Risk factors for NAFPD include obesity, age increase, male, hypertension and dyslipidemia(14). However, most of the subjects studied are adults. Only a few studies(15) have been conducted on school-age children and adolescents with obesity and metabolic syndrome, and no studies have been found in the general children group.
Currently, the internationally recognized indicators to measure the degree of childhood obesity include BMI, WC, WHtR, etc. Research has shown that WHtR was superior to BMI, WC and waist-hip ratio in predicting Metabolic Syndrome(MetS)(16, 17). In our study also found that WHtR in the prediction of dangerous NAFPD most relevant. Meanwhile, children who are overweight and obese need to consult BMI and WC boundary table(18). Similarly, blood pressure level of children increases with age(19), which requires us to refer to percentile boundary table of blood pressure of children of different ages and heights to assess the risk of NAFPD(20), which increases the workload of screening and is not conducive to epidemiological investigation. Therefore, WHtR as a routine physical examination indicator for children can better assess and screen the risk factors of cardiovascular disease and MetS risk in children.
Our study found that the incidence of NAFPD in children was negatively correlated with age and height, but not gender. What’s more, the amount of exercise of preschool children is less than that of school-age children, and they are more prone to fat deposition, this may also be in line with the findings of Afshin A et al, that childhood obesity rates first decline with age before age 14 and then increase(1). Also there was no gender difference in obesity rates before age 20, and childhood obesity rates were the same for boys and girls at all ages.
NAFPD includes features of MetS, which translates into strong association with type 2 DM, NAFLD and cardiovascular risk(21).TG, TC and LDL levels of NAFLD patients were generally higher than those of normal healthy people, while HDL levels were lower(22).Our study found that the TC, LDL, AST, ALT and GGT in patients with NAFPD,TC, LDL, AST, ALT and GGT were higher than the non-NAFPD negative group, however, HDL was lower than the non-NAFPD negative group. This result showed that NAFPD patients in a variety of abnormal biochemical indexes, especially blood lipid metabolic disorder (TC, LDL concentration increase HDL levels), with the risk of MetS. At the same time, this study demonstrated that low levels of blood lipid metabolism disorders were more likely to happen NAFPD, which was similar to our previous study found that the detection of the metabolic syndrome caused by ectopic fat deposition in the examination, abdominal ultrasound examination of the pancreas was superior to the liver(9).
The AST and ALT of NAFPD patients in this study were also higher than those in the negative group, which is the same as the research results of Kim DR et al(23) that in elder obese children and adolescents. GGT has long been used as a marker of alcoholism and liver disease, also GGT can be used as a predictor of MetS(24). In this study, it was found that the GGT level of NAFPD patients was higher than that of the negative group. However, previous studies have shown that the risk of MetS in obese children and adolescents with increased GGT was significantly increased compared to normal(25).
To our knowledge, this is the first and largest study assessing the clinical value of WHtR in children NAFPD. At the same time, WHtR can be used as a sensitive indicator for early screening of children's MetS and used for epidemiological investigation. When WHtR is found to exceed the optimal threshold during the physical examination of children and adolescents, clinicians may be prompted to take necessary measures, such as noninvasive ultrasonography to assess the occurrence of NAFPD and to assess the need to reduce their chance of MetS by increasing exercise, diet control, etc.
This study has several limitations. First, this study is limited by its retrospective nature and its inherent selection bias. Second, this is a single-center study. It would be necessary to conduct larger, multi-center studies of the general population in the future. Third, we just ultrasound examination but no MRI, CT or histological examination (biopsy) to assess NAFPD. Therefore, the results of MRI, CT and biopsy specimens cannot be compared with the results of ultrasound examination, and further studies are necessary to compare the results in the future.
In conclusion, we explored the detection rate of NAFPD through the abdominal ultrasound examination in different age children's pancreas. The results showed that WHtR, TC, LDL and ALT were independent risk factors for NAFPD. A ROC curve was generated for WHtR value to evaluate the potential diagnostic value of WHtR. We found that the area under the ROC curve (AUC) was 0.722. The sensitivity and specificity were 75.6%, and 66.7% respectively. Thus, our study provided reference for early diagnosis and treatment of clinical disease, then it could guide the clinical timely intervention, which can reduce and avoid the occurrence of related diseases.