Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Smoking Cessation Health Center

Font Size

Study: Secondhand Smoke Fading

70% Drop in Nonsmokers With Tobacco Marker in Blood From 1988-2002
WebMD Health News
Reviewed by Louise Chang, MD

June 7, 2006 -- Secondhand smoke exposure may be dwindling in the U.S., a new study shows.

The number of U.S. nonsmokers with detectable blood levels of cotinine -- a marker for tobacco exposure -- fell 70% from 1988 to 2002.

James Pirkle, MD, PhD, and colleagues report that finding in the June issue of Environmental Health Perspectives. Pirkle works at the CDC's National Center for Environmental Health.

A decline was seen in all age, gender, race, and ethnicity groups studied. But children and black nonsmokers had higher cotinine levels than other groups, so Pirkle's team recommends further work to curb the environmental hazard.

Snuffing Out Secondhand Smoke

Data came from 14 years of national health surveys and blood tests including nearly 30,000 nonsmokers.

Here's a look at the percentage of U.S. nonsmokers with detectable blood cotinine levels over the years:

  • 1988-1991: 88% of nonsmokers had detectable blood cotinine levels.
  • 1991-1994: 80% of nonsmokers had detectable blood cotinine levels.
  • 1999-2000: 51% of nonsmokers had detectable blood cotinine levels.
  • 2001-2002: 43% of nonsmokers had detectable blood cotinine levels.

The decline translates to a 70% drop in the number exposed from 1988 to 2002, note Pirkle and colleagues.

Cotinine only shows tobacco exposure over the previous few days, and it may fade faster or slower in some people, the researchers write.

Higher Cotinine Levels for Blacks, Children

The study tracked three racial/ethnic groups: blacks, whites, and Mexican-Americans.

Cotinine levels dropped for all groups. But blacks had higher cotinine levels than whites or Mexican-Americans throughout the study.

The reasons for that pattern aren't clear. Metabolic factors might account for some of the difference, the researchers write.

Children's cotinine levels also fell but not as much as in adults. The study doesn't pinpoint a reason for the smaller decline in kids. Children living with smokers may be exposed to tobacco at home, in cars, and in other settings, Pirkle's team notes.

Progress Made, Room for Improvement

The decline "probably reflects the substantial progress made in reducing the exposure of nonsmokers to [secondhand smoke] during this time," write Pirkle and colleagues.

The researchers call for increased intervention efforts to cut secondhand smoke exposure among kids and blacks. More work may be needed "to further encourage restrictions on smoking in the home, automobiles, and other locations when children are present," they write.

Today on WebMD

hands breaking a cigarette
Is quitting cold turkey an effective method?
14 tips to get you through the first hard days.
smoking man
Surprising impacts of tobacco on the body.
cigarette smoke
What happens when you kick the habit?

Filtered cigarettes
an array of e cigarettes
human heart
Woman experiencing withdrawal symptoms

man smoking cigarette
no smoking sign
Woman ashing cigarette in ashtray
chain watch