Wright J D, Bialostosky K, Gunter E W, Carroll M D, Najjar M F, Bowman B A, Johnson C L
Vital Health Stat 11. 1998 Dec(243):1-78.
This report presents national estimates of serum and red blood cell (RBC) folate and serum vitamin B12 distributions for persons 4 years and over, by sociodemographic variables.
The third National Health and Nutrition Examination Survey (NHANES III) (1988-94), provides information on the health and nutritional status of the civilian noninstitutionalized U.S. population. The analytic sample included 23,378 participants with serum folate data, 23,082 with RBC folate data, and 11,851 with serum vitamin B12 data.
The mean serum and RBC folate concentrations are 7.2 and 196 nanograms per milliliter (ng/mL), respectively, and the mean serum vitamin B12 concentration is 518 picograms per milliliter (pg/mL). Non-Hispanic white people have higher mean serum and RBC folate concentrations than non-Hispanic black or Mexican American people. Serum vitamin B12 concentrations are lowest for older adults, and non-Hispanic black people have higher serum B12 concentrations than non-Hispanic white individuals. Only approximately 3 percent of the population has a serum B12 concentration less than 200 pg/mL.
Inadequate folate status may be more prevalent among non-Hispanic black and Mexican American people. Data also suggest a modest prevalence of low serum B12 concentrations. Future assessments of folate and vitamin B12 status will be important to evaluate the impact of a recently enacted fortification policy.
本报告按社会人口统计学变量，呈现了4岁及以上人群血清和红细胞（RBC）叶酸以及血清维生素B12分布的全国估计数据。
第三次全国健康与营养检查调查（NHANES III）（1988 - 1994年）提供了关于美国非机构化平民人口健康和营养状况的信息。分析样本包括23378名有血清叶酸数据的参与者、23082名有红细胞叶酸数据的参与者以及11851名有血清维生素B12数据的参与者。
血清和红细胞叶酸的平均浓度分别为每毫升7.2纳克（ng/mL）和196纳克（ng/mL），血清维生素B12的平均浓度为每毫升518皮克（pg/mL）。非西班牙裔白人的血清和红细胞叶酸平均浓度高于非西班牙裔黑人或墨西哥裔美国人。老年人的血清维生素B12浓度最低，非西班牙裔黑人的血清B12浓度高于非西班牙裔白人。只有约3%的人群血清B12浓度低于200 pg/mL。
叶酸水平不足在非西班牙裔黑人和墨西哥裔美国人中可能更为普遍。数据还表明血清B12浓度低的情况有一定比例。未来对叶酸和维生素B12状况的评估对于评估最近颁布的强化政策的影响将很重要。
