New research has been presented at ECNP Congress in Vienna into the effects of smoking in women, highlighting oestrogen production and behavioural differences between men.
The new research from Uppsala University in Sweden has sought to explain why the effects of smoking are different in men and women. The researchers identified several behavioural differences including a hypothesis on why women are more resistant than men to quitting smoking.
The researchers also analysed the effects of smoking on oestrogen production, finding that a dose of nicotine, equivalent to a single cigarette could block oestrogen production in a woman’s brain.
“For the first time, we can see that nicotine works to shuts down the oestrogen production mechanism in the brain of women. We were surprised to see that this effect could be seen even with a single dose of nicotine, equivalent to just one cigarette, showing how powerful the effects of smoking are on a woman’s brain,” said Erika Comasco lead researcher and associate professor at Uppsala University.
“This is a newly discovered effect and it is still preliminary work. We’re still not sure what the behavioural or cognitive outcomes are; only that nicotine acts on this area of the brain, however, we note that the affected brain system is a target for addictive drugs, such as nicotine,” she added.
The researchers noticed these effects in the thalamus, which is in the brain’s limbic system. This is the area of the brain responsible for behavioural and emotional responses.
Small amounts of nicotine can have significant effects
The research team worked with a group of ten healthy female participants. Each woman was given a commercially available nicotine dose intranasally. The participants were simultaneously injected with a radioactive tracer attached to a molecule which binds to the aromatase enzyme. This is the enzyme responsible for oestrogen production.
Through MRI and PET brain scans, the researchers were able to see the quantity of aromatase, and where in the brain it was located. They found that a single dose of nicotine moderately reduced the amount of aromatase in the brain.
Previous research has already found that the effects of smoking differ between men and women, with women being more resistant to nicotine replacement therapy. The woman also shows a higher tendency to relapse when trying to quit smoking. However, prior to this research, the biological basis for these differences has not been understood. It is the first time that these inhibitory effects of smoking on aromatase production have been shown.
The effects of smoking on women may be more serious
“This discovery leads us to believe that nicotine’s effect on oestrogen production has a significant impact on the brain, but perhaps also on other functions, such as the reproductive system – we don’t know that yet. There are significant differences in the way men and women react to smoking,” said Comasco.
“Women seem to be more resistant to nicotine replacement therapy, they experience more relapses, show greater vulnerability for heritability of smoking, and are at greater risk of developing primary smoking-related illnesses, such as lung cancer and heart attacks. We need now to understand if this action of nicotine on the hormonal system is involved in any of these reactions,” she explained.
Comasco has recognised the limitations of this research and cited the comparatively small sample size of participants. The research team intend on continuing their research with a larger sample group.
