Food Insecurity and Oral Health Impairment: Evidence from a Rasch-Based Scale and Composite Oral Health Index

Objectives: Food insecurity (FI) is increasingly recognized as a critical social determinant of systemic health. However, there is limited population-level evidence linking FI to cumulative functional oral health outcomes, particularly in low- and middle-income countries like India. This study aimed to examine the association between FI and oral health impairment (OHI) in a nationally representative Indian population, evaluating whether the relationship follows a graded pattern across demographic and socioeconomic groups. Methods: Data were analyzed from Wave-1 of the longitudinal aging study in India (2017–18), comprising 72,250 adults aged ≥18 years. A composite OHI index was developed by standardizing and summing measures of tooth loss, chewing difficulty, and self-reported oral problems. FI was quantified using a one-parameter Rasch-based item response model to capture a severity gradient across five items. Multivariable linear regression was employed to estimate the associations, adjusting for age, sex, residence, education, wealth, marital status, caste, religion, and behavioral factors. Results: Overall, 46.5% of participants reported oral impairment, including 58.4% with tooth loss and 6.3% who were completely edentulous. FI was prevalent, with 40.6% lacking their food of choice and 3.0% experiencing an entire day without food. Rasch analysis confirmed a strong severity gradient in the FI index. After full adjustment, each 1-standard deviation increase in FI was significantly associated with a higher OHI score ( β = 0.030, P < 0.001). This functional impairment was most pronounced among older adults ( β = 0.939 for ≥60 years), women, rural residents, widowed individuals, and tobacco users. Conclusion: The findings demonstrate a progressive, graded relationship between worsening FI and the severity of functional oral health problems. These results highlight the necessity of integrating nutritional and oral health policies to address deep-seated health inequities among vulnerable populations.