Geen verband meeroken en borstkanker
Aan een recent Engels onderzoek naar het verband tussen meeroken en
borstkanker namen maar liefst 1,3 miljoen vrouwen tussen 50 en 64 jaar deel. Het
resultaat was bedroevend voor de onderzoeker, Dr. Michael Thun: er was geen
enkel verband te ontdekken.
In allerhande rapporten die in de
laatste jaren zijn uitgebracht, onder andere het discutabele rapport van het
Californische EPA, werd steeds er van uitgegaan dat dit verband er wel is. Het
EPA rapport beweerde zelfs dat dit verband sterker is dan het verband tussen
meeroken en longkanker. Doorgewinterde anti-rokers als de Californische
wetenschapper Stanton Glantz, zijn niet blij met deze uitkomst en draaien zich
in het artikel in allerhande bochten om de bewering (dat het verband er wel
degelijk is) toch overeind te houden. Andere wetenschappers beamen de
bevindingen van dit onderzoek aan de hand van vorige studies die eenzelfde
resultaat aantoonden.
Al met al weer een onderzoek dat
aantoont hoe er in de meeroken-wetenschap, met name door tegenstanders van roken
en rokers, gemanipuleerd wordt.
So should women get more-frequent mammograms if they worked in smoke-filled restaurants or bars or had parents or a spouse who smoked? There are passionate scientists on both sides of the debate, and the answer may come down to the details of the research.
The British work looked at 1.3 million women ages 50 to 64. The preliminary results, presented at a conference in September, showed absolutely no link between secondhand smoke and breast cancer, according to Dr. Michael Thun, who saw a copy of the presentation and heads up epidemiological research for the American Cancer Society.
“These data are strong, and they seriously weaken the evidence that there is in fact any connection,” said Thun, adding that he is now reconsidering whether it’s worth the American Cancer Society’s resources to study the subject further, as it had planned to do. The study “seems like a major challenge to the hypothesis.”
The California study agreed that there is no association between older secondhand smokers and breast cancer. But it did find that premenopausal women exposed to secondhand smoke were at a 70 percent higher risk for developing breast cancer than those who weren’t exposed.
“According to our calculation, a third of the breast cancer in young women who worked as waitresses is attributable to secondhand smoke,” said Stanton Glantz, a professor of medicine at the University of California-San Francisco who was on the scientific panel that reviewed the study.
Melanie Marty, the California EPA scientist who oversaw the study, said she can’t explain why the finding applies only to younger women. One theory is that breast cancer in older women is caused by different factors than in younger women. Another explanation is that a woman’s breast tissue is most susceptible to carcinogens from puberty until her first child is born, making younger women more vulnerable to tobacco smoke.
But Dr. Valerie Beral, the coordinator of the British study, doesn’t buy it. She said that when she looked at premenopausal women in her group, she found no association between breast cancer and passive smoking.
