What are the odds of your child being diagnosed with Type 1 Diabetes (T1D) if he or she tests positive to a Trialnet antibody test?
TrialNet is a multinational project and set of trials, supported by the ADA, the JDRF, and the NIH among others. It aims to detect (and in a later stage prevent) Type 1 Diabetes as early as possible, if possible before symptoms have appeared. Since relatives of T1Ds are more likely to become T1Ds themselves, the project aims to test siblings, children and parents (in general relatives) of T1D patients, to try and determine their risk of developing diabetes, and, if possible (through their trials) to prevent or delay the onset of the disease.
Who can get tested?
You can get tested if
- you are between the ages of 1 and 45 and have a parent, brother/sister, or child with T1D (ages 3-45 in the United Kingdom)
- you are between the ages of 1 and 20 and have an aunt/uncle, cousin, grandparent, niece/nephew, or half-brother/sister with T1D (ages 3-20 in the United Kingdom)
Why should you get your children tested?
Siblings of T1D children are 15 times more likely to become T1Ds themselves. By testing them early, you can either largely rule out the possibility, or, if they test positive for risks of diabetes, (a) regularly monitor them for early signs of the disease and (b) attempt to prevent the development of the disease through medical trials.
How does Trialnet test for diabetes risk?
Trialnet tests for the presence of five antibodies that are somewhat characteristic of diabetes. 90-95% of PWDs test positive for at least one of these antibodies. A person who tests negative to all five antibody tests is unlikely to develop the disease. A person who tests positive to exactly one antibody test has some chances of developing the disease. A person who tests positive to two or more antibody tests is likely to eventually develop the disease.
I have a T1D child. How likely are my other children to get a negative Trialnet test?
96% of all subjects tested by Trialnet test negative.
My child had a positive Trialnet test. How likely is he/she to develop Type 1 diabetes?
@joshualevy has an outstanding blog post that explains these odds in detail. The following figure describes these odds.
courtesy Joshua Levy, http://cureresearch4type1diabetes.blogspot.com
On this figure, the horizontal axis is the number of years following the test. The vertical axis is the likelihood of NOT being diagnosed with diabetes. Each curve gives, for a given number of positive Trialnet tests, the odds of NOT being diagnosed with diabetes after a certain number of years. Each curve is characteristic of a specific number of positive tests.
The solid black curve at the top shows the likelihood of NOT being diagnosed with diabetes, with Zero positive test. You can see that it remains practically at 1 (100%) all the way through: with zero positive test, you are very unlikely to ever develop diabetes.
The next curve, solid purple, indicates the likelyhood of NOT being diagnosed with diabetes, with One positive test. You can see that, after seven years, a subject with one positive test only has approximately 10% chance to be diagnosed with diabetes.
The next curve, golden dashes, indicates the likelihood of NOT being diagnosed with diabetes, with Two positive tests. You can see that, after seven years, a subject with two positive tests has close to 40% odds to develop diabetes. More positive tests (the dashed lines below) make diagnosis more likely.
In practice, ADA and JDRF consider that, with two or more positive tests, a subject is very likely to eventually develop the disease. Both name the state of being positive for two or more tests but not yet presenting T1D symptoms “early stage Type 1 diabetes.”
You can read @joshualevy 's analysis to get more detail on odds here:
- Trialnet: https://www.trialnet.org/
- Trialnet risk screening eligibility: https://www.trialnet.org/our-research/risk-screening
- @joshualevy 's discussion of T1D diagnosis odds after a Trialnet test: http://cureresearch4type1diabetes.blogspot.com/2013/10/time-to-diabetes-by-number-of-antibodies.html
- Trialnet FAQs: https://www.trialnet.org/our-research/common-questions
- InsulinNation’s discussion of Trialnet: https://insulinnation.com/treatment/cure-insight/good-news-bad-news-trialnets-bittersweet-world/
- Research results of Trialnet as published in 2008 (peer-reviewed journal, accessed through NIH): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2918900/
- Statement of the ADA, JDRF and Endocrine Society on staging presymptomatic Type 1 diabetes: http://care.diabetesjournals.org/content/38/10/1964
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