LOS ANGELES, Aug. 1 (UPI) -- At least 100 of nearly 600 documented cigarette additives have "pharmacological" effects, many of which enhance the delivery of nicotine, a U.S. study found.

Michel D. Rabinoff of the David Geffen School of Medicine at the University of California at Los Angeles investigated tobacco industry documents and other sources for evidence of possible pharmacological and chemical effects of tobacco additives.

The study found one-sixth of the documented cigarette additives had pharmacological actions that camouflage the negative impact of smoke in the environment by masking odor, visibility and irritation; enhance or maintain nicotine delivery; and mask symptoms and illnesses associated with smoking.

The findings appear in the online edition of the American Journal of Public Health.