BLSA Open

The Baltimore Longitudinal Study of Aging (BLSA) is a study of human aging run by the Intramural Research Program of the US National Institute on Aging. It started in 1958 and added neuroimaging in 1994. BLSA Open is the part of its brain MRI that the study releases under its open data tier, distributed through the LONI Image and Data Archive (IDA) after an online data use application.

Composition

The IDA record lists 118 participants in a single cohort, all with MRI. The images are defaced brain MRIs from visits between 2009 and 2020, and participants can have several visits. The record flags clinical and demographic data as included, and genetic data and biospecimens as not included.

The BLSA sorts its data into four tiers: open, permissioned, entrusted and non-shared. Open data are de-identified, come from visits whose consent and participant status allow full public sharing, and are past any embargo, which for most data is a two-year quality control period or until publication. The permissioned data need a pre-analysis plan reviewed by the BLSA Data Sharing Committee and a transfer agreement, and are not part of this entry.

Acquisition

The IDA record does not list sequences, scanners, field strengths or sites.

Annotations

None are described for the open release.

Known limitations

• Only participants and visits cleared for open sharing are included, so the 118 people are a selected subset of the study and not a random sample of it.
• Sex, age, sequence and per-visit counts are not published for the open release.
• The data use agreement warns that processed data may change as analysis methods evolve, and asks users to record the version they downloaded and check for updates before publishing.
• Use is limited to internal, non-commercial research, and the data may not be used for diagnosis, prognosis or treatment.