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We compared the results of self-estimates of physical activity obtained with a novel instrument (the Energy Expenditure Questionnaire, EEQ) to those obtained from questions typically asked in epidemiological investigations (reference method) in a cohort of 42,150 Swedish men and women, aged 18-94. In the EEQ, participants were asked to report total physical activity by estimating the total time during a typical day and night spent on different physical activity intensity levels from the lowest (corresponding to lying in bed, 0.9 Metabolic Energy Turnover; MET) to the highest, (exceeding the intensity of to shovelling snow by hand, i.e., >6 MET). As a comparison, they also estimated hours per week devoted to household chores, commuting and leisure time physical activities classified as; light, moderate and heavy. The average physical activity estimated with the EEQ was 1.36 MET or 32.6 METh/day or 2,341 kcal/day. In comparison, physical activity estimated with the reference method represented no more than 17% of this amount. The Spearman's correlation coefficient between the two measures was 0.26. Using EEQ, men reported significantly more physical activity than women (mean = 36.3 vs. 30.6 METh/day). Body mass index (BMI) > or = 25, education > or = 12 years, and age > or = 60 years were significantly associated with lower physical activity. Questions focusing on leisure time exercise and a few other selected activities provide estimates of activity that correlate poorly with self-reported total energy output from all physical activity and inactivity. Investigators need to be more explicit about which component of activity they investigate.

Although anemia is widely considered an early sign of malignant disease, little is known about the pattern of hemoglobin decline before diagnosis. As an approach to understanding the duration of the preclinical phase of different types of malignant diseases, we investigated prediagnostic hemoglobin concentration changes in a large cohort of blood donors. Using a nested case-control design, we analyzed a population-based cohort comprising 1.1 million Scandinavian blood donors with complete follow-up through record linkage to population and cancer registers. A total of 16,375 cancer cases were identified, for whom we selected 161,995 controls. We used conditional logistic regression to estimate the risk of cancer in relation to hemoglobin concentration during the 5 years preceding the cancer diagnosis. Hemoglobin concentration decline began already 3 years before diagnosis of stomach cancer, multiple myeloma, and lymphatic leukemia; 2 years before diagnosis of small intestinal and colon cancer as well as of Hodgkin lymphoma. A decline was evident during the last year for non-Hodgkin lymphoma and myeloid/monocytic leukemia, whereas no change was found for cancer of the esophagus, breast or prostate. In conclusion, in this study, we have demonstrated that the pattern of declining hemoglobin concentration before cancer diagnosis varies considerably between malignancies without being a suitable screening tool for any of them. For some malignancies, however, the long duration of hemoglobin decline before clinical diagnosis suggests a substantial lead-time with systemic effects, during which earlier diagnosis should be achievable by emerging diagnostic tools. © 2009 UICC.

Although keeping a healthy weight and being physically active are among the few modifiable risk factors for post-menopausal breast cancer, the possible interaction between these two risk factors remains to be established. We analyzed prospectively a cohort of 19,196 women who provided detailed self-report on anthropometric measures, physical activity and possible confounders at enrollment in 1997. We achieved complete follow-up through 2010 and ascertained 609 incident cases of post-menopausal invasive breast cancer. We calculated metabolic energy turnover (MET h/day) per day and fitted Cox proportional hazards models to estimate hazard ratios (HRs) with 95 % confidence intervals (CIs). The incidence of post-menopausal breast cancer among obese women (BMI ≥ 30 kg/m2) was 58 % higher (HR 1.58, CI 1.16–2.16) than in women of normal weight (18.5 ≤ BMI < 25). Women in the lowest tertile of total physical activity (< 31.2 MET h/day) had 40 % higher incidence of post-menopausal breast cancer (HR 1.40, CI 1.11–1.75) than those in the highest tertile (≥ 38.2 MET h/day). The excess incidence linked to these two factors seemed to combine in an approximately additive manner; the incidence among the most obese and sedentary women was doubled (HR 2.07, CI 1.31–3.25) compared with the most physically active women with normal weight. No heterogeneity of the physical activity-linked risk ratios across strata of BMI was detected (p value for interaction = 0.98). This prospective study revealed dose-dependent, homogenous inverse associations between post-menopausal breast cancer incidence and physical activity across all strata of BMI, and between post-menopausal breast cancer incidence and BMI across all strata of physical activity, with no evidence of additive or multiplicative interaction between the two, suggesting independent effects.

The aim of this study was to explore the association between traumatic brain injury and brain tumor development.

Although keeping a healthy weight and being physically active are among the few modifiable risk factors for post-menopausal breast cancer, the possible interaction between these two risk factors remains to be established. We analyzed prospectively a cohort of 19,196 women who provided detailed self-report on anthropometric measures, physical activity and possible confounders at enrollment in 1997. We achieved complete follow-up through 2010 and ascertained 609 incident cases of post-menopausal invasive breast cancer. We calculated metabolic energy turnover (MET h/day) per day and fitted Cox proportional hazards models to estimate hazard ratios (HRs) with 95 % confidence intervals (CIs). The incidence of post-menopausal breast cancer among obese women (BMI ≥ 30 kg/m2) was 58 % higher (HR 1.58, CI 1.16–2.16) than in women of normal weight (18.5 ≤ BMI < 25). Women in the lowest tertile of total physical activity (< 31.2 MET h/day) had 40 % higher incidence of post-menopausal breast cancer (HR 1.40, CI 1.11–1.75) than those in the highest tertile (≥ 38.2 MET h/day). The excess incidence linked to these two factors seemed to combine in an approximately additive manner; the incidence among the most obese and sedentary women was doubled (HR 2.07, CI 1.31–3.25) compared with the most physically active women with normal weight. No heterogeneity of the physical activity-linked risk ratios across strata of BMI was detected (p value for interaction = 0.98). This prospective study revealed dose-dependent, homogenous inverse associations between post-menopausal breast cancer incidence and physical activity across all strata of BMI, and between post-menopausal breast cancer incidence and BMI across all strata of physical activity, with no evidence of additive or multiplicative interaction between the two, suggesting independent effects.

Purpose: Physical activity and body mass index (BMI) are involved in prostate cancer etiology; possible biologic mechanisms include their effects on hormonal levels. Our aim was to investigate the relationship between physical activity, obesity, and prostate cancer. Methods: We followed a cohort of 13,109 Swedish men for 13 years and investigated the association of self-reported physical activity and BMI at baseline with prostate cancer incidence. We further analyzed whether BMI could modulate effects of physical activity. Occupational, recreational, and total physical activity were analyzed in relation to overall, localized, and advanced prostate cancer. Results: During the study follow-up, we observed a total of 904 cases of prostate cancer (429 localized, 407 advanced, and 68 unclassified). High levels of occupational physical activity were associated with a nonsignificantly decreased risk of overall (HR 0.81, 95 % CI 0.61–1.07), localized (HR 0.75, 95 % CI 0.51–1.12), and advanced (HR 0.85, 95 % CI 0.55–1.31) prostate cancer. We found no association between high BMI and risk of prostate cancer incidence: We observed, however, a significant interaction between BMI and leisure physical activity. Conclusion: No association was confirmed between total physical activity and localized or advanced prostate cancer. The highest, relative to the lowest, level of occupational physical activity tended to be linked to a lower risk of prostate cancer, with a suggested dose–response relationship. We found no association between high BMI and risk of prostate cancer incidence; however, our analyses suggested an interaction between BMI and physical activity during recreational time that merits further investigation in future studies.

BACKGROUND: The nature of the association between levels of physical activity and risk of heart failure is little known. We investigated nonlinear associations of total and leisure time physical activity with risk of heart failure.METHODS AND RESULTS: In 1997, 39 805 persons without heart failure completed a questionnaire of lifestyle factors and medical history. We used Cox regression models to investigate total (adjusting for education and previous myocardial infarction) and direct (multivariable-adjusted) effects of self-reported total and leisure time physical activity on risk of heart failure of any cause and heart failure of nonischemic origin. Heart failure diagnoses were obtained until December 31, 2010. Higher leisure time physical activity was associated with lower risk of heart failure of any cause; hazard ratio of the total effect of leisure time physical activity was for fifth versus first quintile 0.54; 95% confidence interval was 0.44 to 0.66. The direct effect was similar. High total daily physical activity level was associated with lower risk of heart failure, although the effect was less pronounced than for leisure time physical activity (total effect hazard ratio, 0.81; 95% confidence interval, 0.69-0.95; fifth versus first quintile). A similar direct effect observed.CONCLUSIONS: Leisure time physical activity was inversely related to risk of developing heart failure in a dose-response fashion. This was reflected in a similar but less pronounced association of total physical activity with risk of heart failure. Only part of the effects appeared to be mediated by traditional risk factors.

Objective: To compare distributions of body mass index (BMI) between individuals with different habitual sleep patterns. Methods: We performed cross-sectional analyses of 40,197 Swedish adults (64% women), who reported sleep duration and quality, weight, height, and possible confounding factors in 1997. Using quantile regression, we estimated associations between sleep patterns and selected percentiles of the distribution of BMI. Results: While the medians were similar, larger adjusted values of BMI were estimated in the upper part of the distribution among men and women with short sleep (≤5 h) compared with medium-length sleep (6-8 h). For example, in men, the 90th percentile of BMI was 0.80 kg/m2 (95% confidence interval: 0.17-1.43 kg/m2) higher among short sleepers. In women, long sleepers (≥9 h) also showed larger values in the upper part of the BMI distribution; the 90th percentile was 1.23 kg/m2 (0.42-2.04 kg/m2) higher than in medium-length sleepers. In male long sleepers, smaller values were estimated in the lower part of the BMI distribution; the 10th percentile was 0.84 kg/m2 lower (0.35-1.32 kg/m2) than in medium-length sleepers. The 90th percentile of BMI in women with poor-quality compared with good-quality sleep was larger by 0.82 kg/m2 (0.47-1.16 kg/m2); the 10th percentile was smaller by 0.17 kg/m2 (0.02-0.32 kg/m2). Conclusions: Short, long or poor-quality sleepers showed larger, or smaller, values at the tails of the BMI distribution, but similar medians. Hence, unfavorable sleep patterns and BMI were associated only in a subset of this study population.

Background: To study the impact of the dietary antioxidant quercetin on risk of gastric adenocarcinoma. Patients and methods: Using data from a large Swedish population-based case-control study of gastric cancer (505 cases and 1116 controls), we studied the association between quercetin and risk of anatomic (cardia/noncardia) and histological (intestinal and diffuse) subtypes of gastric cancer. Results: We found strong inverse associations between quercetin and the risk of noncardia gastric adenocarcinoma, with an adjusted odds ratio (OR) of 0.57 (95% confidence interval 0.40-0.83) for the highest quintile (≥11.9 mg) of daily quercetin intake relative to the lowest quintile of intake (<4 mg quercetin/day), supported by a significant decreasing linear trend (P value < 0.001). Similar findings were observed for the intestinal and diffuse subtype. For cardia cancer, we found a less evident and nonsignificant inverse relationship. The protection of quercetin appeared to be stronger among female smokers, with the OR leveled of at values [removed]6 mg quercetin/day). Conclusions: High dietary quercetin intake is inversely related to the risk of noncardia gastric adenocarcinoma, and the protection appears to be particularly strong for women exposed to oxidative stress, such as tobacco smoking.