Table 1.

Studies on population characteristics and blood concentrations of individual FFA species in cardiovascular subjects and controls of patients with T2DM.

	Country	Year	Number of subjects (Control vs Case)	Match or not+	Affected blood vessels	Case group definition	Research Conclusion	Sample type
The total level of FFA	(15) India	1995	164:213	Unmatched	Coronary	-	Higher FFA levels seem to be a predictor of CHD in diabetes patients, exceeding the effect of abnormal lipoproteins.	Plasma
	(55) Sweden	2000	140:343	Unmatched	Coronary, cerebrovascular	-	High NEFA concentrations in healthy offspring with a family history of diabetes were significantly associated with their parents’ myocardial infarction and stroke.	Serum
	(16) Japan	2002	23:51	Age-matched	Coronary	Medial thickness of intima without plaque segment [IMT]	Serum NEFA levels independently predict the extent of plaque segmental stenosis in diabetes patients, but not in diabetes subjects.	Serum
	(56) Canada	2002	99:103	Age, body mass index, smoking habits and alcohol intake-matched	Coronary	Diagnostic electrocardiogram (ECG) changes or meets the following two criteria: Typical chest pain lasts for at least 20 minutes, Abnormal creatine kinase levels should be at least twice the upper limit of normal Typical chest pain lasts for at least 20 minutes, with abnormal creatine kinase levels at least twice the upper limit of normal.	Elevated plasma FFA concentration is associated with increased risk of ischemic heart disease.	Plasma
	(17) Spain	2010	20:20	Unmatched	Carotid artery	-	The presence of NEFA in the new intima of diabetes plaque increased. The level of NEFA in atherosclerotic plaque of diabetes was higher than that of non-diabetes subjects. NEFA may occur locally and lead to local inflammation.	serum and plaque
	(57) China	2011	51:34	Unmatched	Coronary	coronary angiography	The levels of FFA and hs CRP in serum are closely related to type 2 diabetes and diabetes with coronary atherosclerotic heart disease.	Serum
	(58) China	2014	103:59	Unmatched	Coronary	CTnT ≥ 0.01 ng/L+other evidence	There is a positive correlation between serum FFA levels and HDL levels in T2DM and the control group.	Serum
	(59) China	2016	45:50	Unmatched	Coronary	Coronary CT scan	T2DM combined with CHD coronary plaques are mainly soft plaques and mixed plaques, with extensive coronary artery lesions. Carotid ultrasound shows that the more peripheral vascular plaques and the more branches of coronary artery lesions, the more severe the lesions. Combining CCTA, carotid ultrasound, hsC-RP, and FFA levels in clinical practice can improve the diagnosis rate of T2DM complicated with CHD.	Serum
	(60) China	2017	79:84	Unmatched	Coronary	coronary angiography	FFA, Hcy, CRP, FPG are positively correlated with coronary heart disease in elderly patients with type 2 diabetes.	Serum
	(18) America	2018	40	-	-		The increase in plasma FFA within the physiological range observed in obesity and T2DM induces endothelial activation, vascular inflammation, and thrombosis markers in healthy subjects.	Plasma
	(20) China	2019	1039:1606	Unmatched	Coronary	coronary angiography	Baseline FFA levels are associated with prognosis in patients with DM and pre DM CAD.	Serum
	(19) China	2020	70:232	Unmatched	Coronary, carotid artery	coronary angiography, Carotid ultrasound	Elevated FFA levels seem to be associated with the presence and severity of CAD and CAP in T2DM patients.	Plasma
	(61) China	2021	84:80	Unmatched	Coronary	coronary angiography	The serum FFA level is independently correlated with severe coronary artery calcification and may have a certain predictive ability for severe coronary artery calcification. The DM group has the strongest correlation.	Serum
FFA profile	(62) China	2011	55:55	Age and sex-matched	Carotid artery, femoral artery, internal iliac artery	Carotid artery intima-media thickness, femoral artery intima-media thickness, iliac artery intima-media thickness Using high-resolution color ultrasound measurement, Patients with IMT>1.0mm in any part and/or plaques in the field of view without clinical manifestations Defined as subclinical atherosclerosis (subclinical atherosclerosis)	Saturated fatty acids (C16:0, C18:0), monounsaturated fatty acids (C18:1) Total fatty acid (TFA) is associated with subclinical atherosclerosis in type 2 diabetes and is the most common Significant influencing factors.	Plasma
	(63) China	2016	36:137	Unmatched	Coronary, cerebrovascular, peripheral vascular	Clinical diagnosis includes coronary heart disease, cerebrovascular disease, peripheral vascular disease, and hypertension	Comparison of fatty acid composition between large vessel disease groups: TFA, MUFA, SFA, and C16:0, C18:0, C18:1 significantly increased with the severity of vascular disease.	Serum
	(64) Japan	2017	533:144	Unmatched	Coronary	Pathological Q waves are observed on the electrocardiogram, and there are areas of viable myocardial loss detected on imaging	PMI patients with DM have lower levels of EPA/AA and DHA/AA. The use of statins may affect DHA/AA, but not EPA/AA, so the EPA/AA ratio is a better biomarker for evaluating cardiovascular events.	Serum
	(65) China	2021	35:68	Unmatched	Carotid artery	Carotid artery ultrasound shows that the intima-media thickness (IMT) f 1.2mm/IMT ≥ 1.5mm and/or the formation of atherosclerotic plaques are consistent	1. The composition of blood free fatty acid profiles in patients with T2DM combined with AS and those with T2DM alone In terms of differences, the levels of C16:0 and C18:0 were significantly higher in patients with T2DM alone. 2. C16:0 is the main influencing factor of atherosclerosis in type 2 diabetes patients, Significantly increase the risk of atherosclerosis.	Serum
	(66) China	2022	134:126	Unmatched	Coronary	Acute myocardial infarction (MI), asymptomatic myocardial infarction, or previous coronary artery surgery	Multivariate logistic regression analysis showed that after adjusting for confounding factors and other risk factors, dozens of FFAs were independent risk factors for CHD.	Plasma

⁺ Match refers to the consistency of certain characteristics between the case group and the control group.