A recent study published in the Journal of Clinical Endocrinology and Metabolism found that first-born children have more difficulty absorbing sugars in their bodies, which can put them at higher risk of developing diabetes or hypertension because of higher daytime blood pressure readings. Scientists from the University of Auckland in New Zealand gathered data on 85 children, a sample including 32 first-borns between age 4 and age 11. They found that the first-born children had a lower sensitivity to insulin than the other children in the study. This is attributed to changes in the mother’s uterus that better prepares it to deliver nutrients and blood flow to subsequent children. However, on the positive side, first born children also tended to be taller and thinner than their younger siblings.
This new data may impact public health research and policy, as family size has shrunk in recent years, which may mean first-borns, and their inherent health traits, may compose a larger percentage of the overall population. As the body of research surrounding birth order grows, a series of findings have emerged. A 2008 study in the UK found that first-born babies may be more predisposed to develop asthma and allergies. An Italian study found that first-born children are 60% more likely to develop a heart heart disease than other children. Yet the results are not all bad, first-borns are also found to be more intelligent than younger siblings, and more likely to hold leadership positions, possibly because of perfectionist tendencies. Potential health risks aside, there are many notable first-borns in our history books, including George Washington, Franklin D. Roosevelt, and Abraham Lincoln.