Model of risk probability of in North central region of Sri Lanka

Abstract

The chronic kidney disease of unknown etiology in farmers in North Central region has become an emerging health problem in Sri Lanka. Lack of scientifically proven experiments of epidemiological studies on the etiology is one of the major problems in solving this issue in Sri Lanka. Therefore, identifying the independent preventable risk factors mainly related to the occupation may helps in decreasing the number of patients suffering from CKD-U and slowing its progression. The objective of the study is to identify the epidemiological characteristics and potential risk factors related to agricultural activities in the development of CKD-U by using a case control study and modeling the risk probability of the disease occurrence. The study was undertaken in Madawachchiya, Padaviya and Kebithigollawa area and two hundred and seventy four (274) patients with CKD-U (cases) and two hundred and seventy four (274) healthy individuals were selected as controls for the age and sex 1: 1 matched case control study. The relative risk of each factor was compared in terms of odds ratios (OR) and 95% confidence intervals (CI) by applying the conditional logistic regression model. The risk probability was calculated with the above model in cases and control separately and compared. Involvement in agricultural activities, low protective measures against agrochemicals, and cultivating lands without labour exchange were identified as significant risk factors for the disease. Smoking and family history of CKD-U, drinking water source (shallow wells) and history of snake bite were identified as other life style related risk factors for the disease occurrence. The risk probability can be used as an index of the disease diagnosis and the receivers operating characteristic (ROC) curve plots the true positive fraction (TPF) against the false positive fraction (FPF) for different choice of cut off ranges. Therefore involvement in agricultural activities is significantly related for the disease. Low levels of protective measures in the application of agrochemicals indicate the importance to educate the farmers on protective measures of agrochemical applications.