Congratulations, first-born children. You get all the perks of being the oldest, including, a new study suggests, having a lower risk than your siblings of cardiovascular events such as heart attack and stroke.
This benefit didn’t extend to the first-born in large families, however, suggests the results of a large population study in Sweden, published in the online journal BMJ Open.
According to British Medical Journal: “It is well-known that family history — the health of parents and grandparents — has an impact on a person’s health, including their risk of cardiovascular events, but now there is growing interest in what influence the make-up of a person’s immediate family — the number and age of siblings — might have.”
For their study, the researchers analyzed data from the Multiple-Generation Register in Sweden. Data were used from 1.36 million men and 1.32 million women born between 1932 and 1960 and ages 30-58 years in 1990. Data on fatal and nonfatal cardiovascular and coronary events over the next 25 years were retrieved from national registers.
According to their analysis, first-borns had a lower risk of nonfatal cardiovascular and coronary events than their siblings. First-born men had a higher risk of death than second and third-born siblings, while first-born women had a higher risk of death than second-born siblings, but equal to further siblings.
When factoring in family size, men with one or two siblings had a lower risk of cardiovascular events, while those with four or more siblings had a higher risk than those with no siblings.
Similarly, compared with men with no siblings, those with more than one sibling had a lower risk of death, while those with three or more siblings had an increased risk of coronary events.
A similar pattern was seen in women. Compared with those who had no siblings, women with three or more siblings had an increased risk of cardiovascular events, while those with two or more siblings had an increased risk of coronary events. Women with one or more siblings had a lower risk of death.
Because this is an observational study, the researchers say they can’t establish cause.
“More research is needed to understand the links between sibling number and rank with health outcomes,” they say. “Future research should be directed to find biological or social mechanisms linking the status of being first born to lower risk of cardiovascular disease, as indicated by our observational findings.”
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