Heavy smokers 'at increased risk of dementia'

Smokers who quit will reduce their health risks Heavy smokers with a 40-a-day habit face a much higher risk of two common forms of dementia, a large study shows.

The risk of Alzheimer's is more than doubled in people smoking at least two packs of cigarettes a day in their mid-life.

The risk of vascular dementia, linked to problems in blood vessels supplying the brain, also rose significantly.

The US study, looking at over 21,000 people's records, is published in the journal Archives of Internal Medicine.

Reversible Risk

The long-term research, which used records held by a health insurance firm, found clear evidence of the risk in the heaviest smokers.

No differences in risk were detectable in those smoking less than half a pack a day.

But among those currently smoking two or more packs, equivalent to 40 or more cigarettes a day, there was a 157% increase in the risk of Alzheimer's disease.

There was also a 172% increase in vascular dementia risk compared to someone who had never smoked.