Eldest vs youngest: What your birth order means for your health and happiness

Death is often said to be life's greatest leveller, but it seems birth is far less equitable.

According to a new study by researchers in Sweden, younger siblings are more likely to suffer from cardiovascular disease, heart attacks and strokes than their older brothers and sisters. And the more older siblings you have, the higher your risk of contracting the ailments.

The research found that the youngest child of three is 13 per cent more at risk of suffering from coronary heart disease than the eldest. A girl with two older siblings is two per cent more at risk of cardiovascular disease and 14 per cent more at risk of heart disease than the eldest; while a boy with four older siblings has a seven and 23 per cent increased risk respectively.

According to Dr Peter Nilsson of Lund University, lead author of the study, this could be down to many complex factors. “First-borns receive more parental attention, expectations and stimulation,” he said. “But language development might be faster in later born siblings as they will have older brothers/sisters to learn from. To be a first-born means that you are expected to behave more correctly and avoid bad things (alcohol overuse, drugs, tobacco) that later born siblings with less parental supervision may be prone to try.”

A wider look at science shows that there’s plenty of evidence to suggest that the first-born child is blessed with advantages, in both health and happiness...

Better careers

Your parents may have told you that hard work pays off, but that may not be the full story. A 2017 paper found that first-born children are 30 per cent more likely to be CEOs or politicians. Researcher Sandra Black wrote that first-borns choose occupations that demand more "sociability, leadership ability, conscientiousness, agreeableness, emotional stability, extraversion, and openness." Indeed, Elon Musk, Richard Branson and Jeff Bezos are all first-borns.

Black’s paper only looked at boys, but the drive to succeed is arguably even stronger in women: research from 2014 found that 13 per cent of first-born women end up more ambitious than first-born men.

The foundations of this success are formed early on. A 2013 paper found that school performance declines with birth order, which the researchers put down to “reputational model of strategic parenting.” In other words, the first-born child is blessed – both with their parents' attention, and with the responsibility of enforcing rules on the rest of the family. This role, the researchers say, builds intelligence, discipline, and leadership qualities which filter into later life. Which all points to...

Higher IQs

The 2017 paper also discovered that first-borns stay in school longer, make more money, have a higher IQ, and even spend more time on homework than watching television.

One widely cited Norwegian study from 2007 shows that first-borns have an IQ around three points higher than the next eldest child; a different body of research points out that first-born children outperform their younger siblings on cognitive tests from infancy.

Relationships

There is evidence to show that first-borns are more likely to marry earlier than their siblings. According to a study of more than 3,000 families, the odds of a happy marriage are highest when a first-born woman marries a last-born son. First-borns who are attracted to each other, such as Prince William and Kate Middleton, tend to be more “conventional and rule-following”, as they are used to being responsible for other family members, said Lisette Schuitemaker, co-author of the book The Eldest Daughter Effect.

Yet according to Katrin Schumann, author of The Secret Power of Middle Children, middle children tend to be the happiest in relationships because there’s no pressure to be the best (like the eldest) or a need for constant attention (like the youngest).

Bad habits

A study in the journal Economics and Human Biology reported that later-born children are more likely to have poorer physical and mental health. It found that first-borns were 13 per cent less likely to smoke daily than fifth-borns, potentially saving them from health problems later down the line.

Indeed, these habits could be formed early on. According to a study by researchers in Denmark and Finland, younger brothers are more likely to have disciplinary problems. “In families with two or more children, second-born boys are 20 to 40pc more likely to be disciplined in school and enter the criminal justice system compared to first-born boys even when we compare siblings," they wrote.

Weight

Being the first-born does have its downsides. Black's 2017 study found that the first-born is more likely to be obese, and have higher blood pressure. The researchers suggest this could be down to the stress of having to succeed and meet career expectations.

“Compared to second-borns, first-borns are four per cent more likely to be overweight, and two per cent more likely to be obese,” said Black. “Overall, we find that first-borns are less healthy in terms of physical markers such as blood pressure, triglycerides, and indicators of overweight and obesity."