Environment and Breast Cancer: Science Review
About
Risk factors for breast cancer in elderly women
Sweeney, C., Blair, C. K., Anderson, K. E., Lazovich, D., Folsom, A. R. American Journal of Epidemiology. 2004. 160:9, 868-75.
Topic area
Body size
Body size
Study design
Prospective cohort
Prospective cohort
Funding agency
NCI
NCI
Study Participants
Number of Cases
2,286 (428 cases amongst women aged 55-64) (1,297 cases amongst women aged 65-74) (561 cases amongst women aged 75-84)
2,286 (428 cases amongst women aged 55-64) (1,297 cases amongst women aged 65-74) (561 cases amongst women aged 75-84)
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Number in Cohort
Cohort: 36,658
Cohort: 36,658
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: Age at baseline 55-69 yrs; owned an Iowa driver's license; participants of the Iowa Women's Health Study
Ex: Prior cancer, prior masectomy, premenopausal status and incomplete responses
Comment about participation selection
Strengths: Population based, lengthy follow up, large cohort, many cases, stratified results by age, examined post women only Limitations: participants were 99% white, anthropometric data were self-reported
Strengths: Population based, lengthy follow up, large cohort, many cases, stratified results by age, examined post women only Limitations: participants were 99% white, anthropometric data were self-reported
Exposure Investigated
Exposures investigated
Body Mass Index, W/H ratio, Weight Change, Ht.
Body Mass Index, W/H ratio, Weight Change, Ht.
How exposure was measured
Questionnaire, self-administered
Questionnaire, self-administered
Exposure assessment comment
Self administered questionnaire regarding body size, self measured W/H ratio
Self administered questionnaire regarding body size, self measured W/H ratio
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.
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 at baseline, education, age in years at first live birth, parity, age in years at menarche, age in years at menopause, family history of bc, and body mass index or 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
Effect modifiers: age Follow up: 16 yrs
Effect modifiers: age Follow up: 16 yrs
Strength of associations reported
Association between breast cancer risk in women 55-64 years old and BMI, >29.5 vs. <23.5, HR=1.34(1.03-1.75) trend p=0.004
Association between breast cancer risk in women 65-74 years old and BMI, >29.5 vs. <23.5, HR=1.48(1.26-1.73) trend p<0.0001
Association between breast cancer risk in women 75-84 years old and BMI, >29.5 vs. <23.5, HR=1.44(1.12-1.84) trend p=0.001
Association between breast cancer risk in women 55-64 years old and WHR, >0.89 vs. <0.78, HR=1.38(1.06-1.80) trend p=0.01
Association between breast cancer risk in women 65-74 years old and WHR, >0.89 vs. <0.78, HR=1.34(1.15-1.56) trend p=0.0004
Association between breast cancer risk in women 75-84 years old and WHR, >0.89 vs. <0.78, HR=1.49(1.16-1.90) trend p=0.002
Association between breast cancer risk in women 65-74 years old and height, >66 in vs. <62 in, HR=1.41(1.19-1.67) trend p<0.0001
Association between breast cancer risk in women 75-84 years old and height, >66 in vs. <62 in, HR=1.40(1.08-1.82) trend p=0.005
Association between breast cancer risk in women 55-64 years old and BMI, >29.5 vs. <23.5, HR=1.34(1.03-1.75) trend p=0.004
Association between breast cancer risk in women 65-74 years old and BMI, >29.5 vs. <23.5, HR=1.48(1.26-1.73) trend p<0.0001
Association between breast cancer risk in women 75-84 years old and BMI, >29.5 vs. <23.5, HR=1.44(1.12-1.84) trend p=0.001
Association between breast cancer risk in women 55-64 years old and WHR, >0.89 vs. <0.78, HR=1.38(1.06-1.80) trend p=0.01
Association between breast cancer risk in women 65-74 years old and WHR, >0.89 vs. <0.78, HR=1.34(1.15-1.56) trend p=0.0004
Association between breast cancer risk in women 75-84 years old and WHR, >0.89 vs. <0.78, HR=1.49(1.16-1.90) trend p=0.002
Association between breast cancer risk in women 65-74 years old and height, >66 in vs. <62 in, HR=1.41(1.19-1.67) trend p<0.0001
Association between breast cancer risk in women 75-84 years old and height, >66 in vs. <62 in, HR=1.40(1.08-1.82) trend p=0.005
Author address
University of Minnesota, Minneapolis, MN, USA. Carol.Sweeney@hrc.utah.edu
University of Minnesota, Minneapolis, MN, USA. Carol.Sweeney@hrc.utah.edu