Ideas about causes of dementia

Those more likely to develop dementia include elderly people, people with Down’s syndrome, people who have had severe head or whiplash injuries, people who smoke, and those who have high blood pressure, high cholesterol levels or diabetes and those with a family history of dementia. Among the very elderly (old age is the most important of these risk factors) 1 in 6 people over the age of 80 will develop dementia (Alzheimer’s Society accessed February 2020). Although it is not possible to do anything about most of the causes, some research suggests that certain changes to lifestyle (maintaining a good diet, exercising regularly, and avoiding excessive consumption of alcohol) may help to protect against dementia.

Among the people we talked with, family history was widely acknowledged as a cause of Alzheimer’s, although many of the carers were not aware of dementia in the family. Some knew that early onset forms were more likely to have a genetic cause. In families where living to a ripe, and mentally agile, old age was considered normal, people found it hard to understand why it should have happened. Parents often hoped that family history was not so important, anxious that their children would not be affected.

Thinks that it must be inherited in his wife’s case, though hopes his children will be protected by his genes.

Age at interview 72

Gender Male

Age at diagnosis 62

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Looking back now the similarities now are very great with her mother. Its the same I imagine part of the brain thats affected because in her mothers case after breast cancer the vocabulary went eventually. And exactly the same things happened to my wife again after breast cancer, in 93 and the vocabulary is that part that has gone and we get these connecting words and then about four to five years ago the nouns went. We do occasionally now at the nursing home – just around the corner – suddenly get complete sentences. Re-establishing train of thought.

Yes its fascinating to me the fact that she is following her mother so much in the way this is going. As I say her mother had breast cancer and started it fairly soon after and my wife had breast cancer and started it fairly soon after. Well no I suppose looking back she had started it already but it seemed to start after that which is no doubt purely coincidental.

Well obviously I suppose in my wife’s case it can be inherited because she is so following her mother, although her aunt, her mothers sister never had any problem at all. Of course my daughter says to me now Am I going to be the same? you know and I sort of jokingly say without knowing the answer Well no my genes will counteract it, rather flippantly.

But it seems to me because my wife and her mother, the way theyve gone is so similar it must be, as they say it is, inherited in this particular instance. And it must be the same whichever part of the brain thats affected, the similarity particularly of the speaking. I mean I meet other people who are physically disabled more so.

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Everyone we interviewed was asked if they had any theories about causes. Only a few said they had never really thought about it, or thought that it was just caused by old age. Some had spent a lot of time reading about dementia and puzzling over what might have caused it in their parent or partner. People compared the lifestyle and exposures of people within their family who were thought to be similar, yet had not developed dementia, to try to identify the cause. One wife thought that it might have been caused by a viral infection or whiplash after an accident, reasoning that in every other way her husband had had a lifestyle identical to her own.

Has two theories about why her husband developed dementia in his fifties.

Age at interview 62

Gender Female

Age at diagnosis 50

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Yes I do. I think it’s probably, well at the moment I’m subscribing to two theories. I’m a believer in there being a viral element. If I go back to what I think is the very beginning. My husband had a one-off night time seizure out of the blue, sort of like a semi-epileptic do, and hed never been epileptic in his life and in the months that led up to that hed had a viral infection after viral infection, sort of flu-like colds and I think his immune system was so damaged by all that, well depleted by all that that the one-off night seizure may have caused the ultimate breaching or breakdown of the system, that’s how it seemed to me.

But when I look back two years before that he had a car accident, he was not injured, but he had quite a bad whiplash, it was an empty car transporter backing across a main road at night and in the rain and my husband could see the headlights of oncoming vehicles through the empty transporter and suddenly’ ‘What’s this fence in front of me?’ A dark country road and he crashed into the rear wheel of the transporter, the car’s bonnet was triangular, it was a write-off, he fortunately was wearing his seat belt and he had a slight bump on the front of his head and was jarred, but he was not taken to hospital, he clambered out, apparently unhurt.

And I do subscribe to the theory that, you can’t bash your brain about like that without doing something. Although there was no head injury worth speaking of but there was a very, very severe jolt and talking to a lot of friends that I’ve met through the Alzheimer’s Society groups, it’s surprising the number of people who had some kind of head injury several years before the Alzheimer’s kicked in. So, yeah, those are my two things.

My husband and I had identical life styles, absolutely identical. We were born in the same town, we are almost the same age, went to similar types of school, we went to university together and obviously when we were married we had a similar life style and we finished up with, for the last twenty-five years having the same job. So therefore sharing life style, food, routine, everything, why should he get it and not me, so theres got to be something there.

Theres no genetic thread in [my husband]’s family at all, theres no familial tendency, because often with early onset there can be a familial tendency, there is not in my husbands. He had one or two crazy great aunts but of a great age, but nobody who got it in their fifties. So maybe there is a genetic predisposition and that theres something in the environment like a car accident or viral infections trigger it, but I don’t think theres anything else. It’s the luck of the draw really.

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Several people mentioned another serious illness as a possible trigger – one daughter knew of three women who had been treated for breast cancer shortly before they developed Alzheimer’s and wondered if there could be any connection.

Suspects that her mother had micro-vascular disease dementia and wonders if it was connected to breast cancer.

Gender Female

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I’ve got very strong, views on my mother’s case. You see I don’t think my mother had Alzheimer’s, I think that my mother had micro-vascular dementia. She, hers was very specific in that it was memory loss and then everything that’s followed from that with loss of, it was loss of facts, it want loss of sort of the learnt experience.

You see she could still read, she would read things out to me but couldn’t remember what they meant. Shed read perfectly, and shed read upside down even, you know the actual activity of reading was still there, but she couldn’t remember what it meant, what the words meant. But shed read it properly and coherently. And as I said to you before mum was rational, she was definitely rational she used, her limited information in a very rational way. And, so she had just lost memory, but profound loss of memory.

And she didn’t lose any – in mum’s case – she didn’t lose any physical attributes. She was dextrous right to the end, she walked well, she was particularly dextrous, with her eating I watched the last time I ate with her and she, I never saw her having to be fed except that time when she was, when she was sedated. She, ate beautifully, it was a pleasure to watch her eat, she cut her food very neatly and she put it in her mouth, she didn’t dribble, she didn’t, she kept all her, she kept all those sorts of skills.

She had a blouse with a bow on and the bow would be nicely tied. So mum’s was very much a memory loss which totally altered, altered her behaviour and her ability to communicate in every way but it wasn’t as I say a loss of learned skills. And when she was admitted for invest, for yes, investigation as they call it, after she was sectioned, I Don’t think much investigation went on, they did say to me over the phone it was micro-vascular dementia, which I could have told them.

But I for me, and I wouldn’t altogether be able to prove anything, it dates from the time when she had cancer of the breast in 1978 and she had secondaries almost immediately. She had her first secondary six months afterwards in the rib and I saw it, so there was no doubt about it, she showed it to me, I, I saw the, I felt the first lump, people have doubted her diagnosis because she lived for twenty, she lived for twenty years after her diagnosis, so people have been sceptical about whether she truly had it, but I have no doubt about it.

I would like to have known really but, the more I’ve thought about that recently, the more I think that’s, that’s how her microvascular problems stemmed from. And, yes and her sister who is quite like her and as I say is still alive, and you know is just so different, you just know that something else happened with, you just feel something else happened with mum that my auntie didn’t have because then otherwise they’re, they’re so similar and I think, that’s it. I Don’t think mum had any cerebral secondaries, there was a question of one at one time but, that would have caught up with her and didn’t.

So I don’t, think that had any connection but I do have another little thought. In my, in my dissertation there are three people I mention there was my mother, my mother-in-law and my, neighbour across the road (a different neighbour, a neighbour further on), her mother who took a, whose dementia took a similar pattern to my mother’s. I think hers was micro-vascular as well.

They all survived carcinoma of the breast and they had all had tamoxifen. And I would just be very interested to know if there is any association. Mother-in-law had, my mother-in-law didn’t have secondaries but her dementia began a year or so after that and it was the same for my neighbour across the road, her mother had a carcinoma of the breast and, they’d all had some tamoxifen. I don’t know if I’m blaming tamoxifen, I don’t know if I’m blaming the carcinoma, I don’t know if I’m blaming the hormonal imbalance but, it’s a bit coincidental, so that’s my other little thought.

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Stress (particularly as a result of bereavement), exposure to chemicals, general anaesthetic, heavy drinking, using aluminium cooking pots and having a blow to the head were all mentioned as possible causes. In some cases it was thought that the combination of an underlying susceptibility and a trigger was likely. Sometimes it was hard to say whether behaviour such as heavy drinking, depression or work-related stress was a trigger or an early sign of the disease.

His wife went through a brief period of heavy drinking – he wonders if this was a sign rather than a cause.

Age at interview 57

Gender Male

Age at diagnosis 56

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No, Ive no real understanding of what actually caused it. My wife’s father did have dementia towards the latter part of his life but he was certainly in his latter seventies. And, I think that was part through an operation that he had that went wrong that we understand did affect him in some way mentally. He was never ever diagnosed with any form of Alzheimers’. His sister in her seventies also had a mental health problem. So whether there is anything hereditary from my wife’s side of the family then Im not totally sure.

Before it was diagnosed my wife did have a spell of drinking alcohol and she did not previously consume much alcohol at all. The occasional drink at a party or a celebration or a glass of wine if we went for a meal. But she did go through a spell where she started drinking quite heavily and that was probably within the, a year prior to us going to the doctors. She did stop the drinking. Whether that had any effect I don’t know, and she was drinking quite heavily – a bottle of gin within two days, every two days or so. And I couldn’t stop her doing it; there was no other rhyme nor reason that she was doing it.

We had no family problems; our marriage was good; we had good relations with all our children; we had superb grandchildren which she loved, and had brought one of them up virtually. So there were no family problems; we had no marital problems; we had no financial problems so there was no other reason that I could establish why she started drinking but she did drink quite heavily for a period of time.

But that had stopped when we went to the doctor. Whether she was aware that she had a problem, and I was not aware at that stage, Im not, sure. So in, I cant put any reason on why [my wife] was diagnosed with dementia, especially at an early age – of 56 or 57 which is generally a youngish age to be diagnosed with Alzheimer’s. So no I cant really put any reason behind it.

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A nurse whose husband had Pick’s disease was disappointed that no one seemed interested in exploring possible causal factors, such as his exposure to environmental pollutants. She describes how an early encounter at the clinic encouraged their view that agricultural pesticides might be to blame.

Is surprised that no one has been interested in their ideas about causes and thinks that exposure to chemicals may have been to blame.

Age at interview 52

Gender Female

Age at diagnosis 57

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Its a thing that, in the early days particularly, we both spent quite a lot of time thinking about. And my husband is very, hes had quite a bee in his bonnet about the fact that there have been no epidemiological studies. Nobody’s been interested in his background.

I mean to give you an example, he was a tiny little boy during the War and he, they put a gas mask on various children, put them in an aircraft hanger, sealed it up and let some gas out so that they knew what the smell was like. So he was exposed to some kind of chemical warfare type gas. I mean, it could be completely irrelevant. Im sure it probably is, but nobody’s actually asked and when he’s really confronted people and said Look, you know, Ive got things in my life that I think might be relevant, would you like to hear about them? The answer has been No really.

I mean we’ve moved, we’ve had two houses where we had to have the, the roof space treated with this sort of Rentokil stuff, and in both cases we didn’t move in until the stipulated time, but equally in both cases, that house stank and at the time we said Gosh you know, we hope this isn’t doing us any harm. That kind of stuff nobody’s interested in. I mean Im not a research scientist, I don’t know, you know, whether its wrong that those things are being ignored or not but, yes its,.I mean I, I don’t know again whether early on-set dementias are becoming more common because the system for diagnosis and the awareness of it is heightened or is it becoming more common? In which case is it environmental?

I just, you know all sorts of things go round in your mind. Is it our, I don’t think it would be diet, because we’ve been pretty wholesome on that sort of thing; but certainly environmental. I mean, that was another thing. If it wasn’t tragic it would have been funny. The very first specialist memory clinic we attended, as we were driving over in the car my husband said to me You know Ive always worried about the farm sprays. When we lived in our very first cottage when we got married, in our garden there were certain times of year when we would really smell this very potent agricultural pesticide spray. And you could feel it almost getting into your tubes.

And we used to comment at the time you know, Gosh we hope this int doing any lasting harm. As we were driving to the memory clinic, [my husband] commented on it, named the farmer who was a lady and said you know I wonder if its all her fault, and we laughed. We got to the clinic and it was surreal. The very next person to walk through the door as a patient was that farmer! Now, coincidence or what, I don’t know, but nobody’s ever been interested about hearing that kind of detail of, what could have affected my husband.

But that may be a research science strategy thats moved on and maybe its not relevant in this day and age, there are others ways of doing things, I don’t know. But certainly in my husbands family the, previous generations of his family have lived, I mean they’ve been exceptional in living a very long time. Many of them have lived into their 90s. Driven, served, one old uncle serviced his own car until he was about 95 I mean they, they’ve lived exceptionally long with exceptionally astute minds up until the end. So its something, but who knows what. We just don’t know.

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There was some confusion about smoking. Some had heard that smoking might protect people from dementia, while others were aware that vascular dementia could be caused by smoking. One family were surprised when the doctor suggested smoking was the cause of their fathers dementia since he only smoked a very occasional cigar and had not been known to smoke a cigarette in nearly 40 years.

Although searching for a cause can be helpful for some families, in most cases no single cause will ever be identified. It is likely that complex genetic factors play a part in susceptibility to dementia, and then lifestyle and environmental factors further modify the risk. The observed link between illness and onset of dementia may in some cases be explained by a ‘delirium’ (or acute confusional state) secondary to the illness exposing some underlying cognitive impairment, or the early stages of dementia. Similarly, the link of onset of dementia with major life events may be explained by already present symptoms of dementia being exposed under stress.

Had heard that vascular dementia could be caused by smoking.

Age at interview 61

Gender Female

Age at diagnosis 70

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I don’t know how familiar you are with vascular dementias and what have you. Because well, he stopped smoking all that long time ago and when you see all these anti smoking campaigns they never mention dementia. I mean yes the heart disease, the strokes, emphysema, all sorts of other things but I’ve never ever seen any publicity linking smoking with dementia.

I think why, because it’s the one thing which has had an effect on one of my children he, he tried to give up before but he has given up now, he said ‘If that’s what it does to you, no thank you. I suppose vascular, if it’s vascular it could be affected by the smoking, if it’s like mini, mini strokes or whatever.

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Last reviewed: November 2023

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