Associations of multiple metal intake with all-cause and cardiovascular mortality in US adults stratified by age and sex: A prospective cohort from the NHANES database study

The relationship between dietary metal intake and mortality risk is controversial, and we investigated the relationship between intake of five metals (iron, copper, selenium, zinc, and magnesium) and all-cause, cardiovascular mortality in the total population, gender subgroups, and age subgroups. 17,207 participants from the National Health and Nutrition Examination Survey (NHANES) database from 2009-2016 were included in this study. Kaplan-Meier survival curves, multivariate Cox proportional hazards models, and restrictive cubic spline (RCS) curves were used to explore the association between metal intake and all-cause, cardiovascular mortality. In this study, the average dietary metal intake of men and older people was lower than that of women and younger people. The RCS curves found in the whole population that all-cause mortality was negative linearly associated with copper intakes, L-shaped with zinc and magnesium intakes. Further subgroup analyses of copper, zinc, and magnesium by age and gender revealed that only magnesium showed statistically significant differences in the age subgroups. In the 20-40 population, there was a non-linear increasing trend in magnesium intake and all-cause mortality, whereas there was a non-linear decreasing trend in the > 60 population. The relationship between metal intake and mortality is more than a simple linear correlation, and differences in age can affect this correlation. In metal exposure studies, different populations can be studied to better determine the effect of metal exposure on mortality. The dataset used for statistical analysis in this study is available on the NHANES website: https://www.cdc.gov/nchs/nhanes/index.htm.