Seniors more likely to deny smoking when asked

Feb 8 2008

More elderly adults are lighting up cigarettes and not reporting their nicotine habits to doctors and others, according to findings from one of the first studies to examine the accuracy of self-reported smoking habits by age, race and gender of adults 18 years and older by researchers at the Case Western Reserve University School of Dental Medicine and other university collaborators.

A combined total of 8 percent of people from all age and race groups studied were true smokers but had denied it.

The findings bring into question the validity of using self-reported tobacco use when conducting research projects, reporting tobacco use by the general public or caring for individuals with chronic diseases related to smoking, according to researchers of the study, “Age and Race/Ethnicity-Gender Predictors of Denying Smoking, United States.” The study has been published in the current Journal of Health Care for the Poor and Underserved.

The researchers conducted their study by identifying self-reported non-smokers from 15, 182 adults in the third National Health and Nutrition Examination Survey. They examined usage by age groups of 18-34, 35-54, 55-74, and 75-90. Groups of men and women were broken down by race and ethnicity into Mexican American, non-Hispanic White and non-Hispanic Black groups. The age group of 60 and older was also broken down into cognitively competent.

“Denying smoking overall increased with age from 6% of 18-34 year olds to 25% of the elderly over the age of 75,” said the article's lead author, Monica Fisher, Ph.D., DDS, MS, MPH, an associate professor at the Case Western Reserve University School of Dental Medicine.

Non-Hispanic white men and women followed the pattern of the overall study and increased denial with age. However denial of smoking decreased for older Mexican American women, but the denial rate basically remained stable over age for non-Hispanic black men and women and Mexican American men.

Social taboos against smoking among the older groups may drive some elderly to deny smoking, said Fisher.

But the consequences can be deadly. For example, researchers reported that an earlier study by other researchers showed cotinine—by-product of nicotine use that stays in the blood for several days after smoking -based smokers who self-reported as non smokers—had significantly higher mortality rates (36%) than self-reported true non-smokers (15%).

Fisher and other researchers from Case Western Reserve, the University of Michigan and the University of Kentucky called for the use of biomarkers, such as cotinine, as a more accurate measure of smoking when smoking is an important factor in the outcomes of research or health issues.

They compared the participant's self-reported smoking habits to blood levels of cotinine, to see if self-reported smoking habits matched the blood test. The researchers also used cotinine levels of 15ng/ml or greater to rule out individuals exposed to second-hand smoke. They also eliminated cigar, pipe or smokeless tobacco users from the study.

While researchers detected true smokers, the segment that occasionally smokes was potentially missed, which could raise the number of people who smoke.

Researchers concluded that caution is needed when using self-reported nicotine use as part of survey data and that additional measures are needed to validate who does or doesn't smoke.