Association of Non-Insulin-Based Insulin Resistance Indices with Risk of Incident Prediabetes and Diabetes in a Chinese Rural Population: A 12-Year Prospective Study

Figures & data

Figure 1 Flowchart of participant selection for the study cohort.

Abbreviations: FBG, fasting blood glucose; IFG, impaired fasting glucose; T2DM, type 2 diabetes mellitus.

Table 1 Characteristics of Participants According to Fasting Glycemia Levels at Baseline (n=2209)

Characteristics	Total (n=2209)	T2DM (n=93)	IFG (n=374)	NFG (n=1742)	p-value
TyG index	6.91 [6.58–7.30]	7.85 [7.44–8.36]	7.19 [6.87–7.58]	6.83 [6.52–7.16]	<0.001
TG/HDL-C	0.87 [0.59–1.33]	1.50 [0.99–2.47]	1.00 [0.69–1.60]	0.83 [0.58–1.22]	<0.001
METS-IR	40.18 [35.90–45.59]	49.29 [42.82–55.73]	42.85 [38.28–48.54]	39.35 [35.17–44.13]	<0.001
Age (years)	48.22±11.94	54.41±11.67	50.51±11.14	47.40±11.96	<0.001
Male, n (%)	885 (40.06)	27 (29.03)	141 (37.70)	717 (41.16)	0.040
Current smoker, n (%)	383 (17.34)	9 (9.68)	50 (13.37)	324 (18.60)	0.007
Current drinking, n (%)	228 (10.32)	7 (7.53)	42 (11.23)	179 (10.28)	0.571
Education, n (%)
Illiterate/primary school	918 (41.60)	58 (62.37)	171 (45.72)	689 (39.55)	<0.001
Middle or higher school	1291 (58.40)	35 (37.63)	203 (54.28)	1053 (60.45)
WC (cm)	81±9	88±9	84±10	80±9	<0.001
BMI (kg/m^2)	23.53±3.26	25.76±3.46	24.45±3.30	23.22±3.16	<0.001
WHtR	0.50±0.06	0.56±0.06	0.52±0.06	0.50±0.06	<0.001
WHR	0.87±0.07	0.92±0.07	0.89±0.07	0.87±0.07	<0.001
SBP (mmHg)	126±20	142±22	130±19	124±20	<0.001
DBP (mmHg)	79±12	86±11	81±11	79±12	<0.001
FBG (mmol/L)	5.72±1.07	9.16±3.02	6.35±0.24	5.41±0.36	<0.001
TG (mmol/L)	1.35±0.96	2.31±2.31	1.61±1.13	1.24±0.73	<0.001
TC (mmol/L)	3.94±0.85	4.45±1.07	4.16±0.91	3.86±0.81	<0.001
HDL-C (mmol/L)	1.31±0.33	1.25±0.34	1.31±0.33	1.31±0.33	0.187
LDL-C (mmol/L)	2.02±0.68	2.18±0.83	2.13±0.74	1.99±0.66	<0.001

Notes: Data are expressed as mean±standard deviation or median [interquartile ranges] for continuous variables and as number (%) for categorical variables.

Abbreviations: TyG, triglyceride glucose; METS-IR, metabolic score for insulin resistance; WC, waist circumference; BMI, body mass index; WHtR, waist-to-height ratio; WHR, waist-to-hip ratio; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBG, fasting blood glucose; TG, triglyceride; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol.

Table 2 Association of Three IR Indices with T2DM or IFG at Baseline Using Logistic Regression Analysis (n=2209)

	OR (95% CIs) for T2DM			OR (95% CIs) for IFG
	Model 1	Model 2	Model 3	Model 1	Model 2	Model 3
TyG (tertile)
T1 (<6.69)(n=728)	1.00	1.00	1.00	1.00	1.00	1.00
T2 (6.69–7.14) (n=752)	11.79 (1.53–90.90)	10.73 (1.39–82.93)	9.21 (1.19–71.57)	2.47 (1.76–3.47)	2.38 (1.69–3.36)	2.40 (1.68–3.42)
T3 (>7.14) (n=729)	89.62 (12.44–645.83)	77.50 (10.70–561.38)	46.49 (6.21–347.92)	4.78 (3.46–6.61)	4.53 (3.25–6.31)	4.65 (3.06–7.06)
p for trend	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
TG/HDL-C (tertile)
T1 (<0.67) (n=728)	1.00	1.00	1.00	1.00	1.00	1.00
T2 (0.67–1.11) (n=752)	2.11 (0.95–4.70)	2.10 (0.94–4.70)	1.79 (0.77–4.19)	1.30 (0.96–1.75)	1.32 (0.98–1.79)	1.26 (0.91–1.75)
T3 (>1.11) (n=729)	7.58 (3.75–15.34)	7.21 (3.53–14.71)	3.60 (1.47–8.86)	2.08 (1.57–2.75)	2.05 (1.54–2.73)	1.61 (1.07–2.43)
p for trend	<0.001	<0.001	0.003	<0.001	<0.001	0.025
METS-IR (tertile)
T1 (<37.39) (n=734)	1.00	1.00	1.00	1.00	1.00	1.00
T2 (37.39–43.37) (n=741)	7.46 (2.22–25.02)	7.66 (2.28–25.80)	12.75 (3.29–49.41)	1.99 (1.46–2.73)	2.00 (1.46–2.75)	2.95 (1.96–4.45)
T3 (>43.37) (n=734)	24.88 (7.79–79.44)	23.72 (7.39–76.12)	55.70 (11.58–267.78)	3.09 (2.29–4.17)	3.00 (2.21–406)	6.22 (3.42–11.32)
p for trend	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001

Notes: Test for trend based on variable containing median value for each tertile. Model 1, unadjusted; model 2, adjusted for age, sex, educational status, cigarette smoking, drinking, physical activity, and family history of hypertension and diabetes; model 3, adjusted for all the factors in model 2 and BMI, WC, SBP, TC, TG, and HDL-C.

Abbreviations: IR, insulin resistance; T2DM, type 2 diabetes mellitus; IFG, impaired fasting glucose; OR, odds ratio; CI, confidence interval; TyG, triglyceride glucose; TG/HDL-C, triglyceride/high-density lipoprotein cholesterol; METS-IR, metabolic score for insulin resistance.

Table 3 Cox Proportional Hazards Regression Analysis of Risk of Incident IFG by Tertile of Baseline TyG Index, TG/HDL-C Ratio and METS-IR (n=1205)

	Events (n/Total)	No. of Person-Years	Incidence Rate*	HR (95% CIs)
				Model 1	Model 2	Model 3
TyG (tertile)
T1 (<6.63)	42/399	4333.11	9.69	1.00	1.00	1.00
T2 (6.63–7.03)	56/409	4183.77	13.39	1.44 (0.97–2.15)	1.28 (0.86–1.92)	1.21 (0.79–1.86)
T3 (>7.03)	59/397	3776.37	15.62	1.78 (1.20–2.66)	1.47 (0.98–2.20)	1.06 (0.58–1.96)
p for trend				0.004	0.067	0.784
TG/HDL-C (tertile)
T1 (<0.64)	48/401	4110.61	11.68	1.00	1.00	1.00
T2 (0.64–1.02)	54/401	4110.61	13.14	1.13 (0.76–1.67)	1.09 (0.74–1.61)	1.38 (0.88–2.16)
T3 (>1.02)	55/403	4072.03	13.51	1.17 (0.79–1.72)	1.06 (0.72–1.57)	1.12 (0.59–2.11)
p for trend				0.464	0.837	0.967
METS-IR (tertile)
T1 (<36.46)	61/401	3965.41	15.38	1.00	1.00	1.00
T2 (36.46–42.39)	40/403	4120.43	9.71	0.62 (0.41–0.92)	1.20 (0.83–1.74)	0.58 (0.35–0.96)
T3 (>42.39)	56/401	4207.41	13.31	0.83 (0.58–1.19)	0.69 (0.46–1.03)	0.47 (0.21–1.04)
p for trend				0.391	0.033	0.069

Notes: Test for trend based on variable containing median value for each tertile. *Per 1000 person-years. Model 1, unadjusted; model 2, adjusted for age, sex, educational status, cigarette smoking, drinking, physical activity, family history of hypertension and diabetes; model 3, adjusted for all the factors in model 2 and BMI, WC, FBG, SBP, TC, TG, LDL- C and HDL- C.

Abbreviations: IFG, impaired fasting glucose; TyG, triglyceride glucose; TG/HDL-C, triglyceride/high-density lipoprotein cholesterol; METS-IR, metabolic score for insulin resistance; HR, hazard ratio; CI, confidence interval.

Table 4 Cox Proportional Hazards Regression Analysis of Risk of Incident T2DM by Tertile of Baseline TyG Index, TG/HDL-C Ratio and METS-IR (n=1205)

	Events (n/Total)	No. of Person-Years	Incidence Rate*	HR (95% CIs)
				Model 1	Model 2	Model 3
TyG (tertile)
T1 (<6.63)	19/399	4333.11	4.38	1.00	1.00	1.00
T2 (6.63–7.03)	34/409	4183.77	8.13	1.94 (1.11–3.40)	1.77 (1.01–3.12)	1.86 (1.02–3.39)
T3 (>7.03)	44/397	3776.37	11.65	2.96 (1.72–5.07)	2.65 (1.53–4.59)	2.84 (1.26–6.37)
p for trend				<0.001	<0.001	0.011
T1 (<0.64)	22/401	4110.61	5.35	1.00	1.00	1.00
T2 (0.64–1.02)	33/401	4110.61	8.03	1.50 (0.88–2.57)	1.48 (0.86–2.54)	2.04 (1.10–3.79)
T3 (>1.02)	42/403	4072.03	10.31	1.95 (1.16–3.26)	1.87 (1.11–3.15)	2.59 (1.13–5.93)
p for trend				0.013	0.022	0.052
T1 (<36.46)	25/401	3965.41	6.30	1.00	1.00	1.00
T2 (36.46–42.39)	32/403	4120.43	7.77	1.21 (0.71–2.03)	1.25 (0.74–2.11)	1.18 (0.61–2.28)
T3 (>42.39)	40/401	4207.41	9.51	1.45 (0.88–2.38)	1.43 (0.87–2.37)	0.91 (0.33–2.54)
p for trend				0.144	0.167	0.786

Notes: Test for trend based on variable containing median value for each tertile. *Per 1000 person-years. Model 1, unadjusted; model 2, adjusted for age, sex, educational status, cigarette smoking, drinking, physical activity, family history of hypertension and diabetes; model 3, adjusted for all the factors in model 2 and BMI, WC, FBG, SBP, TC, TG, LDL- C and HDL- C.

Abbreviations: IFG, impaired fasting glucose; TyG, triglyceride glucose; TG/HDL-C, triglyceride/high-density lipoprotein cholesterol; METS-IR, metabolic score for insulin resistance; HR, hazard ratio; CI, confidence interval.

Figure 2 Linear relationship of the TyG index with risk of incident diabetes (p for linear=0.011). The model was adjusted for age, sex, educational status, cigarette smoking, drinking, physical activity, family history of hypertension and diabetes, BMI, WC, FBGSBP, TC, TG, LDL and HDL-C.

Abbreviations: T2DM, type 2 diabetes mellitus; TyG, triglyceride glucose; CI, confidence interval; BMI, body mass index; WC, waist circumference; FBG, fasting blood glucose; SBP, systolic blood pressure; TC, total cholesterol; TG, triglyceride; LDL and HDL-C, low- and high-density lipoprotein cholesterol.