(HealthDay News) — Larger waist circumference correlates with increased risk of postmenopausal breast cancer, but not beyond its contribution to body mass index (BMI), according to a study published online April 9 in Cancer Causes & Control.
Noting that high BMI is a risk factor for postmenopausal breast cancer, Mia M. Gaudet, Ph.D., from the American Cancer Society in Atlanta, and colleagues examined whether a larger waist circumference is associated with risk beyond its contribution to BMI. Data were analyzed for 28,965 postmenopausal women who reported weight and waist circumference on a questionnaire in 1997, and were followed for a median of 11.58 years.
The researchers identified 1,088 cases of invasive breast cancer during follow-up. A larger waist circumference was associated with an increased risk of breast cancer (hazard ratio per 10 cm increase in waist circumference, 1.13; 95 percent confidence interval [CI], 1.08 to 1.19), without adjustment for BMI. There was no longer a correlation after adjustment for BMI (hazard ratio per 10 cm increase in waist circumference, 1.00; 95 percent CI, 0.92 to 1.08). BMI was significantly associated with risk before and after adjustment for waist circumference (hazard ratio per 1 kg/m², 1.04 [95 percent CI, 1.03 to 1.05] and 1.04, [95 percent CI, 1.02 to 1.06], respectively).
“Our data support the value of measuring BMI to capture the increased risk of postmenopausal breast cancer associated with larger body size,” the authors write.