The Fatty Liver Index (FLI) is a non-invasive algorithm that estimates the presence of hepatic steatosis based on body mass index (BMI), waist circumference, triglycerides, and gamma-glutamyl transferase (GGT). In recent years, FLI has been increasingly recognized for its associations with various metabolic disorders. Whether FLI is linked to low back pain (LBP) remains unclear. This study aims to explore the association between FLI and LBP.
Methods
Participants from the NHANES 1999–2004 survey were included. LBP was defined by self-reports. FLI was calculated from metabolic indicators using a standard formula. Logistic regression models assessed the association between FLI and LBP, adjusting for potential confounders, with restricted cubic splines to check for nonlinearity. Subgroup analyses and sensitivity analyses using multiple imputation for missing data were also conducted.
Results
A total of 5339 participants were included. Higher FLI levels were significantly associated with increased odds of LBP. For each 20-unit increase in FLI, the risk of LBP increased by 9% (OR = 1.09, 95% CI: 1.03, 1.14, P = 0.0017). The highest quartile of FLI had a 42% higher risk of LBP compared to the lowest quartile (OR = 1.42, 95% CI: 1.13, 1.79, P = 0.0029). Subgroup analysis showed a stronger association among individuals with lower physical activity levels. Sensitivity analyses confirmed robustness.
Conclusions
Higher FLI values corresponded to an increased risk of LBP, especially in individuals with lower physical activity. Further studies are needed to validate this relationship.
FreburgerJKHolmesGMAgansRP, et al.The rising prevalence of chronic low back pain. Arch Intern Med2009; 169: 251–258. PubMed PMID: 19204216; PubMed Central PMCID: PMCPMC4339077.
2.
HoyDBainCWilliamsG, et al.A systematic review of the global prevalence of low back pain. Arthritis RHeum2012; 64: 2028–2037. PubMed PMID: 22231424.
3.
ZhangCQinLYinF, et al.Global, regional, and national burden and trends of low back pain in middle-aged adults: analysis of GBD 1990–2021 with projections to 2050. BMC Musculoskelet Disord2024; 25: 86.. PubMed PMID: 39511565; PubMed Central PMCID: PMCPMC11542344.
4.
KatzJN. Lumbar disc disorders and low-back pain: socioeconomic factors and consequences. Journal of Bone and Joint Surgery2006; 88: 21–24. PubMed PMID: 16595438.
5.
HongJReedCNovickD, et al.Costs associated with treatment of chronic low back pain. Spine2013; 38: 75–82. PubMed PMID: 23038621.
6.
SchofieldDJShresthaRNPercivalR, et al.The personal and national costs of early retirement because of spinal disorders: impacts on income, taxes, and government support payments. Spine J2012; 12: 1111–1118. PubMed PMID: 23092718.
7.
ChenXZhangAZhaoK, et al.The role of oxidative stress in intervertebral disc degeneration: mechanisms and therapeutic implications. Ageing Res Rev2024; 98: 102323.. PubMed PMID: 38734147.
8.
SongYLuSGengW, et al.Mitochondrial quality control in intervertebral disc degeneration. Exp Mol Med2021; 53: 1124–1133. PubMed PMID: 34272472; PubMed Central PMCID: PMCPMC8333068.
9.
RobertsKEFerreiraMLBeckenkampPR, et al.Global trends in risk factors for low back pain: an analysis of the global burden of disease study data from 1990 to 2021. Arthritis Care Res (Hoboken)2025; 77: 837–847. PubMed PMID: 40051120.
10.
KnezevicNNCandidoKDVlaeyenJWS, et al.Low back pain. Lancet2021; 398: 78–92. PubMed PMID: 34115979.
11.
HuangJWangX. Association of depressive symptoms with risk of incidence low back pain in middle-aged and older Chinese adults. J Affect Disord2024; 354: 627–633. PubMed PMID: 38522815.
12.
MotamedNSohrabiMAjdarkoshH, et al.Fatty liver indexvswaist circumference for predicting non-alcoholic fatty liver disease. World J Gastroenterol2016; 22: 3023–3030. PubMed PMID: 26973398; PubMed Central PMCID: PMCPMC4779925.
13.
KanevaAMBojkoER. Fatty liver index (FLI): more than a marker of hepatic steatosis. J Physiol Biochem2024; 80: 11–26. PubMed PMID: 37875710.
14.
LeutnerMGöblCSchlagerO, et al.The fatty liver Index (FLI) relates to diabetes-specific parameters and an adverse lipid profile in a cohort of nondiabetic, dyslipidemic patients. J Am Coll Nutr2017; 36: 287–294. PubMed PMID: 28506114.
15.
MiaoYWangYYanP, et al.Association between the fatty liver Index (FLI) and incident coronary heart disease: insights from a cohort study on the Chinese population. Front Endocrinol (Lausanne)2024; 15: 1367853.. PubMed PMID: 39758343; PubMed Central PMCID: PMCPMC11695934.
16.
BaiQChenHGaoZ, et al.Advanced prediction of heart failure risk in elderly diabetic and hypertensive patients using nine machine learning models and novel composite indices: Insights from NHANES 2003-2016. Eur J Prev Cardiol2025.PubMed PMID: 40036490.
17.
JeongSOhYHChoiS, et al.Association of non-alcoholic fatty liver disease with incident dementia later in life among elder adults. Clin Mol Hepatol2022; 28: 510–521. PubMed PMID: 35299291; PubMed Central PMCID: PMCPMC9293607.
18.
BedogniGBellentaniSMiglioliL, et al.The fatty liver Index: a simple and accurate predictor of hepatic steatosis in the general population. BMC Gastroenterol2006; 6: 33.. PubMed PMID: 17081293; PubMed Central PMCID: PMCPMC1636651.
19.
ChengLWangSJSR. Lower serum testosterone is associated with increased likelihood of arthritis. Sci Rep2023; 13: 19241.
20.
KlisicAIsakovicAKocicG, et al.Relationship between oxidative stress, inflammation and dyslipidemia with fatty liver Index in patients with type 2 diabetes Mellitus. Exp Clin Endocrinol Diabetes2018; 126: 371–378. PubMed PMID: 28895641.
21.
BellantiFLo BuglioADobrakowskiM, et al.Impact of sodium glucose cotransporter-2 inhibitors on liver steatosis/fibrosis/inflammation and redox balance in non-alcoholic fatty liver disease. World J Gastroenterol2022; 28: 3243–3257. PubMed PMID: 36051336; PubMed Central PMCID: PMCPMC9331534.
22.
KohsariMMoradinazarMRahimiZ, et al.New inflammatory biomarkers (lymphocyte and monocyte percentage to high-density lipoprotein cholesterol ratio and lymphocyte to monocyte percentage ratio) and their association with some cardiometabolic diseases. Wien Klin Wochenschr2022; 134: 626–635. PubMed PMID: 35471616.
23.
HandbergAHøjlundKGastaldelliA, et al.Plasma sCD36 is associated with markers of atherosclerosis, insulin resistance and fatty liver in a nondiabetic healthy population. J Intern Med2012; 271: 294–304. PubMed PMID: 21883535.
24.
KoelmanLReichmannRBörnhorstC, et al.Determinants of elevated chemerin as a novel biomarker of immunometabolism: data from a large population-based cohort. Endocr Connect2021; 10: 1200–1211. PubMed PMID: 34431786; PubMed Central PMCID: PMCPMC8494416.
25.
PuchałowiczKRaćME. The multifunctionality of CD36 in diabetes Mellitus and its complications—update in pathogenesis, treatment and monitoring. Cells2020; 9: 1877. PubMed PMID: 32796572; PubMed Central PMCID: PMCPMC7465275.
26.
KhanANJacobsenHEKhanJ, et al.Inflammatory biomarkers of low back pain and disc degeneration: a review. Ann N Y Acad Sci2017; 1410: 68–84. PubMed PMID: 29265416; PubMed Central PMCID: PMCPMC5744892.
27.
XiangQWuZZhaoY, et al.Cellular and molecular mechanisms underlying obesity in degenerative spine and joint diseases. Bone Res2024; 12: 71. PubMed PMID: 39658574; PubMed Central PMCID: PMCPMC11632072.
28.
ALMAReddyRSAlkhamisBA, et al.A cross-sectional study investigating lumbar proprioception impairments in individuals with type 2 diabetes Mellitus: correlations with glycated hemoglobin levels. Biomedicines2023; 11: 2068. PubMed PMID: 37509707; PubMed Central PMCID: PMCPMC10377327.
29.
JensenTSKarlssonPGylfadottirSS, et al.Painful and non-painful diabetic neuropathy, diagnostic challenges and implications for future management. Brain2021; 144: 1632–1645. PubMed PMID: 33711103; PubMed Central PMCID: PMCPMC8320269.
30.
AhnSHSeoDHKimSH, et al.The relationship between fatty liver index and bone mineral density in Koreans: KNHANES 2010-2011. Osteoporos Int2018; 29: 181–190. PubMed PMID: 29051986.
31.
MorganEFUnnikrisnanGUHusseinAI. Bone mechanical properties in healthy and diseased states. Annu Rev Biomed Eng2018; 20: 119–143. PubMed PMID: 29865872; PubMed Central PMCID: PMCPMC6053074.
32.
KimMJKimMSLeeHB, et al.Relationship between the high fatty liver Index and risk of fracture. Gut Liver2023; 17: 119–129. PubMed PMID: 35892266; PubMed Central PMCID: PMCPMC9840917.
33.
HanAL. Association between metabolic associated fatty liver disease and osteoarthritis using data from the Korean national health and nutrition examination survey (KNHANES). Inflammopharmacol2021; 29: 1111–1118. PubMed PMID: 34269951.
34.
JoIHSongDSChangUI, et al.Change in skeletal muscle mass is associated with hepatic steatosis in nonalcoholic fatty liver disease. Sci Rep2023; 13: 6920. PubMed PMID: 37117864; PubMed Central PMCID: PMCPMC10147659.
35.
LeeTChungTH. Comparative analysis of the relationship between four hepatic steatosis indices and muscle mass. Sci Rep2023; 13: 1645. PubMed PMID: 36717652; PubMed Central PMCID: PMCPMC9886852.
36.
SuoMZhangJSunT, et al.The association between morphological characteristics of paraspinal muscle and spinal disorders. Ann Med2023; 55: 2258922. PubMed PMID: 37722876; PubMed Central PMCID: PMCPMC10512810.
37.
ChengZLiYLiM, et al.Correlation between posterior paraspinal muscle atrophy and lumbar intervertebral disc degeneration in patients with chronic low back pain. Int Orthop2023; 47: 793–801. PubMed PMID: 36352306.
38.
PereraRSChenLFerreiraML, et al.Age- and sex-specific effects of obesity, metabolic syndrome and its components on back pain: the English longitudinal study of ageing. Joint Bone Spine2022; 89: 105366. PubMed PMID: 35227920.
39.
VerbuntJASmeetsRJWittinkHM. Cause or effect? Deconditioning and chronic low back pain. Pain2010; 149: 428–430. PubMed PMID: 20153582.
40.
WasserJGVasilopoulosTZdziarskiLA, et al.Exercise benefits for chronic low back pain in overweight and obese individuals. PM&R2017; 9: 181–192. PubMed PMID: 27346092.
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