Overall mortality was the primary outcome and defined as death due to any cause during follow-up, including diseases of heart (I00-I09, I11, I13, I20-I51), malignant neoplasms (C00-C97), chronic lower respiratory diseases (J40-J47), accidents (unintentional injuries) (V01-X59, Y85-Y86), cerebrovascular diseases (I60-I69), Alzheimer’s disease (G30), Diabetes mellitus (E10-E14), influenza and pneumonia (J09-J18), nephritis, nephrotic syndrome and nephrosis (N00-N07, N17-N19, N25-N27), all other causes (residual). Follow-up commenced at the baseline examination date. CVD mortality was considered as the secondary outcome and included death due to diseases of heart (I00-I09, I11, I13, I20-I51). The comprehensive information on this program and its procedures were published on the NHANES website (https://www.cdc.gov/nchs/nhanes/).