Association between dietary copper intake and respiratory disease mortality

Area of Science:

• Nutritional Epidemiology
• Public Health
• Respiratory Medicine

Background:

• Copper is an essential trace element vital for numerous physiological processes.
• Dietary intake of essential nutrients can influence chronic disease risk.
• Respiratory diseases represent a significant cause of mortality globally.

Purpose of the Study:

• To investigate the association between dietary copper intake and mortality from respiratory diseases in a US adult population.
• To identify potential non-linear relationships and optimal intake thresholds for copper concerning respiratory mortality.

Main Methods:

• Utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, linked with National Death Index mortality data.
• Employed multivariable Cox proportional hazard models and sensitivity analyses.
• Applied restricted cubic splines (RCS) to assess non-linear dose-response relationships.

Main Results:

• A total of 580 respiratory disease deaths were recorded during 500,324 person-years of follow-up.
• Higher tertiles of dietary copper intake (≥0.88 mg/d) were associated with significantly lower hazard ratios for respiratory disease mortality compared to the lowest tertile (<0.88 mg/d).
• RCS analysis indicated an L-shaped association, with a protective threshold identified at approximately 1.07 mg/day of copper intake. Below this threshold, increased intake correlated with reduced mortality risk (HR=0.48); above it, no significant reduction was observed (HR=0.98).

Conclusions:

• An L-shaped association exists between dietary copper intake and respiratory disease mortality among US adults.
• Maintaining an optimal level of dietary copper intake, around 1.07 mg/day, may be associated with a decreased risk of mortality from respiratory diseases.
• Further research is warranted to confirm these findings and explore underlying biological mechanisms.