Association of ultra-processed food with diabetes and impaired fasting glucose in elderly populations (urban and rural): a cross-sectional study

Objectives This study examined the association between ultra-processed food (UPF) consumption and chronic diseases in elderly Koreans. Methods Data from the 2019–2021 Korea National Health and Nutrition Examination Survey were analyzed. Dietary intake and UPF consumption were assessed using the NOVA food classification based on 24-hour recall data from 3,790 participants (aged 65+ years). Participants were divided into 4 groups based on the quartile of energy intake from UPFs. Regions were classified as urban or rural. Multivariable logistic regression was employed to estimate the adjusted odds ratios (AORs) with 95% confidence intervals (CIs) after controlling for potential confounders. Results Among the participants, 71.3% resided in urban and 28.7% in rural areas. Compared to the urban elderly, rural participants tended to be older, have lower education and income levels, be more likely to live in single-person households, and have a higher smoking rate (P < 0.05). Urban elderly consumed more UPFs daily (146.1 g) compared to rural residents (126.6 g; P < 0.05). “Sugar-sweetened beverages” were the most consumed category in both regions. “Sweetened milk and its products” and “traditional sauces” were prominent in urban areas, while rural elderly consumed more “traditional sauces” and “distilled alcoholic beverages.” Rural areas also had a higher carbohydrate-to-calorie ratio than urban areas. Compared to the lowest quartile of UPF intake, the highest quartile was significantly associated with impaired fasting glucose only in rural areas (AOR, 1.48; 95% CI, 1.00–2.19; P for trend = 0.0014). No significant associations were observed for diabetes in either urban or rural areas. Conclusions This study suggests that high intake of UPFs is associated with increased odds of impaired fasting glucose in rural elderly. Further research is needed to elucidate the specific negative health effects of UPFs in different populations, and targeted efforts should promote healthy diets in both urban and rural areas.