Remember, diseases aren't 100% the zodiac's fault
Of course, it's extremely important to note that there are many, many different factors that result in developing such conditions, from genetics to environment to diet to exercise. You probably realize that people born in July get heart disease, and having a September birthday isn't an ironclad guarantee of asthma.
Whatever you do, don't blame your parents or the calendar too much, don't freak out that you're going to croak at any moment, and don't let this info stress you into an early grave. It's just a horoscope (albeit a science-y one), and as everyone knows, it doesn't always speak your truth.