title: Changes in levels of hemoglobin and hematocrits among children and youth registrants between 1968 and 1971.
mesh_terms: D000293:Adolescent; D001741:Black or African American; D002648:Child; D002662:Child Health Services; D002675:Child, Preschool; D005260:Female; D006306:Health Surveys; D006400:Hematocrit; D006452:Hemoglobinometry; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008403:Mass Screening; D011203:Poverty; D014481:United States; D044465:White People
chemical_list: D006454:Hemoglobins