Obesity at age 50 may be tied to an increased risk of Alzheimer’s disease at a younger age.

Previous studies have shown that being overweight at midlife is associated with an increased risk of developing Alzheimer’s. Now researchers have found that it also predicts occurrence at a younger age.

Scientists studied 1,394 cognitively normal people, with an average age of around 60, following them for an average of 14 years. During the study, 142 developed Alzheimer’s.

After controlling for age, race, level of education and cardiovascular risk factors, the researchers found that each unit increase in body mass index at age 50 was associated with a 6.7-month decrease in the age at which Alzheimer’s developed.

The study, in Molecular Psychiatry, also found that a higher BMI was associated with larger deposits of neurofibrillary tangles on autopsy, one of the characteristics of brain damage in Alzheimer’s disease.

“Age of onset is not as well studied as risk,” said the senior author, Dr. Madhav Thambisetty, a neurologist at the National Institute on Aging. “As we try to cure Alzheimer’s disease, we also want to delay the onset of symptoms. Until we know what factors accelerate onset, we won’t be able to test any potential interventions. And that is perhaps as important as the search for treatment.”

Antibiotic Use Tied to Diabetes Risk

Danish researchers have found an association between the use of antibiotics and the development of Type 2 diabetes.

In 2012, the researchers identified 170,504 cases of Type 2 diabetes and matched them with 1,364,008 controls without diabetes. Then they used Danish government databases to check the participants’ antibiotic use over the previous 13 years.

Compared with those who filled no prescriptions for antibiotics, those who filled two to four prescriptions had a 23 percent higher risk of diabetes, and those who filled five or more had a 53 percent higher risk.

The study, in The Journal of Clinical Endocrinology & Metabolism, acknowledges that reverse causation is a possibility — in other words, people who have diabetes or are at risk of developing the disease may take more antibiotics than others. Still, the risk was apparent up to 15 years before a diabetes diagnosis, which argues against this reverse causation.

The scientists suggest that antibiotics may disrupt the gut biota, causing changes in insulin sensitivity and glucose tolerance, which can lead to diabetes.

Longer Lunch Periods Mean Fuller Students

In schools with short lunch periods, children eat less and discard more than in schools where they are allowed more time to eat, a new study has found.

Researchers tracked the eating habits of 1,001 students in third through eighth grades at six elementary and middle schools in low-income school districts during the 2011-12 school year.

Compared with schools where children could sit at the table for 25 minutes or more, those who had 20 to 24 minutes consumed an average of 6.9 percent less of their entrees, 3.7 percent fewer vegetables and 2.3 percent less milk. In schools that allowed less than 20 minutes, students consumed 12.8 percent less of their entrees, 11.8 percent fewer vegetables and 10.3 percent less milk. The study is in The Journal of the Academy of Nutrition and Dietetics.

“We need to focus on how to get kids to select and consume the appropriate food,” said the lead author, Juliana F.W. Cohen, an assistant professor at Merrimack College in North Andover, Massachusetts. “Giving kids enough time to eat appears to play an important role.”

There are things parents can do to help, she added. “Push for longer lunch periods, more lunch lines, automated point-of-sale equipment, anything that will get the kids through the lunch line faster so they can spend more time eating.”