This study seems like a lot of work to prove something I could have told you after sharing a room with my younger brother for 15 years. But at least now I feel justified at times when I feel stressed and my brother doesn't seem to have a care in the world.
A new study on Bolivian adults shows younger brothers aren't just pests while they are kids, they also contribute to raise the blood pressure of older siblings into adulthood. The study is published in the journal Economics and Human Biology.
The scientists can't say for sure if one causes the other, but do say in the region they looked at younger brothers take parental attention away from older children, forcing the older kids to take on extra responsibility.
"If there are more siblings in the family, the parents' resources are limited," said author Wu Zeng in a LiveScience article. "The older brother will see the younger brother as a competitor and it will kind of stress them out."
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Zeng and his team measured blood pressure on 374 adults in 13 different villages in the Amazon. Many participants came from families with up to six or seven children. Those with younger brothers had blood pressures six per cent higher.
Having a younger sister was only an issue for women and raised their blood pressure by an average of 3.8 per cent.
"In a large family, the number of younger brothers may exert an impact on an individual's blood pressure," reads the study abstract.
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Zeng doesn't believe it was sibling spats, but rather how parents treat older siblings differently and because older siblings take on some of the parenting roles when it comes to looking after their younger siblings.
"The older brothers have responsibility to help the younger brothers to find a job in the future or to find a wife or a girlfriend," Zeng told LiveScience.
Zeng's team has also discovered adults with younger siblings tend to have higher total cholesterol than other children.
Zeng says the same doesn't hold true in developed countries such as Canada because with fewer siblings, parents have more resources and time to spend with each child.
I disagree that it doesn't apply in Canada at least in one case. I love my little brother, but he was a real bother when we were younger and it has always seemed like I'm the more stressed out one. At least I have one reason for why it may be the case.
(Getty Images photo not of my brother and me)
The week in silly studies is a feature that appears each Tuesday.
It is not intended to mock real science.
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