TABLE 3.
Cross-sectional associations of usual total iron intake with serum ferritin (μg/L) and sensitivity analyses in the IDEFICS/I.Family study
| Model | Main model | Sensitivity analysis including usual vitamin C intake2 | Sensitivity analysis with usual iron intake from heme sources2 as exposure | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Wave 0 (N = 883) | |||||||||
| Logistic regression | |||||||||
| Odds ratio for having a sufficient iron status (ref.: deficient status)1 | OR | 95% CI | OR | 95% CI | OR | 95% CI | |||
| Total iron intake2 (mg/d) | 1.36 | 0.91 | 2.08 | 1.35 | 0.88 | 2.15 | 1.28 | 0.77 | 2.13 |
| Mainly vegetarian diet3 (ref: omnivore diet) | 0.44 | 0.07 | 8.40 | 0.44 | 0.07 | 8.42 | 0.48 | 0.08 | 9.27 |
| Vitamin C intake2 (mg/d) | 1.00 | 0.98 | 1.03 | ||||||
| Linear model | |||||||||
| β estimate | β | 95% CI | β | 95% CI | β | 95% CI | |||
| Total iron intake2 (mg/d) | 1.18 | −0.50 | 2.85 | 0.95 | −0.88 | 2.78 | 3.21 | 0.71 | 5.71 |
| Mainly vegetarian diet3 | −4.34 | −15.55 | 6.86 | −4.24 | −15.45 | 6.98 | −2.56 | −13.83 | 8.72 |
| Vitamin C intake2 (mg/d) | 0.03 | −0.06 | 0.12 | ||||||
| Wave 3 (N = 1394) | |||||||||
| Logistic regression | |||||||||
| Odds ratio for having a sufficient iron status (ref.: deficient status)1 | OR | 95% CI | OR | 95% CI | OR | 95% CI | |||
| Total iron intake2 (mg/d) | 1.09 | 0.92 | 1.31 | 1.10 | 0.92 | 1.33 | 1.93 | 1.14 | 3.39 |
| Mainly vegetarian diet3 (ref: omnivore diet) | 0.40 | 0.21 | 0.81 | 0.40 | 0.21 | 0.81 | 0.64 | 0.30 | 1.41 |
| Vitamin C intake2 (mg/d) | 1.00 | 0.98 | 1.01 | ||||||
| Linear model | |||||||||
| β estimate | β | 95% CI | β | 95% CI | β | 95% CI | |||
| Total iron intake2 (mg/d) | 0.50 | −0.36 | 1.36 | 0.25 | −0.66 | 1.16 | 4.48 | 2.09 | 6.87 |
| Mainly vegetarian diet3 (ref: omnivore diet) | −3.75 | −8.16 | 0.66 | −3.72 | −8.13 | 0.68 | −0.27 | −5.03 | 4,49 |
| Vitamin C intake2 (mg/d) | 0.06 | −0.01 | 0.13 | ||||||
Abbreviations: β, β estimate; CI, confidence interval; IDEFICS, Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants; OR, odds ratio.
Adjusted for usual energy intake, age, BMI-z-score, sex, country and ISCED.
Iron deficiency defined according to the WHO: children aged <5 y: serum ferritin <12 μg/L; children of 5 y or older: serum ferritin <15 μg/L.
Usual dietary intakes of total iron, iron from heme sources and vitamin C were estimated from 24-h dietary recalls linked to food composition tables.
Children were classified as mainly vegetarian if they replied to the specific question to typically exclude meat, poultry, sausage and fish from their diet in the food frequency questionnaire. Some of them reported to occasionally consume meat or fish.