Hemoglobin and hematocrit values are higher and prevalence of anemia is lower in the post-folic acid fortification period than in the pre-folic acid fortification period in US adults.
BACKGROUND: It is not known whether the improved folate status from mandatory folic acid fortification had any impact on indexes and prevalence of anemias in the United States. OBJECTIVE: We investigated trends in indexes and prevalence of anemia and macrocytosis with a focus on comparison of prefortification data with postfortification data. DESIGN: Hemoglobin, hematocrit, mean corpuscular volume (MCV) and prevalences and likelihood of anemia and macrocytosis were determined for 26,596 adults examined in the National Health and Nutrition Examination Surveys, 1988-2004. RESULTS: From 1988-1994 to 1999-2004, hemoglobin modestly but significantly improved from 15.1 to 15.4 g/dL (approximately 2.0%; P < 0.0001) and from 13.3 to 13.6 g/dL (approximately 2.3%; P < 0.0001) in men and women, respectively. There was a significant increase in MCV from 1988-1994 to 1999-2004 in men (from 90.2 to 90.7; P = 0.0123) and older (>60 y) men (from 91.6 to 92.4; P = 0.0105) and in women (from 90.7 to 91.4; P = 0.0141). Only in women was the prevalence of anemia significantly lower in 1999-2004 than in 1988-1994 (27.9% reduction; P = 0.0005). The odds of having anemia in the postfortification period relative to the prefortification period was 0.64 (95% CI: 0.54, 0.75; P < 0.0001) in women and 0.79 (95% CI: 0.62, 0.99; P < 0.0433) in men. In general, the prevalence of macrocytosis and the odds of having macrocytosis did not change significantly from 1988-1994 to 1999-2004. CONCLUSION: The improvement in hemoglobin and the decreased prevalence of anemia from 1988-1994 to 1999-2004, especially in women, may be attributable to improved folate status, increased vitamin/mineral supplements use, and other unknown causes after the initiation of folic acid fortification. The cause of increased MCV in men, and in older persons of both sexes, warrants further investigation.
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机译：背景：尚不清楚通过强制性叶酸强化来改善叶酸状态是否会对美国贫血的指数和患病率产生任何影响。目的：我们研究了贫血和大细胞增多症的指数和患病率趋势，重点是加强预备数据与加强后数据的比较。设计：在1988-2004年美国国家健康和营养调查中，对26,596名成年人进行了血红蛋白，血细胞比容，平均红细胞体积（MCV）以及贫血和巨噬细胞的患病率和患病率的测定。结果：从1988-1994年到1999-2004年，血红蛋白水平从15.1 g / dL（约2.0％; P <0.0001）和13.3至13.6 g / dL（约2.3％; P <0.0001）适度但显着改善。男人和女人。从1988-1994年到1999-2004年，男性（从90.2到90.7; P = 0.0123）和老年（> 60岁）男性（从91.6到92.4; P = 0.0105）和女性（从90.7至91.4; P = 0.0141）。仅在女性中，1999-2004年的贫血患病率显着低于1988-1994年（减少27.9％; P = 0.0005）。女性在强化后阶段相对于强化前阶段发生贫血的几率是0.64（95％CI：0.54，0.75; P <0.0001），男性是0.79（95％CI：0.62，0.99; P <0.0433）。通常，从1988-1994年到1999-2004年，巨噬细胞的患病率和发生巨噬细胞的几率没有显着变化。结论：1988-1994年至1999-2004年期间血红蛋白的改善和贫血患病率的降低，尤其是女性，可能归因于叶酸状况改善，维生素/矿物质补充剂的使用增加以及叶酸引发后其他未知原因筑城。男性和两性老年人中MCV升高的原因值得进一步研究。
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