Differences in Risk Factors for Anemia between Adolescent and Adult Women

Background: Iron deficiency anemia (IDA) affects 2%-5% of reproductive-age women. Screening is based on risk factors, such as a low-iron diet and menstruation. However, published IDA risk factors fail to consider age-related risks specific to adolescent women, potentially limiting identification of high-risk adolescents for objective testing. The goal of the study was to examine IDA risk factors in a nationally representative sample of younger (12-21 years) and older (22-49 years) reproductive-age women. Materials and Methods: Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2003-2010. IDA was defined using hemoglobin, ferritin, soluble transferrin receptor, standard NHANES laboratory measures. Sex-, age-, and race-specific hemoglobin values defined anemia. Iron deficiency was calculated using ferritin and soluble transferrin receptor in the body iron formula. Logistic regression assessed the association of potential risk factors (race, body mass index, poverty, iron intake, tobacco/nicotine exposure, physical activity, menses, and contraceptive use) with IDA in younger and older women. Results: The prevalence of IDA was 2.4% and 5.5% among younger and older women, respectively. Among younger women, contraceptive use was marginally protective from IDA (risk ratio 0.50, 95% confidence interval [CI] 0.25-1.00). Among older women, significant variables included Black race (risk ratio 2.31, 95% CI 1.33-4.02) and increased years menstruating (≥25 years vs. <25 years; risk ratio 1.93, 95% CI 0.99-3.76). Conclusions: Risk factors for IDA among older reproductive-age women do not apply to adolescent women. To better inform the timing and frequency of screening recommendations, further research must identify adolescent-specific IDA risk factors.