快猫短视频

WOMEN who live in the world鈥檚 highest communities tend to give birth to
underweight babies, a new study suggests. These babies may grow into adults with
a high risk of heart disease and strokes.

Research has hinted that newborns in mountain communities are lighter than
average. But it wasn鈥檛 clear whether this is due to reduced oxygen levels at
high altitude or because their mothers are undernourished鈥攎any people who
live at high altitudes are relatively poor compared with those living lower
down.

To find out more, Dino Giussani and his team at Cambridge University studied
the records of 400 births in Bolivia during 1997 and 1998. The babies were born
in both rich and poor areas of two cities: La Paz and Santa Cruz. La Paz is the
highest city in the world, at 3.65 kilometres above sea level, while Santa Cruz
is much lower, at 0.44 kilometres.

Sure enough, Giussani found that the average birthweight of babies in La Paz
was significantly lower than in Santa Cruz. This was true in both high and
low-income families. Even babies born to poor families in Santa Cruz were
heavier on average than babies born to wealthy families in lofty La Paz. 鈥淲e
were very surprised by this result,鈥� says Giussani.

The results suggest that babies born at high altitude are deprived of oxygen
before birth. 鈥淭his may trigger the release or suppression of hormones that
regulate growth of the unborn child,鈥� says Giussani.

His team also found that high-altitude babies tended to have relatively large
heads compared with their bodies. This is probably because a fetus starved of
oxygen will send oxygenated blood to the brain in preference to the rest of the
body.

Giussani wants to find out if such babies have a higher risk of disease in
later life. People born in La Paz might be prone to heart trouble in adulthood,
for example. Low birthweight is a risk factor for coronary heart disease
(快猫短视频, 14 December 1996, p 14).
And newborns with a high ratio of
head size to body weight are often predisposed to high blood pressure and
strokes in later life.