The Latest With close to 90 percent of all lung cancer cases attributable to smoking, and with chronic obstructive pulmonary disease (which includes emphysema and bronchitis, both of which are strongly tied to smoking) now the third-leading cause of death in the United States, about the best thing you can do to keep your lungs healthy is to quit smoking. Aside from that, getting an annual flu shot can reduce your risk of suffering not just the flu but also potentially deadly lung-related complications, especially for those with asthma or other lung diseases.

Air pollution poses about the same risk of death from lung cancer as does long-term exposure to secondhand smoke, according to a study in the March issue of the Journal of the American Medical Association (JAMA). People living in cities with higher levels of "fine particulate matter" had a greater risk of dying from lung cancer than those in cities with cleaner air. A spokesman for the American Lung Association credits the study with establishing a definitive link between air pollution and lung cancer and says the work has "major public policy implications."

A study published in the August issue of JAMA showed that cohabiting with dogs or cats may help protect your infant against future allergies. The study, funded by the National Institutes of Health (NIH), found that those who lived with two or more dogs or cats during their first year of life were half as likely to develop common allergies -- not only to pets but to ragweed, grass and dust mites, too -- at age 6 or 7 as their pet-free peers. The study adds to a growing field of evidence that too-clean environments may contribute to allergy development. But if you're already allergic, don't rush to the pet store: Hanging out with a dog or cat at this late date won't boost your resistance -- just your misery.

In a similar vein, an Australian study reported in the July issue of the Journal of Allergy and Clinical Immunology (JACI) presented data showing that babies who were exclusively breast-fed for at least four months gained protection against developing asthma.

A study published in the October issue of the journal Chest showed that treating sleep-disordered breathing (SDB) -- sleep apnea (in which breathing ceases for 10 seconds at a time or longer during sleep) and hyperopea (when breathing is so shallow that it leads to lowering of blood oxygen levels) -- not only helped subjects breathe easier but lowered their blood pressure, too. The upshot -- SBD, which often goes undiagnosed, may be quietly contributing to your hypertension. Ask your doctor to check it out.

Recommendations Because no reliable means of detecting lung cancer early enough to treat it effectively has been found, routine screening for lung cancer is not currently recommended, even for smokers and others at increased risk.

The American Academy of Allergy, Asthma and Immunology (AAAAI) has new asthma management guidelines posted on its Web site (though they are tricky to find: Go to aaaai.org/members/jaci.stm. Click on the link to JACI, the organization's journal, then on "Editors' Selections for Open Access," which appears on the left side of the page. Scroll down to "Guidelines for the Diagnosis and Management of Asthma Update on Selected Topic{ndash}2002." The guide covers use of inhaled steroids for adults and children.

The Next Thing The National Cancer Institute in September opened enrollment in a major clinical trial designed to determine whether spiral CT scanning, an X-ray technique that's shown promise in detecting early lung cancers, will in fact save lives among those at high risk for the disease. Slated to run through 2009, the National Lung Screening Trial could lead to establishment of a screening method in which physicians and patients can have some confidence.

A new flu vaccine that is inhaled through the nostril is working its way, slowly, through the Food and Drug Administration (FDA). FluMist, developed by a researcher at the University of Michigan as a painless alternative to injected vaccines, was found to contribute to asthma risk in kids under 5, and there's not sufficient evidence that it works on folks over 50. As a result, an FDA committee in December recommended its approval only for use by those between 5 and 50.

Worry Index Allergies affect more than 50 million people in the United States each year. (NIH)

An estimated 17 million people -- 4.8 million of them under 18 years old -- currently have asthma. (AAAAI)

Sleep apnea affects 12 million Americans. (NIH)

Lung cancer: The top cancer killer in the United States was expected to claim about 154,900 lives in 2002; an estimated 169,400 new cases were expected to be diagnosed last year. (ACS)

Hype-O-Scope Ads for the top-selling antihistamine Claritin make much of the convenience consumers gained when the drug was approved for over-the-counter sale in November, but leading allergists are decrying the move, saying it is likely to severely limit some patients' access to the drug. Bob Lanier, president of the American Academy of Allergy, Asthma and Immunology, says insurers are now likely to drop Claritin and similar nonsedating drugs like Zyrtec and Allegra (both of which are in line for OTC approval) from their formularies. While many people will have no trouble paying out-of-pocket to buy Claritin, Lanier says, others -- particularly those on low incomes -- may find themselves unable to afford the drugs they've come to count on for managing their allergies and turn to older, less desirable drugs that can cause drowsiness (and impair driving more than alcohol).

For More Information American Lung Association: www.lungusa.org.

American Academy of Allergy, Asthma and Immunology: www.aaaai.org.

National Cancer Institute: www.cancer.gov.

-- Jennifer Huget

Pollution is nearly as damaging as secondhand smoke.