Table 1.

Cross-sectional studies regarding the relationship between nonalcoholic fatty liver disease (NAFLD) and periodontal disease.

Ref. No.	Study Country Year Sample Size	Parameters Evaluated for the Diagnosis of NAFLD	Parameters Evaluated for the Diagnosis of Periodontitis	Major Findings
[34]	Furuta et al. Japan 2010 n = 2225	Serum ALT level	PD, BOP	An association between periodontitis and serum ALT in male without smoking (OR = 2.3, 95% CI = 1.0–5.2)
[35]	Ahmad et al. Japan 2017 n = 5683	Serum ALT level	PD, CAL	An association among deep periodontal pockets and combination of increased serum ALT and symptoms of metabolic syndrome in male with low alcohol consumption
[36]	Morita et al. Japan 2014 n = 1510	Serum GGT, ALT, AST level	CPI	An association between elevation of alglutamyltranspeptidase and having deep periodontal pockets (OR = 1.48, 95% CI = 1.16–1.90)
[37]	Iwasaki et al. Japan 2018 n = 1226	Ultrasonography	PD, BOP	An association between periodontitis and NAFLD (OR = 1.881, 95% CI = 1.184–2.987)
[38]	Kim et al. Korea 2020 n = 4272	FLI	CPI	An association between periodontal disease and FLI (OR = 1.63; 95% CI = 1.23–2.16)
[39]	Shin et al. Korea 2019 n = 4061	FLI, HSI	CPI	An association between periodontal disease and FLI, HSI in women (OR = 1.77, 95% CI = 1.05–2.98)
[40]	Qiao et al. China 2018 n = 24,470	Ultrasonography	The number of missing teeth	An association between the missing teeth and NAFLD in men (among those who with more than 6 missing teeth, OR = 1.40, 95% CI = 1.09–1.81)
[41]	Weintraub et al. USA 2019 n = 5421	Ultrasonography, Fibrosis Score, FLI, US-FLI	PD, BOP, CAL the number of missing teeth	An association between periodontitis, tooth loss and all of the parameters for NAFLD
[42]	Alazawi et al. USA 2017 n = 8172	Ultrasonography	PD, CAL Serum antibody titers against 19 oral bacteria	Significant associations among steatosis and bleeding on probing, PD ≥ 4 mm (%), mean PD, CAL ≥ 3 mm, and mean CAL (%) After adjusting for sociodemographic factors, only BOP and mean PD showed a significant association with steatosis (BOP: OR = 1.07, 95% CI = 1.00–1.14, mean PD: OR = 1.08, 95% CI = 1.00–1.17)
[43]	Akinkugbe et al. USA 2017 n = 11,914	Ultrasonography, serum ALT level	PD, CAL	Periodontitis was associated with serum ALT and AST levels (≥ 30% of sites with PD ≥ 4 mm: OR = 1.39, 95% CI = 1.02–1.90), however, the significance was not observed after adjustment of age and sex
[46]	Akinkugbe et al. Germany 2017 n = 2481	Ultrasonography	PD, CAL	A significant correlation between periodontitis and NAFLD among subjects with less than 1 mg/L serum CRP levels and/or with lower than the median weighted genetic CRP score Serum CRP modified the interaction between periodontitis and NAFLD

NAFLD: nonalcoholic fatty liver disease, ALT: alanine aminotransferase, FLI: Fatty Liver Index, HSI: Hepatic Steatosis Index, CPI: Community Periodontal Index, PD: pocket depth, CAL: clinical attachment level, BOP: bleeding on probing, CRP: C-reactive protein.