Assessing tobacco use in an African population: Serum and urine cotinine cut-offs from South Africa.

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.

SUBMITTER: Ware LJ 

PROVIDER: S-EPMC6424978 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature