Thyroid hormone is produced from a tiny gland that curves across the windpipe just below the Adam’s apple; its job is to keep the body’s various functions working at the right pace. Too much and everything goes too fast – you lose weight, can’t sleep and your heart races; too little and your system slows down – fatigue, dry skin and constipation.
Too little (hypothyroidism) is the most common; production can be affected by all sorts of things – an autoimmune response, for example, or other factors such as prolonged stress or intake of certain drugs which can damage your thyroid. Patient groups like Thyroid-UK – set up in 1999 to fight for better treatment for this condition – claim pollutants and even a lack of fruit and vegetables can also reduce your thyroid gland’s output. The official NHS line, which Dr Skinner, author of Diagnosis and Management of Hypothyroidism disregarded, is that if the level of a marker for thyroid levels in your blood is within the ‘normal’ range, then you aren’t hypothyroid and you shouldn’t get a hormone supplement.
Dr Skinner’s approach was to treat the individual patient, not a blood test. “I’d run the regular test and some more besides,” he says. “But if the patient had all the symptoms that you get with low thyroid, then I’d prescribe a low dose supplement and gradually increase it. If their symptoms improved, that was a pretty good sign that their body needed more than the normal range.” In fact, whether you are found to be inside or outside the normal range can depend on where the test is being done.
The difference between the UK and the USA is particularly striking. In the UK, the healthy range for the most commonly used test – known as TSH (thyroid stimulating hormone) – is between 0.5 and 5, although many experts will refuse to treat a patient until the level reaches 10 (the job of TSH is to make the thyroid produce more, so when it is high it means the thyroid is in trouble). Yet four years ago, the American Association of Clinical Endocrinologists recommended that: “Doctors consider treatment for patients who test outside a TSH range of 0.3 to 3”. How many more patients that would mean should be officially treated in the UK isn’t known. But the Association commented that it would make 20% of the USA hypothyroid.
Thyroid expert Dr Leonard Wartofsky from the Department of Medicine at Washington Hospital Centre in the US thinks an upper level of 3 may even be too high. “According to the latest thinking, the upper level should be about 2.5,” he says. “My UK colleagues say there’s no evidence that treating below 10 is beneficial but I’d say it was mixed; studies showing benefit are coming in. We certainly see dramatic improvements in patients treated within reference levels here.” So there is certainly hot academic debate going on about just what counts as a healthy thyroid level. In fact, as Lynn Mynott of Thyroid-UK points out: “The Department of Health guidelines say that ‘blood tests are useful but should not be used in isolation’. In other words, you need to take symptoms into account as well.” So the first thing to do if you are worried about your thyroid levels and have had them tested by the doctor, is not to accept vague phrases about their being ‘high’ or ‘low’ but instead ask for actual numbers and ask what the testing lab considers a normal range.
If possible, get a copy of the actual report. If it shows that your TSH level is above 2.4 to 3.0 and you are told that this is normal, point out that the American Association of Clinical Endocrinologist (AACE) now recommends treating when TSH goes above 3.0. A more detailed test can be run by Genova Diagnostics. The lab’s Total Thyroid Screen includes tests for TSH, anti-thyroid antibodies and the two kinds of thyroxine (your thyroid hormone) called T4 and T3. T4 is converted into T3, the active form of thyroxine. For details, contact Genova at 020 8336...