This research is a systematic review and meta-analysis study that was conducted in 2021 based on Cochrane's guidelines. Accordingly, to determine the intervention research, databases, Sid, ISI, Google Scholar, Embase, PubMed, Science Direct, Scopus and publications of the Ministry of Science were examined to find valid articles by combining the following textual words to formulate a search strategy in the target databases.
[exercise OR training OR physical activity OR insurance training] AND, NAFLD, NAFL, NASH, nonalcoholic steatohepatitis, non-alcoholic fatty liver disease, fatty liver, hepatic steatosis, and liver steatosis].
Based on searches in databases, 220 articles were selected and after the initial review of related articles, 120 articles entered the evaluation stage. After reviewing the full text of the remaining articles, if the articles met the inclusion criteria, their information was extracted. Therefore, a total of 20 articles were included in the meta-analysis (flowchart 1). Accordingly, 710 people with NAFLD were divided into control and experimental groups of 307 and 403 people, respectively. The mean age of the subjects in the present study was 52 ± 10 years.
Inclusion criteria of the present study articles included studies that had more than 4 weeks of practice intervention, including people with NAFLD, and articles that had merely human samples and were clinical trials. As well as, the studies in which aerobic exercise have been performed on people with NAFLD.
According to the exclusion criteria, studies with the following characteristics were excluded: review articles, case reports, animal studies, conference papers, articles with inappropriate data for statistical analysis, studies that examined resistance training, and duplicate studies.
The following information were extracted from the articles after the initial review: name of the first author of the article, year of publication, city of study, sample size, age, gender of participants, sampling method, sport program specifications, type of exercise, intensity and duration of training. The text quality of the articles was evaluated by two expert referees using the Cochrane checklist [12]. The results of research biases indicate asymmetry. Research bias can also affect the results of content analysis, such as the date of publication of anomalous data. The collected data were analyzed by STATA software and statistical tests to determine the effect of standardized mean difference.
Table 1 Specifications of studies performed on individuals with NAFLD entered in a systematic review and meta-analysis
Exercise intensity
|
Marker
|
BMI
|
age
|
Control group NO.
|
Experimental group NO.
|
Total NO.
|
sex
|
Disease
|
type
|
Author (year)
|
High intensity
|
Glucose
Hba1c
Insulin
Triglyceride
HOMA-IR
|
C: 32± 6
E: 31± 5
|
C: 59± 9
E: 61± 9
|
14
|
14
|
28
|
Male/female
|
NAFLD
|
Aerobics
|
Cassidy et al (2013) [13]
|
High intensity
|
Glucose
Insulin
HDL
LDL
Triglyceride
HOMA-IR
|
C: 29.3± 3.7
E: 30.7± 4.3
|
C: 37.7± 6.6
E: 36.0± 6.9
|
15
|
23
|
38
|
Male/female
|
NAFLD
|
Aerobic, cycling
|
Chen et al (2008) [14]
|
Moderate, 60% HRR
|
Glucose
HDL
LDL
Triglyceride
HOMA-IR
|
29.7
|
50
|
31
|
38
|
69
|
Male/female
|
NAFLD
|
Aerobic and treadmill
|
Cuthbertson et al (2016) [15]
|
Moderate
|
Glucose
Insulin
|
34.7 ± 6.4
|
50 ± 11
|
14
|
41
|
55
|
Male/female
|
NAFLD
|
Aerobics
|
Eckard et al (2013) [16]
|
NR
|
Glucose
Insulin
Hba1c
HDL
LDL
Triglyceride
HOMA-IR
|
26.9
|
67.4-76.3
|
50
|
50
|
100
|
Male/female
|
NAFLD
|
Aerobics
|
Finucane et al (2010) [17]
|
High intensity
|
Glucose
Insulin
Hba1c
Triglyceride
HOMA-IR
|
31
|
54
|
12
|
11
|
23
|
Male/female
|
NAFLD
|
Aerobics
|
Hallsworth et al (2015) [18]
|
moderate
|
Glucose
Insulin
Triglyceride
|
C: 35 ± 8
E: 33 ± 6
|
C: 45 ± 14
E: 50 ± 9
|
16
|
13
|
29
|
Male/female
|
NAFLD
|
Aerobics, compound exercises
|
Hickman et al (2013) [19]
|
NR
|
Glucose
Insulin
Hba1c
Triglyceride
HOMA-IR
|
C:33
E:33
|
C:51
E:54
|
12
|
12
|
24
|
Male/female
|
NAFLD
|
Aerobics, cycling
|
Houghton et al (2017) [20]
|
Moderate
|
Glucose
Insulin
HDL
LDL
Triglyceride
|
31-36
|
39-45
|
12
|
48
|
60
|
Male/female
|
NAFLD
|
Aerobic
|
Keating et al (2015) [11]
|
NR
|
Glucose
Insulin
Hba1c
HOMA-IR
|
C:33.7
E:33.9
|
C:47.6
E:47.9
|
34
|
33
|
67
|
Male/female
|
Adults with NASH
|
Aerobic
|
Promrat et al (2010) [21]
|
Moderate, 60% HRR
|
Glucose
HDL
LDL
Triglyceride
|
C: 26-34
E: 29-33
|
C: 38-57
E: 44-56E: 39.7 ± 6.3
|
5
|
6
|
11
|
Male/female
|
Adults with NAFLD
|
Aerobics, 30-45min a day treadmill, 45 min per session
|
Pugh et al (2013) [22]
|
Moderate, 60% HRR
|
Glucose
Insulin
HDL
LDL
|
C: 28-31
E: 30-32
|
C: 43-51
E: 44-51
|
20
|
34
|
54
|
Male/female
|
NAFLD
|
Aerobics, treadmill, Ergometer bike 30 to 45 min per session
|
Pugh et al (2014) [23]
|
NR
|
Glucose
Insulin
Hba1c
HDL
LDL
Triglyceride
|
C:32.2
E:33.6
|
C:12.9
E:12.9
|
27
|
31
|
58
|
Male/female
|
NFALD
|
Aerobics
|
Savoye et al (2014) [24]
|
NR
|
Glucose
Insulin
HDL
LDL
Triglyceride
|
C: 32.9. ± 3.5
E: 32.4 ± 3.9
|
C: 55 ±6
E: 54± 4
|
21
|
22
|
43
|
Male/female
|
NFALD
|
Aerobics
|
Straznicky et al (2012) [25]
|
Low intensity, 45-55% VO2Peak
|
HDL
LDL
|
C: 40.1 ± 2.1
E: 37.1 ± 1.1
|
NR
|
12
|
6
|
18
|
NR
|
Adults with NFALD
|
Aerobics, walking
|
Sulivan et al (2012) [26]
|
NR
|
Glucose
Insulin
HDL
Triglyceride
|
C: 28.4±1
E: 27.3±1.1
|
C: 52±2
E: 61±2
|
18
|
15
|
33
|
NR
|
Adults with NASH
|
Aerobic, cycling, running, walking
|
Yoshimura et al (2014) [27]
|