[1] Univ Liverpool, Liverpool Sch Trop Med, Liverpool L3 5QA, Merseyside, England
[2] MRC Dunn, Nutr Unit, Cambridge, England
[3] Univ Glasgow, Dept Child Hlth, Glasgow G12 8QQ, Lanark, Scotland
[4] Univ Newcastle Upon Tyne, Dept Child Hlth, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[5] Scottish Execut, Environm Grp, Water Serv Unit, Edinburgh, Midlothian, Scotland