U-shaped nonlinear relationship between dietary copper intake and peripheral neuropathy

Area of Science:

• Nutritional Neuroscience
• Neurology
• Epidemiology

Background:

• Dietary copper intake is a potential predictor of peripheral neuropathy.
• Limited research exists on the specific link between dietary copper and peripheral neuropathy.
• Peripheral neuropathy is a condition affecting nerves outside the brain and spinal cord.

Purpose of the Study:

• To investigate the relationship between dietary copper intake and peripheral neuropathy.
• To determine if copper intake levels (insufficient or excessive) are associated with neuropathy risk.

Main Methods:

• Utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999-2004.
• Employed multivariate logistic regression and restricted cubic spline (RCS) analyses.
• Examined the dose-response relationship between copper intake and neuropathy incidence.

Main Results:

• A significant U-shaped nonlinear relationship was observed between dietary copper intake and peripheral neuropathy (P < 0.001).
• Copper intake below 0.889 mg/d showed a decreased risk of neuropathy.
• Copper intake at or above 0.889 mg/d indicated an increased risk of neuropathy, with the highest risk in the fourth quantile of intake.

Conclusions:

• Both insufficient and excessive dietary copper intake are associated with a higher incidence of peripheral neuropathy.
• A specific intake threshold (0.889 mg/d) appears to differentiate risk levels.
• Further research is warranted to confirm these findings and elucidate the underlying mechanisms.