What has birth order got to do with the state of one's health, you ask? Well, there's increasing evidence that where you fall in the sibling lineup may affect your physical health and up your risk of certain health issues.

But don't fret just yet: Birth order alone is not a predictor. If you adopt healthy lifestyle habits such as not smoking and eating a balanced diet, you can still reduce your overall risks, say experts. So what does your birth order reveal about you? Here are some of the interesting findings from the latest research:

1. Birth order and risks of diabetes and high blood pressure

Being the firstborn in your family may increase your risk for diabetes and hypertension, according to a study from the University of Auckland in New Zealand. The researchers found a 21 percent drop in insulin sensitivity -- a major risk factor for diabetes -- among firstborns compared to later-borns. The oldest also had higher blood pressure, which could eventually develop into hypertension.

2. Birth order and BMI

Firstborns and only children tend to be taller and slimmer than their later-born counterparts, the researchers found, even after the height and body mass index of their parents was taken into account.

3. Birth order and allergies

In a survey of more than 13,000 schoolchildren in Japan aged 7 to 15, researchers found that several types of allergies, such as allergic rhinitis (hay fever or seasonal allergies), allergic conjunctivitis (eye inflammation due to allergies), and food allergy are more prevalent in firstborns.

4. Birth order and IQ

A Norwegian study showed that firstborns are generally smarter, with an average of two-point IQ advantage over the next eldest sibling. The researchers hypothesize mentoring younger siblings and helping them with day-to-day tasks provide the IQ boost.