Environment and Breast Cancer: Science Review

Dietary glycemic load and breast cancer risk in the Women's Health Study
Higginbotham, S., Zhang, Z. F., Lee, I. M., Cook, N. R., Buring, J. E., Liu, S. Cancer Epidemiol Biomarkers Prev. 2004. 13:1, 65-70.

Topic area
Diet
Diet
Study design
Prospective cohort
Prospective cohort
Funding agency
NCI, and other: NHLBI, NIDDK
NCI, and other: NHLBI, NIDDK

Study Participants
Number of Cases
946
946
Menopausal Status
The menopausal status of women included in this study is listed here.
Postmenopausal and premenopausal combined and separate
Number in Cohort
Cohort 38,446
Cohort 38,446
Cohort participation rate
Not reported
Not reported
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In : Women participating in the WHS, who were 45 years or older at baseline in 1993-1995 and who had no history of coronary heart disease, cerebrovascular disease, or cancer, other than non-melanoma skin cancer.
Ex: IF questionnaire was left with more than 70 blanks or extreme daily total energy intake reported
Comment about participation selection
Large cohort
Large cohort
Exposures investigated
Glycemic Load (GL), Glycemic Index (GI)
Glycemic Load (GL), Glycemic Index (GI)
How exposure was measured
Questionnaire, self-administered, FFQ
Questionnaire, self-administered, FFQ

Statistical Analysis
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.
Not considered: race
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
Adjusted RR with 95% CI, higher versus lower quintile of intake, stratified by baseline measurement of post-menopausal status, physical activity, and both menopausal status at baseline and physical activity, median follow-up: 6.8 years
Adjusted RR with 95% CI, higher versus lower quintile of intake, stratified by baseline measurement of post-menopausal status, physical activity, and both menopausal status at baseline and physical activity, median follow-up: 6.8 years
Strength of associations reported
GL: 1.01 (0.76-1.35); GI: 1.03 (0.84-1.28)
Pre-menopausal: GL:1.27(0.79-2.03); GI: 1.29(0.92-1.81)
Postmenopausal: GL: 0.9(0.63-1.31); GI: 0.89(0.67-1.17)
GL: 1.01 (0.76-1.35); GI: 1.03 (0.84-1.28)
Pre-menopausal: GL:1.27(0.79-2.03); GI: 1.29(0.92-1.81)
Postmenopausal: GL: 0.9(0.63-1.31); GI: 0.89(0.67-1.17)
Results Comments
No overall association between dietary GL or overall GI and breast cancer incidence in this cohort of women. High dietary GL and overall GI were weakly associated with increased breast cancer risk in premenopausal women, although this increase was not seen in premenopausal women who reported a high level of physical activity.
No overall association between dietary GL or overall GI and breast cancer incidence in this cohort of women. High dietary GL and overall GI were weakly associated with increased breast cancer risk in premenopausal women, although this increase was not seen in premenopausal women who reported a high level of physical activity.

Author address
Department of Epidemiology, UCLA School of Public Health, University of California at Los Angeles (UCLA), Los Angeles, California, USA.
Department of Epidemiology, UCLA School of Public Health, University of California at Los Angeles (UCLA), Los Angeles, California, USA.