Human papillomavirus types by age in cervical cancer precursors: predominance of human papillomavirus 16 in young women.

In a population-based study conducted in Guanacaste, Costa Rica, we investigated the human papillomavirus (HPV) types detected in 233 cases of cervical intraepithelial neoplasia (CIN) 2/3 and cancer by age. CIN2+ and CIN3+ in young women were significantly more likely to be associated with HPV 16 than the same lesions in older women (80% of CIN3+ were associated with HPV 16 among women ages 18-26 years compared with only 32% among women older than 55 years; Ptrend=0.018). There were no differences by age in HPV 18 positivity. Lesions in older women were mainly caused by other carcinogenic types. This association was present for both prevalent and incident lesions and supports the notion that HPV 16 is a stronger carcinogen than other HPV types. It also has implications for prevention, including the need to vaccinate young women before exposure to HPV vaccine-containing types (HPV 16 and HPV 18) to prevent the majority of cervical cancer precursors.