Study leader Dina Borzekowski of the University of Maryland School of Public Health and Joanna Cohen of the Johns Hopkins Bloomberg School of Public Health found only 38 percent of 2,423 5- and 6-year-old children in the six countries studied had any awareness of warning labels currently featured on cigarette packages.
Even after showing warning labels to participating children, about two-thirds of the children were unable to explain what the health warnings were about, the study found.
Among the six countries studied, awareness and understanding of health warning labels was greatest among children in Brazil, where graphic warning labels, often featuring extremely gruesome pictures, cover 100 percent of either the front or back of the cigarette package.
An earlier study -- drawn from the same sample of 5- and 6-year-olds -- showed more than two-thirds could identify cigarette brand logos, with the highest percentages in the sample from China, where 86 percent could identify at least one brand.
"Pro-smoking messages are reaching the world's most susceptible audiences," Borzekowski said in a statement. "We need to do a better job globally to reach children with anti-smoking messages. To do this, health warning messages should be big and clear, especially for low-literacy populations, children and young people."
The findings were published in the Journal of Public Health.