Women suffer from more arterial damage caused by cigarette smoking than men do, new EU-funded research shows. The amount of tobacco exposure during a person's lifetime correlates with the thickness of carotid arterial walls in both men and women, but the effect is twofold in females. The result is an outcome of the IMPROVE ('Carotid intima media thickness (IMT) and IMT-progression as predictors of vascular events in a high risk population') project, a large-scale epidemiological study that clinched a EUR 2.5 million grant under the 'Quality of life and management of living resources' (LIFE QUALITY) Thematic Programme of the EU's Fifth Framework Programme (FP5).
The European Society of Cardiology recently reported that researchers assessed almost 3 600 people (1 694 men and 1 893 women) from France, Italy, the Netherlands, Finland and Sweden, and used sophisticated ultrasound technology to measure the presence of wall thickening and plaques in the carotids, the arteries that supply the head and neck with oxygenated blood.
Besides discovering that women are more affected by the amount of tobacco exposure that correlates with the thickness of carotid arterial walls, the number of cigarettes smoked each day on the progression of the disease over time is five times bigger in women than men as well. It should be noted that these associations are not dependent on other factors that could impact atherosclerosis like blood pressure, cholesterol level, obesity, age and social class.
Commenting on the results of the study, Professor Elena Tremoli of the Institute of Pharmacological Sciences at the University of Milan in Italy and scientific director of the Monzino Cardiology Centre in Milan, says: 'This is a particular relevant finding, especially in view of the fact that educational campaigns carried out in the last years have been less successful in reducing the number of smokers in women than in men.'
The World Health Organization (WHO) says despite the fact that the majority of European countries have reported a considerable drop in the number of men smokers, including Italy and Finland, the number of women smokers has remained relatively the same within a 30-year period. The number has even increased in Spain and France, the data show.
'The reasons for the stronger effect of tobacco smoke on women's arteries are still unknown,' says project leader Professor Tremoli, 'but some hints may come from the complex interplay between smoke, inflammation and atherosclerosis.'
Apart from smoking, researchers also show how other factors have a differential effect on the arteries of the two genders: for instance, education is one such factor. The findings reveal that even though men who studied less had a greater thickening of arterial walls than those who studied more, the same was not true for women.
Also, there is a greater proportion of women who are protected against the damaging effects of systemic inflammation. The IMPROVE study found that the association between arterial wall thickening and the levels of C-reactive protein (CRP) and white blood cells (WBCs) is important; the two indexes of inflammation are very strong in men but non-existent in women.
'It is important to mention, however, that, when women smoke they lose their protection against the harmful effect of inflammation,' the Italian researcher says. 'In particular, if we stratify the female population according to smoking habits, we see that in the group of women who smoke, especially in heavy smokers, the relationship between CRP and arterial wall thickening becomes similar to that observed in men,' she adds.
'We all know that women are "naturally" protected against cardiovascular disease, particularly before menopause, and this has led to less attention of health professionals and researchers in regard to this disease in women. Women themselves tend to think that they are less susceptible to the damages of cardiovascular risk factors, such as high blood pressure and cholesterol, a diet rich in saturated fats and, finally, tobacco smoke. Our results indicate that, at least for the latter, this is not true.'
It should be noted that despite that IMPROVE ended in 2007 and gender differences and smoking were not primary objectives of this study, this latest study is a good example of how key results and interesting data from academic studies emerge only three to five years after the projects close, and how many of them continue finalising their results and continue publishing well beyond the official project's closing date.