|
Article Excerpt
Elderly persons are more food-secure than are nonelderly persons, according to recent nationally representative food security surveys sponsored by the U.S. Department of Agriculture (USDA) (Nord, 2002; Nord et al., 2002; Guthrie & Lin, 2002; Andrews, Nord, Bickel, & Carlson, 2000; Bickel, Carlson, & Nord, 1999). In these surveys, food security--defined as access at all times to enough food for an active, healthy life for all household members--is measured by a series of questions about behaviors and experiences known to characterize households that are having difficulty meeting their food needs (Fitchen, 1981; Fitchen, 1988; Radimer, Olson, & Campbell, 1990; Radimer, Olson, Green, Campbell & Habicht, 1992; Wehler, Scott, & Anderson, 1992). The U.S. Food Security Scale, calculated from responses to these questions, measures the food security of the household and classifies each as food-secure, food-insecure without hunger, or food-insecure with hunger (Bickel, Nord, Price, Hamilton, & Cook, 2000; Hamilton et al., 1997a; 1997b). Concerns have been raised about whether this measurement method, based on self-reported food-access conditions and behaviors, fairly represents the food security of elderly persons, compared with that of non-elderly persons. Food insecurity is known to be associated with poor nutrition and health outcomes for elderly people, and age aggravates the negative effects of poor nutrition on the elderly; so accurate, reliable measurements of the food security of the elderly are important both for monitoring and research purposes (Sahyoun & Basiotis, 2000; Guthrie & Lin, 2002). In this study, I assess the appropriateness of the U.S. Food Security Scale for measuring the food security of elderly persons and, in particular, whether prevalence rates of food insecurity and hunger are comparable between households with and without elderly persons present.
Statistics based on the September 2000 Food Security Survey Module--the most recent food security data available--indicate that 94 percent of households with an elderly person (i.e., age 65 or over) present were food-secure throughout the year (Nord, 2002). Thus, the remaining 6 percent of households with elderly persons were food-insecure, meaning that at some time during the previous year, these households were either uncertain of having or unable to acquire enough food to meet basic needs of all their members because they had insufficient money or other resources for food.
One in four of the food-insecure elderly households (1.5 percent of all elderly households) were food-insecure to the extent that one or more household members were hungry at least some time during the year because they could not afford enough food. The other three-fourths of food-insecure elderly households obtained enough food to avoid hunger by using a variety of coping strategies such as eating less varied diets, participating in Federal food assistance programs, or getting emergency food from community food pantries. These rates of food insecurity and hunger were about half those of households with no elderly members, and this relationship was observed at all income levels, including households with incomes below the Federal poverty line. The extent of food insecurity and hunger among elderly households remained almost unchanged from that of 1995 (when the first nationally representative food security survey was conducted) through 2000. The corresponding prevalence rates for the nonelderly, on the other hand, declined substantially during this period of economic growth.
There are two areas of greatest concern regarding application of the standard methods for measuring food security to the elderly. The first is whether the questions in the Food Security Scale are understood similarly by the elderly and the nonelderly and whether they experience and respond to food insecurity in similar ways. The standard method depends on self-reported conditions and behaviors related to food access and, as such, may be subject to differences in how people understand and interpret the questions and may be subject to biases in the direction of perceived social desirability. For example, ethnographic findings have suggested that the least severe question in the Food Security Scale, which asks whether respondents worried that their food would run out before they received money to buy more, might be less sensitive for elders. Some elderly persons, at least, report that they just do not worry about such things.
The second area of concern is whether the Food Security Scale is appropriately sensitive to obstacles that particularly affect elders' ability to get adequate, nutritious meals. The Food Security Scale measures, specifically, food insecurity and hunger that are caused by insufficient money or other resources for food. Each question in the scale specifies this resource constraint as a reason for the behavior or condition--for example: "In the last 12 months, did you ever cut the size of your meals or skip meals because there wasn't enough money for food?" Factors other than economic resource constraints (e.g., health problems, mobility limitations, and lack of transportation) may be obstacles to elders' ability to obtain adequate nutritious meals, and food-access problems caused by such factors might not be registered by the Food Security Scale (Guthrie & Lin, 2002).
Data and Methods
Data to assess these concerns about measuring the food security of elderly persons were drawn from the August 1998, April 1999, and September 2000 Current Population Survey Food Security Supplements (CPS-FSS). The CPS-FSS is an annual, nationally representative survey of about 42,000 households, which is conducted as a supplement to the monthly CPS labor force survey. In each household, the person most knowledgeable about the food purchased and eaten in the home responds to the questions in the Food Security Supplement. Annual statistics on household food security in the United States are published by the USDA and are based on data from the CPS-FSS.
Separate analysis files were constructed for households in which all persons were age 65 or older (i.e., elderly-only households) and households in which no person was age 65 or older (i.e., nonelderly households). Households with mixed elderly and nonelderly--about 7 percent of all households--were excluded from the analysis.
Scaling Analysis: Do the Elderly and Nonelderly Experience and Respond Similarly to Food Insecurity?
To assess whether the questions in the Food Security Scale are understood similarly by the elderly and the nonelderly and whether they experience and respond similarly to food insecurity, I compared response patterns of elderly-only and nonelderly households. To do so, I used statistical methods based on the Rasch measurement model--the methods originally used to develop the Food Security Scale. This analysis exploits one of the strengths of multiple-indicator measures such as the Food Security Scale: associations among the indicators comprising the scale provide evidence of its validity and reliability.
Furthermore, if the patterns of association among the items in a multiple-indicator measure are similar in two populations, this suggests that the items relate similarly in the two populations to the underlying phenomenon that accounts for their interrelationships; that is, the items measure the same phenomenon in the two populations. These methods of scale assessment are more widely used in psychometric research and educational testing than in nutrition and economic research, so I present first a brief summary of the Rasch model and the scale assessment statistics based on it. More detailed information on the Rasch model and associated statistics is available elsewhere. (1)
An essential characteristic of the Food Security Scale is that the items comprising it vary across a wide range of severity of food insecurity. The precise severity level of each item (the "item calibration" or...
|
