Alzheimer's disease has a worse effect on women than on men, researchers have said.
Women with Alzheimer's have poorer cognitive abilities than men at the same stage of the disease, the study has found.
Researchers from the University of Hertfordshire conducted a detailed overview of existing evidence and found that women have poorer language skills and worse thinking functions - as well as poorer memory - than men at the same stage of the illness.
Reasons behind the "female disadvantage" could include "a reduction of oestrogen in post-menopausal women", "greater cognitive reserve in men" or the influence of the Alzheimer's-linked APOE 4 gene, according to the research, published in World Journal of Psychiatry.
"Our findings may have important implications for variation in the risk factors, progression and possibly the treatment of Alzheimer's disease in men and women," said Professor Keith Laws of the School of Life and Medical Sciences at the University of Hertfordshire.
"For instance, genetics are hard to change but easier to screen, cognitive reserve is modifiable and with more women working, the next generation may suffer less. It is therefore fundamental that we continue to identify the role of sex differences to enable more accurate diagnoses and open up doors for new treatments to emerge."
Commenting on the study, Dr James Pickett, head of research at Alzheimer's Society said: "We already know that two-thirds of people living with dementia are women. This could be in part due to the fact that women live longer, but it also appears that women are at a higher risk of developing dementia for reasons that we don't yet know.
"This review pulls together much of the existing evidence to give us a clearer idea about the impact that Alzheimer's disease has, particularly for women.
"The authors of the review have some interesting theories about why women may be affected by Alzheimer's more than men - including genetics and hormones. These need to be explored in greater depth so we can understand if there are ways we can address the particular needs and experiences of women with Alzheimer's disease and other forms of dementia."