Feasibility of Linking Long-Term Cardiovascular Cohort Data to Offspring Birth Records: The Bogalusa Heart Study.

Introduction Researchers in perinatal health, as well as other areas, may be interested in linking existing datasets to vital records data when the existence or timing of births is unknown. Methods 5914 women who participated in the Bogalusa Heart Study (1973-2009), a long-running study of cardiovascular health in childhood, adolescence, and adulthood, were linked to vital statistics birth data from Louisiana, Mississippi, and Texas (1982-2010). Deterministic and probabilistic linkages based on social security number, race, maternal date of birth, first name, last name, and Soundex codes for name were conducted. Characteristics of the linked and unlinked women were compared using t-tests, Chi square tests, and multiple regression with adjustment for age and year of examinations. Results The Louisiana linkage linked 4876 births for 2770 women; Mississippi linked 791 births to 487 women; Texas linked 223 births to 153 women; After removal of duplicates and implausible dates, this left a total of 5922 births to 3260 women. This represents a successful linkage of 55% of all women ever seen in the larger study, and an estimated 65% of all women expected to have given birth. Those linked had more study visits, were more likely to be black, and had statistically lower BMIs than unlinked participants. Discussion Linking unrelated study data to vital records data was feasible to a degree. The linked group had a somewhat more favorable health profile and was less mobile than the overall study population.