Abstract
Background:
Many epidemiologic studies have found an association between physical activity and breast cancer risk, although this has not been a consistent finding.
Methods:
Studies were identified through a systematic review of literature available on PubMed through February 2006. We included all cohort and case-control studies that assessed total or leisure time activities in relation to occurrence or mortality of breast cancer. The fully adjusted risk estimates and 95% confidence intervals for the highest versus lowest level of activity were documented for each study as well as evidence for a dose-response relationship. Methodologic quality was also assessed. Due to statistical and methodologic heterogeneity among studies, we did not carry out statistical pooling. To draw conclusions, we performed a best-evidence synthesis taking study quality into account.
Results:
Nineteen cohort studies and 29 case-control studies were evaluated. There was strong evidence for an inverse association between physical activity and postmenopausal breast cancer with risk reductions ranging from 20% to 80%. For premenopausal breast cancer, however, the evidence was much weaker. For pre- and postmenopausal breast cancer combined, physical activity was associated with a modest (15-20%) decreased risk. Evidence for a dose-response relationship was observed in approximately half of the higher-quality studies that reported a decreased risk. A trend analysis indicated a 6% (95% confidence interval = 3% to 8%) decrease in breast cancer risk for each additional hour of physical activity per week assuming that the level of activity would be sustained.
Conclusions:
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.
| Original language | English |
|---|---|
| Pages (from-to) | 137-157 |
| Journal | Cancer Epidemiology |
| Volume | 18 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 2007 |
| Externally published | Yes |
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Keywords
- Breast Neoplasms
- Case-Control Studies
- Cohort Studies
- Exercise
- Female
- Humans
- Motor Activity
- Risk
- Journal Article
- Review
Cite this
}
Physical activity and breast cancer : A systematic review. / Monninkhof, Evelyn M; Elias, Sjoerd G; Vlems, Femke A; van der Tweel, Ingeborg; Schuit, A.J.; Voskuil, Dorien W; van Leeuwen, Flora E; TFPAC.
In: Cancer Epidemiology, Vol. 18, No. 1, 01.2007, p. 137-157.Research output: Contribution to journal › Review article › Scientific › peer-review
TY - JOUR
T1 - Physical activity and breast cancer
T2 - A systematic review
AU - Monninkhof, Evelyn M
AU - Elias, Sjoerd G
AU - Vlems, Femke A
AU - van der Tweel, Ingeborg
AU - Schuit, A.J.
AU - Voskuil, Dorien W
AU - van Leeuwen, Flora E
AU - TFPAC
PY - 2007/1
Y1 - 2007/1
N2 - Background: Many epidemiologic studies have found an association between physical activity and breast cancer risk, although this has not been a consistent finding.Methods: Studies were identified through a systematic review of literature available on PubMed through February 2006. We included all cohort and case-control studies that assessed total or leisure time activities in relation to occurrence or mortality of breast cancer. The fully adjusted risk estimates and 95% confidence intervals for the highest versus lowest level of activity were documented for each study as well as evidence for a dose-response relationship. Methodologic quality was also assessed. Due to statistical and methodologic heterogeneity among studies, we did not carry out statistical pooling. To draw conclusions, we performed a best-evidence synthesis taking study quality into account.Results: Nineteen cohort studies and 29 case-control studies were evaluated. There was strong evidence for an inverse association between physical activity and postmenopausal breast cancer with risk reductions ranging from 20% to 80%. For premenopausal breast cancer, however, the evidence was much weaker. For pre- and postmenopausal breast cancer combined, physical activity was associated with a modest (15-20%) decreased risk. Evidence for a dose-response relationship was observed in approximately half of the higher-quality studies that reported a decreased risk. A trend analysis indicated a 6% (95% confidence interval = 3% to 8%) decrease in breast cancer risk for each additional hour of physical activity per week assuming that the level of activity would be sustained.Conclusions: 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.
AB - Background: Many epidemiologic studies have found an association between physical activity and breast cancer risk, although this has not been a consistent finding.Methods: Studies were identified through a systematic review of literature available on PubMed through February 2006. We included all cohort and case-control studies that assessed total or leisure time activities in relation to occurrence or mortality of breast cancer. The fully adjusted risk estimates and 95% confidence intervals for the highest versus lowest level of activity were documented for each study as well as evidence for a dose-response relationship. Methodologic quality was also assessed. Due to statistical and methodologic heterogeneity among studies, we did not carry out statistical pooling. To draw conclusions, we performed a best-evidence synthesis taking study quality into account.Results: Nineteen cohort studies and 29 case-control studies were evaluated. There was strong evidence for an inverse association between physical activity and postmenopausal breast cancer with risk reductions ranging from 20% to 80%. For premenopausal breast cancer, however, the evidence was much weaker. For pre- and postmenopausal breast cancer combined, physical activity was associated with a modest (15-20%) decreased risk. Evidence for a dose-response relationship was observed in approximately half of the higher-quality studies that reported a decreased risk. A trend analysis indicated a 6% (95% confidence interval = 3% to 8%) decrease in breast cancer risk for each additional hour of physical activity per week assuming that the level of activity would be sustained.Conclusions: 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.
KW - Breast Neoplasms
KW - Case-Control Studies
KW - Cohort Studies
KW - Exercise
KW - Female
KW - Humans
KW - Motor Activity
KW - Risk
KW - Journal Article
KW - Review
U2 - 10.1097/01.ede.0000251167.75581.98
DO - 10.1097/01.ede.0000251167.75581.98
M3 - Review article
VL - 18
SP - 137
EP - 157
JO - Cancer Epidemiology
JF - Cancer Epidemiology
SN - 1877-7821
IS - 1
ER -