South American babies and toddlers living at high altitude were more likely to score poorly on early tests of neurodevelopment, in a new study.
Of all kids age three months to two years, one in five was at high risk of developmental delays, according to tests done at their paediatrician’s offices. That rose to between one in three and one in four for those who lived above 2 600 metres, or 8 530 feet.
Researchers said blood flow in the uterus may be decreased at altitude.
"The findings emphasise the need for health care providers and policy-makers to recognise that altitude may increase developmental risks not just for physical growth, as has been reported, but for neurologic and cognitive development," wrote Dr George Wehby from the University of Iowa in Iowa City, who conducted the research.
How the study was done
His study involved over 2 000 young kids evaluated at offices in Argentina, Brazil, Bolivia, Chile, and Ecuador in 2005 and 2006.
The babies and toddlers were all given the Bayley Infant Neurodevelopmental Screener.
Dr Wehby found that on average, for every 100-metre (328-feet) increase in elevation, kids were 2% more likely to be judged at high risk of future developmental problems.
Compared to kids living below 800 metres (2 625 feet), those above 8,530 feet were twice as likely to be at high risk, according to their paediatrician’s evaluations.
The study, funded by the National Institutes of Health, was published in The Journal of Pediatrics.
What the study found
All of the babies in Bolivia lived above the 8 530-foot cut-off, and all the kids in Argentina, Brazil, and Chile lived below it. Ecuador was the only country in the study that included kids from both high- and low-altitude regions.
It's hard to know whether the results apply to other communities at high elevation, according to Dr Alexis Handal, an epidemiologist from the University of New Mexico in Albuquerque, who does her research in Ecuador.
"We're starting to realise there's such a complicated social context within which these populations live that it's very hard to look at one area and try to generalise to other areas," said Dr Handal, who wasn't involved in the new study.
For example, she said, parents' work hours, whether families have access to nutritious food, and what environmental toxins communities might be exposed to can all interact with factors like altitude to influence maternal and child health.
"Perhaps what we also have to focus on is how can we also develop programmes that promote infant development, that help families?" she added.
Dr Wehby said in the study that babies born at higher elevations may be helped by earlier health screening to make sure they're developing normally.
But he also pointed to the need for more research on why altitude may affect development - and whether similar patterns apply to kids in other high-altitude regions.
(Reuters Health, November 2012)
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