In Alzheimer’s disease, an accumulation of abnormal proteins in the brain leads to the death of brain cells and then, the gradual loss of brain function.
The exact cause is not fully understood, although Dr Zhao said: “It is believed to involve a combination of genetic, environmental and lifestyle factors.”
Alzheimer’s disease tends to affect those above 60 years and accounts for 60 to 70 per cent of dementia cases, said Dr Hung. “Eventually, patients may have memory loss so severe that it results in the loss of communication and motor skills, resulting in total dependence on others for their everyday activities.”
Besides Alzheimer’s disease, other types of dementia include vascular dementia, often a result of a stroke, and Parkinson’s disease, which affects the nervous system and parts of the body controlled by the nerves.
Less common forms of dementia include Lewy body dementia, which affects thinking, memory and movement. Another type, frontotemporal dementia, affects the frontal and temporal lobes of the brain and can lead to changes in personality, language ability and movement.
DEMENTIA RISK: A LONGER LIFESPAN AND MENOPAUSE
“Age is one of the biggest risk factors contributing to dementia”, said Dr Hung. As women tend to live longer, we’re likely to reach the age where the dementia risk is higher.
Dr Zhao added that the decline of oestrogen levels during menopause is also a risk factor. These hormonal changes may contribute to the process that leads to Alzheimer’s disease.
Furthermore, the risk of cardiovascular disease increases in women post-menopause, which can also raise the risk of dementia, said Dr Chan Wan Xian, a cardiologist at Mount Elizabeth Hospital.
DEMENTIA RISK: HEART DISEASE, HYPERTENSION AND DIABETES
Dr Chan said cardiovascular disease, which is the most common cause of death among women in Singapore, also increases their risk of dementia.
A long-term study published in the Journal of the American Heart Association in 2013 found that female heart attack survivors were twice as likely to experience a decline in memory and cognition.
“Heart failure may lead to cognitive decline due to dysfunction in the brain neurons, thereby causing neurodegeneration,” she said. “Atrial fibrillation can cause small blood clots that can block the small arteries supplying blood to the brain, which can lead to poor circulation to the brain or even cause a stroke,” said Dr Chan.
The result of all these, she added, can lead to cognitive decline and dementia in the long term.