Factors associated with non-participation in cervical cancer screening - A nationwide study of nearly half a million women in Denmark.

Cervical cancer occurs most often in under-screened women. In this nationwide register study, we described differences in sociodemographic characteristics between passive and active non-participants and examined socio-demographic characteristics, reproductive history, and mental and physical health as potential determinants for passive non-participation compared with participation in the Danish cervical cancer screening program. Screening history in women aged 23-49 years invited for cervical cancer screening in 2008-2009 was retrieved from the Danish Pathology Databank with information about dates of invitation and unsubscription. We identified participants (n = 402,984), active non-participants (n = 10,251) and passive non-participants (n = 63,435) within four years following baseline invitation and retrieved data about the study population from high-quality registries. We examined differences in socio-demographic characteristics of passive and active non-participants, and used multiple logistic regression analyses to identify potential determinants of passive non-participation. We found that active and passive non-participants differed in relation to socio-demography. When compared with screening participants, the odds of passive non-participation was increased in women who originated from less developed countries; were unmarried; had basic education or low income; had four or more children; smoked during pregnancy; had multiple induced abortions; or had a history of obesity, intoxicant abuse or schizophrenia or other psychoses. In conclusion, in this nationwide, prospective, population-based study, differences in socio-demographic characteristics between passive and active non-participants were found. Furthermore, sociodemography, reproductive history, and mental and physical health were determinants for passive non-participation. Addressing inequalities in screening attendance may help to further decrease the incidence of and mortality from cervical cancer.