Serum zinc is positively associated with bone mineral density: A cross-sectional analysis of NHANES 2011–2016

This study aimed to investigate the association between serum zinc levels and bone mineral density (BMD) in a nationally representative sample of US adults, using National Health and Nutrition Examination Survey 2011-2016 data. We sought to determine whether serum zinc is independently correlated with BMD. A cross-sectional analysis was conducted including adults aged 20 years and older from National Health and Nutrition Examination Survey 2011-2016 cycles. Serum zinc concentrations were measured by inductively coupled plasma dynamic reaction cell mass spectrometry, and BMD was assessed by dual-energy x-ray absorptiometry. Multivariable linear regression models adjusted for demographic, socioeconomic, lifestyle, and clinical covariates were used to examine the relationship between serum zinc and BMD. Nonlinear associations and threshold effects were evaluated using smooth curve fitting. A total of 2515 participants were included. Higher serum zinc quartiles were associated with progressively higher BMD (P for trend <.001). In the fully adjusted model, serum zinc was positively associated with BMD (β = 0.002, 95% CI: 0.000-0.004, P = .016). Participants in the highest serum zinc quartile (>13.91 μmol/L) had significantly greater BMD than those in the lowest quartile (6.67-10.88 μmol/L; β = 0.024, 95% CI: 0.012-0.036, P < .001). Threshold analysis revealed a nonlinear relationship, with a stronger positive association above approximately 13.9 μmol/L serum zinc. This nationally representative study provides evidence that higher serum zinc levels are independently associated with greater BMD in US adults. The observed dose-response and threshold effects highlight the potential importance of maintaining adequate zinc status for bone health and osteoporosis prevention. Further prospective studies are warranted to confirm these findings and investigate the effects of zinc supplementation.