May 26, 2021 — Birth order and number of siblings may be tied to a person’s risk for heart disease and mortality, according to a study covering 2.68 million people in Sweden.
Being the oldest child may have benefits: For first-born men and women with one or two younger siblings, the risk of death and for nonfatal cardiovascular events is slightly lower than it is for those without siblings.
But, the study found that having more than two younger siblings may actually cause the benefit to fade or even shift to an increased risk. The findings were published online Tuesday in BMJ Open.
No one can change their birth order or their sibling status, of course, but Peter Nilsson, professor of clinical cardiovascular research at Lund University in Sweden, and first author on the study, said that the findings show that family history isn’t just about genetics — it’s also about social ties and early influences in life.