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Table 2 Association of dietary iron intake with diabetic retinopathy and vision-threatening diabetic retinopathy

From: Dietary iron intake is nonlinearly associated with the risk of diabetic retinopathy in adults with type 2 diabetes

Iron intake (mg/d)

No a

No (%) b

Crude model

Model 1c​

Model 2 d

Model 3 e

OR (95%CI)

P value

OR (95%CI)

P value

OR (95%CI)

P value

OR (95%CI)

P value

For diabetic retinopathy

Quartiles

          

Q1 (1.81–9.60)

324

118 (36.4)

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

Q2 (9.61–13.1)

304

97 (31.9)

0.82 (0.59–1.14)

0.234

0.86 (0.62–1.21)

0.385

0.84 (0.60–1.18)

0.324

0.99 (0.67–1.46)

0.945

Q3 (13.2–18.1)

279

69 (24.7)

0.57 (0.40–0.82)

0.002

0.60 (0.42–0.86)

0.006

0.60 (0.42–0.87)

0.006

0.59 (0.39–0.90)

0.014

Q4 (18.2–52.9)

265

74 (27.9)

0.68 (0.48–0.96)

0.029

0.72 (0.50–1.05)

0.086

0.72 (0.50–1.06)

0.094

0.74 (0.48–1.15)

0.179

Adequate intake f

          

Yes

245

84 (34.2)

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

 

No

927

274 (29.6)

0.80 (0.60–1.08)

0.153

0.82 (0.60–1.13)

0.223

0.79 (0.57–1.09)

0.148

0.83 (0.58–1.21)

0.335

For vision-threatening diabetic retinopathy

Quartiles

          

Q1 (1.81–9.60)

238

32 (13.4)

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

Q2 (9.61–13.1)

222

15 (6.8)

0.47 (0.25–0.89)

0.020

0.52 (0.27-1.00)

0.049

0.51 (0.26–0.99)

0.048

0.77 (0.35–1.72)

0.526

Q3 (13.2–18.1)

224

14 (6.3)

0.43 (0.22–0.83)

0.012

0.51 (0.26-1.00)

0.050

0.50 (0.25–0.98)

0.044

0.42 (0.19–0.94)

0.036

Q4 (18.2–52.9)

204

13 (6.4)

0.44 (0.22–0.86)

0.016

0.62 (0.31–1.27)

0.192

0.60 (0.29–1.24)

0.167

0.80 (0.33–1.94)

0.628

Adequate intake f

          

Yes

182

21 (11.5)

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

-

1.00 (reference)

 

No

706

53 (7.5)

0.62 (0.36–1.06)

0.082

0.78 (0.44–1.36)

0.377

0.71 (0.40–1.26)

0.246

0.86 (0.42–1.76)

0.680

  1. Abbreviations: CI, confidence interval; OR, odds ratio
  2. a Number of participants with T2D in NHANES 2005–2008
  3. b Number of participants with T2D and diabetic retinopathy or vision-threatening diabetic retinopathy in NHANES 2005–2008
  4. c​ Model 1: Adjusted for demographic variables (age, sex, race/ethnicity, education, marital status, poverty income ratio)
  5. d Model 2: Adjusted for demographic and lifestyle variables (smoking, drinking, body mass index)
  6. e Model 3: Adjusted for demographic, lifestyle, diabetes related variables (duration of diabetes, HbA1c level), and medical comorbidity variables (general health condition, history of angina/angina pectoris, congestive heart failure, coronary heart disease, heart attack, hypercholesteraemia, hypertension, and stroke)
  7. f Adequate dietary iron intake is defined according to Recommended Dietary Allowance (RDA) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) of the National Academies (formerly National Academy of Sciences)
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BMC Endocrine Disorders

ISSN: 1472-6823

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