Iron Deficiency is Related to Depressive Symptoms in United States Nonpregnant Women of Reproductive Age: A Cross-Sectional Analysis of NHANES 2005-2010.
Level 4 - case-series / case-control
Cross-sectional observational analysis of survey data
PubMed 37783449 · doi:10.1016/j.tjnut.2023.09.023
What was done
Cross-sectional analysis of 2,516 nonpregnant women of reproductive age (20–44 years) from NHANES (2005–2010) with complete biomarker, depressive symptom, and sociodemographic data. Iron status was evaluated using ferritin, transferrin receptor (TfR), body iron, and hemoglobin. Depressive symptoms were assessed via the Patient Health Questionnaire-9 (PHQ-9). Logistic and negative binomial regression models evaluated odds ratios for depression presence and prevalence ratios for symptom severity scores across iron status categories, adjusted for confounders and stratified by poverty-to-income ratio (≤1.85 vs. >1.85).
What was found
Prevalence was 8% to 16% for iron deficiency (depending on biomarker), 8% for anemia (52%–65% of which was iron-deficient), and 10% for depressive symptoms. In crude logistic models, iron deficiency defined by TfR ≥8.3 mg/L or body iron <0 mg/kg was associated with higher odds of depressive symptoms (OR 1.82, 95% CI: 1.24, 2.68 and OR 1.62, 95% CI: 1.05, 2.48, respectively), but these associations attenuated after adjusting for confounders. In adjusted negative binomial models, TfR-defined iron deficiency remained associated with higher depressive symptom severity scores in the total sample (prevalence ratio 1.19, 95% CI: 1.00, 1.40) and in the low-income subgroup (prevalence ratio 1.27, 95% CI: 1.03, 1.58).
Why it matters
Using nationally representative US data, the study shows that iron deficiency measured by transferrin receptor is associated with greater depressive symptom burden in reproductive-age women, particularly those experiencing low income.
Limits
Cross-sectional design cannot establish temporality or causal direction between iron status and depressive symptoms. Depressive symptoms were screened with PHQ-9 rather than diagnosed clinically. Binary associations with depressive symptom presence were not statistically significant after adjustment for confounders, and adjusted symptom score associations were modest. Findings rely on data collected between 2005 and 2010.
Cited by
- supports Approximately 16% of menstruating women are iron deficient.