[1] St Georges Univ London, Div Commun Hlth Sci, London SW17 0RE, England
[2] UCL, Ctr Paediat Epidemiol & Biostat, Inst Child Hlth, London WC1N 1EH, England
[3] Ctr Longitudinal Studies, Inst Educ, Bedford Grp Lifecourse & Stat Studies, London WC1A 0AL, England
[4] Natl Ctr Social Res, London EC1V 0AX, England
[5] Univ Manchester, MRC Hearing & Commun Grp, Manchester M13 9PL, Lancs, England
[6] Royal Victoria Infirm, Dept Clin Biochem, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England
[7] UCL, Dept Epidemiol & Publ Hlth, London WC1E 6BT, England
[8] Univ Glasgow, Royal Infirm, Div Cardiovasc Med Sci, Glasgow G31 2ER, Lanark, Scotland
[9] Univ Aberdeen, Aberdeen Pain Res Collaborat, Epidemiol Grp, Aberdeen AB25 2ZD, Scotland
[10] Australian Natl Univ, Natl Ctr Epidemiol & Populat Hlth, Canberra, ACT 0200, Australia
[11] Ctr Psychiat, Queen Mary Sch Med & Dent, London EC1M 6BQ, England