## 4 Discussion  
Our study confirmed the relevance of using the new anthropometric index WWI in assessing the risk of obesity and other non-communicable diseases. Based on the results, a group of adult Slovak female volunteers of middle to older age was evaluated as a group at risk of central obesity. The results showed significant differences between WWI quartiles in almost all monitored variables. The women in the higher quartile groups had higher values of parameters than those in the lower quartile groups. This finding confirmed a higher risk of obesity and metabolic syndrome in the higher quartiles. The results also confirmed an inverse relationship between WWI quartiles and the proportion of FFM and SMM in body weight, as we found an increasing proportion of fat mass at the expense of fat-free and muscle mass. In the case of the biochemical and somatic parameters, the values of the parameters also increased with increasing WWI quartiles. We found an inverse relationship in the case of HDL-C, where its values decreased with increasing quartiles. With increasing quartiles, the prevalence of obesity, sarcopenia, sarcopenia, hypercholesterolemia, cardiovascular risks, metabolic syndrome and other health risks also increased. The threshold values of health status indicators were exceeded almost in all WWI quartiles, and the highest prevalence of risks was found in the highest quartile. The correlations showed a strong positive relationship of the WWI with fat parameters and a strong negative relationship with fat-free and muscle mass and the ratio of total body water to body weight. The correlation analysis also confirmed a strong positive relationship with most anthropometric indices. A moderate positive association of the WWI with BPd and TG and a moderate negative association with HDL-C were also confirmed. Excessive body fat, especially in the visceral area, is the cause of non-communicable diseases of a cardiovascular, metabolic or carcinogenic nature [35; 36]. However, evidence is accumulating not only pointing to the importance of adipose tissue in disease processes, but also of muscle mass [37; 38]. Its low proportion is shown to be an independent indicator of loss of strength, age-related disorders and, in some cases, even the risk of premature death [39]. For this reason, measuring muscle mass is becoming an essential part of assessing body composition and the resulting health risks. However, determining muscle mass without a special examination is difficult. Special methods and devices are required for this, and until now there has been no relevant anthropometric index as an indicator of muscle mass [40]. Most anthropometric indices tend to be proportional to both fat and muscle mass [41; 42]. However, a newly introduced anthropometric index, the weight-adjusted waist index (WWI), is characterized by its ability to assess fat and muscle mass together. The WWI is an index that standardizes WC to body weight [43]. A high WWI value indicates that a person with a larger WC value has a larger proportion of fat mass and a proportionally smaller proportion of muscle mass than a person with the same weight but a smaller WC. The WWI integrates WC with body weight, while maintaining the advantages of WC-related indicators and at the same time moderating the correlation between WC and BMI [8; 44; 45]. The WWI primarily reflects central obesity independently of total weight, which is also confirmed by our results. Compared to BMI, it demonstrates greater accuracy [46; 47]. Our results indicate that the traditional indices of BMI (r = 0.968), WHR(r = 0.899) and WHtR (r = 0.974) have a stronger association with high fat mass compared to the WWI (r = 0.896). Similar conclusions have been reached by other authors [48]. The WWI has a positive correlation with adiposity (FM r = 0.288, %FM r = 0.524) and a negative one with muscle mass (r = \(-\)0.536) [12]. Our results also confirm this, but we found stronger correlations (WC r = 0.924, FM r = 0.896, %FM r = 0.901, VFA r = 0.907 and %FFM r = \(-\)0.900, %SMM r = \(-\)0.887).