A fuzzy logic approach to the evaluation of health risks associated with obesity

Excessive body weight, especially in the form of the so-called abdominal obesity (AO) is an important factor of the cardio-metabolic risks (CMR). The paper presents a fuzzy model of AO and CMR assessments based on such key indicators of anthropometric measurements as body mass index (BMI as a measure of the global adiposity) as well as waist circumference (WC) and waist-to-height ratio (WHtR) as AO indicators. For the construction of a membership function (MF) the Zadeh´s Extension Principle (EP) and mapping of the BMI fuzzy sets into adequate AO fuzzy sets using different transformation functions have been applied. Taking advantage of the results of a screening study, the AO membership functions for adult population of Lodz (WHO-CINDI project) are presented. MF design based on the EP theory is a useful methodology for assessing the AO and, consequently for a better assessment of CMR.