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Table 3 Sensitivity analysis on the decomposition of the total association of general and central obesity and the risk of CVD into direct and indirect associations mediated by the TyG index

From: Insulin resistance mediates obesity-related risk of cardiovascular disease: a prospective cohort study

Exposures

Associationa

Proportion mediated, %

Total effectb

Indirect effect

Direct effect

HR (95% CI)

P value

HR (95% CI)

P value

HR (95% CI)

P value

Sensitivity analysis 1: Excluding participants with baseline FBG ≥ 7 mmol/L

General obesity

       

 Overweight (25 ≤ BMI < 28, kg/m2)

1.18 (1.12–1.26)

 < 0.0001

1.06 (1.05–1.07)

 < 0.0001

1.12 (1.06–1.18)

 < 0.0001

36.35

 Obesity (BMI ≥ 28 kg/m2)

1.49 (1.40–1.59)

 < 0.0001

1.10 (1.08–1.12)

 < 0.0001

1.36 (1.27–1.46)

 < 0.0001

26.96

Central obesity

       

 WC ≥ 90 cm in men or ≥ 85 cm in women

1.35 (1.29–1.43)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.27 (1.21–1.34)

 < 0.0001

23.69

 WHR ≥ 0.90 in men or ≥ 0.80 in women

1.22 (1.16–1.29)

 < 0.0001

1.06 (1.05–1.07)

 < 0.0001

1.16 (1.10–1.22)

 < 0.0001

29.45

 WHTR ≥ 0.60

1.33 (1.23–1.44)

 < 0.0001

1.06 (1.05–1.07)

 < 0.0001

1.26 (1.17–1.36)

 < 0.0001

21.57

Sensitivity analysis 2: Adding a lag time between exposures and mediator

General obesity

       

 Overweight (25 ≤ BMI < 28, kg/m2)

1.22 (1.15–1.30)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.14 (1.07–1.22)

 < 0.0001

36.15

 Obesity (BMI ≥ 28 kg/m2)

1.49 (1.39–1.60)

 < 0.0001

1.13 (1.10–1.15)

 < 0.0001

1.33 (1.23–1.43)

 < 0.0001

34.02

Central obesity

       

 WC ≥ 90 cm in men or ≥ 85 cm in women

1.33 (1.26–1.40)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.24 (1.17–1.31)

 < 0.0001

27.85

 WHR ≥ 0.90 in men or ≥ 0.80 in women

1.23 (1.16–1.30)

 < 0.0001

1.06 (1.05–1.07)

 < 0.0001

1.15 (1.09–1.22)

 < 0.0001

32.32

 WHTR ≥ 0.60

1.30 (1.20–1.41)

 < 0.0001

1.06 (1.05–1.07)

 < 0.0001

1.22 (1.13–1.33)

 < 0.0001

25.39

Sensitivity analysis 3: Adding a lag time between the confounders and set of exposures and mediator

General obesity

       

 Overweight (25 ≤ BMI < 28, kg/m2)

1.16 (1.09–1.23)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.08 (1.02–1.15)

0.0102

46.37

 Obesity (BMI ≥ 28 kg/m2)

1.40 (1.30–1.51)

 < 0.0001

1.13 (1.11–1.16)

 < 0.0001

1.24 (1.14–1.33)

 < 0.0001

41.32

Central obesity

       

 WC ≥ 90 cm in men or ≥ 85 cm in women

1.32 (1.25–1.39)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.23 (1.17–1.30)

 < 0.0001

26.63

 WHR ≥ 0.90 in men or ≥ 0.80 in women

1.13 (1.07–1.19)

 < 0.0001

1.04 (1.03–1.04)

 < 0.0001

1.09 (1.03–1.15)

0.0038

33.04

 WHTR ≥ 0.60

1.42 (1.30–1.55)

 < 0.0001

1.08 (1.07–1.09)

 < 0.0001

1.31 (1.20–1.43)

 < 0.0001

25.13

Sensitivity analysis 4: Adding interaction terms into the models

General obesity

       

 Overweight (25 ≤ BMI < 28, kg/m2)

1.18 (1.12–1.25)

 < 0.0001

1.07 (1.06–1.09)

 < 0.0001

1.10 (1.04–1.17)

 < 0.0001

34.68

 Obesity (BMI ≥ 28 kg/m2)

1.45 (1.16–1.82)

0.0012

1.09 (1.06–1.12)

 < 0.0001

1.33 (1.06–1.68)

0.0142

30.52

Central obesity

       

 WC ≥ 90 cm in men or ≥ 85 cm in women

1.35 (1.14–1.60)

0.0004

1.08 (1.06–1.09)

 < 0.0001

1.25 (1.06–1.48)

0.0080

39.07

 WHR ≥ 0.90 in men or ≥ 0.80 in women

1.25 (1.14–1.36)

 < 0.0001

1.07 (1.06–1.08)

 < 0.0001

1.16 (1.06–1.28)

0.0010

30.00

 WHTR ≥ 0.60

1.31 (1.22–1.40)

 < 0.0001

1.08 (1.05–1.10)

 < 0.0001

1.21 (1.13–1.31)

 < 0.0001

27.43

  1. All models were adjusted for age, sex, education, income, smoking status, drinking status, history of hypertension, diabetes, dyslipidemia, antihypertensive agents, antidiabetic agents, lipide-lowering agents, systolic blood pressure, diastolic blood pressure, total cholesterol, high density lipoprotein cholesterol, and high sensitivity C-reactive protein
  2. BMI body mass index, CI confidence interval, CVD cardiovascular disease, HR hazard ratio, TyG triglyceride-glucose index, WC waist circumference, WHR waist circumference to hip ratio, WHTR waist circumference to height ratio
  3. aCompared with normal weight participants for general obesity and WC < 90 cm in men or < 85 cm in women, WHR < 0.90 in men or < 0.80 in women, and WHTR < 0.60 as a reference for central obesity
  4. bDecomposition of total associations into natural indirect and natural direct associations was done according to the 2-stage regression method proposed by VanderWeele and performed with the SAS macro provided by ValerWeele. Confidence intervals were calculated according to the delta method procedure
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Cardiovascular Diabetology

ISSN: 1475-2840