Asthma is a disease that plagues many Americans, but a new study says weight may make it worse.Meg Oliver has that story and more in today's health watch report.Despite concerns by some parents childhood vaccination rates are at or near record highs.The CDC announced most parents are vaccinating their kids, with less than 1 percent of children not getting any vaccines by the time they're between 19 and 35 months.The results are based on telephone interviews conducted last year with parents of about 17 thousand kids.Obesity may make asthma worse.A new study finds obese people who have asthma are nearly 5 times more likely to be hospitalized for the condition compared with non - obese people with asthma.Researchers hope the study will convince doctors to monitor obese people with asthma more carefully since it's harder to control their condition.Tobacco use caused 2.4 million cases of cancer in the US from 1994 to 2004 according to a new report.Lung and bronchial cancers accounted for nearly half of the cases.The research team looked at cancer surveys and registries covering 92 percent of the US population.Those are some of today's top medical stories.I'm Meg Oliver, CBS News, New York.