The average age of the participants was 47.52 ± 8.29 years, 45.30% were men and 41.13% were rural residents. Among the 8,899 participants, 1445 (17.36%) had a CVD. Participants in the highest WWI quartile had significantly higher age compared to those in the lowest quartile (43.90 ± 7.16 vs. 51.10 ± 8.38, Ptrend < 0.001). The prevalence of hypertension and CVD has increased significantly across WWI quartiles (Ptrend < 0.001). The level of vigorous physical activity in the fourth WWI quartile is lower than that in the first quartile (Ptrend < 0.001). The average FBS, LDL-C, HDL-C and TC across WWI quartiles have increased significantly (Ptrend < 0.001) (Table 1).
Table 1
Baseline characteristics of the study participants according to weight-adjusted-waist index quartiles
Variables | Weight-adjusted-waist index | P value trend* |
Q1 (n = 2114) | Q2 (n = 2195) | Q3 (n = 2281) | Q4 (n = 2309) |
Age, (year) | 43.90 ± 7.16 | 46.39 ± 7.76 | 48.34 ± 8.04 | 51.10 ± 8.38 | < 0.001 |
Sex | | | | | |
Men | 1578 (39.15) | 1283 (31.83) | 884 (21.93) | 286 (7.10) | < 0.001 |
Women | 536 (11.01) | 912 (18.73) | 1397 (28.70) | 2023 (41.56) |
Residence | | | | | |
Urban | 1535 (29.30) | 1378 (26.30) | 1222 (23.33) | 1104 (21.07) | 0.001 |
Rural | 579 (15.82) | 817 (22.32) | 1059 (28.93) | 1205 (32.92) |
Socioeconomic status |
Low | 458 (21.67) | 617 (28.12) | 840 (36.83) | 1079 (46.77) | < 0.001 |
Moderate | 683 (32.31) | 714 (32.54) | 779 (34.15) | 778 (33.72) |
High | 973 (46.03) | 863 (39.33) | 662 (29.02) | 450 (19.51) |
Smoking | | | | | |
Never | 764 (36.33) | 906 (41.56) | 963 (42.37) | 1079 (46.91) | < 0.001 |
Current | 360 (17.12) | 290 (13.30) | 221 (9.72) | 95 (4.13) |
Former | 191 (9.08) | 195 (8.94) | 192 (8.45) | 162 (7.04) |
Passive | 788 (37.47) | 789 (36.19) | 897 (39.46) | 964 (41.91) |
Physical activity (MET/h per day) |
Low | 677 (32.02) | 717 (32.67) | 639 (28.01) | 703 (30.45) | < 0.001 |
Moderate | 850 (40.21) | 970 (44.19) | 1184 (51.91) | 1294 (56.04) |
Vigorous | 587 (27.77) | 508 (23.14) | 458 (20.08) | 312 (13.51) |
Hypertension | 243 (11.49) | 321 (14.62) | 364 (15.96) | 488 (21.13) | < 0.001 |
CVD | 207 (9.79) | 307 (13.99) | 413 (18.11) | 618 (26.76) | < 0.001 |
FBS (mg/dL) | 92.39 ± 24.34 | 96.24 ± 29.30 | 98.73 ± 32.16 | 100.60 ± 31.18 | < 0.001 |
TG (mg/dL) | 139.42 ± 87.48 | 135.65 ± 81.74 | 134.66 ± 78.23 | 137.47 ± 78.98 | 0.551 |
LDL-C (mg/dL) | 108.11 ± 30.03 | 109.31 ± 29.08 | 112.33 ± 30.90 | 116.49 ± 33.64 | < 0.001 |
HLD-C (mg/dL) | 43.44 ± 10.58 | 45.14 ± 10.76 | 47.66 ± 11.35 | 49.83 ± 11.62 | 0.001 |
TC (mg/dL) | 179.44 ± 36.12 | 181.57 ± 35.93 | 186.91 ± 36.79 | 193.82 ± 40.51 | < 0.001 |
* P- value was obtained one-way ANOVA and Chi square tests. Abbreviation: HDL-C: High-density lipoprotein cholesterol, LDL-C: Low-density lipoprotein cholesterol, TG: Triglycerides, TC: Total cholesterol, FBS: Fasting blood sugar, CVD: cardiovascular diseases; Q: quartile |
Table 2 presents the status of anthropometric indicators and nutritional intake of the participants based on WWI quartile. The participants in the highest WWI quartile had higher values of BMI, WC, WHR, FMI, VFA and PBF compared to those in the lowest quartile of WWI (Ptrend < 0.001). The average SMM in the first quartile was significantly higher than that in the fourth quartile of WWI (29.61 ± 5.70 vs. 22.32 ± 3.62, Ptrend < 0.001). Additionally, the average TBW was lower in the highest WWI quartile (Q1: 39.34 ± 6.92 vs. Q4: 30.25 ± 4.37, Ptrend < 0.001). The fourth quartile of WWI showed the highest percentage of energy intake from carbohydrates, while the first quartile of WWI showed the highest percentage of energy intake from protein.
Table 2
Anthropometric indices and dietary intake of the study participants according to weight-adjusted-waist index quartiles
Variables | Weight-adjusted-waist index | P value trend* |
Q1 (n = 2114) | Q2 (n = 2195) | Q3 (n = 2281) | Q4 (n = 2309) | |
Anthropometric indices |
BMI (kg/m2) | 26.58 ± 4.36 | 27.07 ± 4.50 | 27.31 ± 4.48 | 28.76 ± 4.90 | < 0.001 |
WHR | 0.93 ± 0.06 | 0.94 ± 0.06 | 0.94 ± 0.06 | 0.95 ± 0.06 | < 0.001 |
WC (cm) | 90.13 ± 9.20 | 95.58 ± 8.83 | 98.56 ± 8.80 | 104.10 ± 10.10 | < 0.001 |
SMM (kg) | 29.61 ± 5.70 | 27.21 ± 5.36 | 25.10 ± 4.54 | 22.32 ± 3.62 | < 0.001 |
FMI | 7.94 ± 3.51 | 8.97 ± 3.77 | 9.85 ± 3.77 | 11.87 ± 3.87 | < 0.001 |
VFA (cm2) | 102.73 ± 45.80 | 114.64 ± 50.22 | 123.81 ± 49.97± | 147.77 ± 48.94 | < 0.001 |
PBF | 28.80 ± 8.58 | 32.01 ± 9.11 | 34.95 ± 8.74 | 40.25 ± 7.48 | < 0.001 |
TBW (liter) | 39.34 ± 6.92 | 36.53 ± 6.50 | 33.58 ± 5.55 | 30.25 ± 4.37 | < 0.001 |
Dietary intake |
Energy (kcal/d) | 2792.39 ± 718.69 | 2622.03 ± 720.97 | 2476.39 ± 719.08 | 2224.99 ± 690.78 | < 0.001 |
Carbohydrate (%E) | 61.10 ± 6.10 | 61.46 ± 6.10 | 61.56 ± 6.21 | 61.70 ± 6.35 | 0.002 |
Fat (%E) | 26.88 ± 5.94 | 26.62 ± 5.98 | 26.79 ± 5.89 | 26.85 ± 6.09 | 0.613 |
Protein (%E) | 14.03 ± 2.26 | 13.83 ± 2.11 | 13.60 ± 2.10 | 13.48 ± 2.09 | < 0.001 |
Bread and cereals (g/d) | 520.49 ± 3.47 | 523.99 ± 3.38 | 508.03 ± 3.27 | 506.45 ± 3.31 | 0.001 |
Fruits (g/d) | 264.70 ± 4.43 | 259.83 ± 4.31 | 269.18 ± 4.18 | 266.51 ± 4.23 | 0.397 |
Vegetables (g/d) | 270.31 ± 3.51 | 268.68 ± 3.55 | 266.84 ± 3.45 | 269.07 ± 3.48 | 0.910 |
Dairy (g/d) | 371.58 ± 8.01 | 427.60 ± 7.78 | 472.84 ± 7.54 | 482.39 ± 7.63 | 0.001 |
Legumes (g/d) | 36.10 ± 0.66 | 32.17 ± 0.64 | 31.98 ± 0.62 | 31.24 ± 0.63 | 0.001 |
Red meat (g/d) | 22.22 ± 0.56 | 20.50 ± 0.57 | 20.30 ± 0.56 | 18.81 ± 0.56 | 0.004 |
White meat (g/d) | 53.31 ± 0.86 | 51.03 ± 0.84 | 48.24 ± 0.80 | 48.11 ± 0.82 | < 0.001 |
*P- value was obtained one-way ANOVA test The mean ± SE of dietary intake is adjusted for daily energy intake Abbreviation: BMI: Body mass index; TBW: Total body water; VFA: Visceral fat area; PBF: Percent body fat; WC: Waist circumference; WHR: Waist hip ratio; SMM: Skeletal muscle mass; FMI: Fat mass index; Q: quartile |
The unadjusted model shows that CVD increases significantly with increasing WWI in men and women (Ptrend < 0.001). After adjusting for age, sex and residence, it was observed that the risk of CVD has increased 1.07 times (OR: 1.07, 95%CI: 0.88, 1.31) in the second quartile, 1.13 times (OR: 1.13, 95%CI: 0.93, 1.38) in the third quartile, and 1.26 times (OR: 1.26, 95%CI: 1.04, 1.54) in the fourth quartile of WWI (Ptrend = 0.025). After adjusting for age, sex, residence, SES, smoking, physical activity, hypertension, energy intake, FBS, LDL, HDL, TG, TC variables, we observed that the odds of developing CVD in the second, third, and fourth quartiles of WWI increased by 1.03, 1.25, and 1.36 times, respectively, compared to the first quartile (Ptrend = 0.010) (Table 3).
Table 3
The association between weight-adjusted-waist index and cardiovascular diseases
Weight-adjusted-waist index quartiles | Model 1 | Model 2 | Model 3 |
OR (95% CI) |
Q1 | Ref (1.00) | Ref (1.00) | Ref (1.00) |
Q2 | 1.50 (1.24, 1.81) | 1.07 (0.88, 1.31) | 1.03 (0.79, 1.33) |
Q3 | 2.03 (1.70, 2.43) | 1.13 (0.93, 1.38) | 1.25 (0.98, 1.61) |
Q4 | 3.37 (2.83, 3.99) | 1.26 (1.04, 1.54) | 1.36 (1.11, 1.78) |
P trend | < 0.001 | 0.025 | 0.010 |
Model 1: Unadjusted; Model 2: Adjusted for age, sex and residence; Model 3: Adjusted for age, sex, residence, SES, smoking, physical activity, hypertension, energy intake, FBS, LDL, HDL, TG, TC |
Table 4 presents subgroup analyses stratified by age, sex, place of residence, SES, smoking, hypertension, physical activity, and obesity to assess the association between WWI and CVD.
Table 4
Subgroup analysis of the association between weight-adjusted-waist index and cardiovascular diseases
Subgroup | OR (95% CI) * | P value |
Age | | |
35–50 years | 1.22 (1.04, 1.45) | 0.022 |
51–65 years | 1.26 (1.10, 1.46) | 0.002 |
Sex | | |
Men | 1.24 (1.02, 1.59) | 0.036 |
Women | 1.14 (1.02, 1.10) | 0.048 |
Residence | | |
Urban | 1.17 (1.03, 1.33) | 0.025 |
Rural | 1.21 (0.98, 1.49) | 0.069 |
Socioeconomic status | | |
Low | 1.10 (0.92, 1.31) | 0.312 |
Moderate | 1.19 (0.98, 1.45) | 0.072 |
High | 1.30 (1.04, 1.63) | 0.020 |
Smoking | | |
Never | 1.13 (0.95, 1.35) | 0.164 |
Current | 0.90 (0.60, 1.34) | 0.614 |
Former | 1.26 (0.89, 1.78) | 0.184 |
Passive | 1.28 (1.10, 1.53) | 0.007 |
Physical activity (MET/h per day) | | |
Low | 1.15 (0.93, 1.40) | 0.180 |
Moderate | 1.23 (1.06, 1.44) | 0.008 |
Vigorous | 1.10 (0.82, 1.45) | 0.530 |
Hypertension | | |
No | 1.18 (1.03, 1.36) | 0.017 |
Yes | 1.14 (0.94, 1.36) | 0.172 |
Body mass index | | |
< 25 kg/m2 | 1.18 (1.02, 1.40) | 0.023 |
≥ 25 kg/m2 | 1.10 (0.92, 1.32) | 0.286 |
*Adjusted for age, sex, residence, SES, smoking, physical activity, hypertension, energy intake, FBS, LDL, HDL,TG, TC |
A positive relationship between WWI and CVD was observed in two age groups, with a stronger association found in the 50 to 65-year-old age group (OR: 1.26, 95% CI: 1.10, 1.46). Moreover, with every unit increase in the WWI, the odds of CVD increased by 24% in men and 14% in women (P < 0.05). In urban and rural, the odds of CVD have increased with the rise in the WWI, although this increase was not statistically significant in the rural.
The findings of the ROC analysis revealed that the WWI exhibited superior predictive capability (AUC: 0.64, 95% CI: 0.61, 0.64) compared to BMI (AUC: 0.60, 95% CI: 0.58, 0.61) and WC (AUC: 0.61, 95% CI: 0.59, 0.62) in predicting CVD within the studied population (Fig. 2).