Writing in the American Journal of Respiratory and Critical Care Medicine, David A. Lomas, Ph.D., of the Cambridge Institute for Medical Research, Cambridge, UK, along with five associates, showed that 44 (34.9 percent) of 126 current or ex-smoking siblings of COPD patients had airflow obstruction in keeping with COPD.

In addition, 36 of the siblings also had forced expiratory volume in 1 second lung function tests of less than 80 percent of the predicted value, which was also in keeping with COPD.

In another part of this study, 111 current or ex-smoking siblings were matched for age, sex, and smoking history with 419 control subjects who had no known history of COPD. The prevalence of COPD in the sibling group was 31.5 percent in contrast with 9.3 percent for the control subjects.

COPD manifests itself as both bronchitis and severe emphysema. A slowly progressive lung disease characterized by gradual loss of lung function, the disease is caused primarily, in the U.S. and throughout most of the developed world, by smoking.

Victims have an abnormal inflammatory response in their lungs to noxious particles or gases from cigarettes. Patients have persistent disruption of airflow in and out of their lungs that gets progressively worse. Dyspnea, difficult or labored breathing, is the overriding symptom. During year 2000, it is estimated that 2.88 million people died from this condition worldwide.

For this study, the scientists first identified 150 index cases (81 men and 69 women) with airflow obstruction and low gas transfer factor associated with severe COPD. The mean age of the group was slightly over 52. These individuals were contacted in person or by phone and asked to complete the American Thoracic Society (ATS) respiratory questionnaire to record details associated with their occupation, smoking, respiratory symptoms, medical visits and demographic history.

Lung function data and other information was recorded from the patients’ hospital notes.

Thirty-eight of the parents of the 150 index cases and 173 siblings (out of 221 total) of the COPD victims also completed the ATS questionnaire. They were then asked to take a simple lung function test at a local general practitioner’s office. If their screening test showed airflow obstruction, they were invited to go to a local hospital and take a full series of lung function tests.

“Approximately one-quarter of the siblings who completed the questionnaire and spirometry test were nonsmokers,” said Dr. Lomas. “These siblings had essentially normal lung function. This reinforces the clear message that irreversible airflow obstruction is linked to tobacco smoking.”


[Contact: David A. Lomas Ph.D.]

19-Nov-2001