Serum Zinc Levels in Early Life and Risk of Elevated Carotid Intima-Media Thickness: An 8-Year Prospective Study

The association between serum zinc (SZn) concentration in adolescence-early adulthood and the risk of elevated carotid intima-media thickness (CIMT) in adulthood was investigated. A total of 519 participants (12-29 years) from the Tehran Lipid and Glucose Study with complete baseline data (2009-2011), including SZn concentrations, were recruited and followed through 2015-2018. CIMT was measured using high-resolution B-mode ultrasonography, and high-CIMT was defined as values above the sex-specific 90th percentile (i.e., 0.65 mm for men, 0.70 mm for women). Binary logistic regression models were used to estimate odds ratio (ORs) and 95% confidence intervals (CIs) for the association between baseline SZn and high-CIMT, considering SZn both as a continuous variable (per SD) and in tertiles [< 90, 90-120 (reference), ≥ 120 µg/dL), adjusted for potential confounders. Over a median follow-up of 8.6 years, 10.0% of participants developed high CIMT (7.0% of men, and 12.5% of women). Mean baseline age was 21.1 ± 4.2 years, mean SZn was 116 ± 49.2 µg/dL, and 23.9% were zinc deficient (18.7% of men, and 28.0% of women). In multivariable logistic regression models, each 50 µg/dL increase in baseline SZn was associated with a 43% lower odds of high CIMT at follow-up, although the association did not reach conventional statistical significance (OR = 0.57, 95% CI = 0.0.32-1.01, P = 0.056). Participants in the highest compared to the lowest SZn tertile (≥ 120 vs. <90 µg/dL) showed a 63% lower odds of high-CIMT (HR = 0.37, 95% CI = 0.14-1.00, P = 0.050). Higher SZn levels in adolescence-early adulthood may be associated with high-CIMT in adulthood, highlighting the potential importance of adequate zinc status for early-life vascular health.