4/ Data Source: NHANES (2005–2012), 22,692 U.S. adults (≥20 yrs).
Depression Measure: PHQ-9, ≥10 score = depression.
Creatine Intake: Two 24-hour dietary recalls, categorized into quartiles.
Covariates: Age, sex, race, BMI, education, income, smoking, physical, antidepressant