Environment and Breast Cancer: Science Review
About
Lifetime physical activity and breast cancer risk in a multiethnic population: the San Francisco Bay Area Breast Cancer Study
John, E.M.,, Horn-Ross, P.L.,, Koo, J. Cancer Epidemiology, Biomarkers, & Prevention. 2003. 12, 1143-1152.
Topic area
Physical Activity
Physical Activity
Study design
Population based case-control
Population based case-control
Funding agency
NCI US Army Medical Research Program California Br
NCI US Army Medical Research Program California Br
Study Participants
Number of Cases
1,250 (invasive only) (403 pre (166 Latina, 124 African-American, 113 White)) (847 post (278 Latina, 270 African-American, 299 White))
1,250 (invasive only) (403 pre (166 Latina, 124 African-American, 113 White)) (847 post (278 Latina, 270 African-American, 299 White))
Menopausal Status
Post menopausal
The menopausal status of women included in this study is listed here.
Pre menopausalPost menopausal
Number of Controls
control: 1,548 (483 pre (228 Latina, 128 African-American, 127 White)) (1,065 post (421 Latina, 316 African-American, 328 White))
control: 1,548 (483 pre (228 Latina, 128 African-American, 127 White)) (1,065 post (421 Latina, 316 African-American, 328 White))
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women newly diagnosed with invasive breast cancer between 4/1995 and 4/1998 (cases); age 35-79 years at enrollment; Latina, African-American and White women who lived in the San Francisco Bay area; women with a listed telephone number (controls)
Ex: women with missing information on risk factors or with implausibly high physical activity responses
Comment about participation selection
Strengths: large population based study; performed in-person interviews; included a food-frequency questionnaire; used MET (metabolic equivalent of energy expenditure) to measure physical activity; stratified results by menopausal status and ethnicity; one of the only studies to analyze breast cancer risk by lifetime physical activity in terms of frequency, duration, and intensity; analyzed breast cancer risk by different types of physical activity; assessed a multiethnic population; confounded by a broad range of factors Limitations: physical activity was self-reported; response rate amongst controls was low
Strengths: large population based study; performed in-person interviews; included a food-frequency questionnaire; used MET (metabolic equivalent of energy expenditure) to measure physical activity; stratified results by menopausal status and ethnicity; one of the only studies to analyze breast cancer risk by lifetime physical activity in terms of frequency, duration, and intensity; analyzed breast cancer risk by different types of physical activity; assessed a multiethnic population; confounded by a broad range of factors Limitations: physical activity was self-reported; response rate amongst controls was low
Exposure Investigated
Exposures investigated
Physical inactivity
Physical inactivity
How exposure was measured
Questionnaire, in person Anthropometric measurement, self-administered Other: physical activity, self reported
Questionnaire, in person Anthropometric measurement, self-administered Other: physical activity, self reported
Exposure assessment comment
Anthropometric and physical activity data self-reported
Anthropometric and physical activity data self-reported
Breast cancer outcome investigated
Primary breast cancer
Primary breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
African Americans
Hispanic Americans
Non-hispanic White Americans
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Adequately controlled, confounders: age, race/ethnicity, country of birth, education, family history of breast cancer, parity, age at menarche, breast feeding, age at menopause, BMI, age at first full term pregnancy and other components of total activity
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Effect modifiers: menopausal status
Effect modifiers: menopausal status
Strength of associations reported
No association between premenopausal breast cancer risk and total physical activity, >20.8 hrs/wk vs. <9.1hrs/wk, OR=0.74(0.52-1.05)
No association between postmenopausal breast cancer risk and total physical activity, >21.7 hrs/wk vs. <9.6hrs/wk, OR=0.81(0.64-1.02)
Inverse association between postmenopausal breast cancer and moderate to strenuous occupational physical activity, >10.3 hrs/wk vs. 0 hrs/wk, OR=0.70(0.55-0.88)
Inverse association between premenopausal breast cancer and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.67(0.46-0.96)
Inverse association between postmenopausal breast cancer and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.74(0.59-0.94)
Inverse association between premenopausal breast cancer in white women and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.44(0.20-0.99)
Inverse association between postmenopausal breast cancer in African-American women and total moderate physical activity, >17.8 hrs/wk vs. <7.6 hrs/wk, OR=0.60(0.40-0.92)
No association between premenopausal breast cancer risk and total physical activity, >20.8 hrs/wk vs. <9.1hrs/wk, OR=0.74(0.52-1.05)
No association between postmenopausal breast cancer risk and total physical activity, >21.7 hrs/wk vs. <9.6hrs/wk, OR=0.81(0.64-1.02)
Inverse association between postmenopausal breast cancer and moderate to strenuous occupational physical activity, >10.3 hrs/wk vs. 0 hrs/wk, OR=0.70(0.55-0.88)
Inverse association between premenopausal breast cancer and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.67(0.46-0.96)
Inverse association between postmenopausal breast cancer and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.74(0.59-0.94)
Inverse association between premenopausal breast cancer in white women and total moderate physical activity, >16.7 hrs/wk vs. <6.8 hrs/wk, OR=0.44(0.20-0.99)
Inverse association between postmenopausal breast cancer in African-American women and total moderate physical activity, >17.8 hrs/wk vs. <7.6 hrs/wk, OR=0.60(0.40-0.92)
Controls participation rate
Greater than 70%
Greater than 70%