Prevalence of Non-alcoholic Fatty Liver Disease Detected by Computed Tomography in the General Population Compared with Ultrasonography

Prevalence of MAFLD in the U.S. based on NHANES 2009-2018: differences in demographic characteristics, physical indices and lifestyle conditions

BACKGROUND

The incidence of metabolic dysfunction-associated fatty liver disease (MAFLD) is high among U.S. adults, but studies on its occurrence in different ethnic and age groups are limited. The aim of the present study was to assess MAFLD occurrence among the U.S. adults by considering demographic characteristics, physical indices, and lifestyle conditions.

METHODS

This study utilized the National Health and Nutrition Examination Survey (NHANES) data 2009-2018 from 23,546 participants aged ≥ 20 years. Variables such as age, sex, race, body mass index (BMI), waist circumference (WC), blood pressure, sedentary behavior, sleep, and depression were analyzed.

RESULTS

Among 9933 participants, 3562 had MAFLD (34.1%), with notably higher percentages of Mexican-Americans (54.1%) and lower percentages of blacks (20.5%). The incidence of MAFLD was significantly greater (P < 0.001) in males (39%) than in females (29.2%), which was particularly evident within the 36-40 years age group. The MAFLD incidence exhibited an age-dependent pattern, initially increasing and subsequently declining (except for whites). Compared to white MAFLD patients, black MAFLD patients exhibited greater BMI, WC, systolic blood pressure (SBP), and diastolic blood pressure (DBP) values, whereas values for these measures were lower among Mexican-American patients. Logistic regression analysis adjusting for age and sex revealed that depression was more common among MAFLD patients (P < 0.001), except for severe depression (P > 0.05). Notably, the MAFLD incidence was not significantly associated with sedentary behavior or sleep duration.

CONCLUSIONS

The MAFLD incidence varies across different racial, age, and sex groups, and targeted interventions are essential for reducing the burden of MAFLD. However, further research is necessary to explore the correlations among MAFLD incidence, sleep patterns, and an inactive lifestyle.

Role of Nonalcoholic Fatty Liver Disease in Periodontitis: A Bidirectional Relationship

Nonalcoholic fatty liver disease (NAFLD) and periodontitis share common risk factors such as obesity, insulin resistance (IR), and dyslipidemia, which contribute to systemic inflammation. It has been suggested that a bidirectional relationship exists between NAFLD and periodontitis, indicating that one condition may exacerbate the other. NAFLD is characterized by excessive fat deposition in the liver and is associated with low-grade chronic inflammation. There are several risk factors for the development of NAFLD, including gender, geriatric community, race, ethnicity, poor sleep quality and sleep deprivation, physical activity, nutritional status, dysbiosis gut microbiota, increased oxidative stress, overweight, obesity, higher body mass index (BMI), IR, type 2 diabetes mellitus (T2DM), metabolic syndrome (MetS), dyslipidemia (hypercholesterolemia), and sarcopenia (decreased skeletal muscle mass). This systemic inflammation can contribute to the progression of periodontitis by impairing immune responses and exacerbating the inflammatory processes in the periodontal tissues. Furthermore, individuals with NAFLD often exhibit altered lipid metabolism, which may affect oral microbiota composition, leading to dysbiosis and increased susceptibility to periodontal disease. Conversely, periodontitis has been linked to the progression of NAFLD through mechanisms involving systemic inflammation and oxidative stress. Chronic periodontal inflammation can release pro-inflammatory cytokines and bacterial toxins into the bloodstream, contributing to liver inflammation and exacerbating hepatic steatosis. Moreover, periodontitis-induced oxidative stress may promote hepatic lipid accumulation and IR, further aggravating NAFLD. The interplay between NAFLD and periodontitis underscores the importance of comprehensive management strategies targeting both conditions. Lifestyle modifications such as regular exercise, a healthy diet, and proper oral hygiene practices are crucial for preventing and managing these interconnected diseases. Additionally, interdisciplinary collaboration between hepatologists and periodontists is essential for optimizing patient care and improving outcomes in individuals with NAFLD and periodontitis.

Markers of insulin resistance associated with non-alcoholic fatty liver disease in non-diabetic population

Insulin resistance (IR) plays an important role in the development of non-alcoholic fatty liver disease (NAFLD). IR markers are divided into two types: (1) insulin-based IR marker, homeostatic model assessment of IR (HOMA-IR); and (2) non-insulin-based IR markers, such as triglyceride-glucose (TyG) index, TyG index with body mass index (TyG-BMI), triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-c), and metabolic score for IR (METS-IR). The non-insulin-based IR markers are often associated with lipids. The aim of this study was to analyse the association between IR markers and NAFLD in non-diabetic population. Baseline data of NAFLD and non-NAFLD groups were compared. Logistic regression was used to evaluate the relationship between five IR markers and NAFLD risk. The odds ratios (ORs) and 95% confidence intervals (CIs) of IR markers were calculated. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to evaluate the ability of different IR markers to detect NAFLD. Subgroup analyses were performed in obese and non-obese subgroups. This study found a positive correlation between NAFLD risk and elevation in five IR markers (HOMA-IR, TyG, TyG-BMI, TG/HDL-c, and METS-IR). In non-obese subjects, the AUC of TyG-BMI was larger than that of the other four IR markers to detect NAFLD. The AUC of HOMA-IR was larger than that of the other four IR markers to detect NAFLD in obese subjects. In non-diabetic population, the five IR markers are associated with the risk of NAFLD, including non-obese and obese NAFLD. TyG-BMI and HOMA-IR can be used to detect non-obese and obese NAFLD, respectively, with better detection ability compared with the other IR markers.