Environment and Breast Cancer: Science Review


Evidence From Humans
 
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Long-term recreational physical activity and breast cancer in the National Health and Nutrition Examination Survey I epidemiologic follow-up study
Breslow, R. A., Ballard-Barbash, R., Munoz, K., Graubard, B. I. Cancer Epidemiology, Biomarkers & Prevention. 2001. 10:7, 805-8.
Topic area
Physical Activity - Body size
Study design
Prospective cohort
Funding agency
Not reported
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 6,160
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: participant of National Health and Nutrition Examination Survey (NHANES I); age 24-75 when interviewed for NHANES I in 1971-1975; had complete data on recreational physical activity in both 1982-1984 and 1971-1975
Comment about participation selection
Strengths: most cases were confirmed by computer matching; conducted in-person interviews; anthropometric measurements were obtained by trained staff; analyzed breast cancer risk in women > 50 according to long term activity levels stratified by BMI and and adult weight gain; data was collected prospectively Limitations: small number of breast cancer cases especially after stratifying by age; crude assessment of recreational activity; inability to capture patterns between assessments
Exposures investigated
BMI and adult weight gain
How exposure was measured
Questionnaire, in person Anthropometric measurement, researcher-administered
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
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 in 1982-1984, BMI in 1982-1984, BMI in 1971-1975, BMI at age 25, adult weight change, adult weight gain, education, age at menarche, parity, menstrual status, and family history of breast cancer
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
Follow-up: 9.2 years (mean) Effect modifiers: long term physical activity
Strength of associations reported
Association between breast cancer and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.58(0.31-1.07) trend p=0.107
Association between breast cancer in women < 50 years old and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=1.19(0.43-3.30) trend p=0.732
Association between breast cancer in women >50 years old and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.33(0.14-0.82) trend p=0.026
Association between breast cancer in women 50 years or older with a BMI of <25.1 and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.40(0.13-1.28) trend p=0.158
Association between breast cancer in women 50 years or older with a BMI of >25.1 and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.26(0.06-1.13) trend p=0.085
Association between breast cancer in women 50 years or older with a weight gain/loss of 4.9 kg and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.43(0.08-2.28) trend p=0.284
Association between breast cancer in women 50 years or older with a weight gain of 20 kg and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.32(0.04-2.50) trend p=0.314
Association between breast cancer in women 50 years or older with a BMI of <25.1 and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.40(0.13-1.28) trend p=0.158
Association between breast cancer in women 50 years or older with a BMI of >25.1 and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.26(0.06-1.13) trend p=0.085
Association between breast cancer in women 50 years or older with a weight gain/loss of 4.9 kg and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.43(0.08-2.28) trend p=0.284
Association between breast cancer in women 50 years or older with a weight gain of 20 kg and women who participated in consistently high levels of physical activity vs. consistently low levels , RR=0.32(0.04-2.50) trend p=0.314
Results Comments
Associations were not modified by BMI or by weight gain as an adult
Author address
Epidemiology and Health Services Research Branch, Division of Cancer Prevention and Control, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, USA. zyd12@cdc.gov