Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.
BMJ. 2013 Jun 17;346:f3703. doi: 10.1136/bmj.f3703.
To quantify the relation between food prices and the demand for food with specific reference to national and household income levels.
Systematic review with meta-regression.
Online databases of peer reviewed and grey literature (ISI Web of Science, EconLit, PubMed, Medline, AgEcon, Agricola, Google, Google Scholar, IdeasREPEC, Eldis, USAID, United Nations Food and Agriculture Organization, World Bank, International Food Policy Research Institute), hand searched reference lists, and contact with authors.
We included cross sectional, cohort, experimental, and quasi-experimental studies with English abstracts. Eligible studies used nationally representative data from 1990 onwards derived from national aggregate data sources, household surveys, or supermarket and home scanners.
The primary outcome extracted from relevant papers was the quantification of the demand for foods in response to changes in food price (own price food elasticities). Descriptive and study design variables were extracted for use as covariates in analysis. We conducted meta-regressions to assess the effect of income levels between and within countries on the strength of the relation between food price and demand, and predicted price elasticities adjusted for differences across studies.
136 studies reporting 3495 own price food elasticities from 162 different countries were identified. Our models predict that increases in the price of all foods result in greater reductions in food consumption in poor countries: in low and high income countries, respectively, a 1% increase in the price of cereals results in reductions in consumption of 0.61% (95% confidence interval 0.56% to 0.66%) and 0.43% (0.36% to 0.48%), and a 1% increase in the price of meat results in reductions in consumption of 0.78% (0.73% to 0.83%) and 0.60% (0.54% to 0.66%). Within all countries, our models predict that poorer households will be the most adversely affected by increases in food prices.
Changes in global food prices will have a greater effect on food consumption in lower income countries and in poorer households within countries. This has important implications for national responses to increases in food prices and for the definition of policies designed to reduce the global burden of undernutrition.
定量分析食品价格与食品需求之间的关系，并特别关注国家和家庭收入水平。
系统综述与元回归分析。
同行评议和灰色文献的在线数据库（ISI Web of Science、EconLit、PubMed、Medline、AgEcon、Agricola、Google、Google Scholar、Idea-REPEC、Eldis、USAID、联合国粮食及农业组织、世界银行、国际粮食政策研究所），手工检索参考文献列表，并与作者联系。
我们纳入了具有英文摘要的横断面、队列、实验和准实验研究。合格研究使用了 1990 年以来具有全国代表性的数据，这些数据来自国家综合数据来源、家庭调查或超市和家庭扫描。
从相关论文中提取的主要结果是量化食品需求对食品价格变化的反应（食品自有价格弹性）。提取描述性和研究设计变量，作为分析中的协变量。我们进行了元回归分析，以评估国家之间和国家内部的收入水平对食品价格与需求之间关系强度的影响，并预测了调整研究之间差异后的价格弹性。
从 162 个不同国家的 136 项研究中确定了 3495 个自有价格食品弹性。我们的模型预测，所有食品价格的上涨都会导致贫困国家的食品消费减少更多：在低收入和高收入国家，粮食价格每上涨 1%，消费分别减少 0.61%（95%置信区间为 0.56%至 0.66%）和 0.43%（0.36%至 0.48%），肉类价格每上涨 1%，消费分别减少 0.78%（0.73%至 0.83%）和 0.60%（0.54%至 0.66%）。在所有国家中，我们的模型预测，较贫穷的家庭将受到食品价格上涨的最大不利影响。
全球食品价格的变化将对低收入国家和国家内部较贫穷家庭的食品消费产生更大的影响。这对各国应对食品价格上涨的措施以及制定旨在减轻全球营养不足负担的政策具有重要意义。
