Pediatrics：叶酸或许可以减少儿童罹患某些癌症

含叶酸食品或许可减少最常见的肾细胞癌症类型和一种儿童脑肿瘤癌症类型的发病率，由美国明尼苏达大学博士后研究员Kimberly J. Johnson博士带领完成的一项研究证实了这一观点。

自1998年以来，FDA已责成推广含叶酸食物，因为早先的研究已经表明产前孕妇消耗叶酸的话能显著降低婴儿神经管缺陷的发病率。

Johnson表示：这项研究是迄今为止规模最大的相关研究，研究证实了叶酸也可以降低美国儿童人群某些癌症类型的发病率。相关研究论文发表在本期的Pediatrics杂志上。

Johnson说：“我们发现在1986年至1997年之间，肾母细胞瘤发病率增加了，但随后其发病率又下降了，这是一个非常有趣的发现，当我们发现伴随肾母细胞瘤发病率趋势向下变化的同时，我们发现刚好叶酸处于营养强化时期。

从1986年到1993年始神经外胚层瘤发病速率增长了，但此后又下降了。这种趋势的变化与叶酸的营养强化不完全重合，但却很好地与1992年育龄妇女每天消耗400微克的叶酸相吻合了。

研究作者采用1986年至2008年期间美国国家癌病署的“监测、流行病学与最终结果”计划的数据，这些数据来自1973年以来美国各个区域的癌症病例信息。这项研究涉及诊断出患有癌症的刚出生到4岁年龄不等的8829名儿童。

Johnson说：多个数据的分析发现肾母细胞瘤和儿童原始神经外胚层瘤（PNETs）的患病率呈跌幅趋势。

更重要的是，肾母细胞瘤率的降低在加拿大安大略省同样也被发现，其相关研究结果在2011年已经发表出版了。

研究人员表示需要更多的研究来确认这些结果，并排除任何其他可能的干扰因素。

美国明尼苏达大学儿科系儿科流行病学和临床研究部主任Julie A. Ross博士是这项研究的主要领导人，也是该论文的共同作者。（生物谷：Bioon.com）

doi:10.1542/peds.2011-3418
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Childhood Cancer Incidence Trends in Association With US Folic Acid Fortification (1986–2008)

Amy M. Linabery, MS, PhDa, Kimberly J. Johnson, MPH, PhDb, and Julie A. Ross, PhDa,c

OBJECTIVE: Epidemiologic evidence indicates that prenatal vitamin supplementation reduces risk for some childhood cancers; however, a systematic evaluation of population-based childhood cancer incidence trends after fortification of enriched grain products with folic acid in the United States in 1996–1998 has not been previously reported. Here we describe temporal trends in childhood cancer incidence in association with US folic acid fortification.

METHODS: Using Surveillance, Epidemiology, and End Results program data (1986–2008), we calculated incidence rate ratios and 95% confidence intervals to compare pre- and postfortification cancer incidence rates in children aged 0 to 4 years. Incidence trends were also evaluated by using joinpoint and loess regression models.

RESULTS: From 1986 through 2008, 8829 children aged 0 to 4 years were diagnosed with malignancies, including 3790 and 3299 in utero during the pre- and postfortification periods, respectively. Pre- and postfortification incidence rates were similar for all cancers combined and for most specific cancer types. Rates of Wilms tumor (WT), primitive neuroectodermal tumors (PNETs), and ependymomas were significantly lower postfortification. Joinpoint regression models detected increasing WT incidence from 1986 through 1997 followed by a sizable decline from 1997 through 2008, and increasing PNET incidence from 1986 through 1993 followed by a sharp decrease from 1993 through 2008. Loess curves indicated similar patterns.

CONCLUSIONS: These results provide support for a decrease in WT and possibly PNET incidence, but not other childhood cancers, after US folic acid fortification.