[1] Univ Calgary, Div Respirol, Dept Med, Calgary, AB, Canada
[2] Univ Calgary, Dept Obstet & Gynecol, Calgary, AB, Canada
[3] Univ Calgary, Dept Community Hlth Sci, Calgary, AB, Canada
[4] Univ Western Ontario, Div Rheumatol, Dept Med, St Josephs Hlth Care, London, ON, Canada
[5] Univ Calgary, Snyder Inst Chron Dis, Calgary, AB, Canada