Consumption of Cooked Meat Not Linked to sporadic CJD

[Guest guest]

I found this in a doctor's guide on-line. What a shame that the US doesn't

care as much as France obviously does about the origins of " sporadic " CJD.

Beverly G.

Consumption Of Cooked Meat Not Linked To Sporadic Mad Cow Disease

PARIS, France -- April 13, 1998 -- Creutzfeldt-Jakob disease (CJD) is

currently the most frequent transmissible subacute spongiform encephalopathy

(TSSE) in humans. The cause of the most common form, sporadic CJD, remains

unknown. There is no laboratory test for the disease and no curative

treatment.

Since 1990 CJD has been the focus of a European epidemiological study. An

article in this week’s issue of The Lancet gives the results of the European

network on risk factors for sporadic CJD.

Ninety percent of cases of CJD are " sporadic " , meaning they strike people at

random, independently of known biological or environmental causes. In this

sense these cases differ from the new form of CJD ( " new variant " CJD)

described in 1996, which has been linked to bovine spongiform encephalopathy

(BSE) (see inset).

Given the rarity of CJD (its yearly incidence is still less than one case per

million inhabitants), only a very large survey study could identify the

several hundred of cases of CJD required for a fine epidemiological analysis.

A European network was launched in 1990 . It now counts five countries which,

over three years, analyzed the risk factors for sporadic CJD. No study of

this scale had previously been undertaken.

Between 1993 and 1995 a questionnaire focusing on the patient’s medical

history, dietary habits and occupational environment was submitted to carers

of the 405 notified subjects with sporadic CJD (most patients are too ill to

answer themselves). All the patients included in the study had a firm

diagnosis ruling out the new variant CJD described in 1996. The

epidemiologists submitted the same questionnaire to 405 individuals forming a

control population.

Comparison of the two sets of replies showed no link with previous surgery or

blood transfusion, or consumption of beef, veal, lamb, cheese or milk. In

contrast, the scientists identified a weak but significant association

between certain factors and sporadic CJD, including consumption of raw meat

or brain tissue, exposure to fertilizer manufactured from animal remains

(horn and hoof), and activities bringing people into contact with skins,

leathers and furs.

The researchers underline the fact that the study is only a first step, and

that many questions remain to be answered. In particular, it is conceivable

that the risk factors identified simply reflect another, unidentified habit

or behavior. In addition, there is a risk of bias as in all epidemiological

studies, particularly those based on indirect testimony. Finally, the authors

themselves state that even if there is effectively a direct link between

these risk factors and CJD, it would only explain a small number of sporadic

cases (3 or 4 per year in France) and the French program on TSSE and prions.

A new study is under way within the framework of the European Biomed 2

program (1997-1999).

Sporadic forms, which are most frequent in subjects over 60, account for

about 90 percent of all cases of CJD. The remaining 10 percent are

distributed among genetic forms, iatrogenic forms (treatment with pituitary

hormone growth, dura mater transplants) and new variant CJD due to the BSE

prion described in 1996.