Not getting enough sleep is a common affliction in the modern age. If you don’t always get as many hours of shut-eye as you’d like, perhaps you were concerned by news of a recent study that found people who sleep less than six hours a night are at higher risk of type 2 diabetes.

So what can we make of these findings? It turns out the relationship between sleep and diabetes is complex.

The study

Researchers analysed data from the UK Biobank, a large biomedical database which serves as a global resource for health and medical research. They looked at information from 247,867 adults, following their health outcomes for more than a decade.

The researchers wanted to understand the associations between sleep duration and type 2 diabetes, and whether a healthy diet reduced the effects of short sleep on diabetes risk.

As part of their involvement in the UK Biobank, participants had been asked roughly how much sleep they get in 24 hours. Seven to eight hours was the average and considered normal sleep. Short sleep duration was broken up into three categories: mild (six hours), moderate (five hours) and extreme (three to four hours). The researchers analysed sleep data alongside information about people’s diets.

Some 3.2% of participants were diagnosed with type 2 diabetes during the follow-up period. Although healthy eating habits were associated with a lower overall risk of diabetes, when people ate healthily but slept less than six hours a day, their risk of type 2 diabetes increased compared to people in the normal sleep category.

The researchers found sleep duration of five hours was linked with a 16% higher risk of developing type 2 diabetes, while the risk for people who slept three to four hours was 41% higher, compared to people who slept seven to eight hours.

One limitation is the study defined a healthy diet based on the number of servings of fruit, vegetables, red meat and fish a person consumed over a day or a week. In doing so, it didn’t consider how dietary patterns such as time-restricted eating or the Mediterranean diet may modify the risk of diabetes among those who slept less.

Also, information on participants’ sleep quantity and diet was only captured at recruitment and may have changed over the course of the study. The authors acknowledge these limitations.

Why might short sleep increase diabetes risk?

In people with type 2 diabetes, the body becomes resistant to the effects of a hormone called insulin, and slowly loses the capacity to produce enough of it in the pancreas. Insulin is important because it regulates glucose (sugar) in our blood that comes from the food we eat by helping move it to cells throughout the body.

We don’t know the precise reasons why people who sleep less may be at higher risk of type 2 diabetes. But previous research has shown sleep-deprived people often have increased inflammatory markers and free fatty acids in their blood, which impair insulin sensitivity, leading to insulin resistance. This means the body struggles to use insulin properly to regulate blood glucose levels, and therefore increases the risk of type 2 diabetes.

Further, people who don’t sleep enough, as well as people who sleep in irregular patterns (such as shift workers), experience disruptions to their body’s natural rhythm, known as the circadian rhythm.

This can interfere with the release of hormones like cortisol, glucagon and growth hormones. These hormones are released through the day to meet the body’s changing energy needs, and normally keep blood glucose levels nicely balanced. If they’re compromised, this may reduce the body’s ability to handle glucose as the day progresses.

These factors, and others, may contribute to the increased risk of type 2 diabetes seen among people sleeping less than six hours.

While this study primarily focused on people who sleep eight hours or less, it’s possible longer sleepers may also face an increased risk of type 2 diabetes.

Research has previously shown a U-shaped correlation between sleep duration and type 2 diabetes risk. A review of multiple studies found getting between seven to eight hours of sleep daily was associated with the lowest risk. When people got less than seven hours sleep, or more than eight hours, the risk began to increase.

The reason sleeping longer is associated with increased risk of type 2 diabetes may be linked to weight gain, which is also correlated with longer sleep. Likewise, people who don’t sleep enough are more likely to be overweight or obese.

Good sleep, healthy diet

Getting enough sleep is an important part of a healthy lifestyle and may reduce the risk of type 2 diabetes.

Based on this study and other evidence, it seems that when it comes to diabetes risk, seven to eight hours of sleep may be the sweet spot. However, other factors could influence the relationship between sleep duration and diabetes risk, such as individual differences in sleep quality and lifestyle.

While this study’s findings question whether a healthy diet can mitigate the effects of a lack of sleep on diabetes risk, a wide range of evidence points to the benefits of healthy eating for overall health.

The authors of the study acknowledge it’s not always possible to get enough sleep, and suggest doing high-intensity interval exercise during the day may offset some of the potential effects of short sleep on diabetes risk.

In fact, exercise at any intensity can improve blood glucose levels.

Giuliana Murfet, Casual Academic, Faculty of Health, University of Technology Sydney and ShanShan Lin, Senior Lecturer, School of Public Health, University of Technology Sydney

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

Receiving a cancer diagnosis is life-changing and can cause a range of concerns about ongoing health.

Fear of cancer returning is one of the top health concerns. And managing this fear is an important part of cancer treatment.

But how likely is it to get cancer for a second time?

Why can cancer return?

While initial cancer treatment may seem successful, sometimes a few cancer cells remain dormant. Over time, these cancer cells can grow again and may start to cause symptoms.

This is known as cancer recurrence: when a cancer returns after a period of remission. This period could be days, months or even years. The new cancer is the same type as the original cancer, but can sometimes grow in a new location through a process called metastasis.

Actor Hugh Jackman has gone public about his multiple diagnoses of basal cell carcinoma (a type of skin cancer) over the past decade.

The exact reason why cancer returns differs depending on the cancer type and the treatment received. Research is ongoing to identify genes associated with cancers returning. This may eventually allow doctors to tailor treatments for high-risk people.

What are the chances of cancer returning?

The risk of cancer returning differs between cancers, and between sub-types of the same cancer.

New screening and treatment options have seen reductions in recurrence rates for many types of cancer. For example, between 2004 and 2019, the risk of colon cancer recurring dropped by 31-68%. It is important to remember that only someone’s treatment team can assess an individual’s personal risk of cancer returning.

For most types of cancer, the highest risk of cancer returning is within the first three years after entering remission. This is because any leftover cancer cells not killed by treatment are likely to start growing again sooner rather than later. Three years after entering remission, recurrence rates for most cancers decrease, meaning that every day that passes lowers the risk of the cancer returning.

Every day that passes also increases the numbers of new discoveries, and cancer drugs being developed.

What about second, unrelated cancers?

Earlier this year, we learned Sarah Ferguson, Duchess of York, had been diagnosed with malignant melanoma (a type of skin cancer) shortly after being treated for breast cancer.

Although details have not been confirmed, this is likely a new cancer that isn’t a recurrence or metastasis of the first one.

Australian research from Queensland and Tasmania shows adults who have had cancer have around a 6-36% higher risk of developing a second primary cancer compared to the risk of cancer in the general population.

Who’s at risk of another, unrelated cancer?

With improvements in cancer diagnosis and treatment, people diagnosed with cancer are living longer than ever. This means they need to consider their long-term health, including their risk of developing another unrelated cancer.

Reasons for such cancers include different types of cancers sharing the same kind of lifestyle, environmental and genetic risk factors.

The increased risk is also likely partly due to the effects that some cancer treatments and imaging procedures have on the body. However, this increased risk is relatively small when compared with the (sometimes lifesaving) benefits of these treatment and procedures.

While a 6-36% greater chance of getting a second, unrelated cancer may seem large, only around 10-12% of participants developed a second cancer in the Australian studies we mentioned. Both had a median follow-up time of around five years.

Similarly, in a large US study only about one in 12 adult cancer patients developed a second type of cancer in the follow-up period (an average of seven years).

The kind of first cancer you had also affects your risk of a second, unrelated cancer, as well as the type of second cancer you are at risk of. For example, in the two Australian studies we mentioned, the risk of a second cancer was greater for people with an initial diagnosis of head and neck cancer, or a haematological (blood) cancer.

People diagnosed with cancer as a child, adolescent or young adult also have a greater risk of a second, unrelated cancer.

What can I do to lower my risk?

Regular follow-up examinations can give peace of mind, and ensure any subsequent cancer is caught early, when there’s the best chance of successful treatment.

Maintenance therapy may be used to reduce the risk of some types of cancer returning. However, despite ongoing research, there are no specific treatments against cancer recurrence or developing a second, unrelated cancer.

But there are things you can do to help lower your general risk of cancer – not smoking, being physically active, eating well, maintaining a healthy body weight, limiting alcohol intake and being sun safe. These all reduce the chance of cancer returning and getting a second cancer.

Sarah Diepstraten, Senior Research Officer, Blood Cells and Blood Cancer Division, Walter and Eliza Hall Institute and Terry Boyle, Senior Lecturer in Cancer Epidemiology, University of South Australia

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