Environment and Breast Cancer: Science Review
About
Exercise activity, body size and premenopausal breast cancer survival
Enger, S. M., Bernstein, L. British Journal of Cancer. 2004. 90:11, 2138-41.
Topic area
Body size - Physical Activity
Body size - Physical Activity
Study design
Prospective cohort
Prospective cohort
Funding agency
NCI
NCI
Study Participants
Number of Cases
251 deaths (in situ or invasive only) (white or Hispanic)
251 deaths (in situ or invasive only) (white or Hispanic)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Number in Cohort
Cohort: 717
Cohort: 717
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: participated in a population based case-control study (Bernstein et al, 1994); age 40 or younger at baseline of earlier study; diagnosed with first primary in situ or invasive breast cancer between 7/1/83 and 12/31/89
Ex: postmenopausal women; women with an unknown cancer stage; women with an unknown cause of death
Comment about participation selection
Strengths: in person interviews; obtained stage at diagnosis; one of the only studies to analyze physical activity and breast cancer survival; women were interviewed prior to the widespread publication of papers that indicated the association between exercise activity and reduced breast cancer risk Limitations: patients who were lost to follow early on may have differed from those with complete follow up, leading to a possible bias in results; recall of past exercise activities may have resulted in misclassification; breast cancer diagnosis may have influenced recall of past exercise activities; focused on younger women; does not specify how anthropometric data were obtained
Strengths: in person interviews; obtained stage at diagnosis; one of the only studies to analyze physical activity and breast cancer survival; women were interviewed prior to the widespread publication of papers that indicated the association between exercise activity and reduced breast cancer risk Limitations: patients who were lost to follow early on may have differed from those with complete follow up, leading to a possible bias in results; recall of past exercise activities may have resulted in misclassification; breast cancer diagnosis may have influenced recall of past exercise activities; focused on younger women; does not specify how anthropometric data were obtained
Exposures investigated
BMI, weight, weight gain and height
BMI, weight, weight gain and height
How exposure was measured
Not specified
Not specified
Breast cancer outcome investigated
Mortality from breast cancer
Mortality from breast cancer
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, stage at diagnosis, physical activity, weight and height
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: 10.4 years (median)
Follow-up: 10.4 years (median)
Strength of associations reported
Association between breast cancer mortality in women aged 40 and younger and BMI, >24.9 vs. <20.4, HR=0.76(0.53-1.07) trend p=0.21
Association between breast cancer mortality in women aged 40 and younger and weight, >68.2 kg vs. < 54.1 kg, HR=0.86(0.60-1.23) trend p=0.21
Association between breast cancer mortality in women aged 40 and younger and height, >1.69 m vs. <1.60m, HR=1.17(0.81-1.69) trend p=0.52
Association between breast cancer mortality in women aged 40 and younger and physical activity from menses to reference date, >3.8 hrs/wk vs. none, HR=1.30(0.81-2.09) trend p=0.88
Association between breast cancer mortality in women aged 40 and younger and BMI, >24.9 vs. <20.4, HR=0.76(0.53-1.07) trend p=0.21
Association between breast cancer mortality in women aged 40 and younger and weight, >68.2 kg vs. < 54.1 kg, HR=0.86(0.60-1.23) trend p=0.21
Association between breast cancer mortality in women aged 40 and younger and height, >1.69 m vs. <1.60m, HR=1.17(0.81-1.69) trend p=0.52
Association between breast cancer mortality in women aged 40 and younger and physical activity from menses to reference date, >3.8 hrs/wk vs. none, HR=1.30(0.81-2.09) trend p=0.88
Author address
Department of Research and Evaluation, Kaiser Permanente Medical Care Program, Pasadena, CA 91101, USA.
Department of Research and Evaluation, Kaiser Permanente Medical Care Program, Pasadena, CA 91101, USA.