Comparison of the effect of oral and transdermal hormone therapy on fasting and postmethionine homocysteine levels

Objective: To compare the modifications on basal and post-methionine homocysteine (Hcy) levels induced by transdermal vs. oral continuous combined hormone therapy (HT). Design: Prospective randomized study. Setting: Outpatient service at university hospital. Patient(s): Twenty-four healthy postmenopausal women. Intervention(s): Six-month administration of transdermal (50 mug/d of E-2 and 140-170 mug/d of norethisterone [NET] acetate; n = 12) or oral (2 mg of E2 and 1 mg of NET acetate; n = 12) HT. Main Outcome Measure(s): Fasting levels of Hey, cysteine (Cys), folate, and vitamin B 12. Post-methionine Hey concentrations. Result(s): During HT, a slight decrease of fasting Hey (8.9 [6.7; 15.2] mol/L vs. 8.3 [4.9; 12.0] mumol/L) and fasting Hcy/Cys, a possible index of Hey trans-sulfuration (0.061 [0.039; 0.107] mumol/L vs. 0.048 [0.032; 0.093] mumol/L) was observed. Modifications were similar in the transdermal and oral group. Net decreases of Hey and Hcy/Cys observed during HT were related linearly to pretreatment values (r = 0.821 and r = 0.775, respectively), and were significant for Hey above, but not below, 9 mumol/L. Transdermal (33.5 [27.5; 75.9] mumol/L vs. 28.4 [17.4; 48.9] mumol/L) or oral HT (36.1 [17.7; 74.8] mumol/L vs. 29.9 [17.5; 50.3] mumol/L), decreased, similarly, post-methionine Hey levels. Conclusion(s): Similarly to oral, transdermal HT reduces post-methionine Hey and fasting Hey when it is elevated.