To examine the longitudinal associations between adherence to multiple healthy dietary patterns and frailty progression among older Chinese adults, and to determine whether these associations differ across population subgroups.

Prospective cohort study.

A total of 1,374 community-dwelling older adults from the China Health and Nutrition Survey (CHNS), 2004–2011.

Frailty was repeatedly assessed using a 27-item frailty index. Adherence to eight dietary patterns was evaluated, including the Planetary Health Diet Index (PHDI), Alternative Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH), Alternative Mediterranean Diet (aMED) score, American Cancer Society 2020 diet score (ACS2020), healthful plant-based diet index (hPDI), low-carbohydrate diet score (LCD), and Chinese Healthy Eating Index (CHEI). Linear mixed-effects models were used to examine associations between dietary patterns and longitudinal frailty progression, with subgroup analyses to assess population differences.

Higher adherence to AHEI, DASH, aMED, hPDI, LCD, and CHEI showed significant inverse dose–response associations with frailty progression (all p for trend <0.05), whereas no significant associations were observed for PHDI or ACS2020 (p for trend = 0.728 and 0.653, respectively). No effect modification was observed by age, sex, BMI, or baseline frailty level (all p for interaction >0.05). However, significant interactions were observed by geographical region for PHDI and hPDI, and by urbanization level for PHDI, AHEI, and ACS2020 (all p for interaction <0.05).

These findings support the role of high-quality dietary patterns in slowing frailty progression, with associations varying across geographical regions and levels of urbanization.