Researchers have discovered a gene which they think could increase a person's risk of developing Alzheimer's disease.
The five-year study was conducted by scientists from across the international community and appears in the online edition of Nature Genetics.
Based on DNA samples of 6,000 Caucasians, Hispanics, Israeli-Arabs and African Americans, the research found a link between Alzheimer's and the SORL1 gene.
Further investigation was needed to confirm the results of the study, the researchers concluded.
"Despite the breadth of the study, it's important to have independent replication, which is the only way to be certain that the results are generalisable," said professor Richard Mayeux, the co-director of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University.
Professor Lindsay Farrer, the chief of Boston University's genetics course, agreed and said the relationship between ethnicity and lifestyle differences and SORL1 was still unclear.
According to the Alzheimer's Society, dementia currently affects over 750,000 people in the UK with 55 per cent of these suffering from Alzheimer's.