[1] Univ Western Ontario, St Josephs Hlth Ctr, Dept Med, London, ON N6A 4V2, Canada
[2] Univ Western Ontario, St Josephs Hlth Ctr, Lawson Res Inst, London, ON N6A 4V2, Canada
[3] Univ Calgary, Fac Med, Div Endocrinol & Metab, Calgary, AB T2N 1N4, Canada
[4] Univ Toronto, St Michaels Hosp, Div Endocrinol & Metab, Toronto, ON M5B 1W8, Canada