In August of 1996, a homocysteine substudy was added to CATCH. The substudy used serum samples collected in eighth graders in the spring of 1997 for analyses of homocysteine, folic acid, vitamin B-12, vitamin B-6, lipids, lipoproteins, blood pressure, weight and height. A mail survey was conducted to collect data on the children's family history of cardiovascular disease and vitamin supplementation. The results paper was published in JAMA in 1998.