Lothian Birth Cohort study links water quality to Alzheimer’s

Lothian Birth Cohort study links water quality to Alzheimer’s


Monday, 25 March, 2019

Dr Tom Russ, Prof Ian Deary, Prof John Starr and colleagues (Alzheimer’s Scotland Dementia Research Centre, and Centre for Cognitive Ageing & Cognitive Epidemiology) have published a large longitudinal study using data from the Lothian Birth Cohort which explored whether there was a link between quality of drinking water with dementia risk, in men and women.  They found that there was an increased risk in both men and women with increasing levels of aluminium and of fluoride in drinking water.

The study involved around 7,000 individuals born in 1921 who undertook an intelligence test in 1932 which was the forerunner of the historical 11-plus exam. A total of 1,972 out of 6,990 participants in the study had developed dementia by 2012.

Aluminium is often found in drinking water because coagulants such as alum (aluminium sulphate) are used to trap impurities in raw water by binding them together to form particles before they are filtered out. Fluoride occurs naturally and is not added to the water supply in Scotland and, although low levels are beneficial to teeth, this may be offset by the potential for increasing dementia risk. It might be worth noting that levels of Aluminium and Fluoride in Scottish water are low in relation to World Health Organisation guidelines.

Dr Tom Russ siad:

“Everybody included in the study was alive in 2005 and they were all born in 1921,” he said. “Everybody who subsequently died with dementia was compared with those who died without, and the people who lived in areas of higher levels of aluminium in drinking water were more likely to die than those in areas where the aluminium levels were lower. “We still see this well accepted finding that higher levels of aluminium in particular are associated with an increased risk of dementia. It’s confirmatory rather than anything else.”