Re: Risk of venous thromboembolism from use of oral contraceptives containing different progestogens and oestrogen doses: Danish cohort study, 2001-9
In this study on risk of venous thromboembolism from use of oral contraceptives containing different progestogens and oestrogen doses (a Danish cohort study, 2001-9), the length of use of oral contraceptives was adjusted during analysis. Obesity, increasing age, prolonged immobilization (long distance travel or bed rest) are other risk factors (confounders) for venous thromboembolism and should also have been adjusted during analysis in this population based study. This study is done in women aged 15-49 years whereas, age above 40 years is a risk factor for VTE.
1. BMJ 2011;343:d6423
Competing interests: No competing interests