The risk of uterine malignancy is linearly associated with body mass index in a cohort of US women.

OBJECTIVE: We sought to quantify the relationship of uterine malignancy with body mass index (BMI).

STUDY DESIGN: The University HealthSystem Consortium database was queried to identify all women undergoing total hysterectomy with a recorded BMI in the overweight and obese categories. Least squares regression was applied to evaluate the association between increasing BMI and the proportion of women with a diagnosis of uterine malignancy. Multivariate binary logistic regression was performed to adjust for other known risk factors including age, race, and other comorbidities.

RESULTS: There were 6905 women who met inclusion criteria; 1891 (27.4%) of these had uterine malignancy. There is a linear relationship (y = 0.015x - 0.23, R(2) = 0.92) of the probability of uterine malignancy vs BMI. After adjusting for other risk factors, we found that each 1-U increase in BMI was significantly, independently associated with an 11% increase in the proportion of patients diagnosed with uterine malignancy (odds ratio, 1.11; 95% confidence interval, 1.09-1.13; P < .001).

CONCLUSION: In a population of women undergoing hysterectomy, we observed a linear increase in the frequency of uterine cancer associated with increasing BMI. This finding suggests that even relatively modest weight gain may significantly raise cancer risk. In the United States, the mean BMI for women is 26.5 kg/m(2) and it is estimated that more than half of US women have a BMI within the study's range. Our results could, therefore, be relevant to a majority of the population. The findings could increase popular acceptance of weight management as a key component of general health maintenance and, possibly, as an additional approach to cancer risk reduction.