Association between dietary acid load and frailty in older adults with lung cancer: a cross-sectional study

Dietary acid load (DAL) may be a risk factor for chronic diseases, but evidence of its potential effects on frailty in older adults with lung cancer is lacking. This cross-sectional study explored the association between DAL and frailty in older adults with lung cancer. Frailty status was assessed using the Fried frailty criteria. Dietary intake was assessed in 262 patients with a 3-day, 24 h dietary recall, followed by the DAL assessment with both the potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores. Among all participants, 104 (39.7%) patients were classified as frail. Compared with the non-frail patients, the frail patients had significantly lower intakes of protein, potassium, calcium, phosphorus, and magnesium and higher NEAP scores (all P < 0.05). Logistic regression analysis showed that after fully adjusting for covariates, high NEAP scores were associated with an increased risk of frailty (OR = 1.03, 95% CI = 1.01-1.05, P = 0.002), whereas a high protein intake was associated with a reduced risk (OR = 0.97, 95% CI = 0.95-0.99, P = 0.013). Restricted cubic spline analysis showed a significant inverse nonlinear association between potassium intake and frailty (P = 0.017), with the frailty risk decreasing at intake levels of 1500-2000 mg d^-1 and increasing markedly below 669.2 mg d^-1. No association was found between PRAL and frailty after adjustment (P > 0.05). Overall, high NEAP scores and low intakes of protein and potassium were significantly associated with increased risk of frailty among older adults with lung cancer, supporting the potential role of diet in frailty intervention.