Long-term unprocessed and processed red meat consumption and risk of chronic obstructive pulmonary disease: a prospective cohort study of women.

Purpose: Limited studies have examined red meat consumption in relation to risk of chronic obstructive pulmonary disease (COPD), and none have examined the impact of long-term diet on COPD risk. We sought to investigate the association between long-term red meat consumption and risk of COPD.

Methods: The population-based prospective Swedish Mammography Cohort included 34,053 women, aged 48-83 years, followed for the current analyses from 2002 to 2014. Unprocessed and processed red meat consumption was assessed with a self-administered questionnaire in 1987 and 1997. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results: Over a mean follow-up of 11.6 years (2002-2014; 393,831 person-years), 1488 COPD cases were ascertained via linkage to the Swedish health registers. A positive association between long-term processed red meat (average from 1987 to 1997) and risk of COPD was observed. In contrast, no association was observed with unprocessed red meat with corresponding HRs of 1.36 (95% CI 1.03-1.79) for processed and 0.87 (95% CI 0.74-1.02) for unprocessed red meat among women who consumed ≥ 50 g/day compared to < 25 g/day. The observed association with processed meat was confined to ex-smokers (P for interaction = 0.30); women consuming of ≥ 50 g/day of processed meat had a 2.3-fold (95% CI 1.24-4.12) higher risk of COPD than those consuming < 25 g/day. No similar associations were observed among current or never smokers.

Conclusion: In this prospective cohort of women with moderate red meat consumption, long-term processed red meat consumption was associated with an increased risk of COPD particularly among ex-smokers.