According to a new study, birth order affects weight in women.
Scientists have long studied the birth order in families and have found many characteristics that tend to favor the firstborn. Some of these include being more reliable, sociable, and high achievers. Now, the new study, published in the Journal of Epidemiology & Community Health, shows that being the first born may not be all that it is cracked up to be.
Researchers recently analyzed 13,406 pairs of sisters in Sweden, one of the largest studies of its kind, and found that firstborn women were more likely to have a higher body mass index and to be considered obese, even though most were born with a lighter birth weight. Specifically, 29 percent were more likely to be overweight and 40 percent more likely to be obese. The study also found that firstborn children tend to be taller than the second born.
“The researchers wanted to find out if birth order affected adult women’s height and weight as it appears to among adult men,” a statement accompanying the study’s results read. “They therefore drew on data from the Swedish Birth Register, which was started in 1973, and which contains information dating back to the first antenatal visit on virtually all (99 percent) births in Sweden.”
“This is an observational study so no definitive conclusions can be drawn about cause and effect, and only young women were included in the study,” the scientists said in a statement, according to News Max. “And [researchers] point to mounting evidence which suggests that firstborns may be more at risk of health problems, such as diabetes and high blood pressure, in later life than their siblings, although the potential underlying triggers for these differences are far from clear.”
Dr. Maria Peña, Director of the Center for Weight Management at Lenox Hill Hospital in New York City, said environmental factors could be the root cause of the weight differences based on birth order.
“In many cultures, moms are more meticulous with their firstborns,” she told CBS News. “With the very firstborn, everyone’s helping out and over-feeding the baby, making sure it’s at a ‘healthy weight.’ But with second children, parents know what to expect and they’re not so overprotective so maybe they feed them a little less.”
“People that develop obesity later on in life forget to listen to the signal in their brain that tells them to stop eating. Early on in life, some kids are taught to override that signal,” Maria continued. “If a parent tells a child to keep eating even when they’re not hungry, then that’s a habit they learn.”
The most recent study, which suggests that birth order affects weight in women, showed nearly matching results to a similar study that was done in men.
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