0
Sign In  | Subscribe
19 February 2002, Vol 136, No. 4>
Summaries for Patients | 19 February 2002

Lung Function and Death from Chronic Obstructive Pulmonary Disease in α1-Antitrypsin MZ Heterozygotes FREE

[+] Article and Author Information

The summary below is from the full report titled “Change in Lung Function and Morbidity from Chronic Obstructive Pulmonary Disease in α1-Antitrypsin MZ Heterozygotes: A Longitudinal Study of the General Population.” It is in the 19 February 2002 issue of Annals of Internal Medicine (volume 136, pages 270-279). The authors are M Dahl, A Tybjærg-Hansen, P Lange, J Vestbo, BG Nordestgaard.


Ann Intern Med. 2002;136(4):I35-. doi:10.7326/0003-4819-136-4-200202190-00002
Text Size: A A A

What is the problem and what is known about it so far?

Chronic obstructive pulmonary disease (COPD) is a type of lung disease that is usually caused by cigarette smoking. The lungs of people with this disease are progressively destroyed by the irritation caused by cigarette smoke and by infection (bronchitis) that often accompanies smoking. Normal people can usually limit the destructive effects of this irritation because the body manufactures a protein that calms the inflammation caused by irritation from cigarette smoke. This protein (α1-antitrypsin) is produced because of the genes that we inherit from our parents. Each parent contributes one copy of the gene to make α1-antitrypsin. Very few people have a total lack of α1-antitrypsin (called α1-antitrypsin deficiency)—meaning that both parents have contributed a defective gene. The totally deficient person is known as a homozygote and is very likely to develop COPD and die at an early age. Many more people have inherited the defective gene from only one parent (heterozygotes). Physicians have been uncertain whether heterozygotes are more likely to develop COPD than are other persons in the normal population.

Why did the researchers do this particular study?

To compare heterozygotes with normal people to find out if they had more COPD, more hospitalizations for COPD, and more deaths from COPD than those who have two copies of the normal gene for α1-antitrypsin.

Who was studied?

9187 people, aged 20 years or older, who were part of the Copenhagen City Heart Study in Denmark.

How was the study done?

Exams were done three times (1976–1978, 1981–1983, and 1991–1994). Participants completed a questionnaire about smoking habits, underwent breathing tests, and had blood drawn during the third exam to see whether they had one copy of the normal α1-antitrypsin gene or two copies.

What did the researchers find?

451 participants (4.9%) had only one copy of the gene for α1-antitrypsin (heterozygotes), and they produced 31% less α1-antitrypsin than normal individuals. Heterozygotes had a slightly faster decline in lung function than genetically normal people. Nineteen percent of heterozygotes had COPD, while 15% of genetically normal participants had COPD. Hospitalization or death from COPD occurred 1.5 times more frequently in heterozygotes than in those with two copies of the normal gene.

What were the limitations of the study?

Approximately one third of the participants had only one breathing test, and their data could not be used to calculate the rate of decline in lung function over time. Blood to test genetic makeup was drawn only during the third examination; because people with more severe lung disease may have dropped out of the study before the third examination, the researchers may not have recorded the genetic makeup of many of these participants.

What are the implications of the study?

People with only one copy of the gene for α1-antitrypsin have an increased risk for developing COPD and are more likely to die of COPD than genetically normal people. Because heterozygotes are much more numerous than are homozygotes, the number of heterozygotes with COPD is about the same as the number of homozygotes.

Figures

Tables

References

Letters

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s “Cited By” API will populate this tab (http://www.crossref.org/citedby.html).
Compression-Only CPR: Pushing the Science Forward
Cone
AAM 2010;304:1493-1495.
All you need to read in the other general jounals
BMJ 2010;341:c5893-c1494.

Comments

Submit a Comment
Submit a Comment

Summary for Patients

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.

Toolkit

Buy This Article

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Register Now for a free account
Advertisement

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles
Update in Hospital Medicine: Evidence Published in 2011
Ann Intern Med. 2012;156(12):875-879.
In the Clinic
Chronic Obstructive Pulmonary Disease
Ann Intern Med. 2011;154(7):ITC4-1.
Chronic Obstructive Pulmonary Disease
Ann Intern Med. 2008;148(5):ITC3-1.
Topic Collections

Annals of Internal Medicine

Other Resources

Copyright © 2013 The American College of Physicians. All Rights Reserved.
Print ISSN: 0003-4819 | Online ISSN: 1539-3704

Buy This Article

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Register Now for a free account
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.
(Required)
(Required)