The cohorts' history

Find out about the history of the Lothian Birth Cohort 1921 and 1936 studies, and the studies' participants.

LBC female participant with school photo at reunion

The Lothian Birth Cohort 1921 (LBC1921) study and the Lothian Birth Cohort 1936 (LBC1936) study are two longitudinal studies of cognitive, brain and general ageing. They aim to understand how our brain and thinking skills change throughout life, and why some brains age better than others. 

Unique tests of intelligence 

The Lothian Birth Cohort studies were designed as follow-ups to the Scottish Mental Surveys of 1932 and 1947, which tested the intelligence of almost every 11-year-old child attending school in Scotland in the month of June in those years.

The Scottish Mental Surveys fell into relative obscurity for several decades, until in 1997, Professor Ian Deary, and his colleague, Professor Lawrence Whalley, 'rediscovered' the Surveys' data.

Professor Ian Deary and the late Professor John Starr founded the Lothian Birth Cohort 1921 (LBC1921) study in 1999 and the Lothian Birth Cohort 1936 (LBC1936) study in 2004.

Professor Ian Deary was Director of LBC from 1998 until his retirement in November 2020 and continues to work on the studies as professor emeritus.

A rare research opportunity

Ian Deary and John Starr receiving the Margaret MacLellan Award in 2006

Surviving members of the Scottish Mental Surveys of 1932 and 1947 living in Edinburgh and the surrounding Lothians region were traced and recruited into LBC1921 and LBC1936 in older age.

They re-sat the same cognitive ability test first taken in childhood, along an extensive programme of cognitive, physical, and medical testing.

Their intelligence scores from age 11 provide a baseline measure that has enabled the investigation of how childhood intelligence relates to cognitive ability, mental, physical and brain health in older age.

Tracing, recruiting and re-testing people who had taken part in the Scottish Mental Surveys offered a rare opportunity to examine the distribution and causes of cognitive ageing across most of the human life course.

Dedicated participants

LBC1936 participants with Ian Deary

The LBC1921 study followed up on 550 adults with SMS1932 intelligence test scores at age 11 and the LBC1936 study follows up on 1,091 adults with SMS1947 intelligence test scores at age 11.

The LBC1936 participants visit the University every three years from age 70. To date, the team has tested the LBC1936 at average ages of 70, 73, 76, 79, and 82 years. These rounds of testing are known as ‘waves’, from Wave 1 at age 70 to the upcoming Wave 6 at age 85.

At each visit the participants submit a wide range of data, leading to a database of thousands of data points for every single participant, including:

  • cognitive
  • lifestyle
  • social and psychological
  • genetic and epigenetic
  • health and physical fitness
  • biological
  • brain and vascular imaging data.

The data collected have given rise to hundreds of peer-reviewed publications, and the studies continue to make novel and significant contributions to our understanding of the ageing process from a variety of perspectives.

Futher reading about the Lothian Birth Cohorts' profile:

Link to a 2004 article describing Scottish Mental Surveys of 1932 and 1947

Link to a free 2012 article about the Lothian Birth Cohorts

Link to a free 2018 article with an updated profile of the Lothian Birth Cohorts