As if smokers needed another reason to kick the habit: New research has found secondhand smoke markedly increases the risk of severe dementia.
The study, involving nearly 6,000 people in China, adds to the already-long list of hazards tied to “passive smoking” — inhaling smoke from others’ cigarettes — including heart disease and lung cancer. Past studies have linked secondhand tobacco smoke and cognitive impairment, but the new study — involving an international team of scientists from King's College London, Anhui Medical University in China, and the U.S. — is the first to find a significant link with dementia syndromes.
The findings, published in the journal Occupational and Environmental Medicine, are based on interviews with 5,921 people aged over 60 to gauge their levels of tobacco exposure, smoking habits, and dementia.
The results showed 10 percent had severe dementia syndromes, most often among those exposed to high levels of secondhand smoke for long periods of time.
“Passive smoking should be considered an important risk factor for severe dementia syndromes, as this study in China shows,” said Dr. Ruoling Chen, a senior lecturer at King’s College and visiting professor at Anhui Medical University who helped conduct the study.
“Avoiding exposure to ETS may reduce the risk of severe dementia syndromes. China, along with many other countries, now has a significantly aging population, so dementia has a significant impact not only on the patients but on their families and carers. It's a huge burden on society.”
A second recent study by Chen and colleagues, published in the journal Alzheimer's & Dementia, identified significant links between secondhand smoke and Alzheimer's disease.
According to the World Health Organization, nearly 90 percent of the world's population is not protected by smoke-free laws that govern the habits of more than one billion smokers worldwide.
“More campaigns against tobacco exposure in the general population will help decrease the risk of severe dementia syndromes and reduce the dementia epidemic worldwide,” Chen said. “The increased risk of severe dementia syndromes in those exposed to passive smoking is similar to increased risk of coronary heart disease — suggesting that urgent preventive measures should be taken, not just in China but many other countries.”