Joint analysis of diet quality, inflammatory potential of diet and ultra-processed food exposure in relation to chronic respiratory diseases and lung cancer mortality

Objective: Examined the combined effects of ultra-processed food (UPF), Dietary Inflammatory Index (DII), Healthy Eating Index-2015 (HEI-2015), and Dietary Antioxidant Index (DAI) on mortality from chronic respiratory diseases (CRDs), chronic obstructive pulmonary disease (COPD), and lung cancer.

Methods: A prospective analysis included 96,607 participants (53 % women). Diet intake was measured using food frequency questionnaire. Associations of dietary exposures with CRD, COPD, and lung cancer mortality were examined using Cox regression.

Results: During 1,459,299 person-years of follow-up, there were 30,623 all-cause deaths, including 5218 from CRDs, 1613 from COPD, and 2127 from lung cancer. A 10 % increase in UPF intake (% grams/day) showed a non-linear association with higher CRD and COPD mortality but not lung cancer. Stronger curvature was observed between DII and mortality from all three conditions. However, HEI-2015 was inversely associated with CRD, COPD, and lung cancer mortality, while DAI showed an inverse relationship with CRD and COPD mortality but not lung cancer. Adjusting for DII attenuated UPF-related mortality risks by 39 % (CRD), 11 % (COPD), and 18 % (lung cancer), while HEI-2015 adjustment showed less attenuation. Additionally, the DII-mortality associations were less attenuated after adjusting for UPF intake but were offset after adjusting for HEI-2015. However, the HEI-2015-mortality associations remained unaffected when adjusted for UPF, DII, or DAI.

Conclusions: The findings highlight that the UPF-mortality relationship is potentially explained by DII and, to a lesser extent, by HEI-2015. Adhering to HEI-2015 guidelines can counterbalance the effects of DII on respiratory health but may not offset the effects associated with UPF.