The participants included 813 cases with documented PCAD and 471 controls with normal CAGs. Table 1 shows the demographic and socioeconomic characteristics, medical history, anthropometric, blood pressure, and biochemical measurements. Participants in the highest quartile of dairy intake in the case group were more likely to be male and in the control group, be ever smokers (P value = 0.010 and P = 0.028, respectively). In addition, Patients with PCAD and higher dairy intake had lower FBG levels (P = 0.049). In the control group, those with a higher intake of dairy had lower BMI (P = 0.025) (Table 1).
Table 1
Baseline characteristics of the study population based on premature coronary artery disease occurrence
Variables | PCAD (n = 813) | P | Control group (n = 471) | P |
Q1 | Q2 | Q3 | Q4 | Q1 | Q2 | Q3 | Q4 |
Gender (male), n (%) | 120(67.8) | 143(68.4) | 161(74.9) | 171(80.7) | 0.010 | 50(35.0) | 35(32.1) | 48(44.4) | 51(45.9) | 0.080 |
Age (years) | 54.71 ± 6.35 | 54.50 ± 6.94 | 54.17 ± 6.70 | 53.32 ± 7.03 | 0.175 | 52.48 ± 7.64 | 51.80 ± 6.96 | 51.38 ± 8.34 | 50.97 ± 8.68 | 0.476 |
Ever smoking, n (%) | 86(48.6) | 91(44.0) | 108(50.2) | 108(50.9) | 0.480 | 31(21.7) | 24(22.0) | 28(25.9) | 41(36.9) | 0.028 |
Education, n (%): | |
Less than high school | 109(61.6) | 147(70.3) | 146(67.9) | 142(67.0) | 0.283 | 113(79.0) | 83(76.1) | 79(73.1) | 71(64.0) | 0.128 |
High school or college | 48(27.1) | 39(18.7) | 51(23.7) | 55(25.9) | 21(14.7) | 22(20.2) | 24(22.2) | 30(27.0) |
University | 20(11.3) | 23(11.0) | 18(8.4) | 15(7.1) | 9(6.3)) | 4(3.7) | 5(4.6) | 10(9.0) |
Alcohol drinking, n (%) | 21(11.9) | 35(16.7) | 34(15.8) | 41(19.3) | 0.254 | 13(9.1) | 4(3.7) | 10(9.3) | 13(11.7) | 0.187 |
Physical activity (MET-min/wk) | 19.05 ± 31.13 | 28.65 ± 48.66 | 22.45 ± 39.94 | 23.19 ± 38.44 | 0.180 | 17.33 ± 33.01 | 20.50 ± 43.38 | 29.35 ± 103.64 | 27.30 ± 37.71 | 0.053 |
Aspirin use, n (%) | 22(12.5) | 16(7.7) | 13(6.0) | 24(11.4) | 0.085 | 59(41.8) | 46(42.6) | 52(49.5) | 52(47.3) | 0.590 |
Antihypertensive agents, n (%) | 45(25.7) | 74(35.9) | 56(26.3) | 52(24.6) | 0.040 | 34(23.8) | 36(33.6) | 30(28.0) | 34(30.9) | 0.353 |
Lipid-lowering agents, n (%) | 53(29.9) | 60(29.1) | 65(30.4) | 59(28.1) | 0.960 | 48(33.8) | 33(30.3) | 35(32.4) | 39(35.5) | 0.868 |
Diabetes agents n (%) | 47(26.7) | 59(28.2) | 46(21.5) | 51(24.1) | 0.402 | 34(23.8) | 22(20.4) | 14(13.0) | 20(18.0) | 0.184 |
SBP (mmHg) | 127.65 ± 19.71 | 126.91 ± 19.20 | 125.84 ± 18.89 | 124.92 ± 18.95 | 0.570 | 123.69 ± 17.09 | 124.06 ± 18.89 | 125.20 ± 16.87 | 124.79 ± 16.37 | 0.904 |
DBP (mmHg) | 80.95 ± 11.11 | 81.42 ± 11.15 | 81.10 ± 12.14 | 80.14 ± 12.14 | 0.521 | 79.36 ± 9.97 | 80.78 ± 10.49 | 80.23 ± 11.17 | 78.82 ± 10.66 | 0.510 |
BMI (kg/m2) | 28.12 ± 4.84 | 28.30 ± 4.40 | 27.90 ± 4.46 | 27.54 ± 4.61 | 0.339 | 28..47 ± 5.05 | 29.89 ± 4.75 | 29.47 ± 5.17 | 28.14 ± 4.64 | 0.024 |
WC (cm) | 101.69 ± 11.47 | 101.97 ± 11.18 | 101.71 ± 11.23 | 100.18 ± 11.31 | 0.357 | 98.59 ± 11.99 | 101.07 ± 10.71 | 101.57 ± 11.14 | 98.82 ± 11.16 | 0.095 |
TC (mg/dL) | 161.15 ± 43.13 | 164.04 ± 40.79 | 158.50 ± 46.72 | 159.15 ± 48.40 | 0.187 | 179.34 ± 51.07 | 179.96 ± 43.38 | 184.89 ± 40.25 | 184.38 ± 43.22 | 0.685 |
TG (mg/ dL) | 158.20 ± 85.98 | 161.31 ± 96.63 | 155.86 ± 72.98 | 149.02 ± 69.37 | 0.732 | 146.84 ± 72.16 | 151.69 ± 65.99 | 148.10 ± 70.39 | 157.99 ± 90.46 | 0.644 |
LDL-C (mg/ dL) | 86.69 ± 32.86 | 87.27 ± 27.06 | 85.24 ± 30.66 | 84.95 ± 29.50 | 0.650 | 99.09 ± 34.81 | 99.34 ± 30.83 | 101.60 ± 27.91 | 103.05 ± 31.11 | 0.736 |
HDL-C (mg/dL) | 41.97 ± 11.02 | 41.68 ± 8.93 | 41.44 ± 9.01 | 41.23 ± 10.65 | 0.703 | 47.18 ± 12.27 | 46.68 ± 12.51 | 47.56 ± 12.56 | 45.68 ± 11.23 | 0.760 |
FBG (mg/dL) | 123.74 ± 51.57 | 121.99 ± 55.20 | 111.09 ± 38.13 | 112.49 ± 46.04 | 0.049 | 105.14 ± 28.84 | 113.12 ± 48.93 | 105.27 ± 40.11 | 105.17 ± 31.88 | 0.405 |
PCAD: Premature coronary artery disease; SD: Standard deviation; P: P value; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; TC: Total cholesterol; TG: Triglyceride; LDL-C: Low density lipoprotein cholesterol; HDL-C: High density lipoprotein cholesterol; FBG: Fasting blood glucose |
Total energy and nutrient intake including carbohydrate, protein, total fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and fiber were statistically higher among those consuming higher dairy in both cases, and control groups (all P-value < 0.05). In addition, higher consumption of dairy had a significant association with higher consumption of foods consisting of vegetables, fruits, legumes, fish in both groups, non-HVO and total nuts and seeds intake in case (all P-value < 0.05) and refined grains and sweets intake in control (all P-value < 0.05) (Table 2). Regarding total dairy intake, the crude model revealed an increase in the risk of PCAD by 59%, 60% and 56% for those in the 2nd, 3rd and 4th quartiles compared with subjects in the 1st quartile [(OR:1.59; 95%CI: 1.15, 2.19), (OR:1.60; 95%CI: 1.16, 2.20) and (OR:1.56; 95%CI: 1.13, 2.14), respectively; P for trend = 0.008]. There was a significant association between intake of total dairy in the 2nd and 3rd quartile and higher risk of PCAD compared with the 1st quartile in models 1 and 2. However, the risk of PCAD was not significant with an increase in total dairy intake in the 4th quartile (P for trend = 0.122 and 0.124, respectively). This relationship was significant in all levels of increasing total dairy intake in models 3 and 4 (P < 0.001). Compared to the lowest quartile, the ORs (95%CIs) were 2.23 (1.47,3.37) and 2.44 (1.50,3.97) (both P for trend < 0.001) in the highest quartile of total dairy intake in model 3 and 4, respectively (Table 3). In model 3, any increase in the intake of high-fat dairy over was associated with increased risk of PCAD [(OR:1.59; 95%CI: 1.10, 2.30), (OR:1.90; 95%CI: 1.30, 2.78) and (OR:1.58; 95%CI: 1.07, 2.33), respectively; P for trend = 0.011]. After full adjustment, those in the 3rd and 4th quartiles of high-fat dairy intake had an increase in the risk of PCAD [1.87 (1.20,2.93) and 1.68 (1.05,2.69); P = 0.011, respectively]. Low-fat consumption in the top quartile had a relationship with increasing PCAD risk in models 3 and 4 [1.78 (1.17,2.71); P = 0.015 and 1.99 (1.20,3.27); P = 0.005, respectively] (Table 3).
Table 2
Dietary intake based on premature coronary artery disease occurrence
Dietary intake | PCAD (n = 813) | P | Control group (n = 471) | P |
Q1 | Q2 | Q3 | Q4 | Q1 | Q2 | Q3 | Q4 |
Energy (Kcal/ day) | 1586.58 ± 511.9 9 | 1769.48 ± 690.6 1 | 1870.62 ± 564.1 7 | 2225.97 ± 761.9 4 | < 0.001 | 1684.34 ± 652.6 7 | 1885.39 ± 704.6 8 | 2021.29 ± 638.0 1 | 2408.09 ± 732.9 3 | < 0.001 |
Carbohydrate (% of energy) | 223.22 ± 89.68 | 242.07 ± 101.64 | 247.43 ± 91.74 | 279.22 ± 107.51 | < 0.001 | 206.80 ± 96.77 | 240.20 ± 102.70 | 252.48 ± 99.17 | 290.98 ± 111.47 | < 0.001 |
Protein (% of energy) | 61.40 ± 22.27 | 69.13 ± 27.38 | 76.68 ± 23.13 | 96.28 ± 34.68 | < 0.001 | 65.38 ± 26.80 | 75.15 ± 27.84 | 84.67 ± 28.01 | 105.89 ± 29.21 | < 0.001 |
Total fat (% of energy) | 56.75 ± 20.33 | 65.27 ± 29.04 | 71.48 ± 24.75 | 88.69 ± 37.81 | < 0.001 | 74.11 ± 31.64 | 79.05 ± 32.83 | 83.95 ± 29.74 | 100.73 ± 35.80 | < 0.001 |
SFA (% of energy) | 20.24 ± 8.49 | 24.22 ± 12.36 | 26.65 ± 10.85 | 33.94 ± 16.84 | < 0.001 | 23.11 ± 11.01 | 25.59 ± 11.54 | 29.33 ± 11.13 | 35.96 ± 15.53 | < 0.001 |
MUFA (% of energy) | 16.76 ± 6.74 | 18.84 ± 8.15 | 20.60 ± 8.07 | 25.37 ± 10.53 | < 0.001 | 21.24 ± 10.25 | 22.45 ± 9.96 | 24.01 ± 9.36 | 29.24 ± 11.75 | < 0.001 |
PUFA (% of energy) | 15.54 ± 7.53 | 17.57 ± 9.60 | 19.31 ± 8.60 | 22.22 ± 11.63 | < 0.001 | 23.99 ± 10.70 | 25.04 ± 11.74 | 24.88 ± 10.51 | 28.45 ± 12.19 | 0.032 |
Fiber (gr/ day) | 18.65 ± 7.13 | 19.98 ± 8.29 | 19.77 ± 7.96 | 21.70 ± 8.27 | 0.002 | 19.60 ± 8.60 | 21.33 ± 8.84 | 21.01 ± 8.05 | 24.45 ± 9.46 | < 0.001 |
Foods: |
Vegetables | 217.84 ± 88.06 | 235.01 ± 101.62 | 264.28 ± 106.80 | 299.01 ± 128.52 | < 0.001 | 317.34 ± 100.16 | 341.33 ± 146.04 | 321.18 ± 92.57 | 384.58 ± 162.20 | 0.009 |
Fruit | 176.99 ± 75.26 | 186.87 ± 95.52 | 209.28 ± 74.95 | 245.22 ± 109.87 | < 0.001 | 251.46 ± 102.39 | 268.45 ± 134.65 | 273.14 ± 78.71 | 301.94 ± 90.26 | 0.001 |
Legumes | 36.59 ± 26.34 | 37.72 ± 27.49 | 48.50 ± 31.81 | 61.91 ± 42.26 | < 0.001 | 65.88 ± 30.83 | 70.58 ± 31.57 | 81.63 ± 47.77 | 82.35 ± 41.67 | 0.003 |
Fish | 8.43 ± 12.00 | 10.53 ± 15.60 | 16.70 ± 18.14 | 23.82 ± 76.54 | < 0.001 | 14.43 ± 17.24 | 18.34 ± 23.64 | 21.33 ± 33.10 | 23.16 ± 22.99 | 0.014 |
Whole grains | 103.98 ± 113.14 | 114.67 ± 142.11 | 103.98 ± 112.05 | 112.12 ± 118.10 | 0.933 | 128.44 ± 153.42 | 132.58 ± 129.66 | 133.58 ± 155.99 | 138.84 ± 174.49 | 0.781 |
Refined grain | 194.76 ± 128.09 | 205.05 ± 135.58 | 219.57 ± 142.29 | 221.33 ± 153.14 | 0.251 | 189.09 ± 129.20 | 212.95 ± 131.34 | 222.76 ± 154.84 | 241.95 ± 160.77 | 0.042 |
Non-HVO | 13.65 ± 9.21 | 13.73 ± 8.90 | 16.52 ± 10.29 | 19.05 ± 13.09 | < 0.001 | 22.69 ± 15.97 | 23.64 ± 13.73 | 22.06 ± 10.95 | 24.65 ± 12.18 | 0.152 |
HVO | 3.43 ± 6.39 | 3.50 ± 6.13 | 3.57 ± 6.70 | 3.47 ± 6.49 | 0.842 | 1.88 ± 2.66 | 2.25 ± 4.31 | 2.12 ± 3.63 | 2.05 ± 3.54 | 0.985 |
Red meat | 25.59 ± 22.70 | 30.78 ± 43.68 | 31.20 ± 26.50 | 39.44 ± 56.01 | 0.016 | 25.13 ± 26.47 | 24.78 ± 22.94 | 32.43 ± 26.32 | 36.23 ± 36.73 | 0.005 |
Sweets | 17.68 ± 22.03 | 19.26 ± 23.60 | 19.23 ± 26.48 | 25.32 ± 37.90 | 0.462 | 13.07 ± 27.50 | 16.44 ± 23.59 | 20.99 ± 33.20 | 17.86 ± 24.12 | 0.006 |
SSB | 33.70 ± 80.44 | 47.12 ± 103.47 | 40.56 ± 65.65 | 42.24 ± 99.28 | 0.191 | 19.81 ± 40.52 | 27.36 ± 107.17 | 24.68 ± 37.52 | 36.14 ± 104.22 | 0.680 |
Total nuts and seeds | 12.64 ± 15.59 | 13.62 ± 13.58 | 15.17 ± 17.48 | 18.02 ± 24.90 | 0.021 | 28.17 ± 29.56 | 25.54 ± 31.82 | 25.56 ± 26.35 | 32.20 ± 34.82 | 0.622 |
Low fat dairy | 72.34 ± 37.85 | 168.13 ± 59.34 | 280.68 ± 84.97 | 460.60 ± 176.50 | < 0.001 | 66.02 ± 35.50 | 167.31 ± 47.72 | 269.87 ± 89.54 | 532.18 ± 205.73 | < 0.001 |
High fat dairy | 13.33 ± 18.96 | 35.87 ± 52.30 | 55.54 ± 80.36 | 147.85 ± 163.69 | < 0.001 | 14.11 ± 20.44 | 29.04 ± 40.33 | 64.49 ± 80.82 | 116.64 ± 152.01 | < 0.001 |
PCAD: Premature coronary artery disease; SD: Standard deviation; P: P value; SFA: Saturated fatty acids; MUFA: Monounsaturated fatty acid; PUFA: Polyunsaturated fatty acid; HVO: Hydrogenated vegetable oil; SSB: Sugar sweetened beverage |
Table 3
Odds ratios and 95% confidence interval of premature coronary disease occurrences based on quartiles of dairy intake
| Q1 | Q2 | Q3 | Q4 | P for trend |
| Total dairy |
Median | 86.42 | 202.86 | 327.14 | 567.48 | |
Crude model | 1 | 1.59 (1.15,2.19) | 1.60 (1.16,2.20) | 1.56 (1.13,2.14) | 0.008 |
Model 1 | 1 | 1.66 (1.16,2.37) | 1.44 (1.01,2.05) | 1.39 (0.97,1.98) | 0.122 |
Model 2 | 1 | 1.66 (1.16,2.38) | 1.46 (1.02,2.07) | 1.38 (0.97,1.98) | 0.124 |
Model 3 | 1 | 1.85 (1.27,2.70) | 1.74 (1.19,2.54) | 2.23 (1.47,3.37) | < 0.001 |
Model 4 | 1 | 1.73 (1.12,2.67) | 2.00 (1.27,3.14) | 2.44 (1.50,3.97) | < 0.001 |
| High-fat dairy | |
Median | 0.00 | 8.00 | 28.47 | 187.80 | |
Crude model | 1 | 1.26 (0.92,1.73) | 1.74 (1.26,2.41) | 1.22 (0.89,1.68) | 0.067 |
Model 1 | 1 | 1.49 (1.04,2.12) | 1.67 (1.17,2.40) | 1.19 (0.83,1.68) | 0.247 |
Model 2 | 1 | 1.50 (1.05,2.14) | 1.69 (1.18,2.42) | 1.20 (0.84,1.70) | 0.234 |
Model 3 | 1 | 1.59 (1.10,2.30) | 1.90 (1.30,2.78) | 1.58 (1.07,2.33) | 0.011 |
Model 4 | 1 | 1.38 (0.89,2.11) | 1.87 (1.20,2.93) | 1.68 (1.05,2.69) | 0.011 |
| Low-fat dairy | |
Median | 58.95 | 155.71 | 272.14 | 470.00 | |
Crude model | 1 | 1.10 (0.80,1.50) | 0.89 (0.64,1.25) | 1.35 (0.97,1.89) | 0.176 |
Model 1 | 1 | 1.00 (0.70,1.41) | 0.79 (0.55,1.15) | 1.06 (0.73,1.54) | 0.957 |
Model 2 | 1 | 0.99 (0.70,1.41) | 0.79 (0.55,1.16) | 1.04 (0.71,1.52) | 0.889 |
Model 3 | 1 | 1.07 (0.74,1.54) | 0.98 (0.66,1.46) | 1.78 (1.17,2.71) | 0.015 |
Model 4 | 1 | 0.96 (0.62,1.48) | 1.11 (0.69,1.79) | 1.99 (1.20,3.27) | 0.005 |
P: P value |
Model 1: Adjusted for age and sex |
Model 2: Additionally adjusted for education (less than high school/ high school or college/ university), smoking (never/ ex-smoker/ current smoker), physical activity (METS/ minute per week) |
Model 3: Additionally adjusted for energy (Kcal/ day), carbohydrate (%of energy), total fat (% of energy) |
Model 4: Additionally adjusted for body mass index (Kg/ m2), hypertension (yes/ no), diabetes mellitus (yes/ no), hypercholesterolemia (yes/ no), aspirin use (yes/ no) |
Figure 1–3 demonstrates the association of total, high-fat and low-fat dairy intake with the severity of PCAD. For total dairy intake, individuals in the 2nd quartile had significantly higher ORs of severe PCAD in crude and all adjusted models. After a full adjustment model, the total dairy intake in the 2nd quartile had a relationship with 43% higher severity of PCAD (OR: 1.43; 95%CI: 1.02,2.02), but not in the further amount of intake. In addition, the highest intake of high-fat dairy was associated with PCAD severity in adjustment model 3 (OR:1.76; 95%CI: 1.27,2.44) and 4 (OR:1.84; 95%CI: 1.27,2.68). Furthermore, the highest intake of low-fat intake was associated with lower PCAD severity in crude (OR:0.74; 95%CI: 0.56,0.98), 1 (OR:0.66; 95%CI: 0.50,0.89) and 2 (OR:0.66; 95%CI: 0.49,0.89) models. However, intake of low-fat dairy to any extent had no significant relationship with PCAD severity in model 3 and after full adjustment.