Socioeconomic differences in incidence of cervical cancer in Finland by cell type

Introduction. We studied variation in incidence of cervix cancer during 1971-1995 among Finnish women born in 1906 to 1945 by social class and cell type. Material and methods. The Finnish Cancer Registry data were linked to the 1970 Population Census, which included social class data. There were 0.8 million individuals in the cohort under follow-up, with 5 102 squamous cell cancers and 573 cases of cervical adenocarcinoma diagnosed after the census date. Results. Incidence of squamous cell cancer was more than two-fold in the lowest social class (standardized incidence ratio (SIR) 1.29, 95% Cl 1.21-1.36) as compared with the highest one (SIR 0.59, 0.51-0.66), while there was no association between social class and risk on adenocarcinoma (SIR 1.07, 0.87-1.28 and 1.08, 0.79-1.45, respectively). Discussion. Oncogenic HPV is regarded as the necessary cause of all types of cervix cancer. Sexually transmitted diseases and social status are correlated. Lack of association between adenocarcinoma and social class makes the HPV-etiology of this cell type less credible than that of squamous cell cancer.