Temporal Trends in Absolute Iron Deficiency Among US Adults.

BACKGROUND

The temporal trends in the prevalence of iron deficiency in the United States is incompletely defined.

METHODS

We examined trends in absolute iron deficiency among US adults using data from the National Health and Nutrition Examination Survey (NHANES) from 1999-2002 and 2017-2020 cycles. Iron deficiency was defined as a serum ferritin concentration below 30 ng/mL with a sensitivity analysis using below 15 ng/mL. A generalized linear model using a quasi-binomial identity link was used to estimate the age- and sex-adjusted absolute difference in iron deficiency prevalence between 1999-2002 and 2017-2020.

RESULTS

The age- and sex-adjusted prevalence of absolute iron deficiency increased from 11.2% (95% CI, 10.4%-12.0%) in 1999-2002 to 14.2% (95% CI, 13.3%-15.2%) in 2017-2020, equivalent to 22.8 million in 1999-2002 and 32.3 million in 2017-2020. The age- and sex-adjusted absolute difference (95% CI) was +3.0% (+1.8% to +4.2%; P < 0.001).

CONCLUSIONS

Iron deficiency represents a common, treatable contributor to morbidity in the United States (32.3 million). Defining the primary drivers of the rising prevalence of iron deficiency and designing novel prevention and treatment strategies represent important public health initiatives.