Atherosclerosis 145 (1999) 221 – 224 Rapid communication Prevalence of mild fasting hyperhomocysteinemia in renal transplant versus coronary artery disease patients after fortification of cereal grain flour with folic acid Andrew G. Bostom a,b, *, Reginald Y. Gohh c , Gintaras Liaugaudas a , Andrew J. Beaulieu c , Haewook Han b , Paul F. Jacques b , Lance Dworkin c , Irwin H. Rosenberg b , Jacob Selhub b a Diision of General Internal Medicine, Memorial Hospital of Rhode Island, 111 Brewster Street, Pawtucket, RI 02860, USA b Tufts Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, MA, USA c Diision of Renal Diseases, Rhode Island Hospital, Proidence, RI, USA Received 19 November 1998; received in revised form 23 December 1998; accepted 11 January 1999 Abstract Cereal grain flour products fortified with 140 g folic acid per 100 g flour became widely available in southeast New England by July 1997. We hypothesized that improved folate status secondary to this fortification policy would have a much more limited impact on the prevalence of mild fasting hyperhomocysteinemia in renal transplant versus coronary artery disease patients. Between October 1997 and October 1998, fasting plasma total homocysteine (tHcy), folate and vitamin B12 levels were determined in a total of 86 renal transplant patients with stable allograft function, and 175 coronary artery disease patients whose serum creatinine was (1.4 mg/dl). All subjects lived in the Providence, RI, metropolitan area, and were either non-users of any supplements containing folic acid, vitamins B6 or B12, or had refrained from using such supplements for 6 weeks. Geometric mean fasting tHcy levels were 88.0% higher (15.6 vs. 8.3 mol/l; P 0.001), and the prevalence of fasting tHcy levels 12 M (69.8% vs. 10.9%, P 0.001) was markedly increased in the renal transplant patients, despite a much younger mean age and a relative preponderance of women. In the era of folic acid fortified flour, hyperhomocysteinemia is much more common in stable renal transplant versus coronary artery disease patients. As a result, renal transplant patients are a preferable high risk target population for controlled trials evaluating the tenable hypothesis that lowering total homocysteine levels will reduce cardiovascu- lar disease outcomes. © 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Arteriosclerosis; Folate; Homocysteine; Renal disease 1. Introduction Mild hyperhomocysteinemia may increase the risk for both recurrent cardiovascular disease in patients with established coronary artery disease [1] and de novo cardiovascular disease in stable renal transplant pa- tients [2]. Folate status is a determinant of mild hyper- homocysteinemia in general populations [3], coronary artery disease patients [4] and renal transplant patients [5]. Cereal grain flour products fortified with 140 g folic acid per 100 g flour began appearing voluntarily in the USA after March 1996 [6]. The availability of such products was widespread in southeast New England by July 1997 (J. Watson, Watson Foods, New Haven, CT, personal communication), and mandated throughout the USA by 1 January 1998 [7]. Given that renal disease renders individuals some- what refractory to the effect of low dose folic acid * Corresponding author. Tel.: +1-401-729-2859; fax: +1-401-729- 2950. E-mail address: abostom@loa.com (A.G. Bostom) 0021-9150/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved. PII:S0021-9150(99)00023-4