Poor lung function tied to higher stroke risk

NEW YORK, Dec 29 (Reuters) The chances of having a stroke are modestly increased in people with impaired lung function, even if they have never smoked nor had respiratory symptoms, researchers report. However, that finding only applies to whites, it seems, not to blacks.

Dr Aaron R Folsom of The University of Minnesota, Minneapolis and colleagues note in the medical journal Chest that few studies have examined the relation between lung function and stroke, and none have studied African Americans.

To do so, the researchers tracked 13,842 middle-aged adults, about a quarter of whom were black. During 13 years of follow-up, there were 472 strokes.

The researchers found that chances of a stroke went up as lung function went down, but the relationship weakened once other risk factors were taken into account.

Nevertheless, it remained statistically significant for white subjects. Their risk of having a stroke was 59 per cent higher for those with the lowest lung function compared to those with the highest.

Moreover, although the relationship was also seen in whites who had never smoked or had had no respiratory symptoms, this was not the case in blacks.

The researchers suggest that the finding might be explained by chance, because of the relative small numbers of blacks in the study, or that the lung function measurements may have been less reliable in the African American group.

Dr Stephan F van Eeden, of the University of British Columbia, Vancouver, co-author of accompanying editorial, told Reuters Health that in a previous study he and his colleagues helped establish that exposure to air pollutants can lead to hardening of the arteries.

This could explain the relationship between reduced lung function and stroke in people who had never smoked, he pointed out.

These and other findings, he concluded, help put ''exposure to air pollution in the same category of risk for heart attacks and stroke as the other known risk factors ... such as cigarette smoking, high cholesterol levels and diabetes.'' REUTERS SB PM0843