Nonlinear Relationships Between Dietary Selenium Intake and Ischemic Heart Disease Incidence and Mortality: A Cross-Sectional and Longitudinal Ecological Study.

Objective: Selenium, an essential mineral with antioxidant properties, can potentially prevent atherosclerosis and maintain cardiovascular health. However, the association between selenium and ischemic heart disease (IHD) remains unclear. This study aimed to determine the impact of selenium on global IHD incidence (IHDi) and mortality (IHDd) over a 28-year period from 1990 to 2018, using open data for global comparisons.

Method: IHDi and IHDd per 100,000 people were obtained from the Global Burden of Disease Study (GBD) 2019 database and estimated selenium intake from the Global Dietary Database. Covariates were obtained from the World Bank and GBD databases. The associations of selenium intake with IHDi and IHDd in the 28 years from 1990 onward were analyzed for 149 countries with populations >1 million, using a Bayesian generalized additive mixed model, controlling for covariates.

Results: A nonlinear relationship existed between selenium intake and IHDi and IHDd. The selenium intake levels with the lowest risk for IHDi and IHDd were 93.3 and 78.5 µg/d, respectively. The risk ratios (RRs) for IHDi were 2.30 (95% CI, 1.82-2.84) and 1.40 (95% CI, 1.13-1.73) for selenium intakes of 10.0 µg/d and 200.0 µg/d, respectively. For IHDd, the RRs were 3.40 (95% CI, 2.62-4.40) for intakes of 10.0 µg/d and 1.72 (95% CI, 1.31-2.20) for 200.0 µg/d. The risk was higher for selenium underintake than for overintake.

Conclusions: This study revealed a nonlinear relationship between selenium intake and IHDi and IHDd, aiding in establishing a selenium target intake for the primary prevention of IHD and addressing public health problems.