Featured Research

from universities, journals, and other organizations

No increase in most common preventable cause of intellectual disability over 20 years, Quebec study finds

Date:
July 19, 2011
Source:
University of Montreal
Summary:
A new study that was prompted by recent reports of an increase in cases of congenital hypothyroidism in the United States, and aimed at assessing the incidence of this condition among Quebec newborns, suggests that the increase is entirely artifactual.

A new study that was prompted by recent reports of an increase in cases of congenital hypothyroidism in the United States, and aimed at assessing the incidence of this condition among Quebec newborns, suggests that the increase is entirely artifactual. CH is characterized by inadequate thyroid hormone production and is the most common cause of preventable intellectual disability.

The results were published in the Journal of Clinical Endocrinology and Metabolism by Dr. Johnny Deladoëy, a pediatric endocrinologist and researcher in metabolic and genetic diseases at CHU Sainte-Justine Research Center and an assistant professor of pediatrics and biochemistry at University of Montreal.

The increase in the number of cases identified may be an artifact due to changes in screening methods and results in the treatment of some children who may, in fact, not benefit from treatment. "Overly sensitive screening methods that identify mild cases of CH represent an obvious shift in neonatal screening from its original purpose, which was to identify severe cases in which the benefits from treatment would be clearly documented," Deladoëy said. "This might explain why, in the United States, more than a third of children labelled as having CH on the basis of neonatal screening no longer receive treatment after four years of age."

The lack of consensus about the thresholds on which to base detection has always presented a challenge for CH screening. Quebec pioneered universal screening for CH in newborns, being the first jurisdiction on the globe to initiate such a program in 1973. Quebec strategies and methodologies have proven to deliver reliable results and may serve as a model in the standardization of CH screening and diagnosis worldwide.

Thanks to a contribution rate of more than 90 % of hospitals and physicians to a provincial database over a period of 20 years, the results from the detection and diagnosis of 620 cases of CH could be analyzed.

Details about the study:

Historical data were analyzed for the study jointly with the Québec newborn blood screening laboratory located at the Centre hospitalier universitaire de Québec (CHUQ). More precisely, of the 1,660,857 newborns tested over the 20-year period, 620 cases of CH were detected, diagnosed and treated. During the second half of the period, a slightly more sensitive detection threshold was applied -- in addition to those expected, 49 further cases of CH were detected, representing an 18 % increase. Most of these additional cases had mild functional disorders whose impact on mental development is uncertain. Most importantly, the number of detected cases would have remained stable throughout the period studied if the screening threshold had been unchanged.

The study was published ahead of print on June 1, 2011 in the Journal of Clinical Endocrinology and Metabolism by Dr. Johnny Deladoey of the CHU Sainte-Justine Research Center and University of Montreal, jointly with Dr. Guy Van Vliet, also of the CHU Ste-Justine, and Dr. Jean Ruel and Dr. Yves Giguère, of the Québec newborn blood screening laboratory at the CHUQ.

The study was supported by scholarships of the Fonds de la recherche en santé du Québec and by a fellowship from the Canadian Child Health Clinician Scientist Program. Research in pediatric thyroid diseases at CHU Sainte-Justine is supported by the Girafonds/CHU Sainte-Justine Foundation. The University of Montreal is known officially as Université de Montréal.

Congenital Hypothyroidism

CH occurs in approximately one in 3,000 newborns, and its major consequence, intellectual disability, can be prevented through a universal screening test done on blood samples in the first few days of life, which enables initiation of thyroid hormone replacement during the second week of life. The test is considered one of the major public health breakthroughs of the last decades and has now long been implemented in all industrialized countries. Further studies assessing the benefits of the treatment of benign and transient cases need to be undertaken in order to evaluate whether or not they should be the object of screening.


Story Source:

The above story is based on materials provided by University of Montreal. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Deladoey, J. Ruel, Y. Giguere, G. Van Vliet. Is the Incidence of Congenital Hypothyroidism Really Increasing? A 20-Year Retrospective Population-Based Study in Quebec. Journal of Clinical Endocrinology & Metabolism, 2011; DOI: 10.1210/jc.2011-1073

Cite This Page:

University of Montreal. "No increase in most common preventable cause of intellectual disability over 20 years, Quebec study finds." ScienceDaily. ScienceDaily, 19 July 2011. <www.sciencedaily.com/releases/2011/07/110719072811.htm>.
University of Montreal. (2011, July 19). No increase in most common preventable cause of intellectual disability over 20 years, Quebec study finds. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2011/07/110719072811.htm
University of Montreal. "No increase in most common preventable cause of intellectual disability over 20 years, Quebec study finds." ScienceDaily. www.sciencedaily.com/releases/2011/07/110719072811.htm (accessed August 23, 2014).

Share This




More Health & Medicine News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) — An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) — Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) — Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) — It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins