Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study

Matthews, Charles E.; Shu, Xiao‐Ou; Jin, Fan; Dai, Qi; Hébert, James R.; Ruan, Zonghai; Gao, Yu‐Tang; Wang, Zheng

doi:10.1054/bjoc.2000.1671

Cited by 105 publications

(103 citation statements)

References 33 publications

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“…50 Changes in diet with an overall increase in dietary calories and a reduction in physical activity levels, particularly among urban residents (caused by the increased industrialization, life style and leisure activities transformation), 51 with a resulting in an increase in obesity, 52 have been shown to increase risk of breast cancer in China, as elsewhere. 53,54 Conclusions Population-based cancer incidence data are widely used in research 55 and in the decision-making process with respect to cancer control planning and evaluation by local or national authorities. This article shows that the cancers of high lethality that have been common in the Chinese population (stomach, liver, oesophagus) are showing some evidence of decline, at least in younger generations, but they remain major problems.…”

Section: Discussionmentioning

confidence: 99%

Trends in the incidence of cancer in Qidong, China, 1978–2002

Chen

Zhu

Parkin

et al. 2006

Intl Journal of Cancer

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A population-based cancer registry was established in Qidong, Jiangsu Province, China, in 1972, and the trends in incidence rates of the major cancer sites have been analyzed for a 25-year period, 1978-2002. Five-year age-specific rates, crude incidence rates, world age-standardized rates (ASR), percent change (PC) and annual percent change (APC) were calculated using annual data on population size, and estimates of its age structure. The indices of histological verification of diagnosis, death certificate only and proportion of mortality to incidence were employed for assessing the registration quality. A total of 51,933 incident cases of cancer were registered in Qidong from years 1978 to 2002, with a maleto-female sex ratio of 1.9:1. Crude incidence increased markedly over the 25-year period (PC and APC of 155.6% and 12.1%, respectively), but ASR showed a slight decrease (20.4% in males, and 20.3% in females), indicating that the major part of this is due to population ageing. The leading cancer sites in rank were liver (average ASR 5 50.8 per 100,000), stomach (26.7), lung (22.7), colon-rectum (8.9), oesophagus (7.4) and breast (5.4). Cancers of liver, lung, colon-rectum and female breast all showed increases in incidence during the study period, with APCs (ASR) of 10.1%, 11.7% and 11.4% for males, and 10.2%, 10.9%, 11.9% and 11.1% for females, while the cancers of stomach (APC: 23.2% in male, and 22.4% in female) and cervix (APC: 24.7%) showed notable declines. Examination of age-specific rates showed declining trends in the younger generations for liver cancer, but increases for cervix cancer. The results underline the increasing importance of cancer as a cause of mortality and morbidity in a population that is ageing and undergoing profound changes in socioeconomic development and lifestyle. The cancers of high lethality that have been common in the Chinese population (liver, stomach, oesophagus) are showing some evidence of decline, at least in younger generations, but they remain major problems. At the same time, the cancers associated with economically ''developed'' societies-lung, colon-rectum and female breastare showing increases. The population-based cancer registry is an indispensable tool for providing data for planning and evaluation of programmes for cancer control in all societies. ' 2006 Wiley-Liss, Inc.

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Section: Discussionmentioning

confidence: 99%

Trends in the incidence of cancer in Qidong, China, 1978–2002

Chen

Zhu

Parkin

et al. 2006

Intl Journal of Cancer

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“…Recent reviews concluded that physical activity both at young ages and in adulthood reduced the risk of breast cancer; IARC (2002) and Lagerros et al (2004). However, subsequent findings concerning premenopausal breast cancer are inconsistent, both for physical activity at young ages (Dorn et al, 2003;Steindorf et al, 2003;Yang et al, 2003;Margolis et al, 2005) and around diagnosis (AdamsCampbell et al, 2001;Gilliland et al, 2001;Matthews et al, 2001;Colditz et al, 2003;Dorn et al, 2003;Hirose et al, 2003;John et al, 2003;Steindorf et al, 2003;Yang et al, 2003;Margolis et al, 2005). Without evidence from a formal meta-analysis using individual data from all relevant studies, it is difficult to interpret the available results.…”

Section: Discussionmentioning

confidence: 99%

“…Although an expert group convened by the International Agency for Research on Cancer concluded that there was sufficient evidence that physical activity reduced the risk of premenopausal breast cancer (IARC, 2002), results from more recent studies have been contradictory (Adams-Campbell et al, 2001;Gilliland et al, 2001;Matthews et al, 2001;Colditz et al, 2003;Dorn et al, 2003;Hirose et al, 2003;John et al, 2003;Steindorf et al, 2003;Yang et al, 2003;Margolis et al, 2005).…”

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confidence: 99%

Body fatness and physical activity at young ages and the risk of breast cancer in premenopausal women

et al. 2005

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We examined the relationship between body fatness, sports participation and breast cancer risk in 1560 premenopausal cases and 1548 controls, from three related population-based case -control studies in the UK. Half of the women with breast cancer were aged less than 36 years at diagnosis. Women who perceived themselves as plump at age 10 years had a relative risk of 0.83 (95% confidence interval 0.69 -0.99, P ¼ 0.03) as compared with those who perceived themselves as thin. Self-reported obesity compared with leanness at diagnosis was associated with a relative risk of 0.78 (95% confidence interval 0.56 -1.06, P ¼ 0.11). Women who reported having been plump at age 10 years and overweight or obese at diagnosis had a relative risk of 0.75 (95% confidence interval 0.56 -1.01, P ¼ 0.06) as compared with those who reported being thin at age 10 years and at diagnosis. Findings for three related measures of body fatness suggested that obesity is associated with a reduced risk of premenopausal breast cancer. There was no association between sports participation and breast cancer risk in these premenopausal women. The relative risk for spending an average of more than 1 h per week in sports compared with less from ages 12 to 30 years was 1.00 (95% CI 0.86 -1.16, P ¼ 0.98).

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“…2 Nevertheless, epidemiologic data in studies on physical activity and breast cancer risk remain inconclusive. [3][4][5][6][7][8][9][10][11][12] Although some studies show a clear protection, 5,7,8,[12][13][14][15][16][17] others reveal only a weak, often nonsignificant association 18,19 or no association at all. 10,11,20,21 Many factors could explain these discrepancies.…”

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Physical activity and risk for breast cancer a prospective cohort study among Swedish twins

Moradi

Adami

Ekbom

et al. 2002

Intl Journal of Cancer

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The epidemiologic association between physical activity and breast cancer has been corroborated in many studies. Some inconsistencies remain, possibly due to variation in life periods for exposure assessment, confounding and undetected effect modification. In our cohort study, we address some of these questions by taking into account physical activity in different periods of life and by investigating effect modification by birth cohort and body mass index (BMI). Altogether 9,539 same-sex twin women aged 42-70 years who answered a questionnaire about their work and leisure-time physical exercise from ages 25 to 50 during 1967 and 1970 were included in our cohort. During follow-up, 506 breast cancer cases occurred through 1997. We used multivariate Cox models to estimate relative risk (RR) with 95% confidence interval (CI). We found no associations between physical activity and breast cancer overall. Women born between 1901 and 1917 (aged 51-70 at baseline) who reported regular leisure-time activity had a borderline significant 40% lower risk compared with those who reported no activity (RR 0.6; 95% CI 0.4 -1.0; test for trend, p ‫؍‬ 0.07). This association appeared to be confined to women with a low BMI after the age of 50 and to women with a high BMI during the premenopausal period. We found no evidence that work activity reduces risk for breast cancer. Physical activity might be one of the few realistic approaches toward primary prevention of breast cancer through changes in lifestyle. A protective effect is biologically plausible because physical activity may influence several factors relevant to breast carcinogenesis, such as menstrual characteristics, body size, the immune system 1 and the hormonal system including insulin-like growth factor I (IGF-I) levels. 2 Nevertheless, epidemiologic data in studies on physical activity and breast cancer risk remain inconclusive. [3][4][5][6][7][8][9][10][11][12] Although some studies show a clear protection, 5,7,8,[12][13][14][15][16][17] others reveal only a weak, often nonsignificant association 18,19 or no association at all. 10,11,20,21 Many factors could explain these discrepancies. First of all, obtaining reliable information about physical exercise throughout adult life is a complicated affair. Hence, misclassification of exposure could easily entail underestimation of any true association or cancel it altogether. In addition, several other breast cancer risk factors may modify the effect of physical activity on breast cancer risk, as indicated by recent studies. For example, we observed that physical activity reduced breast cancer risk only among women with a low body mass index (BMI) who were nonusers of postmenopausal hormone therapy. 15 Moreover, such therapy may increase breast cancer risk, chiefly in women with a low BMI. 22 Hence, if women with a low BMI are both more susceptible to exogenous hormones and more protected by physical activity, the protective effect of physical activity on breast cancer risk may be obscured among lean women who use exogenous...

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Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study

Cited by 105 publications

References 33 publications

Trends in the incidence of cancer in Qidong, China, 1978–2002

Trends in the incidence of cancer in Qidong, China, 1978–2002

Body fatness and physical activity at young ages and the risk of breast cancer in premenopausal women

Physical activity and risk for breast cancer a prospective cohort study among Swedish twins

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