European Journal of Cardiovascular Medicine

The worldwide epidemic of non-alcoholic fatty liver disease (NAFLD) is characterized by its slow progression and lack of symptoms ^[1]. Over the past two decades, the prevalence of NAFLD has doubled, whereas the prevalence of other chronic liver diseases has plateaued or even decreased ^[2]. The most common cause of liver transplants in the future may be non-alcoholic fatty liver disease (NAFLD), which is detected by abnormal liver tests, imaging studies, and liver biopsies ^[1]. In the general population, the most popular method for screening for fatty liver is liver ultrasonography ^[3]. The various diagnostic techniques used to define NAFLD (biopsy, ultrasound, elevation of liver function tests, controlled attenuation parameter [CAP], fibro scan, or MRI) frequently lead to conflicting epidemiological studies on the disease. The gold standard for diagnosing non-alcoholic fatty liver disease (NAFLD) is liver biopsy; however, due to its invasive nature, it is not commonly carried out. Furthermore, the epidemiology of NAFLD differs greatly between nations. The prevalence of NAFLD in the general population is roughly 28 per 1,000 persons per year (PY) in western nations ^[4-6]. Incidences in Asia range from 19/1,000 PY to 86/1,000 PY ^[7,8]. 

For NAFLD, four distinct clinical phases have been identified.

Simple steatosis is a defining feature of phase 1, which is regarded as benign. Some patients advance to Phase 2, where they experience ballooning and inflammation (NASH). The presence of NASH with ongoing inflammation that causes liver fibrosis (scarring), which is thought to be the best indicator of liver-related events in NASH patients, characterizes phase 3. A liver transplant is the only treatment available if this third stage progresses into a more severe illness like liver cirrhosis (Phase 4) or even cancer. NASH is the primary cause of death for these patients and is linked to increased cardio metabolic risk in addition to liver-specific pathology ^[9].  In a recent discussion about the best way to refer to non-alcoholic fatty liver disease (NAFLD), a group of experts suggested Metabolic Associated Fatty Liver Disease (MAFLD) as a better term that better captures the disease's diversity ^[10]. The diagnostic criteria are altered by the addition of this new term, but the condition's prevalence in the general population remains unaffected ^[11].

The diagnosis of metabolic syndrome was made using the IDF 2005 criteria. Even though liver biopsy is the gold standard for diagnosing non-alcoholic fatty liver disease (NAFLD) ^{[12, 13]}, non-invasive, straightforward ultrasound can be used to detect NAFLD in asymptomatic patients early. The sensitivity of liver ultrasonography for identifying liver steatosis is 60-94%, while the specificity is 88-95%.

The purpose of this study is to estimate the prevalence of non-alcoholic fatty liver disease (NAFLD), which is identified by liver ultrasound examination ^{[14, 15]}. One endocrine organ that controls body metabolism is adipose tissue ^[16]. One factor contributing to the pathophysiology of NAFLD is the unbalanced synthesis of pro- and anti-inflammatory adipokines released from fat. One significant adipokines that is secreted exclusively by adipocytes and is present in the bloodstream in comparatively high concentrations is adiponectin. It seems to guard against liver damage and is produced outside the liver ^[17]. Adiponectin functions in the liver by inhibiting toll-like receptor-4-mediated signalling and activating the 5-AMP activated protein kinase and peroxisome proliferator-activated receptor-α pathways ^[18]. More directly linked to the pathophysiology of NAFLD/NASH is adiponectin. Serum levels of adiponectin, in contrast to other adipokines, are lowered in obesity and the related health issues. In healthy individuals, there is a negative correlation between liver enzyme levels and serum adiponectin levels. One independent risk factor for NAFLD and liver dysfunction in humans is a lower level of serum adiponectin ^[19]. Also, abnormal lipid metabolism results in fat accumulation in the liver, which in turn increases the production of various adipokines, inflammation, and oxidative stress, all of which play an important role in the NAFLD pathogenesis ^[20].

The current study attempts to diagnose NAFLD non-invasively by ultrasound and compare the results of ultrasonographically diagnosed NAFLD with serum lipid profiles in order to assess and validate the utility of ultrasonography for NAFLD diagnosis. That will aid in the early detection of dyslipidaemia and improved future management.

This cross-sectional study was conducted at the department of biochemistry, index medical college. Participants for the study was chosen from both IPD and OPD, based on inclusion and exclusion criteria. Diagnosis of fatty liver disease was based on ultrasonography evidence of fatty infiltration of hepatocytes. Both males and females undergone upper abdominal ultrasonography were recruited for the study. Informed consent was obtained after explaining the study procedures and outcomes and privacy of data was maintained throughout the study duration. Sample size for the study was (n=246), out of which 121 participants were diagnosed with NAFLD and 125 participants are having normal echotexture of liver and there Diabetic profile, liver function test, Lipid profile was evaluated.

Ethical clearance: Ethical and research committee of Index medical college hospital and research centre in Indore, Madhya Pradesh, gave approval to the research (MU/Research /EC/Ph.D/2020/001dated 28^th November-2020)

Inclusion criteria:

• Age >18 years
• People who consented to participate in the study

Exclusion criteria:

• Hypercalcemia
• Kidney disease 
• Malabsorption
• Prior diagnosis of liver disease

Informed consent: Informed consent was taken for all the participants who was willing to take part in study.

Statistical analysis:

All estimated results were expressed as mean ±SD. Mean values will be assessed for significance by unpaired student –t test. A statistical analysis will be performed using the Statistical Package for the Social Science program (SPSS, 24.0). Frequencies and percentages will be used for the categorical measures. Correlation between them was done by Karl Pearson’s correlation coefficient method and Probability values p < 0.05 will be considered statistically significant.

Table 1: Characteristics of study population (n=246)

Figure 1: Age wise distribution

Figure 2: Gender wise distribution.

Figure 3: BMI wise distribution.

Table 2: NAFLD status in study population (n=246)

NAFLD is more prevalent in age group of 31-60 years, female’s shows a higher number of NAFLD cases compared to males and higher BMI is strongly associated with NAFLD, supporting obesity as a key risk factor.

Figure 4: NAFLD status in different age groups.

Figure 5: NAFLD status in different gender.

Figure 6: NAFLD status according to BMI.

Table 3: Chi-square test is performed to find out the association between NAFLD & serum levels of liver enzymes and diabetic profile.

Chi-square test is performed to find out the association between NAFLD & serum levels of liver enzymes and there is strong association between NAFLD and hepatocellular enzymes.

Table 4: Chi-square test is performed to find out the association between NAFLD & lipid profile.

In the above table chi-square test is performed to find out the association between lipid profile in NAFLD and Non-NAFLD group. Individuals with NAFLD have adverse lipid profile characterized by high cholesterol, TG, LDL, VLDL and lower HDL levels. This suggest that NAFLD is closely associated with dyslipidemia thus monitoring lipid levels in NAFLD patient is necessary to prevent cardiovascular complications.

Figure 7: Scatter diagram between cholesterol levels in NAFLD and Non-NAFLD patients.

Figure 8: Scatter diagram between Triglycerides levels in NAFLD and Non-NAFLD patients.

Figure 9: Scatter diagram between HDL levels in NAFLD and Non-NAFLD patients.

Figure 10: Scatter diagram between LDL levels in NAFLD and Non-NAFLD patients.

Figure 11: Scatter diagram between VLDL levels in NAFLD and Non-NAFLD patients.

Non-Alcoholic Fatty Liver Disease (NAFLD) has a close association with metabolic dysregulation, especially dyslipidemia. As a hepatic expression of metabolic syndrome, NAFLD may coexist with abnormal lipid profiles, such as increased triglycerides (TG), increased low-density lipoprotein cholesterol (LDL-C), and reduced high-density lipoprotein cholesterol (HDL-C) levels. Having insight into the association between NAFLD and lipid metabolism is crucial for disease prevention, risk stratification, and therapeutic management.

Dyslipidemia is extremely common in patients with NAFLD. Research shows that about 50–80% of patients with NAFLD have some type of lipid abnormality ^[21]. The most frequently seen abnormalities are hypertriglyceridemia and low HDL-C, usually accompanied by insulin resistance and central obesity. NAFLD pathogenesis is closely related to lipid metabolism. Insulin resistance in NAFLD promotes enhanced lipolysis in the adipose tissue, releasing FFAs into circulation. FFAs are subsequently ingested by the liver, resulting in triglyceride storage and hepatic steatosis ^[22]. Furthermore, hepatic de novo lipogenesis is enhanced in NAFLD, which further impairs the excess fat accumulation. These changes in metabolism destabilize lipid synthesis, oxidation, and export balance, leading to atherogenic dyslipidemia, which is marked by: Increased TG, Increased small dense LDL particles, Decreased HDL-C ^[23]. The atherogenic lipid pattern in NAFLD patients is an important determinant of enhanced cardiovascular risk, the prime cause of death in these patients ^[24]. Large cohort studies have demonstrated that NAFLD predicts cardiovascular events independently, even after controlling for conventional risk factors ^[25]. The deranged lipid pattern is at the core of this enhanced risk. Lipid Pattern is also linked with the severity of NAFLD. Increased TG and decreased HDL-C have been reported to be associated with higher hepatic inflammation, fibrosis, and risk of progression to NASH and cirrhosis ^[26]. Patients with advanced fibrosis also have more pronounced dyslipidemia as a result of decreased hepatic lipid management and secretion.

Genetic mutations like PNPLA3 I148M and TM6SF2 E167K influence both hepatic lipid storage and plasma lipid concentration. These mutations predispose to NAFLD by changing lipid metabolism, tending to decrease serum lipids (particularly LDL-C) when liver fat content increases ^[27]. The paradox suggests a complex interplay between hepatic lipid storage and plasma lipid concentration. Treatment of dyslipidemia is a central aspect of NAFLD management. Statins are safe, effective in NAFLD patients, and decrease cardiovascular outcomes without exacerbating liver function ^[28].

Other lipid-lowering drugs, including omega-3 fatty acids and fibrates, can also enhance lipid profiles and hepatic steatosis, but evidence is inconsistent ^[29]. Lifestyle intervention is still the mainstay of management, successfully addressing both NAFLD and lipid dysfunctions.

This cross-sectional study was conducted among the adult population who had attended both the IPD and OPD departments of Index Medical College, Hospital, and Research Center. About 246 non-alcoholic subjects of both genders who underwent an abdominal ultrasound were included in the study to evaluate the lipid profile, liver enzymes, and glycemic status among patients with non-alcoholic fatty liver disease (NAFLD).

In our study, 20% of subjects were in the age group of 18-30 years, 64% were in the age group of 31-60 years, and 16% were over the age of 60 years. Among them, 45% were male and 55% were female. According to BMI distribution, 30% had a BMI between 18.5 and 22.5 kg/m², 24% had a BMI between 23 and 24.9 kg/m², and 46% had a BMI greater than 25 kg/m². Regarding NAFLD status across different age groups: 39% of subjects in the 18-30 years age group had NAFLD, while 61% did not; 56% of subjects in the 31-60 years age group had NAFLD, while 44% did not; and in the over-60 years age group, 40% had NAFLD, while 60% did not.

According to gender distribution, 40% of males had NAFLD and 60% did not, while 57% of females had NAFLD and 43% did not. For BMI-based distribution, 30% of those with a BMI between 18.5-22.5 kg/m² had NAFLD and 70% did not. In the BMI range of 23-24.9 kg/m², 61% had NAFLD and 39% did not, while in the BMI range greater than 25 kg/m², 55% had NAFLD and 45% did not.

The prevalence of NAFLD in this study was approximately 50%. NAFLD was most prevalent in the age group of 31-60 years (56%), among females (57%), and among overweight individuals (55%). Patients diagnosed with NAFLD underwent a FibroScan for disease staging. About 56% of patients were at Stage I (Grade I) fatty liver, 40% were at Stage II (Grade II) fatty liver disease, and 4% were at Stage III (Grade III) fatty liver disease.

We performed a chi-square test to assess the association between NAFLD and serum levels of liver enzymes, finding a strong association between NAFLD and hepatocellular enzymes, with a p-value of <0.0001. Additionally, we investigated the relationship between HbA1c levels and hepatic findings to understand the effect of glycemic control on NAFLD, and found that the association was both clinically and statistically significant, with a p-value of <0.05. This suggests that a significant difference exists, and glycemic control is associated with the exacerbation of NAFLD. Even mild deterioration in glycemic control, especially an increase in HbA1c, contributes to the progression of NAFLD. Similarly, we estimated the lipid profile and performed a chi-square test to find the association between NAFLD and lipid profile, which also showed a significant association with a p-value of <0.0001.

From this study, it is suggested that subjects diagnosed with NAFLD through ultrasound should have their fasting lipid and diabetic profiles evaluated, as these are often deranged. Patients should be screened for NAFLD, and vice versa, for early diagnosis and treatment, in order to prevent further complications such as end-stage liver disease.

Non-alcoholic fatty liver disease (NAFLD) and hyperlipidaemia (HL) are common metabolic disorders due to over nutrition and obesity. NAFLD is often associated with hyperlipidaemia. The study found that hyperlipidaemia was present in the majority of NAFLD patients. The presence of NAFLD was significantly positively correlated with rising serum total cholesterol and triglyceride levels and significantly falling HDL. NAFLD was linked to hyperlipidaemia, a prevalent ailment. Since hyperlipidaemia is a known risk factor for cardiovascular and cerebrovascular disease, it is critical for medical professionals to recognize and treat it in NAFLD patients.

Funding support: Nil

Conflict of Interest: Nil

Ethical standard:

1) This material is the authors' own original work, which has not been previously published elsewhere.

2) The paper is not currently being considered for publication elsewhere.

3) The paper reflects the authors' own research and analysis in a truthful and complete manner.

Acknowledgment:

We all authors are very much thankful to all respected patients and all technical staff members for their valuable work in our study.

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