An Examination of the Relationship between Household Food Insecurity and WIC Participation

Thesis (Ph.D.)--University of Washington, 2015Over the last decade, a growing number of American families have struggled to put food on the table. The most recent USDA ERS report, released September 2012, estimates that a record one in five children, over sixteen million in total, currently live in food insecure homes throughout the country. Household food insecurity, defined as not having ‘access to enough food for an active, healthy life,’ is a key indicator of population health and has been recognized as an important area for improvement by initiatives such as Healthy People 2020. Improving access to healthy foods is a cornerstone of many public health programs including SNAP, TANF and the Special Supplemental Nutrition Program for Women, Infants and Children, WIC. WIC’s mission is to safeguard the health of low-income maternal-child populations who are at nutrition risk by providing resources such as nutritious foods, nutrition counseling and health care referrals. As a federally mandated program, WIC is uniquely positioned to not only impact the experience of food insecurity but also improve the life course health of vulnerable maternal-child populations in the US. While research to date supports the notion that participation in WIC has a dose-dependent effect on household food insecurity among participating families, WIC participation rates, defined as participation among eligible families, and coinciding rates of household food insecurity, had yet to be examined. The purpose of this study was to explore the presence and nature of a cross-sectional and longitudinal relationship between state-level household food insecurity rates and WIC participation rates over time. The first aim was to examine the relationship between annual state-level household food insecurity and WIC participation rates cross-sectionally from 2000-2010, controlling for relevant sociodemographic characteristics. The second aim was to examine the relationship between annual state-level household food insecurity and WIC participation rates longitudinally from 2000-2010, controlling for relevant sociodemographic characteristics and national economic trends. This study was an exploratory analysis of existing secondary data. Data sources included the Current Population Survey, WIC administrative files, and US Census. I used a pooled time-series regression model to examine the associations between household food insecurity rates, WIC participation rates, and sociodemographic characteristics. I examined the longitudinal association between household food insecurity and WIC participation with a pooled time-series regression model and marginal effects equations using a linked state-level dataset for years 2000 through 2010, first described in my cross-sectional analysis. The cross-sectional analysis uncovered a complicated relationship between household food insecurity and WIC participation dependent upon the state sociodemographic characteristics, namely the proportions of Hispanic and/or Foreign-Born populations and the rates of teenage and unmarried pregnancies. The longitudinal analysis expanded upon the understanding of the relationship between household food insecurity and WIC participation rates by examining the presence and nature of this relationship over time. A normalized pattern of association, where a change in state-level food insecurity was associated with a similar change in WIC participation, was evident during periods 2000, 2001 and 2010. In contrast, the non-recessionary period from 2002-2006 and Great Recession from 2007-2009 disrupted this pattern. During 2002-2006 and 2007-2009, a state-level change in food insecurity did not elicit a measurable change in WIC participation. This work adds to the overall understanding of the relationship between state-level maternal-child food and nutrition needs and the current public health system’s ability to meet these needs. This research supports public health programming’s ability to positively influence the lives of low-income, vulnerable maternal-child populations in the US struggling with food insecurity. Overall, it is hoped that this evidence of the relationship between food insecurity and WIC participation will encourage consideration of state-level sociodemographic characteristics and national economic climate in the planning and implementation of public health services intended to reduce food insecurity and improve maternal-child health over time