Epidemiology of Chronic Lymphocytic Leukemia in Sardinia, Italy (1974–2003)

Abstract

We explored CLL incidence in Sardinia, Italy, using a validated database including the 1,700 CLL cases diagnosed in 1974-2003. We applied Bayesian methods to map the CLL probability by administrative unit and Poisson regression analysis to investigate socio-economic and environmental determinants adjusting by possible confounders. The standardized (Standard European population) incidence rate for the Sardinian population over the study period was 5.1 per 100,000 (95% Confidence Interval [CI] 4.9 - 5.3), increased annually by 5.8% (95% CI 5.7 - 6.0) consistently by sex and age, and was more noticeable in urban areas. Five administrative units exceeded the 95% posterior probability of an elevated CLL incidence: these were rural areas spread over the regional territory, not suggestive of spatial clustering. The Poisson regression analysis showed that the risk was elevated in urban areas (RR = 1.11, 95% CI 1.05-1.17), among residents ≥ 30 km from the nearest hospital (RR = 1.09, 95% CI 1.06-1.12), and with the local prevalence of cork harvesting (RR = 1.62, 95% CI 1.12-2.34). Our results suggest that better access to healthcare facilities and improvements in diagnostic efficacy might have generated the observed upward trend in CLL incidence, along with contributing environmental factors.