U-shaped association between dietary copper intake and new-onset hypertension

To investigate the relationship of dietary copper intake with new-onset hypertension among Chinese adults.

A total of 12,245 participants who were free of hypertension at baseline from the China Health and Nutrition Survey (CHNS) were included. Dietary intake was measured by 3 consecutive 24-h dietary recalls combined with a household food inventory. New-onset hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg or diagnosed by a physician or under antihypertensive treatment during the follow-up.

During a median follow-up of 6.1 years, 4304 participants developed new-onset hypertension. Overall, the associations between dietary copper intake and new-onset hypertension followed a U-shape (P for nonlinearity <0.001). The risk of new-onset hypertension significantly decreased with the increment of dietary copper intake (per SD increment: HR, 0.71; 95% CI, 0.57-0.88) in participants with copper intake <1.57 mg/day, and increased with the increment of dietary copper intake (per SD increment: HR, 1.09; 95% CI: 1.07-1.12) in participants with copper intake ≥1.57 mg/day.

There was a U-shaped association between dietary copper intake and new-onset hypertension in general Chinese adults, with an inflection point at about 1.57 mg/day. Our results emphasized the importance of maintaining optimal copper intake levels for the primary prevention of hypertension.