The Healthy Thyroid: What you can do to prevent and alleviate thyroid imbalance. Patsy Westcott

virus infecting the thyroid, although no single virus has yet been identified as the culprit. It tends to be especially common between the ages of 20 and 50. The condition usually resolves within two to five months, although one or two out of 10 of those who get it will have a recurrence. Symptoms may include:

      • swelling, pain and tenderness of the thyroid

      • flu-like symptoms and/or a raised temperature

      • symptoms of thyroid overactivity (see page 43) lasting for two to four weeks, sometimes followed by symptoms of hypothyroidism.

      • Autoimmune thyroiditis is yet another autoimmune effect on the thyroid. Mild autoimmune thyroiditis can affect as many as one in five women who are otherwise healthy, often without their even being aware of it. In a small number – about one in 10 – the disease may progress to overt hypothyroidism. The condition tends to run in families, so if you have a family history of this condition (see page 129), the doctor may suggest testing for thyroid antibodies.

      • Postpartum thyroiditis (see Chapter 9).

      Triggers and Causes

      Hashimoto’s thyroiditis, Graves’ disease and most kinds of thyroiditis are autoimmune conditions. What triggers the immune system to see the thyroid as its enemy in such cases? All have a genetic component, yet studies of identical twins show a relatively low genetic effect; clearly, environmental and lifestyle factors must play key roles. Research has been mainly aimed at Graves’ disease, but there is reason to believe that similar mechanisms may be involved in other autoimmune types of thyroid disease.

      Could Infection Play a Part?

      Because the immune system is commonly triggered by infection, the hunt has been on for some time to identify a possible specific infection that might trigger autoimmune thyroid problems. One of the most intriguing suggestions, described by US surgeon Mr David V. Feliciano in the American Journal of Surgery in November 1992, was that Graves’ disease might be sparked off by a food-poisoning bug known as Yersinia enterocolitica, a distant relative of the plague bacteria.

      Although Y. enterocolitica has not proved to be as significant as Feliciano suspected, a study published in the journal Clinical Microbiology and Infection in 2001 reported that patients with Hashimoto’s thyroiditis also had a 14-fold increase in Y. enterocolitica antibodies – so the question is still open.

      Is Stress to Blame?

      Over the past few years, there has been increasing evidence that, in a number of illnesses, the immune system is weakened by negative mental states such as fear, tension, overwork, anxiety and exhaustion – in a word, stress. So, could stress be responsible for autoimmune thyroid problems? The answer seems to be yes, especially in the case of Graves’ disease.

      Doctors in the 19th century observed that Graves’ disease often followed a period of severe emotional stress – a frightening episode or ‘actual or threatened separation from an individual upon whom the patient is emotionally dependent’. One 19th-century doctor, Bath-based physician Caleb Hillier Parry, described the onset of symptoms in the patient ‘Elisabeth S, aged 21’:

       [She] was thrown out of a wheelchair in coming fast down hill, 28th April last, and very much frightened, though not much hurt. From this time she has been subject to palpitation of the heart, and various nervous affections. About a fortnight after this period she began to observe a swelling of the thyroid gland.

      Today, Dr Mark Vanderpump, secretary of the doctors’ organization the British Thyroid Association, observes:

       When compared with people without thyroid disease or patients with toxic nodular goitres, patients with Grave’s more often give a history of psychological stress before the onset of hyperthyroidism through immune suppression followed by immunological hyperactivity. The same phenomenon is seen post pregnancy as well when the immune system is suppressed during pregnancy and relapse follows delivery.

      In Norway and Denmark, the incidence of hyperthyroidism increased during the first years of the Second World War. In their book Thyroid Disease: The Facts, Drs R.I.S. Bayliss and W.M.G. Tunbridge mention research showing a significant rise in the incidence of Graves’ disease in Northern Ireland since the start of political troubles in 1968. More recently, researchers reported a dramatic fivefold increase of Graves’ disease in eastern Serbia during the war in the former Yugoslavia.

      Significance of Life Events

      Back in 1991, a team of Swedish researchers found that those developing Graves’ had often suffered an unhappy event in the recent past. The death of a close relative or friend was reported by 15 per cent of Graves’ patients compared with 10 per cent of a control group. The disease was also more likely to strike those who were divorced or less happy with their jobs – suggesting that long-term anxiety, unhappiness and other negative feelings could be a factor.

      In 1998, Japanese researchers reported in the journal Psychosomatic Medicine that women diagnosed with Graves’ disease were seven-and-a-half times more likely to have experienced stressful life events although, curiously, the same finding did not hold true for men. In 2001, another study, reported in the journal Clinical Endocrinology, found a five-and-a-half-fold increase in ‘life events’ in individuals with Graves’ compared with those with toxic nodular goitre and those without thyroid problems. Intriguingly, in this study, people with Graves’ had also experienced more happy – but still potentially stressful – events like a promotion, a pay rise, getting engaged or married, or having a baby.

      None of these studies prove conclusively that stress is to blame for triggering Graves’ disease, but they do suggest a significant connection. However, fewer connections have been found linking stress with Hashimoto’s thyroiditis. Clearly, more research is needed to unravel the precise mechanism by which stress may tip the thyroid into overactivity and to determine whether it is a factor in thyroid underactivity.

      Smoking

      Smoking has long been a known risk factor for the thyroid eye disease Graves’ ophthalmology (see Chapter 8). However, its role in Graves’ disease has been less clear. Nevertheless, the evidence is beginning to stack up. In the 1998 Japanese study mentioned above, smoking was found to be an independent risk factor for women developing Graves’. This finding was echoed in a Danish study, published in the journal Thyroid in January 2002, in which 45 per cent of women diagnosed with Graves’ disease were current or former smokers, compared with 28 per cent of those with toxic nodular goitre and 23 per cent of those with autoimmune hypothyroidism.