## 4 Discussion  
This study analyzed the mediating effect between DII and metabolic diseases on cataracts among adults aged 40 years and older using data from the 8 th KNHANES (2019-2021). The results showed that in the LOW DII group, metabolic diseases had a significant negative  
Figure 3: Mediating Effect of Metabolic Diseases on the Association Between DII (per 1000 kcal) and Cataract Prevalence. MID, middle; DM, diabetes mellitus; HTN, hypertension; Dys, dyslipidemia; OB, obesity. * \(p<0.05\). indirect effect on cataract prevalence, whereas in the HIGH DII group, metabolic diseases had a significant positive indirect effect on cataract prevalence. In this study, the analysis of the association between DII and metabolic diseases showed that in the LOW DII group, hypertension, dyslipidemia, and obesity had a significant negative (\(-\)) relationship, whereas in the HIGH DII group, diabetes, hypertension, and dyslipidemia had a significant positive (\(+\)) association. These findings suggest that an inflammatory diet may increase the risk of developing metabolic diseases. Previous research analyzing the relationship between an inflammatory diet and metabolic syndrome in Mexican adults found that individuals in the HIGH DII group had approximately twice the risk of developing hypertension, hypertriglyceridemia, and abdominal obesity compared to those in the LOW DII group [21]. Another study also reported that higher DII scores were associated with an increased risk of obesity, diabetes, and cardiovascular diseases [22]. These findings align with the results of the present study, where higher DII scores were associated with an increased prevalence of metabolic diseases, further reinforcing the strong link between DII and metabolic disease development. The analysis of the impact of metabolic diseases on cataract prevalence in this study showed that hypertension, diabetes, and dyslipidemia were significantly associated with cataracts across all groups, with hypertension being the strongest risk factor. A previous study conducted in Bangladesh among adults aged 41 years and older found that the risk of developing cataracts was 4.64 times higher in those with obesity (BMI \(\geq\) 25 kg/m\({}^{2}\)) and 3 times higher in those with dyslipidemia [23]. Similarly, a study conducted in Greece found that hypertension was the most significant risk factor for cataract prevalence among diabetes, hypertension, and dyslipidemia [24]. These findings align with the present study, reinforcing the strong association between metabolic diseases and cataract risk. Hypertension and dyslipidemia have been linked to the effects on ocular blood supply and lipid metabolism [25]. Hypertension is an increase in blood pressure caused by impaired vascular function, which can impede blood flow to the ocular tissues, reducing the supply of nutrients and oxygen to the lens [8]. This can lead to increased oxidative stress and promote the degeneration and clouding of lens proteins, which can increase the risk of developing cataracts [24]. Dyslipidemia is also characterized by abnormalities in lipid metabolism in the blood and can alter the structure and function of the lens cell membrane by promoting lipid peroxidation reactions in the lens, which can increase oxidative damage [9]. These mechanisms contribute to cataract formation, highlighting the importance of preventing and managing hypertension and dyslipidemia as key strategies for cataract prevention. In contrast, obesity did not show a significant impact compared to other metabolic diseases in this study. This may be due to the use of BMI as the sole measure of obesity, whereas previous studies have considered various indicators such as waist circumference and waist-to-hip ratio [23]. Research analyzing the relationship between visceral fat and metabolic diseases has shown that an increase in visceral fat is strongly associated with a higher risk of metabolic syndrome.