New dangers found in secondhand smoke (Commentaar)
by Paul Recer
The Associated Press
Wednesday, March 07, 2001, 12:00 a.m. Pacific
WASHINGTON -- A study indicates for the first time that tobacco-smoke
chemicals that cause cancer are absorbed by people who live in homes with
smokers.
The study, which is reported in today's Journal of the National Cancer
Institute, shows that chemicals linked to lung cancer are five to six times
higher in the urine of women who live with smokers than in women who live with
nonsmokers.
"A number of studies have shown a connection between environmental
tobacco smoke and lung cancer," said Stephen Hecht, the Wallin Professor of
Cancer Prevention at the University of Minnesota, Minneapolis. "Our study
provides the first biochemical support for this data."
Hecht, a co-author of the study, said that analyzing the urine of nonsmoking
wives of men who smoke at home shows that the women's bodies absorb
cancer-causing compounds from the atmosphere through their lungs.
The study found elevated levels of NNAL and NNAL-Gluc, which are metabolized
products of NNK, a proven, tobacco-specific cancer-causing chemical.
"It is clear that environmental tobacco smoke has all the carcinogens
that are contained in tobacco smoke," Hecht said.
In the study, researchers analyzed the urine from 23 women who lived with men
who smoked in the home and compared the results with urine from 22 women who
lived with nonsmokers.
Women who lived with smokers had levels of NNAL and NNAL-Gluc that were five
to six times higher than women who lived with nonsmokers.
Women who lived with smokers had similarly elevated levels of nicotine and
cotinine, a metabolic product of nicotine.
Other studies have shown that environmental tobacco smoke increases the risk
of lung cancer for nonsmokers who work where cigarette and cigar smoking is
common, such as bars or taverns. Additionally, studies have shown that children
living in the homes of smokers have a higher incidence of asthma and other
respiratory problems.
Hecht said tobacco smoke tends to spread throughout the house in homes with
central heating and air-conditioning systems.
Het is ongelooflijk hoe een onderzoeker dit soort onderzoek, gebaseerd op zo
weinig 'proefpersonen' naar buiten kan brengen.
Dat de onderzoekers ook aarzelen blijkt wel als we naar het originele
abstract teruggaan:
Background: Environmental tobacco smoke (ETS) is associated with lung
cancer in nonsmokers. Most epidemiologic studies find a higher risk for lung
cancer in nonsmoking women married to smokers than in those married to
nonsmokers. We measured metabolites of a tobacco-specific lung carcinogen in
urine from healthy, nonsmoking women exposed to ETS.
Methods: We recruited women and their partners through advertisements.
Couples completed questionnaires on smoking history and demographics, and both
partners provided 100 mL of urine; 23
women had male partners who smoked in the home (i.e., exposed women), and 22
women had male partners who did not smoke (i.e., unexposed women). Urine samples
were analyzed for nicotine, for cotinine, for
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide (NNAL-Gluc),
as well as for creatinine. NNAL and NNAL-Gluc are metabolites of the
tobacco-specific lung carcinogen 4-(meth-ylnitrosamino)-1-(3-pyridyl)-1-butanone
(NNK). Unpaired Student's t tests were conducted on log-transformed
values. All statistical tests are two-sided.
Results: Urinary levels of nicotine, cotinine, NNAL, and NNAL-Gluc
were statistically significantly higher in exposed women than in unexposed
women. Geometric means for these compounds in exposed versus unexposed women,
respectively, were as follows: nicotine, 0.050 nmol/mg of creatinine (95%
confidence interval [CI] = 0.033 to 0.076) versus 0.008 nmol/mg of creatinine
(95% CI = 0.004 to 0.014); cotinine, 0.037 nmol/mg of creatinine (95% CI = 0.022
to 0.061) versus 0.007 nmol/mg of creatinine (95% CI = 0.004 to 0.011); NNAL,
0.013 pmol/mg of creatinine (95% CI = 0.007 to 0.024) versus 0.004 pmol/mg of
creatinine (95% CI = 0.002 to 0.007); and NNAL-Gluc, 0.027 pmol/mg of creatinine
(95% CI = 0.016 to 0.045) versus 0.004 pmol/mg of creatinine (95% CI = 0.003 to
0.006).
Conclusions: Nonsmoking women exposed to ETS take up and metabolize
the tobacco-specific lung carcinogen NNK, which could
increase their risk of lung cancer. Within couples, the NNAL plus NNAL-Gluc
level in exposed women compared with that of their smoking partners averaged
5.6%. Notably, epidemiologic studies have estimated the excess risk for lung
cancer in nonsmoking women exposed to ETS as 1%–2%
of that in smokers.
De met geel gemarkeerder onderdelen geven de zwakke punten aan in het verhaal.
Zie verder ook: Cancer
Link to Secondhand Smoke Tightened?
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