One in four smokers over age 75 lied when asked about their tobacco use, compared to just 6 percent of 18- to 34-year-olds, according to researchers who broke down results of self-reported surveys along age, gender, and racial lines.

HealthDay News reported Feb. 14 that Monica Fisher and colleagues at Case Western Reserve University's School of Dental Medicine found that, overall, 8 percent of participants in the National Health and Nutrition Examination Survey who denied smoking were in fact smokers.

Moreover, Fisher and colleagues found that lying about smoking generally increased with age. Social taboos may be especially influential among older people, leading them to conceal their smoking habits, researchers said.

The study results cast doubt on the reliability of self-reported surveys on tobacco use, Fisher and colleagues said.

The research was published in the January 2008 issue of the Journal of Health Care for the Poor and Underserved.