News in brief - Jan. 2, 2012

Smoking and drinking down among youths, but marijuana use rising - Cortex size might indicate higher risk of developing Alzheimer's

Smoking and drinking down among youths, but marijuana use rising

The number of youths smoking cigarettes and drinking alcohol continues to decrease, but the use of drugs, such as marijuana, among this age group is rising, according to data released Dec. 14, 2011, by the National Institute on Drug Abuse.

Researchers surveyed more than 46,000 eighth-, 10th- and 12th-graders from 400 public and private schools on their alcohol, cigarette and drug use.

They found that that 19% of 12th-graders reported smoking a cigarette in the past month, compared with 31% who smoked in 2000 monitoringthefuture.org/data/11data.html.

A similar decline was identified among eighth-graders, 6% of whom reported recently smoking in the 2011 survey. The figure was 15% in 2000.

Alcohol consumption also is down among youths, with four in 10 12th-graders reporting drinking in the past month during 2011, compared with one in two in 2000.

Use of marijuana, however, has been rising during the past few years. For the 2011 survey, 23% of 12th-graders said they used the drug in the past month, up from 18% in 2006.

Cortex size might indicate higher risk of developing Alzheimer's

Among people who do not have memory problems, those with smaller regions of the brain's cortex have an increased risk of developing symptoms of early Alzheimer's disease, according to a study published online Dec. 21 in Neurology.

Researchers used MRI screens to measure the thickness of regions of the brain's cortex in 159 adults without dementia. Participants were an average age of 76.

They identified 19 of the participants as at high risk of developing preclinical Alzheimer's disease due to the smaller size of particular regions in the brain's cortex (www.neurology.org/content/early/2011/12/21/WNL.0b013e31823efc6c.abstract).

Preclinical Alzheimer's is the first phase of the disease in which a person experiences detrimental neurologic changes before overt symptoms are present.

Researchers classified 116 participants as at average risk of developing the condition, and 24 were low risk.

They found that 21% of those at high risk experienced cognitive decline during three years of follow-up after the MRI scan compared with 7% of people at average risk. No one in the low-risk group had cognitive decline.