational physical activity, lung cancer risk was increased for unemployed men (adjusted RR = 1.57; 1.20-2.05) and men with standing occupations (RR = 1.35; 1.02-1.79) compared with sitting professions. There was no evidence of heterogeneity of physical activity associations across countries, or across any of the considered cofactors. For some histologic subtypes suggestive sex-specific reductions, limited by subgroup sizes, were observed, especially with vigorous physical activity. In total, our study shows no consistent protective associations of physical activity with lung cancer risk. It can be assumed that the elevated risks found for occupational physical activity are not produced mechanistically by physical activity itself but rather reflect exposure to occupation-related lung cancer risk factors.     

Physical activity in relation to cancer of the colon and rectum in a cohort of male smokers.

We examined the association between occupational and leisure physical activity and colorectal cancer in a cohort of male smokers. Among the 29,133 men aged 50-69 years in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention study,152 colon and 104 rectal cancers were documented during up to 12 years of follow-up. For colon cancer, compared with sedentary workers, men in light occupational activity had a relative risk (RR) of 0.60 [95% confidence interval (CI), 0.34-1.04], whereas those in moderate/heavy activity had an RR of 0.45 (CI, 0.26-0.78; P for trend, 0.003). Subsite analysis revealed a significant association for moderate/heavy occupational activity in the distal colon (RR, 0.21; CI, 0.09-0.51) but not in the proximal colon (RR, 0.87; CI, 0.40-1.92). There was no significant association between leisure activity and colon cancer (active versus sedentary; RR, 0.82; CI, 0.59-1.13); however, the strongest inverse association was found among those most active in both work and leisure (RR, 0.33; CI, 0.16-0.71). For rectal cancer, there were risk reductions for those in light (RR, 0.71; CI, 0.36-1.37) and moderate/heavy occupational activity (RR, 0.50; CI, 0.26-0.97; P for trend, 0.04), and no association for leisure activity. These data provide evidence for a protective role of physical activity in colon and rectal cancer.     

Risk factors for colorectal cancer in a prospective study among U.S. white men

The association of diet, smoking/drinking and occupation with subsequent risk of fatal colorectal cancer was investigated in a cohort of 17,633 white males aged 35 and older, who completed a mail questionnaire in 1966. During the subsequent 20 years of follow-up, 120 colon cancer and 25 rectal cancer deaths were identified. Due to small numbers, no significant dose-response trends were observed in the study, but risk of colon cancer was elevated among heavy cigarette smokers (≥30/day; RR = 2.3, 95% CI 0.9–5.7), heavy beer drinkers (≥14 times/month; RR = 1.9, 95% CI 1.0–3.8) and white-collar workers (RR = 1.7, 95% CI 1.0–3.0) or crafts workers within service and trade industries (RR = 2.6, 95% CI 1.1–5.8). In addition, an increased risk was seen for those who consumed red meat more than twice a day (RR = 1.8, 95% CI 0.8–4.4). Risk patterns for cancers of the colon and rectum combined were similar to those reported for cancer of the colon, but the estimates were somewhat dampened. Our findings support previous reports that a high intake of red meat and a sedentary life-style may increase the risk of colon cancer. Int. J. Cancer77:549–553, 1998. Published 1998 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Physical activity and prostate cancer in the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study (Finland)

The association between physical activity and prostate cancer was evaluated in the trial-based cohort of the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study (n = 29,133). During up to nine years of follow-up, 317 men developed incident prostate cancer. The relationship between occupational, leisure, and combined activity and prostate cancer was assessed in multivariate Cox regression models that adjusted for intervention group, benign prostatic hyperplasia, age, smoking, and urban residence. Compared with sedentary workers, relative risks (RR) and 95 percent confidence intervals (CI) for occupational walkers, walker/lifters, and heavy laborers were 0.6 (CI = 0.4-1.0), 0.8 (CI = 0.5-1.3), and 1.2 (CI = 0.7-2.0), respectively. Among working men, leisure activity (active cf sedentary) was associated inversely with risk (RR = 0.7, CI = 0.5-0.9). This inverse association for leisure activity was observed, with the exception of heavy laborers, for all occupational acti vity levels, and was strongest among walkers compared with men sedentary at work and leisure, and to a lesser degree among walker/lifters. These results are consistent with a protective effect of physical activity on prostate cancer.     

Physical activity and risk of renal cell carcinoma

The role of physical activity in the development of renal cell carcinoma was examined using a population-based case-control study conducted in the province of Ontario. Physical activity was examined in several ways, including by intensity and during various life periods. Frequency-matching by 5-year age groups and sex produced sets of 486 females (133 cases and 353 controls) and 447 males (172 cases, 275 controls). Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). After adjusting for age, body mass index and smoking, women who performed relatively high amounts of recent recreational activity (OR = 0.41, 95% CI 0.21-0.82 for the highest vs. lowest quartile of activity, 2 years ago), as well as strenuous recreational activity (OR = 0.40, 95% CI 0.22-0.75), had a reduced risk of developing the disease. In general, moderate recreational activity did not appear to be associated with risk in females. In males, a relatively high frequency of total and moderate recreational activity was associated with reduced risk (total, OR = 0.49, 95% CI 0.27-0.87; moderate, OR = 0.49, 95% CI 0.27-0.89), especially during the teen years. Recreational activity during one's 30s was not associated with cancer risk. There was also no association between occupational activity and cancer risk in females or males. The results of our study, in general, suggest that physical activity may be associated with a decreased risk of developing renal cell carcinoma.     

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.     

Dietary patterns and subsequent colorectal cancer risk by subsite: a prospective cohort study

In order to investigate the associations between dietary patterns and the risk of colorectal cancer by subsite in Japan, the baseline data from a population-based cohort study of 20,300 men and 21,812 women were analyzed. We conducted factor analysis and identified 3 major dietary patterns, "healthy," "traditional" and "Western," and calculated the factor scores of each pattern for individuals. During 10 years of follow-up, 370 colorectal cancer cases were identified. We found a positive association between the traditional pattern and colon cancer risk in women [rate ratio for highest quartile (RR) = 2.06; 95% CI = 1.10-3.84; p for trend = 0.11], but not in men. This positive association was slightly stronger for proximal colon cancer (RR = 2.07; 95% CI = 0.84-5.12) than for distal colon cancer (RR = 1.84; 95% CI = 0.75-4.50). After multivariate adjustment, the Western dietary pattern was also positively associated with colon cancer risk in females (RR = 2.21; 95% CI = 1.10-4.45), with the strongest associations being observed for females with distal colon cancer (RR = 3.48; 95% CI = 1.25-9.65). We did not observe any significant association between the healthy dietary pattern and colon cancer risk. For rectal cancer, no significant associations were found for the 3 dietary patterns. In conclusion, we found that the traditional and the Western dietary patterns were positively associated with colon cancer risk in females.     

Physical activity and colon cancer risk among women in the California Teachers Study.

BACKGROUND: Existing data suggest that physical activity reduces colon cancer risk, but the association is not consistently observed in women. One potential explanation for this inconsistency is that hormone therapy, which is associated with lower colon cancer risk, acts as a modifier of the physical activity/colon cancer relationship. METHODS: Participants in the California Teachers Study (N = 120,147), a prospective cohort of female teachers and administrators residing in California, ages 22 to 84 years at baseline and with no prior history of colon cancer were eligible for study. Between 1996 and 2002, 395 patients were diagnosed with invasive colon cancer. The relative risks (RR) associated with lifetime (high school through age 54 years or current age) and recent (past 3 years) strenuous and moderate recreational physical activity were estimated using Cox proportional hazards regression models. RESULTS: Combined lifetime moderate and strenuous recreational physical activity was only modestly associated with colon cancer risk in the cohort [>or=4 versus or=4 versus 相似文献   

Large bowel cancer in women in relation to reproductive and hormonal factors: a case-control study

A community-based case-control study of the effect of reproductive factors on risk of large bowel cancer in Australia is described. The study involved 155 cases (99 colon cancer, 56 rectal cancer) and 311 controls who were interviewed with regard to pregnancies and their outcomes, lactation, menstrual history, and oral contraceptive (OC) use. Increasing parity was associated with a decreasing risk of colon cancer; para 0, relative risk (RR)=1; para 1-2, RR=0.9, 95% confidence interval (CI)=0.4-1.8; para greater than or equal to 3, RR=0.4, 95% CI=0.2-0.8; later age at first live birth (AFLB) was associated with increasing risk (AFLB less than or equal to 21 yr, RR=1; 22-25 yr, RR=2.3, 95% CI=1.0-5.5; greater than or equal to 26 yr, RR=2.7, 95% CI=1.2-6.2). These effects were independent of each other. Parity appeared to exert its predominant effect on risk of cancer of the right colon. OC use was more common among controls than cases (RR=0.5; 95% CI=0.3-1.2 for ever vs. never users) and showed a dose-response effect in multiple logistic analysis. The pattern of point-estimate RR for rectal cancer was largely congruent with those for colon cancer but was not significantly different from 1.0.     

A case-control study of male colorectal cancer in Aichi Prefecture, Japan: with special reference to occupational activity level, drinking habits and family history

The relationships of occupational activity level, drinking habits and family history of cancer to the risk of male colorectal cancer by subsites were investigated in a case-control study involving 1,716 cases with colon cancer, 1,611 cases with rectal cancer and 16,600 controls with other sites of cancer identified from the Aichi Cancer Registry, Japan 1979-1987. An occupation with a low activity level was associated with an increased risk of colorectal cancer; the age-adjusted relative risk (RR) compared to the high activity level group was 1.92 (95% confidence interval (CI): 1.38-2.67) for proximal colon cancer, 1.52 (95% CI: 1.19-1.94) for distal colon cancer and 1.38 (95% CI: 1.17-1.62) for rectal cancer. Beer drinkers showed an increased risk of colorectal cancer; the age-adjusted RR was 1.49 (95% CI: 1.13-1.95) for proximal colon cancer, 1.65 (95% CI: 1.34-2.04) for distal colon cancer and 1.88 (95% CI: 1.62-2.18) for rectal cancer. The RR for family history of colorectal cancer was 3.40 (95% CI: 2.19-5.29) for proximal colon cancer, 2.54 (95% CI: 1.73-3.75) for distal colon cancer and 1.78 (95% CI: 1.28-2.49) for rectal cancer. Multivariate analysis controlled for age, residence, marital status and smoking in addition to occupational activity level, beer drinking and family history of colorectal cancer did not materially change the RRs. When these three variables were combined, the RR was 15.72 (95% CI: 5.40-45.78) for proximal colon cancer, 10.55 (95% CI: 4.24-26.27) for distal colon cancer and 6.69 (95% CI: 3.12-14.36) for rectal cancer.     

A comparative case-control study of colorectal cancer and adenoma

We conducted a comparative case-control study of colorectal cancer and adenoma involving 221 cases with colorectal cancer, 525 cases with colorectal adenoma and 578 neighborhood controls. Daily vegetables intake was associated with lower risks of distal colon adenoma (relative risks (RR) = 0.59, 95% confidence interval (CI): 0.39-0.89) and rectal cancer (RR = 0.46, 95% CI: 0.25-0.84). Daily beans intake was associated with lower risk of colon adenoma (RR = 0.58, 95% CI: 0.37-0.91 for the proximal colon and RR = 0.63, 95% CI: 0.45-0.88 for the distal colon) and daily intake of seaweeds was associated with lower risk of rectal cancer (RR = 0.42, 95% CI: 0.22-0.82). Daily intake of fish and shellfish also showed an inverse association with the risk of colon adenoma (RR = 0.67, 95% CI: 0.45-0.99 for the proximal colon and RR = 0.70, 0.52-0.94 for the distal colon). Generally, intakes of animal or vegetable fat-rich foods, especially meats, were associated with decreases in risks of both adenoma and cancer, though the association of cancer was not statistically significant. Other than dietary factors, daily alcohol drinking was associated with an increased risk of adenoma in the proximal colon (RR = 1.95, 95% CI: 1.15-3.29) and ex-drinkers showed higher risks for colon adenoma and colorectal cancer. Sports or occupational activities and coffee drinking were inversely associated and family history of colorectal cancer was positively associated with the risk of both colorectal adenoma and cancer.     

Physical activity and risk of cancers of the colon and rectum: an Italian case-control study

We investigated the relationships between risk of colon and rectal cancers and physical activity in both sexes at different ages by a case-control study conducted between 1991 and 1996 in six Italian centres. Cases were 1225 patients (688 men, 537 women) below the age of 75 with colon cancer and the controls included 4154 patients (2073 men, 2081 women) admitted to hospital for acute, non-neoplastic conditions. We also analysed 722 cases of rectal cancer. Compared with the lowest level of occupational physical activity at 30-39 years old the odds ratios (OR) for the highest level were 0.64 (95% confidence interval, CI 0.44-0.93) in men and 0.49 (95% CI 0.33-0.72) in women. The inverse association in both sexes was similar at 15-19 and 50-59 years old. No association was found in either sex for leisure-time physical activity. For both sexes the inverse relationship between occupational physical activity at 30-39 years old and colon cancer risk was not significantly heterogeneous across strata of selected covariates, and for ascending, transverse, descending and sigmoid colon. Rectal cancer risk was not associated with any measure of physical activity (OR = 1.32 for men and 0.88 for women for the highest level of occupational physical activity at 30-39 years old compared with the lowest). This study confirms that occupational physical activity is protective against colon, but not against rectal cancer.     

Physical activity and lung cancer risk in male smokers

We examined the association between physical activity and lung cancer in a prospective cohort of 27,087 male smokers, ages 50-69 years, enrolled in the Alpha-Tocopherol, Beta Carotene Cancer Prevention (ATBC) Study. After an average of 10 years of follow-up, 1,442 lung cancer cases were diagnosed. Cox proportional hazards models were used to estimate the relative risk (RR) and 95% confidence intervals (CI) of lung cancer associated with self-reported occupational and leisure-time activity, adjusted for age, supplement group, body mass index, cigarettes smoked daily, years of smoking, education, energy intake and vegetable intake. There were no associations between occupational, leisure-time or combined categories of physical activity with lung cancer risk; however, age appeared to modify the effect of leisure-time activity (p = 0.02). Within increasing quartiles of age, the RRs (CI) for men active in leisure time compared to sedentary men were 0.77 (0.54-1.09), 0.74 (0.57-0.95), 1.09 (0.89-1.33) and 1.03 (0.88-1.21). These data suggest that among smokers, neither occupational nor leisure-time activity is associated with lung cancer risk. There may, however, be some modest risk reduction associated with leisure activity among younger smokers. Published 2002 Wiley-Liss, Inc.     

Physical inactivity,energy intake,obesity and the risk of rectal cancer in Canada

We conducted a population-based case-control study of 1,447 incident rectal cancer cases and 3,106 population controls aged 20-76 years to assess the effect of recreational physical activity, energy intake and obesity on rectal cancer risk in 7 of 10 Canadian provinces in 1994-97. After adjustment for the effect of various potential confounding factors, total recreational physical activity in the highest quartile was associated with an odds ratio (OR) for rectal cancer risk of 0.88 (95% confidence interval [CI] = 0.64-1.20) in women and 1.15 (95% CI = 0.88-1.49) in men. Women and men in the highest quartile of caloric intake (> = 56,741 and > = 63,143 kJ/week) had ORs of 1.50 (95% CI = 1.00-2.25) and 1.61 (95% CI = 1.13-2.28), respectively. Total dietary fat intake was not associated with a risk of rectal cancer after adjustment for caloric intake. Obesity (BMI > = 30 kg/m(2)) was associated with an OR of 1.44 (95% CI = 1.06-1.95) for women and 1.78 (95% CI = 1.36-2.34) for men. Men and women with lifetime maximum body mass index (BMI) > = 30 kg/m(2) had respective ORs of 1.70 (95% CI = 1.30-2.23) and 1.26 (95% CI = 0.96-1.66). The greatest increase in rectal cancer risk was observed in men and women with simultaneous high energy intake, high BMI and low physical activity. Our study provides evidence that physical inactivity, high energy intake and obesity are associated with the risk of rectal cancer, and there is a probable synergic effect among the 3 risk factors.     

Prospective study of body mass index, height, physical activity and incidence of bladder cancer in US men and women

We evaluated prospectively the association between body mass index (BMI), height, recreational physical activity and the risk of bladder cancer among US adults. Data were used from 2 ongoing cohorts, the Health Professionals Follow-up Study and the Nurses' Health Study, with 3,542,012 years of follow-up and 866 incident bladder cancer cases (men = 507; women = 359) for the anthropometric analysis and 1,890,476 years of follow-up and 706 incident bladder cancer cases (men = 502; women = 204) for the physical activity analysis. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between BMI, height, physical activity and bladder cancer risk adjusting for age, pack-years of cigarette smoking and current smoking. Estimates from each cohort were pooled using a random-effects model. We observed no association between baseline BMI and bladder cancer risk, even when we compared a BMI of > or =30 kg/m(2) to a BMI of 18-22.9 kg/m(2) [pooled multivariate (MV) RR, 1.16; 95% CI: 0.89-1.52]. A weak, but statistically significant, association was observed for the same comparison after excluding bladder cancer cases diagnosed within the first 4 years of follow-up (pooled MV RR, 1.33; 95% CI: 1.01-1.76). Height was not related to bladder cancer risk (pooled MV RR, 0.82; 95% CI: 0.65-1.03, top vs. bottom quintile). Total recreational physical activity also was not associated with the risk of bladder cancer (pooled MV RR, 0.97; 95% CI: 0.77-1.24, top vs. bottom quintile). Our findings do not support a role for BMI, height or physical activity in bladder carcinogenesis.     

A Case-Control Study of Male Colorectal Cancer in Aichi Prefecture, Japan: with Special Reference to Occupational Activity Level, Drinking Habits and Family History

The relationships of occupational activity level, drinking habits and family history of cancer to the risk of male colorectal cancer by subsites were investigated in a case-control study involving 1,716 cases with colon cancer, 1,611 cases with rectal cancer and 16,600 controls with other sites of cancer identified from the Aichi Cancer Registry, Japan 1979–1987. An occupation with a low activity level was associated with an increased risk of colorectal cancer; the age-adjusted relative risk (RR) compared to the high activity level group was 1.92 (95% confidence interval (CI): 1.38–2.67) for proximal colon cancer, 1.52 (95% CI: 1.19–1.94) for distal colon cancer and 1.38 (95% CI: 1.17–1.62) for rectal cancer. Beer drinkers showed an increased risk of colorectal cancer; the age-adjusted RR was 1.49 (95% CI: 1.13–1.95) for proximal colon cancer, 1.65 (95% CI: 1.34-2.04) for distal colon cancer and 1.88 (95% CI: 1.62–2.18) for rectal cancer. The RR for family history of colorectal cancer was 3.40 (95% CI: 2.19–5.29) for proximal colon cancer, 2.54 (95% CI: 1.73–3.75) for distal colon cancer and 1.78 (95% CI: 1.28–2.49) for rectal cancer. Multivariate analysis controlled for age, residence, marital status and smoking in addition to occupational activity level, beer drinking and family history of colorectal cancer did not materially change the RRs. When these three variables were combined, the RR was 15.72 (95% CI: 5.40–45.78) for proximal colon cancer, 10.55 (95% CI: 4.24–26.27) for distal colon cancer and 6.69 (95% CI: 3.12–14.36) for rectal cancer.     

Occupational physical activity and risk of adenocarcinomas of the esophagus and stomach

Physical activity may have a role in many cancers, but little is known about its effect on esophageal and gastric adenocarcinoma risk. We investigated occupational physical activity and esophageal and gastric adenocarcinoma risk in a population-based, case-control study including 212 esophageal, 264 gastric cardia and 389 distal gastric cancer cases, and 1,330 controls in Los Angeles County. Lifetime occupational histories were obtained during in-person interviews, and total lifetime occupational activity (Total Activity Index) was calculated using US Census job codes classified as sedentary, or moderately or highly physically active. Average Annual Activity Index was a per-year Total Activity Index counterpart. Unconditional logistic regression was used to calculate odds ratios, 95% confidence intervals and trend tests adjusting for gender, race, age, birthplace, education, smoking, body mass index (BMI) and number of years worked. Esophageal adenocarcinoma risk tended to decrease with increasing Total Activity Index (OR = 0.67, 95% CI = 0.38,1.19 for highest versus lowest quartile), but neither gastric cardia nor distal gastric cancer was associated with the Total Activity Index. This inverse association held for esophageal adenocarcinoma (OR = 0.61, 95% CI = 0.38,0.99 for highest vs. lowest quartile) and modest associations were observed for gastric cardia (OR = 0.76, 95% CI = 0.49,1.18) and distal gastric cancer (OR = 0.77, 95% CI = 0.52,1.14) when based on Average Annual Activity Index before age 65 years. Analyses stratified by gender, race, age, BMI, education and years worked provided similar results. We found a modest protective effect of Total Activity Index on esophageal adenocarcinoma. Future studies with more complete information on occupational and recreational physical activity are needed to confirm and further investigate the suggested protective effect of physical activity on these tumor types.     

Second Primary Cancers Following Colon and Rectal Cancer in Osaka, Japan

The frequencies of second primary cancers following colon and rectal cancers were estimated using the Osaka Cancer Registry's population-based data for Osaka, Japan. A series of 7,312 colon and 6,923 rectal cancer cases newly diagnosed in the period of 1966-1986 were followed up until the end of 1986. The average follow-up period was 3.6 years for colon cancer and 3.7 years for rectal cancer. Significantly elevated risks of second primary cancers following colon cancer were observed for cancers of the rectum (O/E= 2.0; 95% confidence interval (CI) = 1.1-3.4 among males, O/E=4.3; 95% CI=2.4-7.2 among females), corpus uteri (O/E=8.2; 95% CI = 3.3-16.9), ovary (O/E=4.3; 95% CI = 1.0-5.0), and female thyroid gland (O/E=4.7; 95% CI=1.7-8.8). These findings were more notable among right-sided colon cancer patients than left-sided colon cancer patients. The elevated risks of second primary cancers were particularly evident among patients younger than 50 years of age at the time of diagnosis of the initial cancer (colon cancer: O/E = 3.1 among males, 3.4 among females, rectal cancer: O/E=1.7 among males, 1.3 among females). These findings suggest that younger colorectal cancer patients should undergo more careful checkups throughout their lives.