The study, conducted in nearly 200 families from the
Amazonian villages of Bolivia, found that a younger brother can increase blood
pressure by 3 to 5.9 per cent while with a younger sister, the blood pressure
increases by 3.8 per cent.
What could be the possible reason for this increase
in blood pressure? According to the authors,
the arrival of a new child is stressful for the older child. The older child not only has to compete for
attention from parents, he/she may also have to share the responsibility of
taking care of the younger child.
The rise in blood pressure may also depend upon the
number of younger brothers, with a directly proportional relationship.
The significance of this rise in blood pressure has
yet to be determined with further studies.
Moreover, this effect on blood pressure seems to gradually fade away as
a person grows older. Thus, it may not
have any long-term consequences on the person.
However, it does call for extra parental attention towards the older
child on the arrival of the younger one.