Serum zinc concentrations and prediabetes and diabetes in the general population

The association between serum zinc and diabetes development remains uncertain. We examined the associations between serum zinc and prediabetes and diabetes, and adult participants (≥ 20 years) from the 2011-2016 National Health and Nutrition Examination Survey. Serum zinc concentrations were measured with inductively coupled plasma dynamic reaction cell mass spectrometry. Prediabetes and diabetes were defined through questionnaires and fasting plasma glucose and hemoglobin A_1c levels. Weighted logistic regression and restricted cubic splines were adopted to explore the dose-response relationships between serum zinc concentrations and prediabetes and diabetes. Comparing the highest to lowest quartile of serum zinc concentrations, the multivariable-adjusted odds ratio (95% confidence interval) of prediabetes and diabetes was 3.24 (2.33-4.52, P_{for trend} < 0.01) and 1.64 (1.27-2.11, P_{for trend} < 0.01), respectively. In stratified analysis by sex, the association between serum zinc concentrations and prediabetes was found in both men (3.83 (2.60-5.66), P_{for trend} < 0.01) and women (2.41 (1.51-3.87), P_{for trend} < 0.01), and the association between serum zinc concentrations and diabetes was also found in both men (2.05 (1.34-3.13), P_{for trend} < 0.01) and women (1.65 (1.07-2.56), P_{for trend} = 0.15). The association between serum zinc and prediabetes was consistent in stratified analyses by body mass index and hypertension, and the association with diabetes was also found in subjects with hypertension. Restricted cubic splines showed that the relationships between serum zinc concentrations and prediabetes and diabetes were linear, respectively. In conclusion, serum zinc concentrations were positively associated with prediabetes and diabetes in the general population, and the associations were linear. The findings need to be confirmed by prospective cohort studies.