Association between body mass index and risk of breast cancer in Tunisian women.

Background And Objectives: The number of breast cancer in women has increased dramatically in Tunisia. The cause is perceived to stem from adaptation to a westernized life style which increases body mass index (BMI). This study aimed to investigate the association between BMI and breast cancer among Tunisian women.

Design And Setting: Hospital-based case control study of breast cancer patients seen between November 2006 and April 2009 at the University College Hospital Farhat Hached in Sousse, Tunisia.

Patients And Methods: Standardized questionnaires concerning BMI and other anthropometric data were completed on 400 breast cancer cases and 400 controls. The controls were frequency-matched to the cases by age.

Results: BMI at diagnosis was positively correlated with the risk of breast cancer among postmenopausal women (P<.001 for trend). When compared with women with a low BMI (<19), women with a BMI of 23-27 and 27-31 had a 1.7-fold (95% CI, 1.1-2.9) and 2.1-fold (95% CI, 1.1-3.9) increased risk of breast cancer, respectively, after adjustment for non-anthropometric risk factors. BMI at diagnosis was not related to the risk of breast cancer among premenopausal women. The odds ratios for premenopausal women with a BMI of 23-27 and 27-31 were 1.5 (95% CI, 0.8-2.8) and 1.3 (95% CI, 0.4-4.5), respectively. Furthermore, present BMI was not associated with breast cancer risk in either pre- and postmenopausal women.

Conclusions: Weight control in obese women may be an effective measure of breast cancer prevention in postmenopausal women.