Linear regression analyses were conducted using serum PTH as both categorical and continuous variable. Model 1: adjusted for age and sex; Model 2: adjusted for age, sex, race/ethnicity, smoking status, and glycohemoglobin levels (continuous); Model 3: adjusted for variables in Model 2 plus albumin, triglycerides, and highdensity lipoprotein levels (all continuous); Model 4: adjusted for variables in Model 3 plus corrected total calcium, 25hydroxyvitamin D, and estimated glomerular filtration rate (all continuous).
