REPORTS that Michael Jackson weighs 6½st although his height is 5ft 10in would mean that his body mass index is well under 20.7, a level at which any man is considered under weight.

If it is under 17 they are in need of medical help. This is the sort of weight found among prisoners of war returning from the Japanese camps but Mr Jackson is unlikely to suffer such severe vitamin and trace element deficiency.

Such extreme weight loss has well-recorded health risks, and may have accounted for his collapses as the result of low blood pressure, or abnormal cardiac rhythms, especially a slowed heart rate and a prolonged QT interval, which is indicative of a slow transmission of the impulse that triggers the contraction of the chambers of the heart. This may be a cause of collapse and occasionally of death.

Prolonged weight loss has widespread metabolic consequences, including low blood levels of potassium, sodium and blood glucose, as well as changes to bone structure. Thyroid function will also be reduced and the body’s temperature lowered. Intellectual power is affected and there is frequently insomnia. If the anorexia has been induced by anxiety and depression these are made worse. It was interesting to note that Mr Jackson was reluctant to fraternise with his fans and the crowd as social isolation and withdrawal are features of both anorexia and depression.

It is likely that Mr Jackson is anorexic because he has been depressed and anxious and is grieving over the loss of his status, career and wealth. His doctors will want to make certain that there are no other causes for his weight loss. His history of excessive cosmetic surgery suggests that he suffers from dysmorphobia, when someone is obsessively preoccupied by one or more parts of their body that they feel to be abnormal or ugly. It is often associated with anorexia or depression.

Now that the anxiety of being incarcerated for 20 years will have eased, he will be encouraged to eat, but not excessively. Too much, too rich food too fast can result in gastric or duodenal ulceration and perforation.

The physical response to his depressive state is so great that doctors will probably want to treat it immediately rather than wait for the grief to lift. If his blood chemistry has been affected by his weight loss, this will need to be corrected. His cardiac rhythm will need monitoring.

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