Health researchers say there are now nearly 47 million people living with dementia globally, up from 35 million in 2009. They warned that without a medical breakthrough, numbers will likely double every 20 years.

Researchers from Alzheimer's disease International say about 58 percent of all people with dementia live in developing countries and that by 2050, nearly half of all those with the disease will live in Asia. Experts estimate the cost of treating dementia could jump to $1 trillion in just three years.

Older sisters more likely to be bigger

Bad news, big sisters: A study finds that firstborn girls are more likely to be overweight or obese than their second-born sisters. The findings are based on data collected from more than 13,400 pairs of sisters born in Sweden.

According to the study, older sisters are 29 percent more likely to be overweight and 40 percent more likely to be obese than their next-younger sister. Firstborn girls are also, on average, a little taller than their sisters as adults.

Group urges early peanut exposure

A pediatricians' group is recommending that infants at high risk of peanut allergies be given foods containing peanuts before they turn 1. The interim guidance is in response to a major allergy study published this year that found that exposure to peanuts in infancy seemed to help build tolerance — contrary to conventional thinking.

Baby-suitable foods used included smooth peanut butter, peanut soup and finely ground peanuts mixed into yogurt and other foods. Allergy tests are recommended before exposing at-risk infants to peanut-containing foods. The advice comes in a consensus statement that the American Academy of Pediatrics endorsed in June along with the American Academy of Allergy, Asthma & Immunology and several foreign allergy groups.

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