NEW YORK - New research hints that the lower the birthweight, the higher the blood pressure as an adult - and the link becomes stronger with age.

Dr. Anna A. Davies and her associates at the University of Bristol, UK, are studying the origins of adult hypertension (high blood pressure) using a large database of 25,874 employees, average age 38 years, who underwent pre-employment screening for a large British company.

Birthweights were established by recall for most employees. Overall, age- and sex-adjusted systolic blood pressure (the upper number in a standard reading) dropped 0.8 millimeters mercury (mmHg) for every 1 kg increase in birthweight.

For the 744 subjects with birthweight records, systolic blood pressure dropped 1.4 mmHg for every 1 kg increase in birthweight, investigators report.

For subjects older than 55 years, blood pressure change was 33.9 mmHg for each 1 kg increase in birthweight.

Because of the "robust" association between birthweight and blood pressure for subjects with birthweight records in the UK study, the investigators believe that other studies showing a weaker association may be the result of recall bias.

"Further research is required to elucidate whether this birthweight association with adult blood pressure reflects intrauterine programming, a common genetic mechanism, the influence of post-natal growth and development or biologic interactions between these potential mechanisms," the authors write in the journal Hypertension.

In an accompanying editorial, Dr. David J. P. Barker of Oregon Health and Science University in Portland comments that the increasing strength of the link "is consistent with the existence of self-perpetuating cycles of rising blood pressure and renal damage."