Plasma zinc level tied to first stroke risk in patients with hypertension

Takeaway

• This study found an inverse association between baseline plasma zinc levels and the risk for haemorrhagic stroke in patients with hypertension.
• This association was stronger in those with higher body mass index (BMI) and lower plasma copper levels.

Why this matters

• The findings, if further confirmed, may inform clinical and nutritional research on haemorrhagic stroke by considering zinc as a potentially variable risk factor, particularly in obese patients or those with low plasma copper levels

Study design

• This nested case-control study included 599 first stroke cases and 599 matched controls with complete zinc measurements from the China Stroke Primary Prevention Trial (CSPPT, n=20,702).
• Outcomes included the first stroke and its sub-types (first ischaemic and haemorrhagic stroke).
• Funding: National Key Research and Development Program and others.

Key results

• The risk for first haemorrhagic stroke was significantly lower in participants with plasma zinc ≥106.9 μg/dL vs those with baseline plasma zinc <106.9 μg/dL (adjusted OR [aOR], 0.45; 95% CI, 0.21-0.94).
• The inverse association of plasma zinc levels with first haemorrhagic stroke was significantly stronger in participants with (P_interaction<.05 for all):
  • BMI ≥25.0 kg/m², or
  • plasma copper level <100.1 μg/dL.
• Plasma zinc levels demonstrated no significant association with:
  • first total stroke (<104.0 vs ≥104.0 μg/dL; aOR, 0.93; 95% CI, 0.69-1.25), and
  • first ischaemic stroke (<103.3 vs ≥103.3 μg/dL; aOR, 1.16; 95% CI, 0.83-1.61).

Limitation

• Post-hoc analysis.
• Risk for residual confounding.