A new study linking MS and obesity. Michelle Gielan has that story and more in today's health watch report. Obese teenage girls may run a higher risk of developing multiple sclerosis. A study of 238-thousand women found those who were obese at 18 had twice the risk of developing MS compared to thinner women. Weight during childhood or adulthood didn't seem to be linked to the same risk. Having strong muscles may reduce a person's chances of developing Alzheimer's.A study of 900 seniors found those with plenty of muscle power were less likely to develop the disease. They also had a lower risk of developing mild cognitive impairment. What your toddler drinks now could have a lasting impact. According to a new report, children who consume highly sweetened drinks at age 5 -- like fruit and sports drinks -- tend to have higher body fat during their teen years. And higher body fat during adolescence has been tied to other health issues like diabetes. Those are some of today's top medical stories. I'm Michelle Gielan - CBS News - New York.