Living at high altitudes may be associated with giving birth to smaller babies who grow more slowly through childhood.
Researchers studied 964,299 children in 59 low- and middle-income countries in Asia, Africa, Eastern Europe, the Caribbean and Latin America. Among them, 106,441 lived above an altitude of 1,500 meters, or about a mile high.
The study, in JAMA Pediatrics, controlled for sex, maternal age, educational level and other factors, but still found a direct relationship between height and altitude: beginning as low as 500 meters above sea level, the higher the altitude, the shorter the babies’ length at birth and the slower their growth up to 5 years old.
The researchers also looked at a subset of 1,718 children living in what they labeled ideal home environments — that is, singleton births with access to safe water and sanitation, living in a household that owned a television and a car, born in hospitals to mothers with more than a high school education, and having received required childhood vaccinations. The association was weaker, but still significant.
The finding is likely to be relevant in the United States as well, according to the lead author, Kaleab Baye, an associate professor of nutrition at Addis Ababa University in Ethiopia.
“There have been studies consistently showing that children born in Colorado at high altitude have lower average birth weights,” he said.
Unfortunately, he added, “we know little about mechanisms. Understanding the mechanisms and approving some interventions is going to take time.”
