[1] Natl Univ Ireland, Coll Med Nursing & Hlth Sci, Sch Med, Galway, Ireland
[2] Harvard Med Sch, Brigham & Womens Hosp, Div Haematol, Boston, MA 02115 USA
[3] Galway Univ Hosp, Saolta Univ Hlth Care Grp SUHCG, Dept Clin Biochem, Galway, Ireland
[4] Harvard TH Chan Sch Publ Hlth, Dept Epidemiol, Boston, MA USA
[5] London Sch Hyg & Trop Med, Dept Epidemiol & Populat Hlth, London, England