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.