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Low birth weight may affect adult lung health
Reported March 08, 2010
NEW YORK - Middle-aged adults who were born at a relatively low
weight may have more breathing difficulties than those who were bigger
newborns, a new study suggests.
In a study of 627 Chinese men and women in their 40s, researchers found that
participants' scores on standard lung-function tests generally lined up with
their birth weights. The lowest average scores were recorded among adults
who had been born weighing less than 5.5 pounds, while the highest scores
were seen among those whose birth weights topped 7 pounds.
The findings do not prove that low birth weight itself is the reason for the
discrepancy, the researchers note in the journal Pediatrics.
But they do support the so-called "fetal origins hypothesis" that impaired
growth in the womb might ultimately affect adult lung function, write Dr.
Lijun Pei and colleagues at Peking University in Beijing.
According to that theory, environmental factors during early development --
particularly poor maternal nutrition -- might help "program" a person's
risks of various health problems later in life, Pei and senior researcher
Dr. Xiaoying Zheng told Reuters Health in an email.
The findings are based on birth records and lung-function tests for 627
adults born in Beijing between 1948 and 1954.
When the men and women were between the ages of 41 and 47, they underwent a
standard test of lung function called spirometry -- which measures the
amount of air that moves in and out of the lungs with each breath, as well
as the speed at which it flows.
Lower scores can indicate airway obstruction, possibly from lung diseases
like asthma or emphysema.
In this study, the average lung-function score in the group with the lowest
birth weights was within normal range. But Pei and Zheng said that past
studies have found associations between low birth weight and higher risks of
childhood asthma and, in adulthood, chronic obstructive pulmonary disease --
a group of lung diseases that includes emphysema and chronic bronchitis.
The researchers found that lower birth weight was related to poorer lung
function even when they accounted for a number of other factors that affect
birth weight and adult lung health. Those included prematurity,
participants' history of childhood respiratory illnesses, adulthood weight
and smoking habits.
Smoking during pregnancy is a known risk factor for low birth weight, and
there is evidence that children born to smokers have smaller lung volumes
and higher risks of asthma and respiratory infections.
Pei's team lacked information on whether participants' mothers smoked during
pregnancy.
They also had no information on mothers' diets during pregnancy, so the
extent to which poor nutrition in the womb might account for the link
between birth weight and adulthood lung function in unknown.
However, Pei and Zheng pointed out, malnutrition was common in Beijing at
the time study participants were born. A study of Chinese schoolchildren of
that era, for example, found that more than two-thirds were deficient in
vitamin C -- which offers clues to their overall nutritional status.
It's "plausible," according to Pei and Zheng, that poor fetal nutrition and
subsequent underdevelopment of the lungs could affect lung function into
adulthood.
Source : Reuters |
