Decreased prevalence of dysplasia in high-risk population immigrants in a low-risk area for cervical cancer

Incidence rates of cervical cancer and its precursors vary considerably, with the highest rates found in developing countries. Differences are influenced by endogenous and exogenous factors. Comparing cytologic abnormality incidence rates from a high-risk population in the original high-risk area, with those of women from this high-risk population who have immigrated to a low-risk area could give insight in the significance of endogenous versus environmental factors. Smears collected from Surinamese women attending the Surinamese screening program and smears collected from immigrant Surinamese women attending the Dutch screening program were cytologically analyzed using the Dutch microscopical coding system KOPAC. Statistical analysis was performed by using logistic regression to calculate (age-adjusted) odds ratios (ORs). The age-adjusted ORs of having dysplasia were higher for Surinamese women living in Suriname versus Surinamese immigrant women and increased with increasing P-scores: 0.77 (0.31-1.91) for borderline changes, 1.62 (0.58-4.57) for mild dysplasia, and 3.20 (1.55-6.60) for moderate to severe dysplasia/neoplasia. We conclude that fewer cases with dysplasia are present in a high-risk population that has immigrated to a low-risk area for cervical cancer than in the high-risk population continuously living in a high-risk area. This finding emphasizes the importance of environmental factors.