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The smallest surviving premature babies eventually attain levels of education, employment and independence that are almost indistinguishable from those of normal weight babies, according to the latest findings from a continuing Canadian study that began 28 years ago.

By most measures, researchers found no substantial differences between people born at exceptionally low weights and those born at normal weights.

The rates — including high school graduation, pursuit of postsecondary education, aspects of employment, independent living, marriage and parenthood, did not differ significantly between groups. 

The findings held even when those with disabilities — 27 percent of those with low birth weight and 2 percent of those at normal birth weight — were included. Contrary to the scientists’ expectations, a majority of those born unusually small successfully moved from adolescence to adulthood. 

“Children who appear disabled at 2 or 3 are not necessarily doomed to a lifetime of disability,” said Dr. Saroj Saigal, who was the senior author of the study. “These young adults were able to achieve much more than we expected.”

Researchers have been following 166 babies born from 1977 to 1982 who weighed 1.1 to 2.2 pounds at birth along with a matched group of 145 babies of normal weight.

They have now examined those subjects as young adults in face-to-face interviews by trained interviewers who did not know which subjects had been low-birth-weight babies.

Parents responded for participants who were severely impaired and unable to respond themselves. The results were published Feb. 8 in The Journal of the American Medical Association.

The proportion of high school graduates was similar in both groups, although those with extremely low birth weights were less likely to complete the advanced high school course required for university entrance in Canada.

A significantly lower percentage of subjects with low birth weights were enrolled in college or had graduated, though the difference evened out with other forms of postsecondary education.

More subjects with low birth weights were unemployed because of chronic illness or sustained disability.

Among those employed, there were no differences between the groups in part-time or full-time employment, and figures for permanent employment were comparable with Canadian population norms. 

Dr. John M. Lorenz, a professor of clinical pediatrics at Columbia University Medical Center who was not involved in the study, said he found the results impressive. “They’ve followed the great majority of survivors over time into a period of life where you can get some idea about how they are going to function as adults,” he said.

The researchers did find significant sex differences, with women doing better in all respects than men.  “Males are more vulnerable,” said Dr. Saigal, a professor of pediatrics at McMaster University in Hamilton, Ontario. “Survival rates are lower. They have a higher proportion of neurological difficulties, and they don’t do as well in school. This is consistent with every other study.” 

The authors acknowledge that it may not be possible to generalize their results to other populations. The low birth weight group was 94 percent white, with 82 percent from two-parent families. Moreover, all the babies received care at hospitals with specialized neonatal intensive care units under Canada’s universal health care system. 

“I don’t want to say that because our children have done well, the results are going to be the same everywhere,” Dr. Saigal said. “The results would be comparable with similar socioeconomic conditions and similar resources available.”

Dr. Saigal also said the degree of disability varied widely among participants with low birth weights. “I don’t want it to appear that all these children do well,” she said. “Looking at news reports of children born in the 1990’s,” Dr. Saigal said, “the earlier outcome is pessimistic. But most children can, to a large extent, overcome the biological risks. This attests to the resilience of human beings.”
[8Feb06, The Journal of the American Medical Association,  By NICHOLAS BAKALAR, 28Feb06; N Valko RN, 1 Mar06]