Geographic Variation of Incidence Rates of Cancer and Associated Risk Factors in Northern West Bank, Palestine, 2005-2008

Abstract -Background: Cancer is the third leading cause of deaths in the West Bank and Gaza accounting for about 10% of total deaths. Despite its importance, little research has been devoted to characterization of incidence rates and geographic variations. This study compared the incidence rates and some risk factors of cancer among governorates of Northern West Bank and among types of locality (urban, rural, and refugee camps) for the period 2005-2008.Methods: Crude and age-adjusted incidence rates were calculated using cancer data obtained from the registry files of three hospitals in Northern West Bank. Negative binomial regression analysis was performed to compare incidence rate ratios (IRR) among governorates and types of locality while adjusting for age-group, sex and year of diagnosis. Fisher’s exact test was employed to test relationships among cross tabulated variables and test homogeneity of proportions.Results: The lowest overall incidence rate was found in the governorate of Jenin (age-adjusted rate of 45.0 cases per 100,000 over the 4-yr period). With Jenin taken as a reference, the governorate of Nablus had the highest IRR (3.30) with age-adjusted incidence of 148.1 cases per 100,000. Refugee camps had higher overall incidence rate than urban and rural areas (age adjusted rates of 169.0, 103.2, and 79.3 cases per 100,000 for refugee camps, urban, and rural areas, respectively). Geographical differences were found in the distribution of patients with regard to types of environmental pollution, dietary factors, smoking, alcohol consumption, types of stress, and chronic diseases but not in dietary habits and family history.Conclusions: In Northern West Bank, large differences were found among areas of residence (governorates and locality types) in incidence of cancer. Geographical differences in risk factors were also found which could explain part of the geographic differences observed in incidence rates.