Development and Validation of a Physical Food Security Tool for Older Adults

Current measures of food insecurity focus on economic access to food, but not on the physical aspect of food insecurity that captures the inability to access food or prepare meals. This is particularly relevant among the older adult population who are at a high risk of functional impairments.

To develop a short-form physical food security (PFS) tool among older adults using statistical methods based on the Item Response Theory (Rasch) model.

Pooled data from adults aged ≥60 y of the NHANES (2013-2018) (n = 5892) were used. The PFS tool was derived from the physical limitation questions included in the physical functioning questionnaire of NHANES. Item severity parameters, fit and reliability statistics, and residual correlation between items were estimated using the Rasch model. The construct validity of the tool was assessed by examining associations with the Healthy Eating Index (HEI)-2015 scores, self-reported health, self-reported diet quality, and economic food insecurity, using weighted multivariable linear regression analysis, controlling for potential confounders.

A 6-item scale was developed, which had adequate fit statistics and high reliability (0.62). It was categorized based on raw score severity into high, marginal, low, and very low PFS. Very low PFS was associated with respondent's self-reported poor health (OR = 23.8; 95% CI: 15.3, 36.9; P < 0.0001), self-reported poor diet (OR = 3.9; 95% CI: 2.8, 5.5; P < 0.0001), low and very low economic food security (OR = 6.08; 95% CI: 4.23, 8.76; P < 0.0001), and with lower mean HEI-2015 index score, in comparison to older adults with high PFS (54.5 compared with 57.5, P = 0.022).

The proposed 6-item PFS scale captures a new dimension of food insecurity that can inform on how older adults experience food insecurity. The tool will require further testing and evaluation in larger and different contexts to demonstrate its external validity.