Mothers’ and their daughters’ use of preventive measures against cervical cancer

Bente Braad Sander, Miguel Vázquez-Prada, Matejka Rebolj, Palle Valentiner-Branth, Elsebeth Lynge

Aims: Vaccination against human papillomavirus (HPV) and screening are complementary preventive measures against cervical cancer. In Denmark, screening and vaccination are free of charge for the women. In total, 75% of women are screened and about 90% of girls are vaccinated with at least one dose. Our aim was to determine whether, in Denmark, daughters of unscreened mothers are less likely to be vaccinated against HPV than are daughters of screened mothers. Methods: We used population-based data from the Danish Patient Register, Health Service Registration, Pathology Data Bank, and Civil Registration System. Individual-level data on screening, vaccination, and vital status until 31 December 2010 were retrieved. Daughters were linked to their mothers through the link provided in the Civil Registration System. The study population included 149,147 girls born in 1993-1997 and their mothers. We calculated birth cohort-specific relative risks (RRs) of non-initiation of HPV vaccination in daughters depending on their mothers' screening status. Results: In total, 8% of girls did not receive any vaccination, and 35% of their mothers were unscreened. Among the 92% of girls receiving at least one vaccine dose, 14% of mothers were unscreened. The birth cohort-specific RRs of non-initiation of vaccination given an unscreened mother varied between 2.16 (95% CI: 2.00-2.33) and 2.83 (95% CI: 2.63-3.05). Conclusions: The observed association between screening and vaccination suggest that it will be difficult to increase the vaccination coverage by, for example, counselling at the mother's cervical screening appointment. Other measures to increase the coverage with vaccination will be important.