Oral contraceptives and risk of gallbladder disease
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* Mayhar Etminan

We agree with Wang and colleagues that the risk of gallbladder disease with the use of oral contraceptives may be modified by different levels of BMI.1 Unfortunately, information on BMI was not available for our study.2 We agree that future research should examine this issue carefully.

## References

1.  Wang F, Shen X, Guo X, et al. Oral contraceptives and risk of gallbladder disease. CMAJ 2011;183: 1517.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMzoiMTgzLzEzLzE1MTctYSI7czo0OiJhdG9tIjtzOjI0OiIvY21hai8xODMvMTMvMTUxNy4zLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.  Etminan M, Delaney JAC, Bressler B, et al. Oral contraceptives and the risk of gallbladder disease: a comparative safety study. CMAJ 2011;183:899–904.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxODMvOC84OTkiO3M6NDoiYXRvbSI7czoyNDoiL2NtYWovMTgzLzEzLzE1MTcuMy5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=)