Physical activity, body mass index, and mammographic density in postmenopausal breast cancer survivors.
OBJECTIVE
To investigate the association between physical activity, body mass index (BMI), and mammographic density in a racially/ethnically diverse population-based sample of 522 postmenopausal women diagnosed with stage 0-IIIA breast cancer and enrolled in the Health, Eating, Activity, and Lifestyle Study.


METHODS
We collected information on BMI and physical activity during a clinic visit 2 to 3 years after diagnosis. Weight and height were measured in a standard manner. Using an interview-administered questionnaire, participants recalled the type, duration, and frequency of physical activities they had performed in the last year. We estimated dense area and percentage density as a continuous measure using a computer-assisted software program from mammograms imaged approximately 1 to 2 years after diagnosis. Analysis of covariance methods were used to obtain mean density across WHO BMI categories and physical activity tertiles adjusted for confounders.


RESULTS
We observed a statistically significant decline in percentage density (P for trend = .0001), and mammographic dense area (P for trend = .0052), with increasing level of BMI adjusted for potential covariates. We observed a statistically significant decline in mammographic dense area (P for trend = .036) with increasing level of sports/recreational physical activity in women with a BMI of at least 30 kg/m2. Conversely, in women with a BMI less than 25 kg/m2, we observed a non-statistically significant increase in mammographic dense area and percentage density with increasing level of sports/recreational physical activity.


CONCLUSIONS
Increasing physical activity among obese postmenopausal breast cancer survivors may be a reasonable intervention approach to reduce mammographic density.
Irwin
Melinda L
ML
Department of Epidemiology and Public Health, Yale School of Medicine, New Haven, CT 06520-8034, USA. melinda.irwin@yale.edu
Aiello
Erin J
EJ
McTiernan
Anne
A
Bernstein
Leslie
L
Gilliland
Frank D
FD
Baumgartner
Richard N
RN
Baumgartner
Kathy B
KB
Ballard-Barbash
Rachel
R
D000328:Adult; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D017698:Postmenopause; D011379:Prognosis; D011446:Prospective Studies; D018426:SEER Program; D013177:Sports; D011795:Surveys and Questionnaires; D017741:Survivors; D013997:Time Factors; D014481:United States