Gachon University, College of Pharmacy, 534-2 Yeonsu-Dong, Yeonsu-Gu, Inchon, 406-799, South Korea.
Soc Sci Med. 2012 Jun;74(12):1874-81. doi: 10.1016/j.socscimed.2012.02.032. Epub 2012 Mar 20.
We explored the extent to which economic contextual factors moderated the association of Supplemental Nutrition Assistance Program (SNAP) participation with body mass index (BMI) among low-income adults whose family income (adjusted for family size) is less than 130% of the federal poverty guideline. We drew on individual-level data from the Panel Study of Income Dynamics in the United States, including three waves of data in 1999, 2001, and 2003. Economic contextual data were drawn from the American Chamber of Commerce Researchers Association for food prices and Dun & Bradstreet for food outlet measures. In addition to cross-sectional estimation, a longitudinal individual fixed effects model was used to control for permanent unobserved individual heterogeneity. Our study found a statistically significant joint moderating effect of the economic contextual factors in longitudinal individual fixed effects model for both women (BMI only) and men (both BMI and obesity). For both women and men, SNAP participants' BMI was statistically significantly lower if they faced increased numbers of available supermarkets/grocery stores in the longitudinal model. A simulated 20% reduction in the price of fruits and vegetables resulted in a larger decrease in BMI among SNAP participants than non-participants for women and men, whereas a simulated 20% increase in the availability of supermarkets and grocery stores resulted in a statistically significant difference in the change in BMI by SNAP participation for women but not for men. Policies related to economic contextual factors, such as subsidies for fruits and vegetables or those that would improve access to supermarkets and grocery stores may enhance the relationship between SNAP participation and body mass outcomes among food assistance program participants.
我们探讨了经济背景因素在多大程度上调节了补充营养援助计划（SNAP）参与度与家庭收入（按家庭规模调整）低于联邦贫困线 130%的低收入成年人的体重指数（BMI）之间的关联。我们利用了来自美国收入动态面板研究的个人层面数据，包括 1999 年、2001 年和 2003 年的三波数据。经济背景数据来自美国商会研究人员协会的食品价格数据和邓白氏的食品销售点数据。除了横断面估计外，我们还使用纵向个体固定效应模型来控制永久性未观察到的个体异质性。我们的研究发现，在纵向个体固定效应模型中，经济背景因素存在统计学上显著的联合调节作用，无论是对女性（仅 BMI）还是男性（BMI 和肥胖）都是如此。对于女性和男性来说，如果在纵向模型中面临更多的超市/杂货店，SNAP 参与者的 BMI 统计学上显著降低。模拟水果和蔬菜价格降低 20%，会导致 SNAP 参与者的 BMI 比非参与者更大幅度地降低，而模拟超市和杂货店数量增加 20%，会导致 SNAP 参与者的 BMI 变化有统计学意义的差异，但对男性没有影响。与经济背景因素相关的政策，如水果和蔬菜补贴，或那些可以改善超市和杂货店获取途径的政策，可能会增强 SNAP 参与度与食品援助计划参与者体重指数之间的关系。
