Research often suggests that eldest children have it all: brains, attention, success… It's even been implied that the older child tends to be the favourite among parents. However, a new study has identified a drawback to being the first-born, and suggests they are more likely to fall prey to health problems.
The study was based on the health records of almost 400,000 Norwegians over the course of approximately 25 years. Overall, eldest children were found to be less healthy when assessed by physical markers such as blood pressure, triglycerides and weight when compared to younger siblings.
The probability of having high blood pressure declined with birth order and largest gap is between first and second-borns, with the latter assessed to be 3% less likely to have high blood pressure. Comparatively, fifth-borns were judged to be around 7% less likely to have high blood pressure than their eldest brother or sister.
In addition, triglyceride levels (a form of dietary fat made by the liver) were higher in elder children as were the chances of obesity, with 4% more likely to be overweight and 2% more likely to be obese when compared with the second-born.
Why is this?
First-borns are, on average, lighter at birth than their siblings, and experts considered whether a lower nutrient flow to first-borns in the uterus could affect their regulation of fat and cause them to store more fats in adulthood. The report reads:
“The resulting catch-up growth of first-borns also leads to a greater tendency towards high blood pressure. Thus, the greater likelihood of high blood pressure and obesity for first-borns may be largely biologically determined.”
Researchers also took into consideration the fact that elder children were breast fed for an average of two extra weeks as a possible contributing factor to the differences in health, but no real conclusions were made - and further research is needed.
Although it was found that first-borns were more likely to have better mental health than their younger siblings, scientists working on the research did consider personality as another potential explanation for the differences in weight and blood pressure.
“While the empirical evidence is not particularly strong, there is an established set of theories about birth order and personality… First-borns are often perceived to be intense and career-oriented while later-borns are considered to be more laid back and creative. This provides a possible set of explanations for our findings about blood pressure. High blood pressure and triglycerides may be caused by the stress that results from this driven, competitive personality type.”
Via Harper’s Bazaar UK & NetDoctor