Department of Public Health, University of Otago, Wellington, New Zealand.
J Epidemiol Community Health. 2011 Oct;65(10):902-8. doi: 10.1136/jech.2010.118588. Epub 2011 Feb 4.
Reducing health inequalities requires interventions that work as well, if not better, among disadvantaged populations. The aim of this study was to determine if the effects of price discounts and tailored nutrition education on supermarket food purchases (percentage energy from saturated fat and healthy foods purchased) vary by ethnicity, household income and education.
A 2×2 factorial trial of 1104 New Zealand shoppers randomised to receive a 12.5% discount on healthier foods and/or tailored nutrition education (or no intervention) for 6 months.
There was no overall association of price discounts or nutrition education with percentage energy from saturated fat, or nutrition education with healthy food purchasing. There was an association of price discounts with healthy food purchasing (0.79 kg/week increase; 95% CI 0.43 to 1.16) that varied by ethnicity (p=0.04): European/other 1.02 kg/week (n=755; 95% CI 0.60 to 1.43); Pacific 1.20 kg/week (n=101; 95% CI 0.06 to 2.34); Māori -0.15 kg/week (n=248; 95% CI -1.10 to 0.80). This association of price discounts with healthy food purchasing did not vary by household income or education.
While a statistically significant variation by ethnicity in the effect of price discounts on food purchasing was found, the authors caution against a causal interpretation due to likely biases (eg, attrition) that differentially affected Māori and Pacific people. The study highlights the challenges in generating valid evidence by social groups for public health interventions. The null findings for tailored nutritional education across all social groups suggest that structural interventions (such as price) may be more effective.
减少健康不平等需要干预措施，这些措施在弱势群体中同样有效，如果不是更好的话。本研究的目的是确定价格折扣和定制营养教育对超市食品购买（饱和脂肪和购买的健康食品的能量百分比）的影响是否因种族、家庭收入和教育程度而异。
对 1104 名新西兰购物者进行了一项 2×2 析因试验，随机分配接受 12.5%的健康食品折扣和/或定制营养教育（或无干预），为期 6 个月。
价格折扣或营养教育与饱和脂肪的能量百分比之间，或营养教育与健康食品购买之间均无总体关联。价格折扣与健康食品购买有关（每周增加 0.79 公斤；95%CI 0.43 至 1.16），这种关联因种族而异（p=0.04）：欧洲/其他种族每周增加 1.02 公斤（n=755；95%CI 0.60 至 1.43）；太平洋种族每周增加 1.20 公斤（n=101；95%CI 0.06 至 2.34）；毛利人每周减少 0.15 公斤（n=248；95%CI 1.10 至 0.80）。这种价格折扣与健康食品购买之间的关联不因家庭收入或教育程度而异。
尽管发现价格折扣对食品购买的影响在种族方面存在统计学上的显著差异，但由于可能存在偏见（例如，流失），对毛利人和太平洋岛民产生了不同的影响，作者对此持谨慎态度，不进行因果推断。该研究突出了为公共卫生干预措施按社会群体生成有效证据所面临的挑战。在所有社会群体中，定制营养教育的无效结果表明，结构性干预措施（如价格）可能更有效。
