Lisa J Ware1, Karen Charlton2, Ruan Kruger3, Yolandi Breet4, Johannes van Rooyen5, Hugo Huisman6, Shani Botha7, Aletta S Uys8, Kirsten L Rennie9, Nirmala Naidoo10, Paul Kowal11, Aletta E Schutte12. 1. South African MRC Developmental Pathways for Health Research Unit, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. Electronic address: lisa.ware@wits.ac.za. 2. School of Medicine, University of Wollongong, and Illawarra Health and Medical Research Institute, New South Wales, Australia. Electronic address: karenc@uow.edu.au. 3. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, South Africa. Electronic address: ruan.kruger@me.com. 4. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. Electronic address: 21195706@nwu.ac.za. 5. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. Electronic address: Johannes.VanRooyen@nwu.ac.za. 6. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. Electronic address: Hugo.Huisman@nwu.ac.za. 7. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, South Africa. Electronic address: Shani.Botha@nwu.ac.za. 8. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. Electronic address: Lisa.Uys@nwu.ac.za. 9. MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, United Kingdom. Electronic address: Kirsten.Rennie@mrc-epid.cam.ac.uk. 10. World Health Organization (WHO), Geneva, Switzerland. Electronic address: naidoon@who.int. 11. World Health Organization (WHO), Geneva, Switzerland; University of Newcastle Research Centre for Generational Health and Ageing, Newcastle, Australia. Electronic address: kowalp@who.int. 12. Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, South Africa. Electronic address: alta.schutte@nwu.ac.za.
Abstract
BACKGROUND: Cotinine, a nicotine metabolite, is used to measure tobacco use and exposure, but recommended cut-offs to differentiate tobacco users from those exposed through the environment range from 3 to 58 ng/ml in serum, and 2.5 to 550 ng/ml in urine. Cut-offs may differ by ethnicity, sex and age. As data from adults in Africa are scarce, our aim was to evaluate cut-offs for serum and urine cotinine that best predict self-reported tobacco use in South African adults. METHODS: Two datasets were explored: African-PREDICT (n = 941 black and white healthy young adults, 20-30 years, serum cotinine); and WHO SAGE Wave 2 (n = 604 adults, 18-102 years, urine cotinine). Population specific cut-offs (ROC analyses) were compared with published cut-offs and self-reported tobacco use. RESULTS: Overall, 19% (293 of 1545) reported current tobacco use. The following cotinine cut-offs showed the highest sensitivity and specificity: serum ≥15 ng/ml in black and white men, and white women; serum ≥10 ng/ml in black women; urine ≥300 ng/ml for black, mixed ancestry, and older adults (50-plus years); urine ≥500 ng/ml for younger adults (18-49 years). Specificity was lower for urine than for serum cotinine. CONCLUSION: Our study suggests that a serum cotinine level of ≥15 ng/ml and a urine cotinine level of ≥300 ng/ml best distinguish current tobacco users from non-users generally in the South African adult population.
BACKGROUND:Cotinine, a nicotine metabolite, is used to measure tobacco use and exposure, but recommended cut-offs to differentiate tobacco users from those exposed through the environment range from 3 to 58 ng/ml in serum, and 2.5 to 550 ng/ml in urine. Cut-offs may differ by ethnicity, sex and age. As data from adults in Africa are scarce, our aim was to evaluate cut-offs for serum and urine cotinine that best predict self-reported tobacco use in South African adults. METHODS: Two datasets were explored: African-PREDICT (n = 941 black and white healthy young adults, 20-30 years, serum cotinine); and WHO SAGE Wave 2 (n = 604 adults, 18-102 years, urine cotinine). Population specific cut-offs (ROC analyses) were compared with published cut-offs and self-reported tobacco use. RESULTS: Overall, 19% (293 of 1545) reported current tobacco use. The following cotinine cut-offs showed the highest sensitivity and specificity: serum ≥15 ng/ml in black and white men, and white women; serum ≥10 ng/ml in black women; urine ≥300 ng/ml for black, mixed ancestry, and older adults (50-plus years); urine ≥500 ng/ml for younger adults (18-49 years). Specificity was lower for urine than for serum cotinine. CONCLUSION: Our study suggests that a serum cotinine level of ≥15 ng/ml and a urine cotinine level of ≥300 ng/ml best distinguish current tobacco users from non-users generally in the South African adult population.
Authors: Paul A Harris; Robert Taylor; Robert Thielke; Jonathon Payne; Nathaniel Gonzalez; Jose G Conde Journal: J Biomed Inform Date: 2008-09-30 Impact factor: 6.317
Authors: L E Wagenknecht; G R Cutter; N J Haley; S Sidney; T A Manolio; G H Hughes; D R Jacobs Journal: Am J Public Health Date: 1990-09 Impact factor: 9.308