Does a higher dietary inflammatory index increase the risk of developing COPD according to recent studies?

The dietary inflammatory index (DII) is a score that measures how likely a diet is to cause inflammation in the body. A higher DII means a more pro-inflammatory diet. Several large recent studies have found that people with higher DII scores are more likely to develop chronic obstructive pulmonary disease (COPD). This connection appears to be driven by inflammation, as inflammatory markers like C-reactive protein partly explain the link.

What the research says

A large prospective study from the UK Biobank followed over 167,000 people for about 13 years and found that each unit increase in DII was linked to a 5% higher risk of developing COPD ⁴. An even stronger association was seen with the energy-adjusted DII (E-DII), where each unit increase raised risk by 20% ⁴. People in the highest quarter of DII scores had a 27% higher risk of COPD compared to those in the lowest quarter ⁴.

Other studies confirm this pattern. An analysis of over 30,000 US adults found that each unit increase in DII was associated with an 8% higher prevalence of COPD ¹⁰. Similarly, a study of over 13,000 participants reported that each unit increase in DII raised COPD incidence by 8% ¹¹. These findings held even after adjusting for other risk factors like smoking and body weight.

The research also suggests that inflammation is the key mechanism. In the UK Biobank study, inflammatory markers such as C-reactive protein (CRP) and the systemic immune-inflammation index (SII) partly explained the link between DII and COPD ⁴. Another study found that pro-inflammatory diets increased risk through higher white blood cell counts and other inflammation markers ⁹. In contrast, diets rich in antioxidants (measured by the composite dietary antioxidant index) were linked to lower COPD risk ⁹.

Importantly, the link between diet and COPD may work both ways. One study found that a higher Planetary Health Diet Index (which emphasizes plant-based foods) was associated with a 9% lower COPD prevalence, and this protective effect was partly explained by lower DII scores ¹⁰. This suggests that anti-inflammatory diets may help reduce COPD risk.

What to ask your doctor

• Could my current diet be contributing to inflammation that affects my lung health?
• What specific dietary changes might help lower my dietary inflammatory index?
• Are there any blood tests (like CRP) that could help assess my inflammation levels?
• Should I consider working with a dietitian to create an anti-inflammatory eating plan?
• How does my diet interact with other COPD risk factors like smoking or air pollution?