Table 3 Hazard ratios (95% CI) of metabolic syndrome components across energy-adjusted quartiles of iron (total, haem and non-haem) and red meat intake in adult participants of the Tehran Lipid and Glucose Study (n=7630)

Total iron

 Abdominal obesity^a

1.00 ref.

0.74 (0.54–0.95)

1.18 (0.79–1.76)

1.11 (0.34–2.32)

 High blood pressure^b

1.00 ref.

1.00 (0.90–1.13)

1.13 (0.97–1.37)

1.04 (0.59–1.84)

 Low HDL-C^a

1.00 ref.

1.02 (0.72–1.44)

1.20 (0.73–1.99)

1.38 (0.31–5.99)

 Hyperglycaemia^a

1.00 ref.

0.98 (0.81–1.18)

1.07 (0.81–1.42)

1.98 (1.08–3.63)

 High triglyceride^c

1.00 ref.

1.22 (0.96–1.56)

1.62 (1.14–2.29)

1.89 (0.80–4.04)

Haem iron (mg/day)

 Abdominal obesity^d

1.00 ref.

0.82 (0.59–1.14)

0.74 (0.52–1.04)

0.88 (0.62–1.25)

 High blood pressure^e

1.00 ref.

0.93 (0.81–1.07)

0.82 (0.71–0.95)

0.81 (0.70–0.94)

 Low HDL-C^d

1.00 ref.

0.67 (0.44–1.01)

0.67 (0.44–1.02)

0.93 (0.61–1.42)

 Hyperglycaemia^d

1.00 ref.

0.96 (0.77–1.20)

1.04 (0.83–1.30)

0.96 (0.75–1.22)

 High triglyceride^f

1.00 ref.

0.98 (0.75–1.30)

1.14 (0.87–1.51)

1.16 (0.87–1.55)

Non-Haem iron

 Abdominal obesity^g

1.00 ref.

0.73 (0.54–1.00)

0.90 (0.52–1.28)

0.96 (0.60–1.54)

 High blood pressure^h

1.00 ref.

1.03 (0.92–1.15)

1.13 (0.99–1.31)

1.19 (0.98–1.44)

 Low HDL-C^g

1.00 ref.

1.01 (0.79–1.28)

1.13 (0.89–1.43)

1.21 (0.95–1.53)

 Hyperglycaemia^g

1.00 ref.

0.98 (0.79–1.21)

1.03 (0.80–1.33)

1.24 (0.90–1.71)

 High triglycerideⁱ

1.00 ref.

1.00 (0.75–1.34)

1.09 (0.95–1.75)

1.48 (0.99–2.74)

Red meat

 Abdominal obesity^a

1.00 ref.

0.75 (0.55–1.03)

0.74 (0.53–1.04)

0.82 (0.59–1.14)

 High blood pressure^b

1.00 ref.

0.90 (0.79–1.02)

0.82 (0.71–0.96)

0.76 (0.65–0.87)

 Low HDL-C^a

1.00 ref.

0.96 (0.76–1.21)

1.14 (0.91–1.42)

0.95 (0.76–1.19)

 Hyperglycaemia^a

1.00 ref.

1.03 (0.82–1.30)

1.00 (0.80–1.24)

0.91 (0.72–1.13)

 High triglyceride^c

1.00 ref.

1.09 (0.81–1.43)

1.07 (0.82–1.48)

1.11 (0.82–1.45)