The risk of suffering from Alzheimer’s more than doubles for middle-aged people who smoke heavily, an American study has revealed.
Research published in the Archives of Internal Medicine has discovered that those who smoked more than 40 cigarettes a day had a 157% greater chance of suffering from Alzheimer’s, and a 172% increased chance of vascular dementia.
The study examined more than 21,000 middle-aged men and women for an average of 23 years. Those participating in the study took part in a dementia survey between 1978 and 1985 when they were 50 to 60 years old.
A total of 1,136 were eventually diagnosed with Alzheimer’s and 416 with vascular dementia. The results wereunaffected by race or gender.
Smoking is known to contribute to inflammation and oxidative stress, both of which experts believe are contributing factors in the development of Alzheimer’s disease.
Researchers also concluded that the smoking narrows blood vessels, which may account for the increased risk of vascular dementia.
Lead researcher Dr Rachel Whitmer, from the Kaiser Permanente research institution in Oakland, California, said: “We know smoking compromises the vascular system by affecting blood pressure and elevates blood-clotting factors, and we know vascular health plays a role in risk of Alzheimer’s disease.”