People who are taller are at greater risk of developing cancer. The World Cancer Research Fund reports there is strong evidence taller people have a higher chance of of developing cancer of the:

• pancreas
• large bowel
• uterus (endometrium)
• ovary
• prostate
• kidney
• skin (melanoma) and
• breast (pre- and post-menopausal).

But why? Here’s what we know, don’t know and suspect.

A well established pattern

The UK Million Women Study found that for 15 of the 17 cancers they investigated, the taller you are the more likely you are to have them.

It found that overall, each ten-centimetre increase in height increased the risk of developing a cancer by about 16%. A similar increase has been found in men.

Let’s put that in perspective. If about 45 in every 10,000 women of average height (about 165 centimetres) develop cancer each year, then about 52 in each 10,000 women who are 175 centimetres tall would get cancer. That’s only an extra seven cancers.

So, it’s actually a pretty small increase in risk.

Another study found 22 of 23 cancers occurred more commonly in taller than in shorter people.

Why?

The relationship between height and cancer risk occurs across ethnicities and income levels, as well as in studies that have looked at genes that predict height.

These results suggest there is a biological reason for the link between cancer and height.

While it is not completely clear why, there are a couple of strong theories.

The first is linked to the fact a taller person will have more cells. For example, a tall person probably has a longer large bowel with more cells and thus more entries in the large bowel cancer lottery than a shorter person.

Scientists think cancer develops through an accumulation of damage to genes that can occur in a cell when it divides to create new cells.

The more times a cell divides, the more likely it is that genetic damage will occur and be passed onto the new cells.

The more damage that accumulates, the more likely it is that a cancer will develop.

A person with more cells in their body will have more cell divisions and thus potentially more chance that a cancer will develop in one of them.

Some research supports the idea having more cells is the reason tall people develop cancer more and may explain to some extent why men are more likely to get cancer than women (because they are, on average, taller than women).

However, it’s not clear height is related to the size of all organs (for example, do taller women have bigger breasts or bigger ovaries?).

One study tried to assess this. It found that while organ mass explained the height-cancer relationship in eight of 15 cancers assessed, there were seven others where organ mass did not explain the relationship with height.

It is worth noting this study was quite limited by the amount of data they had on organ mass.

Another theory is that there is a common factor that makes people taller as well as increasing their cancer risk.

One possibility is a hormone called insulin-like growth factor 1 (IGF-1). This hormone helps children grow and then continues to have an important role in driving cell growth and cell division in adults.

This is an important function. Our bodies need to produce new cells when old ones are damaged or get old. Think of all the skin cells that come off when you use a good body scrub. Those cells need to be replaced so our skin doesn’t wear out.

However, we can get too much of a good thing. Some studies have found people who have higher IGF-1 levels than average have a higher risk of developing breast or prostate cancer.

But again, this has not been a consistent finding for all cancer types.

It is likely that both explanations (more cells and more IGF-1) play a role.

But more research is needed to really understand why taller people get cancer and whether this information could be used to prevent or even treat cancers.

I’m tall. What should I do?

If you are more LeBron James than Lionel Messi when it comes to height, what can you do?

Firstly, remember height only increases cancer risk by a very small amount.

Secondly, there are many things all of us can do to reduce our cancer risk, and those things have a much, much greater effect on cancer risk than height.

We can take a look at our lifestyle. Try to:

• eat a healthy diet
• exercise regularly
• maintain a healthy weight
• be careful in the sun
• limit alcohol consumption.

And, most importantly, don’t smoke!

If we all did these things we could vastly reduce the amount of cancer.

You can also take part in cancer screening programs that help pick up cancers of the breast, cervix and bowel early so they can be treated successfully.

Finally, take heart! Research also tells us that being taller might just reduce your chance of having a heart attack or stroke.

Susan Jordan, Associate Professor of Epidemiology, The University of Queensland and Karen Tuesley, Postdoctoral Research Fellow, School of Public Health, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Have you ever heard something that others cannot – such as your name being called? Hearing voices or other noises that aren’t there is very common. About 10% of people report experiencing auditory hallucinations at some point in their life.

The experience of hearing voices can be very different from person to person, and can change over time. They might be the voice of someone familiar or unknown. There might be many voices, or just one or two. They can be loud or quiet like a whisper.

For some people these experiences are positive. They might represent a spiritual or supernatural experience they welcome or a comforting presence. But for others these experiences are distressing. Voices can be intrusive, negative, critical or threatening. Difficult voices can make a person feel worried, frightened, embarrassed or frustrated. They can also make it hard to concentrate, be around other people and get in the way of day-to-day activities.

Although not everyone who hears voices has a mental health problem, these experiences are much more common in people who do. They have been considered a hallmark symptom of schizophrenia, which affects about 24 million people worldwide.

However, such experiences are also common in other mental health problems, particularly in mood- and trauma-related disorders (such as bipolar disorder or depression and post-traumatic stress disorder) where as many as half of people may experience them.

Why do people hear voices?

It is unclear exactly why people hear voices but exposure to prolonged stress, trauma or depression can increase the chances.

Some research suggests people who hear voices might have brains that are “wired” differently, particularly between the hearing and speaking parts of the brain. This may mean parts of our inner speech can be experienced as external voices. So, having the thought “you are useless” when something goes wrong might be experienced as an external person speaking the words.

Other research suggests it may relate to how our brains use past experiences as a template to make sense of and make predictions about the world. Sometimes those templates can be so strong they lead to errors in how we experience what is going on around us, including hearing things our brain is “expecting” rather than what is really happening.

What is clear is that when people tell us they are hearing voices, they really are! Their brain perceives voice experiences as if someone were talking in the room. We could think of this “mistake” as working a bit like being susceptible to common optical tricks or visual illusions.

Coping with hearing voices

When hearing voices is getting in the way of life, treatment guidelines recommend the use of medications. But roughly a third of people will experience ongoing distress. As such, treatment guidelines also recommend the use of psychological therapies such as cognitive behavioural therapy.

The next generation of psychological therapies are beginning to use digital technologies and virtual reality offers a promising new medium.

Avatar therapy allows a person to create a virtual representation of the voice or voices, which looks and sounds like what they are experiencing. This can help people regain power in the “relationship” as they interact with the voice character, supported by a therapist.

Jason’s experience

Aged 53, Jason (not his real name) had struggled with persistent voices since his early 20s. Antipsychotic medication had helped him to some extent over the years, but he was still living with distressing voices. Jason tried out avatar therapy as part of a research trial.

He was initially unable to stand up to the voices, but he slowly gained confidence and tested out different ways of responding to the avatar and voices with his therapist’s support.

Jason became more able to set boundaries, such as not listening to them for periods throughout the day. He also felt more able to challenge what they said and make his own choices.

Over a couple of months, Jason started to experience some breaks from the voices each day and his relationship with them started to change. They were no longer like bullies, but more like critical friends pointing out things he could consider or be aware of.

Gaining recognition

Following promising results overseas and its recommendation by the United Kingdom’s National Institute for Health and Care Excellence, our team has begun adapting the therapy for an Australian context.

We are trialling delivering avatar therapy from our specialist voices clinic via telehealth. We are also testing whether avatar therapy is more effective than the current standard therapy for hearing voices, based on cognitive behavioural therapy.

As only a minority of people with psychosis receive specialist psychological therapy for hearing voices, we hope our trial will support scaling up these new treatments to be available more routinely across the country.

We would like to acknowledge the advice and input of Dr Nadine Keen (consultant clinical psychologist at South London and Maudsley NHS Foundation Trust, UK) on this article.

Leila Jameel, Trial Co-ordinator and Research Therapist, Swinburne University of Technology; Imogen Bell, Senior Research Fellow and Psychologist, The University of Melbourne; Neil Thomas, Professor of Clinical Psychology, Swinburne University of Technology, and Rachel Brand, Senior Lecturer in Clinical Psychology, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.