Adolescence is a time of increased iron needs because of the expansion of blood volume and increases in muscle mass. The incidence of iron deficiency among adolescents appears to be rising ; at particular risk are adolescent athletes and adolescents who limit their intake of meat products.
Iron deficiency in adolescents is a complex disorder. The diagnosis often is controversial, and the effects on both physical endurance and cognitive performance in adolescents remain to be fully understood. These issues will be addressed here. Iron deficiency in infants and young children and in adults is discussed in separate topic reviews. (See "Iron deficiency in infants and young children: Screening, prevention, clinical manifestations, and diagnosis" and "Treatment of the adult with iron deficiency anemia".)
The Third National Health and Nutrition Examination Survey (NHANES III) found a 9 percent incidence of iron deficiency and a 2 percent incidence of iron deficiency anemia among American females between the ages 12 and 15 years; the respective values were 11 and 3 percent in girls between the ages of 16 and 19 years . Less than 1 percent of adolescent males had iron deficiency. Studies in other countries have found higher rates of iron deficiency in male and female adolescents [3,4]. Some of the variation in incidence noted among different studies is related to the controversy regarding the appropriate laboratory cutoffs to make the diagnosis. (See 'Diagnosis' below.)
Risk groups — Adolescents with chronic illness, heavy menstrual blood loss (>80 mL/month), or who are underweight or malnourished are at increased risk for iron deficiency and should be screened during health supervision or specialty clinic visits .
Overweight and obese children also appear to be at increased risk for iron deficiency and should undergo screening [6,7]. In one study, data from NHANES III were examined for an association between iron deficiency and weight . The prevalence of iron deficiency increased as body mass index increased from normal weight to >85th percentile for age and sex to >95th percentile for age and sex (2.1 percent, 5.3 percent, and 5.5 percent, respectively). Obesity was a risk factor for iron deficiency anemia in both boys and girls, but rates were approximately three times higher in girls. The etiology of anemia in obese individuals is uncertain but may be related to low-quality diets or increased needs relative to body weight [6,7].