Abstract P077: Plasma Homocysteine, Dietary B Vitamins, and Risk of Peripheral Artery Disease
Background: Clinical trials of vitamin B supplements to lower homocysteine levels have not consistently lowered risk of PAD, but these interventions were typically 1-2 years duration and limited to participants with pre-existing vascular disease. Whether long-term homocysteine levels influence the development of incident PAD remains uncertain.
Objective: To examine the association between levels of plasma homocysteine and dietary B vitamins (folate, B6 and B12) and risk of PAD.
Methods: We identified 276 cases of PAD in the Nurses’ Health Study (NHS) which followed 121,700 female nurses from 1980-2010, and 406 cases in the Health Professionals Follow-up Study (HPFS) which followed 51,529 male health professionals from 1986 to 2008. B vitamin intake was measured using a FFQ administered every four years. After excluding individuals with a history of CVD at baseline, plasma homocysteine was measured in baseline blood samples in two nested case-control studies with three controls matched to each case: NHS (1989-2010; 144 cases and 432 controls) and HPFS (1994-2008; 143 cases and 429 controls). PAD cases were confirmed by medical record based on at least one of: (1) amputation, bypass, or revascularization procedure, (2) angiogram/ultrasound confirming at least 50% stenosis, (3) ankle-brachial index < 0.9, or (4) documented physician’s diagnosis. We used Cox proportional hazards models to estimate hazard ratios (HR) for PAD in the cohorts and conditional logistic regression to estimate relative risks (RR) for PAD in the nested case-control studies.
Results: Men in the highest tertile of plasma homocysteine had more than double the risk of PAD compared to men in the lowest tertile (Table). This association was not replicated in women. Lower folate intake was also associated with an increased risk of PAD in men but not women (Table). Total B6 and B12 intake was not consistently associated with risk of PAD in men or women.
Conclusions: Higher plasma homocysteine levels were associated with an increased risk of PAD in men but not women.
- © 2013 by American Heart Association, Inc.