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.

It’s Saturday afternoon and the kids are all connected to separate devices. So are the parents. Sounds familiar?

Many families want to set ground rules to help them reduce their screen time – and have time to connect with each other, without devices.

But it can be difficult to know where to start and how to make a plan that suits your family.

First, look at your own screen time

Before telling children to “hop off the tech”, it’s important parents understand how much they are using screens themselves.

Globally, the average person spends an average of six hours and 58 minutes on screens each day. This has increased by 13%, or 49 minutes, since 2013.

Parents who report high screen time use tend to see this filtering down to the children in their family too. Two-thirds of primary school-aged children in Australia have their own mobile screen-based device.

Australia’s screen time guidelines recommended children aged five to 17 years have no more than two hours of sedentary screen time (excluding homework) each day. For those aged two to five years, it’s no more than one hour a day. And the guidelines recommend no screen time at all for children under two.

Yet the majority of children, across age groups, exceed these maximums. A new Australian study released this week found the average three-year-old is exposed to two hours and 52 minutes of screen time a day.

Some screen time is OK, too much increases risks

Technology has profoundly impacted children’s lives, offering both opportunities and challenges.

On one hand, it provides access to educational resources, can develop creativity, facilitates communication with peers and family members, and allows students to seek out new information.

On the other hand, excessive screen use can result in too much time being sedentary, delays in developmental milestones, disrupted sleep and daytime drowsiness.

Too much screen time can affect social skills, as it replaces time spent in face-to-face social interactions. This is where children learn verbal and non-verbal communication, develop empathy, learn patience and how to take turns.

Many families also worry about how to maintain a positive relationship with their children when so much of their time is spent glued to screens.

What about when we’re all on devices?

When families are all using devices simultaneously, it results in less face-to-face interactions, reducing communication and resulting in a shift in family dynamics.

The increased use of wireless technology enables families to easily tune out from each other by putting in earphones, reducing the opportunity for conversation. Family members wearing earphones during shared activities or meals creates a physical barrier and encourages people to retreat into their own digital worlds.

Wearing earphones for long periods may also reduce connection to, and closeness with, family members. Research from video gaming, for instance, found excessing gaming increases feelings of isolation, loneliness and the displacement of real-world social interactions, alongside weakened relationships with peers and family members.

How can I set screen time limits?

Start by sitting down as a family and discussing what limits you all feel would be appropriate when using TVs, phones and gaming – and when is an appropriate time to use them.

Have set rules around family time – for example, no devices at the dinner table – so you can connect through face-to-face interactions.

Consider locking your phone or devices away at certain periods throughout the week, such as after 9pm (or within an hour of bedtime for younger children) and seek out opportunities to balance your days with physical activities, such kicking a footy at the park or going on a family bush walk.

Parents can model healthy behaviour by regulating and setting limits on their own screen time. This might mean limiting your social media scrolling to 15 or 30 minutes a day and keeping your phone in the next room when you’re not using it.

When establishing appropriate boundaries and ensuring children’s safety, it is crucial for parents and guardians to engage in open communication about technology use. This includes teaching critical thinking skills to navigate online content safely and employing parental control tools and privacy settings.

Parents can foster a supportive and trusting relationship with children from an early age so children feel comfortable discussing their online experiences and sharing their fears or concerns.

For resources to help you develop your own family’s screen time plan, visit the Raising Children Network.

Elise Waghorn, Lecturer, School of Education, RMIT University

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