Obesity and Kidney Cancer: Understanding How Obesity Elevates Risk

Obesity plays a crucial role in elevating cancer risk due to inflammation and hormonal changes within the body.

One particular cancer affected by this connection is kidney cancer. It ranks among the top 10 most common cancers in both men and women.

For men, the lifetime risk of developing kidney cancer is approximately 1 in 46 (2.02%), while for women, it's about 1 in 80 (1.03%).

In this article, you will learn the relationship between kidney cancer and obesity, exploring how obesity increases the risk of kidney cancer and providing insights into effective ways to lower this risk.

🔑 Key Takeaways

• "Obesity" and "kidney cancer" are interlinked health concerns with a complex relationship.
• The prevalence of overweight or obese children and teenagers aged 5-19 surged from 4% in 1975 to 18% in 2016.
• Sedentary lifestyles, changing transportation modes, and urbanization contribute to obesity.
• Kidney cancer ranks sixth among men and ninth among women in common cancers.
• Fatty tissue within the tumor microenvironment is vital in kidney cancer development and progression.
• Obesity is associated with genomic instability, increasing the risk of genetic mutations linked to kidney cancer.
• Obese kidney cancer patients may experience better outcomes, although the reasons remain complex and not fully understood.

Defining Obesity And Overweight

Obesity is a medical condition characterized by abnormal or excessive fat accumulation in the body.

It is typically assessed using the Body Mass Index (BMI), with a BMI over 30 considered obese and over 25 considered overweight in adults. Different criteria are used for children based on age and growth standards.

But how common is obesity, and what causes it? Let's find out below.

Prevalence Of Obesity

Obesity is a growing global health problem. Here are some of the significant data recorded:

• Global obesity has almost tripled since 1975.
• In 2016, over 1.9 billion adults were overweight, with 650+ million obese.
• 1 in 3 adults (30.7%) being overweight, and more than 2 in 5 adults (42.4%) having obesity.
• About 1 in 11 adults (9.2%) had severe obesity.
• The proportion of overweight or obese children and teenagers aged 5-19 rose from 4% in 1975 to 18% in 2016.
• In 2020, 39 million young children were overweight or obese, and in 2016, over 340 million older children and teens had the same issue.
• Obesity rates are increasing in low- and middle-income nations, particularly within urban areas.

Causes Of Obesity And Overweight

Obesity primarily stems from an energy imbalance, which can be attributed to several factors:

• Eating more calorie-rich foods high in fats and sugars.
• Reduced physical activity due to sedentary lifestyles, changing transportation modes, and urbanization.
• Changes in the environment and society are linked to progress and a deficiency of supportive policies in different areas.

Understanding Kidney Cancer

Kidney cancer, medically called renal cell carcinoma, originates in the kidneys, the bean-shaped organs behind the abdominal cavity.

It begins when certain kidney cells change (mutations) in their DNA, causing these cells to grow and divide rapidly. This uncontrolled growth forms tumors within the kidney, which can extend beyond the organ.

Cancer cells can sometimes break off and metastasize to other body parts.

Keep reading below to find out what causes kidney cancer, its risk factors, symptoms, prevalence, and survival rates.

Causes Of Kidney Cancer

The exact cause of kidney cancer remains unclear, but it typically begins when specific cells in the kidney experience genetic mutations in their DNA. These mutations prompt the affected cells to grow and divide abnormally, forming a tumor within the kidney.

Over time, some of these cancer cells may break away and spread to other body parts, known as metastasis.

Risk Factors For Kidney Cancer

Several factors can influence the likelihood of developing kidney cancer. Understanding these risk factors is essential for early detection and prevention. Here are the factors to consider:

• Older Age: The risk of kidney cancer tends to increase with age, with most cases diagnosed in individuals over 45 years old.
• Smoking: Smoking greatly increases the risk of kidney cancer. Smokers have a higher chance of developing kidney cancer than non-smokers, but the risk decreases after quitting.
• Obesity: Carrying excess weight or being obese is linked to an increased risk of kidney cancer.
• High Blood Pressure (Hypertension): Hypertension increases the risk of kidney cancer.
• Treatment for Kidney Failure: Individuals receiving long-term dialysis to treat chronic kidney failure are at a greater risk of developing kidney cancer.
• Family History: Having close family members with a history of kidney cancer can increase an individual's risk.

Symptoms Of Kidney Cancer

Kidney cancer frequently remain asymptomatic during its initial stages. However, as the condition advances, indications and signs include:

• Blood in Urine (Hematuria): This may appear pink, red, or cola-colored.
• Persistent Back or Side Pain: A pain that doesn't go away and is often felt below the ribs on the side or back.
• Unexplained Weight Loss: A significant, unintentional reduction in body weight.
• Fatigue: Ongoing tiredness and lack of energy.
• Fever: Elevated body temperature that may be associated with other symptoms.

Prevalence Of Kidney Cancer

Kidney cancer is a notable health concern with a significant impact on individuals:

• In the US, it ranks as the sixth most common cancer among men and the ninth most common among women.
• This year, 2023, around 81,800 adults (52,360 men and 29,440 women) will be diagnosed with kidney cancer.
• Globally, the incidence of kidney cancer continues to rise, with approximately 431,288 people diagnosed with kidney cancer in 2020.

Survival Rates for Kidney Cancer

Several key factors influence survival rates for kidney cancer:

• Stage of Cancer: Early detection often leads to higher survival rates. Kidney cancer is typically categorized into stages, with localized cancers having a better prognosis than those that have spread.
• Age and Overall Health: An individual's age and general health can impact their response to treatment and overall survival.
• Treatment Efficacy: The effectiveness of the chosen treatment plan plays a crucial role in determining survival rates.

In the US, kidney cancer has a 5-year relative survival rate of 77%. These survival rates vary depending on the stage of diagnosis:

• Early-stage, localized cancer: 5-year survival rate of 93%
• Cancer spread to surrounding tissues, organs, or lymph nodes: 5-year survival rate of 72%
• Cancer metastasized to distant parts of the body: 5-year survival rate of 15%

Obesity's Impact on Kidney Cancer

Obesity is a risk factor for cancer, stroke, and kidney disease. Specifically, it exerts a profound impact on the development and progression of kidney cancer through several interconnected mechanisms.

Here are the key ways obesity influences kidney cancer:

1. Adipose Tissue and the Tumor Microenvironment

The existence of fat tissue within the tumor's surroundings plays a crucial role in promoting the onset and advancement of kidney cancer.

Fatty tissue is an energy reservoir that releases signaling molecules such as adipokines, proinflammatory cytokines, and proangiogenic factors. These substances create an optimal environment for tumor growth and metastasis.

2. Hormonal Imbalance and Insulin Resistance

Obesity leads to hormonal imbalances, particularly alterations in sex hormones and insulin levels. These imbalances disrupt the delicate equilibrium between cell proliferation, differentiation, and apoptosis, favoring uncontrolled cell growth.

Specifically, obese individuals tend to have higher levels of sex hormones and insulin, which can stimulate cancer cell proliferation.

3. Intracellular Lipid Accumulation and Metabolic Stress

Obesity triggers intracellular lipid accumulation in adipocytes, often resulting in conditions like insulin resistance and mitochondrial stress. These metabolic changes can promote the development of kidney cancer.

The altered cellular metabolism provides cancer cells the necessary energy and building blocks for rapid proliferation.

4. Chronic Tissue Hypoxia and Inflammation

Obesity can induce chronic tissue hypoxia (oxygen deficiency) due to the increased metabolic demands of excess fatty tissue. This hypoxic state can lead to a cascade of events, including inflammation and angiogenesis (forming new blood vessels).

Inflammation and angiogenesis are critical in tumor initiation and progression, including kidney cancer.

5. Genetic Instability and Epithelial-Mesenchymal Transition (EMT)

Obesity has been linked to genomic instability, which can lead to genetic mutations that predispose individuals to kidney cancer.

Additionally, it can induce a process called epithelial-mesenchymal transition (EMT), where cancer cells acquire characteristics that promote invasion and metastasis. EMT is a key driver of cancer progression.

6. Visceral Fat and Tumor Aggressiveness

The distribution of fatty tissue, specifically visceral fat (fat around internal organs), can impact the aggressiveness of kidney tumors.

Studies have shown that a higher percentage of visceral adipose tissue is associated with more aggressive kidney cancer, potentially indicating an independent predictor of tumor grade.

7. The Obesity Paradox

Interestingly, there is a phenomenon known as the "obesity paradox" in kidney cancer.

Some studies have found that obese patients with kidney cancer have better outcomes, including higher overall survival rates, than normal-weight patients. However, the reasons for this paradox are not fully understood and may involve complex interactions between obesity-related factors and cancer progression.

Possible explanations include delays in the development of cachexia (muscle wasting) and the presence of protective factors in obese individuals.

Lowering The Risk Of Kidney Cancer

Lowering the risk of kidney cancer is vital because it can save lives and reduce the need for costly treatments. To lower your risk for kidney cancer, follow these recommendations:

1. Ensure a Healthy Weight: Being overweight is linked to a higher likelihood of developing kidney cancer. To manage your weight, start changing your diet by paying attention to calorie amounts and reading food labels.

2. Stay Physically Active: Aim for 150 minutes of moderate or 75 minutes of intense exercise each week for a healthy weight and well-being.

3. Follow a Healthy Diet: Focus on a balanced diet by:

• Filling at least two-thirds of your plate with non-starchy vegetables, fruits, whole grains, and legumes (beans and peas).
• Limiting your animal protein intake to one-third or less of your plate.
• Reducing or eliminating alcohol consumption to one drink per day for women and two per day for men.

4. Manage Blood Pressure: Monitor your blood pressure regularly, especially if you have hypertension. Follow your healthcare provider's recommendations for managing and controlling high blood pressure.

5. Quit Unhealthy Habits: If you smoke, seek help to quit smoking, as smoking is a significant risk factor for kidney cancer. Additionally, limit alcohol consumption or abstain from it entirely.

6. Regular Check-ups: Consider routine kidney cancer screenings if you have risk factors such as older age, a history of smoking, high blood pressure, or a family history of cancer. Finding an issue early helps treatment work better.

Final Thoughts

Obesity significantly increases the risk of kidney cancer primarily by releasing molecules from fatty tissue within the tumor environment.

Additionally, hormonal imbalances and insulin resistance associated with obesity contribute to the uncontrolled growth of kidney cancer cells.

Keeping a healthy weight and lifestyle and regular check-ups are essential steps to reduce this risk and enhance your overall well-being.

FAQs on Obesity and Kidney Cancer

What is the obesity paradox in kidney cancer?

The obesity paradox in kidney cancer refers to the observation that while obesity increases the risk of renal cell carcinoma (RCC), obese RCC patients tend to have longer overall survival (OS) when treated surgically or with targeted therapies than normal-weight patients.

Who is more susceptible to kidney cancer?

Kidney cancer is more common among older individuals, particularly those over 50. It also occurs more frequently in men than women and is more prevalent among Whites than Blacks. Notably, kidney cancer can affect people of all ages, including children.

What is the connection between obesity and kidney disease?

Obesity is linked to an increased risk of kidney disease, particularly in individuals with diabetes and hypertension. Additionally, obesity indirectly raises the risk of kidney disease by contributing to major risk factors such as type 2 diabetes and high blood pressure.

Can kidney cancer be prevented?

Although there is no guaranteed method to prevent kidney cancer, you can lower your risk by giving up smoking, keeping a healthy body weight, and managing your blood pressure.

What can lower the risk of kidney cancer?

To lower the risk of kidney cancer, especially in the context of obesity and kidney cancer, prioritize a healthy weight. Exercise regularly and eat a diet rich in fruits and vegetables.

Why should I learn about the connection between obesity and kidney cancer?

Learning about obesity and kidney cancer helps individuals recognize the increased risk of kidney cancer associated with obesity. This awareness can encourage lifestyle changes to reduce that risk.