Pes­ti­cides ex­po­sure link to Parkin­son’s

The Weekend Australian - Travel - - Health -

SCI­EN­TISTS have found more ev­i­dence to sup­port the the­ory that ex­po­sure to pes­ti­cides, even in small amounts, can in­crease the risk of Parkin­son’s dis­ease.

Re­search on nearly 1000 Parkin­son’s suf­fer­ers in five coun­tries — one of the largest such stud­ies to date — showed that high-level ex­po­sure in­creased the risk of con­tract­ing the de­bil­i­tat­ing brain dis­ease by 39 per cent.

Lower-level ex­po­sure, con­sis­tent with hob­by­gar­den­ing use of pes­ti­cides, cor­re­sponded with a 9 per cent in­crease, said Fin­lay Dick, the lead au­thor of the study, pub­lished in the Bri­tish jour­nal Oc­cu­pa­tional and En­vi­ron­men­tal Medicine.

Parkin­son’s is an in­cur­able, de­gen­er­a­tive dis­ease of the cen­tral ner­vous sys­tem that causes un­con­trol­lable shak­ing, along with im­paired speech and move­ment. In ap­prox­i­mately one-third of cases it also re­sults in de­men­tia.

In Aus­tralia, Parkin­son’s dis­ease is thought to af­fect about 40,000 peo­ple. The dis­or­der af­fects about one to two peo­ple per 1000, but over the age of 60 the rate in­creases to one in 100. It is slightly more com­mon in men than in women.

Pre­vi­ous stud­ies have also es­tab­lished a clear link be­tween Parkin­son’s and pes­ti­cides, with a ma­jor sur­vey in the US among agri­cul­tural work­ers last year re­port­ing an even higher risk, at some 70 per cent.

But the re­search by Dick and his col­leagues at Aberdeen Univer­sity pro­vides far more de­tailed in­for­ma­tion about how and when, and to what ex­tent ex­po­sure oc­curred.

Us­ing Bri­tish oc­cu­pa­tional safety lim­its as a stan­dard, the re­searchers di­vided the re­spon­dents into two groups based on the in­ten­sity and du­ra­tion of ex­po­sure.

The 959 re­spon­dents were ques­tioned about life­time ex­po­sure to pes­ti­cides and a variety of other chem­i­cals, as well as other po­ten­tial fac­tors that may con­trib­ute to the ill­ness, such as in­ci­dence within the fam­ily and head in­juries.

‘‘ The big­gest risk was fam­ily his­tory,’’ Dick said. A par­ent or sib­ling with Parkin­son’s in­creased the risk by a fac­tor of three.

Not sur­pris­ingly, farm work­ers in the five re­gions ex­am­ined — in Scot­land, Swe­den, Ro­ma­nia, Italy and Malta — were the oc­cu­pa­tional group show­ing the high­est link be­tween pes­ti­cide use and Parkin­son’s. Dick em­pha­sised that an in­creased risk fac­tor does not mean that any­one who has used pes­ti­cides is now in dan­ger of con­tract­ing it.

‘‘ The key mes­sage here is that just un­der half of those in­ter­viewed’’ — in­clud­ing an ad­di­tional 1989 peo­ple in a con­trol group — ‘‘ re­ported some use of pes­ti­cides,’’ he said. ‘‘ The vast ma­jor­ity of peo­ple who used them will never have Parkin­son’s.’’

Ge­netic fac­tors and be­ing knocked un­con­scious also showed a sig­nif­i­cant link with the on­set of the dis­ease, ac­cord­ing to the study. The link with pes­ti­cide ‘‘ is an­other piece in the jig­saw’’, Dick said. AFP

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