Table 3 Subgroup analysis of association between dietary iron intake and osteopenia among U.S. adults in NHANES 2005–2018

Sex

0.557

Female

1.00

0.74

(0.55–0.98)

0.63

(0.47–0.84)

0.70

(0.50–0.98)

Male

1.00

0.81

(0.60–1.09)

0.81

(0.61–1.09)

0.86

(0.65–1.14)

Races

0.747

Mexican American

1.00

0.72

(0.39–1.33)

0.59

(0.31–1.11)

0.99

(0.53–1.86)

Non-Hispanic Black

1.00

0.69

(0.41–1.13)

0.76

(0.45–1.30)

0.65

(0.37–1.12)

Non-Hispanic White

1.00

0.78

(0.59–1.03)

0.73

(0.56–0.95)

0.81

(0.62–1.06)

Other Hispanic

1.00

0.44

(0.22–0.91)

0.50

(0.25–1.02)

0.54

(0.25–1.13)

Other Race - Including Multi-Racial

1.00

1.64

(0.73–3.68)

1.32

(0.59–2.93)

0.90

(0.39–2.07)

Education

0.371

Above high school

1.00

0.79

(0.62–1.01)

0.74

(0.58–0.94)

0.83

(0.65–1.07)

High school

1.00

0.54

(0.36–0.83)

0.64

(0.42–0.97)

0.63

(0.41–0.96)

Less than high school

1.00

1.48

(0.67–3.26)

0.84

(0.36–1.97)

1.16

(0.51–2.61)

Alcohol intake

0.146

Heavy

1.00

0.85

(0.53–1.37)

0.42

(0.25–0.70)

0.62

(0.38–1.02)

Mild

1.00

0.76

(0.58–1.00)

0.77

(0.59–1.00)

0.82

(0.63–1.08)

Moderate

1.00

0.72

(0.48–1.07)

0.90

(0.60–1.36)

0.80

(0.52–1.22)

Smoking status

0.478

Former

1.00

0.81

(0.56–1.15)

0.85

(0.60–1.20)

0.82

(0.57–1.18)

Never

1.00

0.71

(0.52–0.96)

0.60

(0.45–0.82)

0.69

(0.51–0.94)

Now

1.00

0.78

(0.49–1.22)

0.74

(0.46–1.20)

1.03

(0.65–1.62)

The ratio of family income to poverty

0.640

0-1.5

1.00

0.72

(0.49–1.06)

0.62

(0.41–0.93)

0.94

(0.62–1.43)

1.5–3.5

1.00

0.74

(0.51–1.07)

0.82

(0.57–1.17)

0.79

(0.55–1.13)

3.5-

1.00

0.79

(0.58–1.09)

0.70

(0.51–0.96)

0.72

(0.52–1.00)

CVD

0.841

No

1.00

0.78

(0.63–0.97)

0.72

(0.58–0.89)

0.82

(0.65–1.02)

Yes

1.00

0.68

(0.39–1.20)

0.73

(0.41–1.31)

0.66

(0.37–1.16)

DM

0.171

No

1.00

0.73

(0.58–0.92)

0.64

(0.51–0.81)

0.76

(0.60–0.95)

Yes

1.00

0.94

(0.60–1.47)

1.13

(0.72–1.75)

0.93

(0.59–1.45)