U-Shaped Association Between Dietary Copper and New-Onset Hypertension: A Nationwide Cohort Study in China

Background: The prospective association of dietary copper intake with hypertension remains unknown. We aimed to investigate the relationship of diatery copper intake with new-onset hypertension among Chinese adults.  Methods: 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 three consecutive 24-hour dietary recalls combined with a household food inventory. New-onset hypertension was defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg or diagnosed by a physician or under antihypertensive treatment during the follow-up. Findings: The median follow-up duration was 6·1 years. Overall, the associations between total 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 total copper intake (per SD increment: HR, 0·71; 95% CI, 0·57-0·88) in participants with total copper intake <1·57 mg/day, and increased with the increment of total copper intake (per SD increment: HR, 1·09; 95% CI: 1·07-1·12) in participants with total copper intake ≥1·57 mg/day.  Interpretation: 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 prevention of hypertension. Funding Information: This study was supported by the National Natural Science Foundation of China (81973133 and 81730019), Outstanding Youths Development Scheme of Nanfang Hospital, Southern Medical University (2017J009). Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: The institutional review boards of the University of North Carolina at Chapel Hill and the National Institute of Nutrition and Food Safety, and the Chinese Center for Disease Control and Prevention, approved the study. Each CHNS participant provided their written informed consent.