British law used to study education and dementia

A British law from 1972, which increased the minimum school-leaving age from 15 to 16, is being used by researchers to investigate how education might affect the risk of dementia. Scientists at the University of Southern California used this change as a natural experiment to examine the long-term health effects of an extra year of schooling.

Groups compared by birth date

The 1972 law meant that students born after September 1, 1957, had to stay in school until they were 16, while those born just a few days earlier could leave at 15. This created two nearly identical groups of people, differing only by one year of compulsory schooling, allowing researchers to compare their dementia risk over time.

Data from UK Biobank used in study

The study used data from the UK Biobank, a large health database with information on over 100,000 people followed until they reached 65. The law increased the number of people who stayed in school until 16 by 14 percentage points. Those who stayed in school longer had a lower rate of dementia diagnoses than those who left earlier.

Extra year of schooling linked to lower dementia risk

According to a study published in the Proceedings of the National Academy of Sciences, an additional year of schooling was associated with a 0.88 percent reduction in dementia incidence over fifty years. The effect was more noticeable when researchers compared the data with a genetic score that predicted dementia risk, showing that education had a measurable impact even among people with a higher genetic predisposition.