First-born children may have a higher risk than their younger siblings of developing diabetes or hypertension, according to a New Zealand study.
First-born children have greater difficulty absorbing sugars into the body and have higher daytime blood pressure than children who have older siblings, according to the researchers with the University of Aucklands Liggins Institute. The study, scheduled to be published in the March issue of the Journal of Clinical Endocrinology & Metabolism, a publication of The Endocrine Society, is described as the first to document a 21% drop in insulin sensitivity among first-born children.
“Although birth order alone is not a predictor of metabolic or cardiovascular disease, being the first-born child in a family can contribute to a persons overall risk,” study author Wayne Cutfield, MCChB, DCH, FRACP, said in a news release.
The researchers measured fasting lipid and hormonal profiles, height, weight and body composition in 85 healthy children between ages 4 and 11. The researchers focused on children because puberty and adult lifestyle can affect insulin sensitivity.
The 32 first-born children who participated in the study had a 21% reduction in insulin sensitivity and a 4-mmHg increase in blood pressure.
“Our results indicate first-born children have these risk factors, but more research is needed to determine how that translates into adult cases of diabetes, hypertension and other conditions,” Cutfield said.
Oldest and only children tended to be taller and slimmer than children with older siblings, even after accounting for parents height and body mass index.
The researchers noted that with family size shrinking in many countries, a larger proportion of the global population is made up of first-born children who could develop conditions such as type 2 diabetes, coronary artery disease, stroke and hypertension.
The study abstract is available at http://jcem.endojournals.org/content/early/2013/01/30/jc.2012-3531.abstract.