Our study showed that among the anthropometric indices, the VAI had the highest correlation with cardiometabolic indices, while CI had the highest correlation with hepatic indices. In the Hoveyzeh population, the atherogenic index of plasma was the most significant predictor of T2DM in both men and women compared to other indicators.
In our study, the odds ratios in model 2 indicated that among the anthropometric indices, the Weight-Adjusted Waist Index (WWI) and VAI, and among the cardiometabolic indices, AIP, CI, Body Roundness Index (BRI), and Cardiometabolic Index (CMI), as well as Hepatic Steatosis Index (HSI) among the liver indices, were predictors of T2DM. Additionally, men and women in the study showed similar results.
The average energy intake and physical activity levels in healthy individuals were higher than in patients with T2DM, indicating the impact of diabetes on daily life and activity. In our study, systolic and diastolic blood pressure in T2DM patients was higher than in the healthy group, which aligns with findings from other studies in different Iranian populations. Therefore, early diagnosis of T2DM using anthropometric indicators can reduce the complications of diabetes, such as diabetic nephropathy, cardiovascular diseases, and cerebrovascular diseases, over time (
26).
In this study, the average of all conventional anthropometric indices (WC, WHR, BMI, and WHtR) and new anthropometric indices, including WWI, VAI, abdominal volume index (AVI), CI, relative fat mass (RFM), and BRI, were higher in T2DM patients than in healthy individuals. Among the conventional and new anthropometric indices, only WHR and VAI did not show a significant difference between diabetic men and women. The conventional and new anthropometric indices measured in our research, except for WHR and VAI, were higher in healthy women than in healthy men.
Different populations have different predictive factors for diabetes, and there are also differences between male and female groups. In studies conducted in British, Chinese, German, European, and Australian native populations, WC was identified as a predictor of T2DM (
27-
31). Some studies have reported that WHtR is the most sensitive predictive factor for diabetes (
32-
34). Khader et al. reported that WHtR was the most effective predictor of diabetes in the Jordanian adult population (
34). Waist-to-hip ratio is commonly used to determine abdominal obesity, distinguishing between gynoid (buttock) and android (abdominal) obesity (
35). In a study conducted in Iran, it was shown that the risk of T2DM is higher in individuals with high WHR compared to those with high BMI and WC, with the increase being greater in women than in men (OR 2.79 vs. 2.36) (
32). In our study, the multivariate-adjusted OR for T2DM risk in males for WHR, WC, BMI, and WHtR was 1.09, 1.04, 1.08, and 1.06, respectively, while for women, it was 1.08, 1.03, 1.04, and 1.05, respectively. According to the odds ratio greater than one (OR > 1), common anthropometric indices, including WC, BMI, WHR, and WHtR, and new anthropometric indices, including WWI, VAI, AVI, CI, RFM, and BRI, increase the risk of T2DM.
In our study population, AIP was an important predictor of T2DM compared to other indicators. The AIP is composed of two important parameters, triglycerides (TG) and HDL. The simultaneous use of TG and HDL in this ratio indicates multiple interactions between the metabolism of different lipoproteins, which can be used to predict plasma atherogenicity (
36). Atherogenic Index of plasma is an atherogenic factor that can predict atherosclerosis and the risk of cardiovascular events (
37,
38). Atherogenic Index of plasma indices are associated with visceral fat area in patients with T2DM in some studies (
39).
In our study, BMI, WHtR, WWI, CI, BRI, RFM, and LAP had higher optimal cut-off point values in men than in women. Women had higher optimal cut-off point values for WC, WHR, VAI, and AVI than men. The optimal cut-offs for anthropometric indices to predict T2DM differ among different populations (
40). The differences in study results may be largely influenced by the ethnicity, age, gender, and background diseases of the participants, as well as the anthropometric indicators chosen for analysis.
In our research, we found that TC and TG levels were higher in subjects with T2DM compared to healthy subjects. Conversely, HDL levels were higher in healthy subjects than in those with T2DM. We did not observe a significant difference in mean LDL levels between people with T2DM and healthy individuals in our study. This could be due to the use of statin drugs in the diabetic group, which may have reduced their LDL levels and acted as a confounding factor.
One of the limitations of our study was the narrow age range of 35 to 70 years. Expanding the age range to include individuals over 70 years old and under 30 years old could provide a better understanding of the impact of risk factors. Additionally, it's important to note that statin consumption in patients with dyslipidemia and T2DM could influence the results of the lipid profile and could be a confounding factor.
Our research was a cross-sectional study, which has limitations in establishing causal relationships between variables. Since data is collected at a single point in time, it is challenging to determine the temporal sequence of events or to ascertain whether a particular variable directly influences another.
5.1. Conclusions
In our study population, the Atherogenic Index of Plasma is a highly predictive indicator of T2DM. Our results suggest that novel anthropometric and cardiometabolic indices could serve as accessible and cost-effective strategies for assessing health outcomes related to T2DM.
According to previous research, differences in estrogen levels may lead to varying ANI index results in non-menopausal and menopausal women, indicating the need for further investigation to compare this index (
41-
43).
The study utilized the TyG index to assess insulin resistance. It is recommended to use the insulin resistance model or other standard indices of insulin resistance in future studies to allow for comparison of results, as the TyG Index primarily represents the level of insulin resistance.
Several factors, such as the number of hours slept per day and depression, contribute to the incidence and prevalence of diabetes. Therefore, it would be beneficial to conduct more extensive studies aimed at identifying predictive risk factors for type 2 diabetes, taking these factors into account.