Table 4 Multiple linear regression analysis of the associations between sociodemographics and diet quality indices in Iranian households (n = 6935)

 Young age (reference)

–

–

–

–

–

–

 Middle-aged

1.49

1.12, 1.86

< 0.001

1.45

0.97, 1.92

< 0.001

 Older

2.06

1.63, 2.50

< 0.001

2.90

2.34, 3.45

< 0.001

 Males (reference)

–

–

–

–

–

–

 Females

−0.89

−1.56, −0.21

0.010

−0.86

−1.76, − 0.01

0.052

 Low (reference)

–

–

–

–

–

–

 Moderate

2.40

2.07, 2.74

< 0.001

0.39

−0.04, 0.82

0.077

 High

4.54

4.02, 5.06

< 0.001

2.11

1.45, 2.77

< 0.001

 Rural (reference)

–

–

–

–

–

–

 Urban

2.85

2.54, 3.16

< 0.001

0.72

0.32, 1.12

< 0.001

 Less than 5 members (reference)

–

–

–

–

–

–

 5 or more members

−0.95

−1.29, −0.63

< 0.001

0.38

−0.03, 0.79

0.069