They stole all your toys as well as all the attention you used to get from your parents, tattled, played pranks and probably embarrassed you in front of most of your friends, so it probably comes to no surprise that a new study has found that having a younger sibling significantly raises a person's blood pressure.
Researchers found that having a younger brother can raise a person's blood pressure by 3 percent to 5.9 percent, and having a younger sister can raise a person's blood pressure by 3.8 percent.
Higher blood pressure can lead to hypertension and increase a person's risk of serious cardiovascular disease, heart attack and stroke.
However, researchers noted that as a person gets older, the blood pressure increasing effect a younger sibling has on them gradually fades away.
Researchers attributed the increase in blood pressure to people getting less attention from their parents.
Lead researcher Wu Zeng of Brandeis University in Waltham, Massachusetts, looked at the blood pressure rates and sibling structure of 200 families living in Amazonian villages in Bolivia.
Researchers noted that the families lived in a foraging-farming community, so birth order of children was important among parents.
"Sibling configuration, including birth order, or the number, age, and sex of siblings is associated with parental resource allocation between children and is thus associated with a person's well-being," researchers wrote.
Researchers found that younger brothers were more likely to trigger an increase in blood pressure among their older siblings, according to the latest findings published in the journal Economics and Human Biology.
"In a large family, the number of younger brothers may exert an impact on an individual's blood pressure," the researchers wrote.
Researchers said that the responsibilities that come with being an older sister or brother may explain why having younger brother is associated with higher blood pressure among older siblings.
"Studies suggest that the presence of younger siblings is associated with poorer mental health and behavior problems," researchers noted.
"Children see the arrival of a younger sibling as stressful because the newborn competes for parental attention," Zeng and his team concluded. "In addition, more younger siblings might increase the workload of older sisters."