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Table 2 Baseline characteristics of participants across tertiles of dietary and circulating linoleic acid

From: Associations of linoleic acid with markers of glucose metabolism and liver function in South African adults

 

Dietary linoleic acid (en%)

 

Circulating linoleic acid (% total FA)

 

T1

(n = 211)

T2

(n = 211)

T3

(n = 211)

P-trenda

T1

(n = 211)

T2

(n = 211)

T3

(n = 211)

P-trenda

Median (range)

3.9 (0.4–5.3)

6.7 (5.4–8.0)

9.6 (8.0–18.4)

 

12.5 (6.0–14.4)

16.0 (14.4–17.7)

19.5 (17.7–25.7)

 

Age (y)

52.4 ± 9.0

52.8 ± 11.3

53.8 ± 10.6

0.18

53.8 ± 9.4

54.2 ± 11.2

50.9 ± 10.1

0.004

Men

91 (43.1)

80 (37.9)

69 (32.7)

0.09

76 (36.0)

82 (38.9)

82 (38.9)

0.78

Body mass index (kg/m2)

23.8 ± 6.5

25.0 ± 7.5

25.9 ± 6.7

0.002

24.4 ± 7.1

25.2 ± 7.4

25.0 ± 6.3

0.36

 Obesity

40 (19.0)

47 (22.3)

56 (26.5)

0.17

40 (19.0)

52 (24.6)

51 (24.2)

0.30

Waist circumference (cm)

79.6 ± 12.3

80.2 ± 14.3

81.3 ± 12.1

0.20

80.8 ± 13.4

80.6 ± 13.5

79.6 ± 11.9

0.36

Locality (urban)

71 (33.6)

123 (58.3)

131 (62.1)

< 0.001

107 (50.7)

113 (53.6)

105 (50.0)

0.72

Education levelb

   

0.12

   

< 0.001

 No school or primary

94 (45.6)

76 (36.4)

77 (37.9)

 

108 (51.9)

78 (38.2)

61 (29.6)

 

 Secondary or higher

112 (54.4)

133 (63.6)

126 (62.1)

 

100 (48.1)

126 (61.8)

145 (70.4)

 

Smoking statusb

   

0.008

   

0.010

 Non-smoker

84 (40.0)

87 (41.2)

113 (53.6)

 

81 (38.4)

92 (43.6)

111 (52.9)

 

 Past or current smoker

126 (60.0)

124 (58.8)

98 (46.4)

 

130 (61.6)

119 (56.4)

99 (47.1)

 

Physical activityb

   

< 0.001

   

0.006

 Low

1 (0.5)

3 (1.5)

1 (0.5)

 

1 (0.5)

2 (1.0)

2 (1.0)

 

 Moderate

66 (32.4)

100 (49.0)

99 (48.8)

 

107 (52.4)

87 (42.4)

71 (35.2)

 

 High

137 (67.2)

101 (49.5)

103 (50.7)

 

96 (47.1)

116 (56.6)

129 (63.9)

 

Serum lipids (mmol/L)

        

 Total cholesterol

5.10 ± 1.33

5.18 ± 1.31

5.28 ± 1.30

0.16

5.13 ± 1.31

5.34 ± 1.37

5.10 ± 1.25

0.81

 LDL-C

2.92 ± 1.16

3.01 ± 1.14

3.15 ± 1.08

0.047

2.87 ± 1.08

3.15 ± 1.18

3.06 ± 1.11

0.09

 HDL-C

1.60 ± 0.71

1.61 ± 0.60

1.55 ± 0.59

0.42

1.65 ± 0.72

1.60 ± 0.61

1.49 ± 0.56

0.012

 Triglycerides

1.06 (0.85–1.62)

1.07 (0.82–1.69)

1.20 (0.86–1.78)

0.09

1.17 (0.86–1.85)

1.15 (0.85–1.65)

1.04 (0.80–1.53)

< 0.001

High sensitivity C-reactive protein (mg/L)

3.9 (1.3–10.0)

3.2 (1.0–9.5)

3.8 (1.2–11.4)

0.67

4.1 (1.4–14.0)

3.6 (1.5–9.2)

3.5 (0.9–8.8)

0.014

Interleukin-6 (pg/mL)

3.04 (1.58–7.29)

3.00 (0.75–4.91)

2.94 (0.75–5.54)

0.13

4.50 (1.98–8.83)

2.86 (0.76–5.12)

2.09 (0.75–4.16)

0.002

HIV-positive

2 (1.0)

0 (0)

3 (1.4)

0.38

2 (1.0)

0 (0)

3 (1.4)

0.30

Dietary variablesc

 Total energy intake (kJ/d)

7413 ± 3265

7338 ± 2979

7319 ± 2846

0.75

7699 ± 3263

7282 ± 2920

7088 ± 2875

0.038

 Carbohydrate

62.7 ± 10.7

59.3 ± 7.4

54.3 ± 7.2

< 0.001

57.8 ± 9.5

59.4 ± 9.2

59.1 ± 9.0

0.15

 Protein

11.4 ± 2.3

12.8 ± 2.1

13.1 ± 2.1

< 0.001

12.0 ± 2.4

12.7 ± 2.2

12.7 ± 2.3

0.001

 Total fat

16.4 ± 6.1

24.6 ± 5.3

31.7 ± 6.9

< 0.001

22.6 ± 9.0

24.0 ± 8.6

26.0 ± 8.3

< 0.001

 Saturated FA

3.9 ± 2.4

6.2 ± 2.5

7.6 ± 2.9

< 0.001

5.4 ± 2.8

5.9 ± 3.0

6.5 ± 3.1

< 0.001

 Monounsaturated FA

3.8 ± 2.0

6.6 ± 2.4

8.9 ± 3.1

< 0.001

5.8 ± 3.1

6.5 ± 3.4

7.0 ± 3.3

< 0.001

 Polyunsaturated FA

4.3 ± 2.6

7.2 ± 1.1

10.6 ± 2.1

< 0.001

7.1 ± 3.7

7.1 ± 3.0

7.9 ± 3.0

0.013

 n-3 fatty acids (mg/d)

221.1 (145.5–362.4)

325.3 (209.8–497.2)

391.5 (253.5–543.7)

< 0.001

296.0 (182.2–452.5)

319.6 (207.5–487.2)

319.9 (192.6–476.2)

0.37

 Trans-FA (g/d)

0.09 (0.03–0.25)

0.20 (0.08–0.48)

0.33 (0.12–0.68)

< 0.001

0.18 (0.07–0.43)

0.17 (0.06–0.48)

0.19 (0.07–0.53)

0.71

 Total fiber (g/d)

20.4 ± 9.0

21.1 ± 9.3

19.9 ± 9.1

0.55

20.3 ± 9.0

20.4 ± 8.6

20.6 ± 9.9

0.75

 Dietary cholesterol (mg/d)

90 (48–159)

159 (99–268)

204 (129–307)

< 0.001

151 (78–248)

148 (90–246)

143 (81–254)

0.56

 Alcohol use: yesd

118 (55.9)

84 (39.8)

69 (32.7)

< 0.001

117 (55.4)

88 (41.7)

66 (31.3)

< 0.001

 (g/d)

4.6 (0–36.2)

0 (0–11.6)

0 (0–4.3)

< 0.001

2.9 (0–27.0)

0 (0–8.6)

0 (0–5.8)

< 0.001

Fatty acid composition

 Arachidonic acid (20:4n-6), %

13.5 ± 2.7

13.4 ± 2.5

13.7 ± 2.3

0.43

12.9 ± 2.9

14.1 ± 2.4

13.6 ± 2.0

0.011

 Estimated D6D activity (20:3n-6/18:2n-6)

0.200 ± 0.061

0.192 ± 0.055

0.187 ± 0.058

0.016

0.234 ± 0.053

0.196 ± 0.047

0.150 ± 0.040

< 0.001

  1. Values are mean ± SD, median (Q1-Q3), or n (%) unless otherwise stated;
  2. D6D Delta-6-desaturase, FA Fatty acids, HIV Human immunodeficiency virus
  3. aP-values for trend for continuous variables were obtained by assigning median value of dietary or circulating linoleic acid and this value was modelled as continuous; for categorical variables p-values from (exact) Chi-squared tests were displayed;
  4. b Missing values for 15 participants for education level, 1 participant for smoking status, 22 participants for physical activity level, 1 participant for HIV status, 1 participant for dietary n-3 fatty acids and 62 participants for interleukin-6;
  5. c Dietary variables are expressed as percentage of energy unless otherwise stated;
  6. d Alcohol use: ‘No’: alcohol intake = 0 g/d, ‘Yes’ alcohol intake > 0 g/d;