Coffee drinking and cigarette smoking: II. coffee, urinary pH and cigarette smoking behavior

This study was designed to evaluate the relationship between coffee consumption, urinary pH, and cigarette smoking. Urine acidity levels were manipulated and the resulting effect on cigarette smoking was monitored. Each of eight subjects participated in each of four conditions in which they received: water, coffee, coffee plus sodium bicarbonate, or coffee plus ascorbic acid. Subjects provided both pre- and post-session urine specimens, which were analyzed to determine pH, and cigarette butts were collected. The results showed that subjects smoke more cigarettes in a one hour session when they receive coffee. However, coffee did not have the effect of increasing urine acidity in one hour so that increased urine acidity cannot account for observed smoking increases. The results are discussed in terms of a stimulus control explanation for the relationship between coffee consumption and cigarette smoking.