OBJECTIVES: To examine the relation between mammography use and weight category and to examine the influence of race, illness burden, and other factors on this relationship.

DESIGN AND SETTING: The 1998 National Health Interview Survey, a U.S. civilian population-based survey.

PARTICIPANTS: Five thousand, two hundred, and seventy-seven women ages 50 to 75 years who responded to the Sample Adult and Prevention questionnaires.

MEASUREMENTS: Mammogram use in the preceding 2 years.

RESULTS: Among 5,277 eligible women, 72% reported mammography use. The rate was 74% among white women and 70% among black women. Among white women, mammogram use was lowest in women with a body mass index (BMI) greater than 35 kg/m² (64% to 67%). After adjusting for sociodemographic factors, health care access, medical conditions, hospitalizations, and mobility status, higher BMI was associated with lower screening among white women, P=.02 for trend; the relative risk (RR) for screening in moderately obese white women (BMI, 35 to 40 kg/m²) was 0.83 (95% confidence interval [CI], 0.68 to 0.96) compared to normal weight white women. Compared to normal weight black women, mammography use was similar or higher in overweight (BMI, 25 to 30 kg/m²; RR, 1.19; 95% CI, 1.01 to 1.32), mildly obese (BMI, 30 to 35 kg/m²; RR, 1.22; 95% CI, 0.98 to 1.39), and moderately obese black women (RR, 1.37; 95% CI, 1.37 to 1.50) after adjustment. The P value for the race-BMI interaction was .001. Results for white and black women were unchanged after additional adjustment for psychological functioning and health habits.

CONCLUSION: Among white women, those with higher BMI were less likely to undergo breast cancer screening than normal weight women. This relationship was not seen in black women. Our findings were not explained by differences in sociodemographic factors, health care access, illness burden, or health habits. More research is needed to determine the reasons for these disparities so that appropriate efforts can be made to improve screening.