Study: Small babies face higher risk of adult-onset diabetes

PHILADELPHIA -- The smallest newborns are more than twice as likely to develop diabetes in middle and old age as are those who begin life as large babies, U.S. health researchers said.

In the broadest study to date on the link between birthweight and type-2 diabetes, doctors in Boston examined the medical histories of nearly 70,000 women and found that the risk of disease changed little after adjustments for other factors such as ethnic origin, socioeconomic status and lifestyle.

Type-2 diabetes is a form of the disease that usually occurs gradually after the age of 40.

The study provides new evidence that malnutrition causes fetuses to undergo metabolic changes that can leave people vulnerable to disease later in life, even if children enjoy a normal diet after birth.

The research, conducted by the Channing Laboratory in Boston, appears in the February 16 issue of the Annals of Internal Medicine, a journal published by the Philadelphia- based American College of Physicians.

In an editorial that accompanies the study, Dr. David Barker of the University of Southampton in England said fetal malnutrition also has been linked to other illnesses associated with aging, including coronary heart disease, stroke and high blood pressure.

"Even minor modifications to the diet of pregnant animals may be followed by lifelong changes in the offspring in ways that can be related to human disease," wrote Barker, a leading authority on the fetal origins of adult health problems.

Most earlier studies of birthweight and diabetes conducted in Britain, Jamaica and India either were too small to assess the risk of disease accurately or produced results that were skewed by other factors from childhood and adulthood.

The U.S. study, funded by the National Institutes of Health, relied on statistics from the Nurses Health Study, an ongoing cohort survey of more than 121,000 registered nurses born from 1921 to 1946. Seven years ago, 69,526 nurses who had not had diabetes when the study began in 1976 reported their birthweights to researchers, who found 2,123 confirmed cases of type-2 diabetes among them.

Women who weighed less than 5.0 pounds (2.25 kg) at birth were found to be 1.83 times as likely to contract type-2 diabetes as those who weighed 7.1 to 8.5 pounds (3.2 to 3.8 kg) as newborns, and more than twice as likely as those who weighed over 10 pounds (4.5 kg).

Researchers said the connection between birthweight and diabetes was even stronger among women who reported no parental history of diabetes, with low birthweight children facing nearly four times the risk of the heaviest infants.

Barker castigated public-health policymakers for not recognizing the possible importance of low-birthweight studies in preventing type-2 diabetes, which has reached epidemic proportions among the urban and migrant populations of India.

"It seems that the strategy described by the National Institutes of Health is to ignore the issue," he said.