‘Weighing in’ on screening mammography

Abstract

Obesity is associated with increased post-menopausal breast cancer risk. Overweight and obese women also tend to have a poorer prognosis when diagnosed with breast cancer compared with their matched normal weight peers. In previous studies obesity was associated with decreased utilization of screening mammography. We present a study examining the association between Body Mass Index (BMI) and compliance with recommended mammographic screening using data from the 2004 Behavioral Risk Factor Surveillance Survey (BRFSS). We included 130,185 female participants, aged 40 and older, who were randomly selected to participate in the world largest telephone survey. After weighted analysis, this is representative of 56,226,220 non-institutionalized US women. The primary outcome was the proportion of women who underwent screening mammography within the last 2 years preceding the survey stratified by BMI. The mammography screening behavior of normal weight women (BMI 18.5-24.99) was compared with underweight (<18.5), overweight (25-29.99), and women with obesity class I (30-34.99), class II (35-39.99), and class III (>or=40) using logistic regression analysis and weighted to provide estimates of women in the United States (US). Our sample included 1.91% underweight, 37.91% normal weight, 30.15% overweight and 14.36%, 5.44%, and 3.49% women with obesity classes' I-III respectively. Approximately 7% of women age 40 and older had insufficient information to calculate their BMI. Adjusting for age, race, smoking status, general health perception, level of education, and income level, underweight women had lower odds of complying with regular screening mammography (OR 0.57; 95% CI, 0.48-0.68). Women with obesity class III (OR 0.97; 95% CI, 0.84-1.13) showed a trend towards underutilization of screening mammograms which was not clinically significant. In contrary, in overweight women a significantly higher association with appropriate mammography utilization was identified OR 1.08 (95% CI, 1.01-1.15). Although not statistically significant, women with class I and II obesity showed a trend towards a higher utilization 1.08 (95% CI, 0.99-1.18) and 1.10 (95% CI, 0.98-1.25) respectively, when compared to women at desired weight. We present a weighted analysis of the BRFSS, evaluating the association of BMI and appropriate screening mammography among women 40 years and older. These results are generalizable to the US population of women in this age range. Underweight women had significantly lower odds of utilizing screening mammography appropriately when compared with women at desired weight. Results from previous studies reporting underutilization of screening mammography in high risk, obese, and overweighed women were not confirmed in this largest population based analysis performed to date.