School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, United States of America.
PLoS One. 2010 Aug 10;5(8):e12046. doi: 10.1371/journal.pone.0012046.
Vitamin A deficiency (VAD) is an important nutritional problem in India, resulting in an increased risk of severe morbidity and mortality. Periodic, high-dose vitamin A supplementation is the WHO-recommended method to prevent VAD, since a single dose can compensate for reduced dietary intake or increased need over a period of several months. However, in India only 34 percent of targeted children currently receive the two doses per year, and new strategies are urgently needed.
Recent advancements in biotechnology permit alternative strategies for increasing the vitamin A content of common foods. Mustard (Brassica juncea), which is consumed widely in the form of oil by VAD populations, can be genetically modified to express high levels of beta-carotene, a precursor to vitamin A. Using estimates for consumption, we compare predicted costs and benefits of genetically modified (GM) fortification of mustard seed with high-dose vitamin A supplementation and industrial fortification of mustard oil during processing to alleviate VAD by calculating the avertable health burden in terms of disability-adjusted life years (DALY).
We found that all three interventions potentially avert significant numbers of DALYs and deaths. Expanding vitamin A supplementation to all areas was the least costly intervention, at $23-$50 per DALY averted and $1,000-$6,100 per death averted, though cost-effectiveness varied with prevailing health subcenter coverage. GM fortification could avert 5 million-6 million more DALYs and 8,000-46,000 more deaths, mainly because it would benefit the entire population and not just children. However, the costs associated with GM fortification were nearly five times those of supplementation. Industrial fortification was dominated by both GM fortification and supplementation. The cost-effectiveness ratio of each intervention decreased with the prevalence of VAD and was sensitive to the efficacy rate of averted mortality.
Although supplementation is the least costly intervention, our findings also indicate that GM fortification could reduce the VAD disease burden to a substantially greater degree because of its wider reach. Given the difficulties in expanding supplementation to areas without health subcenters, GM fortification of mustard seed is an attractive alternative, and further exploration of this technology is warranted.
维生素 A 缺乏症(VAD)是印度的一个重要营养问题,导致严重发病率和死亡率增加。定期、高剂量的维生素 A 补充是世界卫生组织推荐的预防 VAD 的方法,因为单剂量可以补偿几个月内减少的饮食摄入或增加的需求。然而,在印度,只有 34%的目标儿童目前每年接受两次剂量,迫切需要新的策略。
生物技术的最新进展允许采用替代策略来增加常见食物中的维生素 A 含量。芥菜(Brassica juncea)以油的形式被 VAD 人群广泛食用,可以通过基因改造来表达高水平的β-胡萝卜素,这是维生素 A 的前体。利用消费估计,我们比较了基因改良(GM)芥菜种子强化与高剂量维生素 A 补充和加工过程中芥菜油工业强化以减轻 VAD 的预测成本和效益,通过计算以残疾调整生命年(DALY)衡量的可避免的健康负担。
我们发现所有三种干预措施都有可能避免大量的 DALY 和死亡。扩大维生素 A 补充到所有地区是成本最低的干预措施,每避免一个 DALY 的成本为 23-50 美元,每避免一个死亡的成本为 1000-6100 美元,尽管成本效益因现行健康分中心覆盖率而异。GM 强化可以避免 500 万至 600 万更多的 DALY 和 8000 至 46000 更多的死亡,主要是因为它将使整个人口受益,而不仅仅是儿童。然而,GM 强化相关的成本几乎是补充的五倍。工业强化被 GM 强化和补充所主导。每种干预措施的成本效益比随着 VAD 的流行程度而降低,并且对避免死亡率的功效率敏感。
虽然补充是成本最低的干预措施,但我们的研究结果还表明,由于 GM 强化的覆盖范围更广,它可以更大程度地降低 VAD 的疾病负担。考虑到将补充扩大到没有健康分中心的地区存在困难,芥菜种子的 GM 强化是一种有吸引力的替代方案,值得进一步探索这项技术。