Increased daily sodium intake is an independent dietary indicator of the metabolic syndrome in middle-aged subjects

Figures & data

Table I. Average daily intakes of energy and nutrients in subjects with and without the metabolic syndrome (by IDF-criteria).

	MS− (n = 465)	MS+ (n = 251)	P
Energy
kcal	1865.4 (507.0)	1879.7 (529.7)	NS
MJ	7.8 (2.1)	7.9 (2.2)	NS
Protein
g	76.7 (21.0)	78.9 (21.6)	NS
E-%	16.6 (2.4)	17.0 (2.6)	0.044
Total fat
g	75.5 (25.0)	77.3 (26.8)	NS
E-%	36.2 (5.3)	36.7 (5.6)	NS
SAFA
g	31.0 (11.3)	31.7 (11.6)	NS
E-%	14.9 (3.0)	15.1 (3.1)	NS
MUFA
g	25.5 (9.1)	26.4 (9.6)	NS
E-%	12.2 (2.2)	12.5 (2.3)	0.050
PUFA
g	12.3 (5.1)	12.5 (5.5)	NS
E-%	5.9 (1.6)	5.9 (1.6)	NS
Carbohydrate
g	201.7 (61.1)	191.1 (55.7)	0.023
E-%	43.4 (6.2)	41.1 (6.7)	<0.001
Alcohol
g	6.8 (11.3)	11.2 (18.6)	<0.001
E-%	2.5 (3.9)	3.8 (5.6)	<0.001
Dietary fibre (g) Sodium	20.3 (6.6)	19.2 (6.8)	0.031
mg	3429.6 (1108.7)	3644.3 (1179.4)	0.016
mg(1000 kcal)^−1	1847.8 (387.1)	1956.5 (394.6)	<0.001
Potassium
mg	3563.5 (926.7)	3591.3 (944.5)	NS
mg(1000 kcal)^−1	1947.9 (366.8)	1959.0 (367.8)	NS
Calcium
mg	1028.8 (363.0)	1016.9 (406.2)	NS
mg(1000 kcal)^−1	558.2 (149.7)	546.0 (165.3)	NS
Magnesium
mg	351.1 (92.4)	351.6 (94.9)	NS
mg(1000 kcal)^−1	191.0 (30.9)	190.7 (32.8)	NS

The values are means (SD).

E-% = percentage of total energy intake; SAFA = saturated fatty acids; MUFA = monounsaturated fatty acids; PUFA = polyunsaturated fatty acids.

Table II. Sodium intake (mg(1000 kcal)⁻¹) as means (SD) in subjects positive to individual components of the MS according to IDF criteria and in subjects not having the component of the MS in the whole cohort.

	Sodium intake (mg(1000 kcal)^−1)
	No IDF-criteria fulfilled	IDF criteria fulfilled	ANCOVA
Metabolic syndrome	n = 465 1848 (387)	n = 251 1956 (394)	P = 0.008
Waist	n = 323 1826 (400)	n = 393 1935 (381)	P = 0.002
Triglycerides	n = 505 1867 (399)	n = 211 1932 (374)	P = 0.418
HDL	n = 627 1893 (400)	n = 89 1835 (339)	P = 0.230
Systolic blood pressure	n = 99 1739 (310)	n = 617 1909 (400)	P = 0.003
Plasma glucose	n = 576 1852 (360)	n = 140 2023 (483)	P < 0.001

Table III. Characteristics of the study subjects according to sodium intake tertiles.

Sodium intake (mg(1000 kcal)^−1) tertiles	1st		2^nd		3rd		P ^a	P ^b
n (M/F)	238 (93/145)		240 (112/128)		238 (140/98)		<0.001^†
Hypertensives/Controls	105/133		105/135		132/106		<0.001^†
Impaired glucose tolerance (%)	16.4		14.2		21.7		NS^†
Type 2 diabetics (%)	5.0		6.3		12.3		0.007^†
Age (years)	50.4	49.6–51.2	52.1	51.3–52.9	52.1	51.4–52.9	0.002
Sodium intake (mg(1000 kcal)^−1)	1514.3	1486.1–1542.5	1837.8	1809.7–1865.8	2306.0	2277.8–2334.2	<0.001
BMI (kg/m^2)	26.4	25.9–27.0	27.2	26.6–27.7	28.3	27.7–28.8	<0.001	0.003
Waist (cm)	86.0	84.4–87.5	88.5	87.0–90.1	93.1	91.6–94.7	<0.001	<0.001
Smoking, pack years	9.2	7.5–11.0	9.7	8.0–11.4	14.9	12.8	<0.001	0.005
Systolic BP (mmHg)	146.6	143.7–149.4	148.8	146.0–151.7	151.2	148.4–154.1	NS	NS
Diastolic BP (mmHg)	87.6	86.1–89.2	88.2	86.7–89.8	90.1	88.6–91.6	NS	NS
Fasting glucose (mmol/L)	4.4	4.2–4.6	4.5	4.3–4.6	5.1	4.9–5.2	<0.001	<0.001
Quick index	0.63	0.62–0.65	0.62	0.60–0.63	0.59	0.57–0.60	<0.001	NS
Total cholesterol (mmol/L)	5.6	5.4–5.7	5.8	5.6–5.9	5.8	5.7–5.9	0.025	NS
HDL cholesterol (mmol/L)	1.41	1.36–1.46	1.38	1.33–1.43	1.32	1.27–1.37	0.045	NS
Triglycerides (mmol/L)	1.4	1.3–1.5	1.4	1.3–1.5	1.7	1.6–1.8	<0.001	NS

Data are number (%) or means and 95% CI. Means adjusted for age, sex and study group. P values obtained from ANCOVA or chi-square (‡) analyses before (^a) and after (^b) adjustment for age, sex, study group, and BMI.

Figure 1. Sodium intake (mg(1000 kcal)⁻¹) and the number of MS criteria met by the IDF.

Figure 2. Sodium intake (mg(1000 kcal)⁻¹) and different MS criteria combinations.