There is evidence for an inverse association between physical activity and breast cancer risk. The evidence is stronger for postmenopausal breast cancer than for premenopausal breast cancer.
Objective: To assess the epidemiologic evidence for the association between physical activity and endometrial cancer risk, taking into account the methodologic quality of each study. Design: Systematic review, best evidence synthesis. Data Sources: Studies were identified through a systematic review of literature available on PubMed through December 2006. Review Methods: We included cohort and case-control studies that assessed total and/or leisure time and/or occupational activities in relation to the incidence of endometrial cancer. The methodologic quality of the studies was assessed with a comprehensive scoring system. Results: The included cohort (n = 7) and case-control (n = 13) studies consistently show that physical activity is associated with a decreased risk of endometrial cancer. The best evidence synthesis showed that the majority (80%) of 10 high-quality studies found risk reductions of >20%. Pooling of seven high-quality cohort studies that measured total, leisure time, or occupational activity showed a significantly decreased risk of endometrial cancer (summary estimate: OR, 0.77; 95% CI, 0.70-0.85) for the most active women. Case control studies with relatively unfavorable quality scores reported divergent risk estimates, between 2-fold decreased and 2-fold increased risk. Effect modification by body mass index or menopausal status was not consistently observed. Evidence for an effect of physical activity during childhood or adolescence was limited. Conclusions: Physical activity seems to be associated with a reduction in the risk of endometrial cancer, which is independent of body weight. Further studies, preferably prospective cohort studies, are needed to determine the magnitude of the risk reduction and to assess which aspects of physical activity contribute most strongly to the reduced risk and in which period of life physical activity is most effective.
Background: Higher circulating insulin-like growth factor I (IGF-I) concentrations have been related to a greater risk of cancer. Lycopene intake is inversely associated with cancer risk, and experimental studies have shown that it may affect the IGF system, possibly through an effect on IGF-binding proteins (IGFBPs). Objective: The objective of our study was to investigate the effect of an 8-wk supplementation with tomato-derived lycopene (30 mg/d) on serum concentrations of total IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3. Design: We conducted a randomized, placebo-controlled, doubleblinded crossover study in 40 men and 31 postmenopausal women with a family history of colorectal cancer, a personal history of colorectal adenoma, or both. Results: Lycopene supplementation significantly (P ҃ 0.01) increased serum IGFBP-1 concentrations in women (median relative difference between serum IGFBP-1 concentrations after lycopene supplementation and after placebo, 21.7%). Serum IGFBP-2 concentrations were higher in both men and women after lycopene supplementation than after placebo, but to a lesser extent (mean relative difference 8.2%; 95% CI: 0.7%, 15.6% in men and 7.8%; 95% CI: Ҁ5.0%, 20.6% in women). Total IGF-I, IGF-II, and IGFBP-3 concentrations were not significantly altered by lycopene supplementation. Conclusions: This is the first study known to show that lycopene supplementation may increase circulating IGFBP-1 and IGFBP-2 concentrations. Because of high interindividual variations in IGFBP-1 and IGFBP-2 effects, these results should be confirmed in larger randomized intervention studies.Am J Clin Nutr 2007; 86:1456 -62.
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