Zwangerschap en longkanker.*
Roken blijft de grootste oorzaak voor het ontstaan van longkanker doch uit een Amerikaanse studie blijkt dat los daarvan voortplantingsfactoren ook een duidelijke rol daarbij spelen. Bekend is dat vrouwen een grotere kans op longkanker hebben dan mannen. Omdat de hoeveelheid van het hormoon oestrogeen, dat een risicofactor bij andere soorten kanker is, wisselend is na het krijgen van kinderen werden twaalf jaar lang een kleine 2.000 vrouwen gevolgd. Men vond dat vrouwen die kinderen hadden tot wel 40% minder kans hadden op het ontstaan van longkanker. Bij 1 kind is er nog weinig verschil doch bij 2 kinderen is dat al 20% en bij 3 of meer kinderen is dat 40%.
Parity
and risk of lung cancer
Women's reproductive behavior (having children or not) may increase their risk
of lung cancer later in life, a study at the Harvard School of Public Health has
found.
Jessica Paulus, a graduate student in epidemiology, and her colleagues studied
data from 1,075 women with lung cancer and 867 cancer-free women who took part
in a research study from 1992 to 2004 at the Massachusetts General Hospital in
Boston. The researchers found that women who had any children (one or more) had
nearly 40 percent less risk of lung cancer as compared to women without children.
That risk of lung cancer also declined in a linear fashion with increasing
numbers of children born.
"Patterns of lung cancer incidence suggest that women may be at a greater
risk of lung cancer as compared to men," said Paulus. "Given the role
of estrogen as a risk factor in other cancers, and the relationship between
number of births and estrogen levels in the body, we hypothesized that having
children may be associated with lung cancer risk in women."
While the researchers found a linear relationship between lung cancer and number
of children, having one child did not significantly decrease the cancer risk
compared to women who never had given birth. Having two children reduced the
risk of cancer by 20 percent, and having three or more children reduced that
risk by 40 percent.
The protective effect of childbearing was strongest -- but not significant
statistically -- in women who had never smoked as compared to current and former
smokers. Also, the protective effect of childbearing on lung cancer risk was
limited to cases of average age of onset, and was not observed in women
diagnosed with lung cancer before age 55 years.
"Our study supports the idea of an inverse relationship between having
children and the risk of lung cancer among women," Paulus said. "While
smoking behavior remains the strongest risk factor for lung cancer in women, our
work indicates a need to further examine the role played by reproductive factors
in lung cancer." (Nov.
2006)