BLACK-WHITE DIFFERENCES IN SERUM COTININE LEVELS AMONG PREGNANT-WOMENAND SUBSEQUENT EFFECTS ON INFANT BIRTH-WEIGHT

Objectives. Higher levels of serum cotinine (a metabolite of nicotine) have been found in Black smokers than in White smokers even after sel f-reported cigarette dose was controlled. It is unknown whether higher cotinine levels in Black pregnant smokers may increase the risk of de livering an infant of reduced birthweight. Methods. We analyzed serum cotinine levels of 374 Black and 829 White women who smoked during pre gnancy and who delivered between April 1964 and April 1967. Racial dif ferences in the relationship between cotinine and birthweight were exa mined. Results. Cotinine levels were 27.4 ng/mL higher in Black smoker s after cigarette dose and confounding variables were controlled. Blac ks had higher cotinine levels than Whites at each dose. No significant racial differences in the rate of decrease in birthweight per nanogra m of cotinine per milliliter were found. Conclusions. Our results conf irm previous research showing higher cotinine levels at each smoking d ose in Black smokers than in White smokers. Because there was no diffe rence in the rate of decrease in birthweight due to cotinine, our resu lts suggest that cigarette smoking among Blacks may have a greater eff ect on birthweight than it does among Whites.