highly significantp < 0.0001
Young women (15–19 years) were the most susceptible, with an RR of 2.06 (95% CI: 1.92–2.21), highly significant ( p < 0.0001); this RR was 2.5 after 1 month of HBC use, remained above 2 during the first year, and was 30% higher after 7 years.