What is hs-CRP?

High-sensitivity C-reactive protein (hs-CRP) is a specialized form of the C-reactive protein that is measured with a highly sensitive assay capable of detecting lower levels of the protein in the blood. CRP is a protein produced by the liver in response to inflammation, infection, or tissue injury. Its primary function is to bind to the surface of dead or dying cells (and some types of bacteria) to activate the complement system, a part of the immune system that enhances the ability to clear microbes and damaged cells.

The "high-sensitivity" aspect of hs-CRP refers to the test's ability to detect very low concentrations of CRP, usually in the range of 0.1 to 10 milligrams per liter (mg/L), whereas the standard CRP test measures higher levels of the protein, typically above 10 mg/L. This increased sensitivity allows for the detection of chronic, low-grade inflammation that may not trigger the body's more overt inflammatory responses.

Biological Role and Production

CRP is part of the body's innate immune response and is produced by hepatocytes in the liver. The synthesis of CRP is primarily regulated by the cytokine interleukin-6 (IL-6), which is released by macrophages and adipocytes (fat cells) during inflammatory and immune responses. Elevated levels of IL-6 and CRP can indicate systemic inflammation, a condition linked to various chronic diseases.

Why is hs-CRP measured?

Measuring hs-CRP is useful for assessing the risk of these diseases. It provides a snapshot of the body's inflammatory status. Doctors use hs-CRP levels to:

• Predict Risk: Higher hs-CRP levels can indicate a greater risk of developing heart disease. For example, individuals with hs-CRP levels between 1 and 3 mg/L are considered to have a moderate risk, while those with levels above 3 mg/L have a high risk.
• Monitor Health: Regularly measuring hs-CRP can help monitor how well treatments are working for conditions like heart disease and autoimmune disorders.

Clinical Significance

Several large-scale studies have shown that elevated hs-CRP levels are associated with an increased risk of cardiovascular events. For example, the landmark JUPITER trial found that individuals with hs-CRP levels above 2 mg/L had a higher incidence of heart attacks and strokes, even when their cholesterol levels were normal. This has led to hs-CRP being used not only as a marker for inflammation but also as a predictor for cardiovascular risk.

Normal hs-CRP levels typically range from 0 to 1 mg/L, with the following thresholds used to stratify risk:

• Low risk: <1 mg/L
• Average risk: 1 to 3 mg/L
• High risk: >3 mg/L

Measurement and Interpretation

The hs-CRP test is performed using a blood sample, which is analyzed in a laboratory. The results are interpreted within the context of other risk factors and clinical findings. It is important to note that transient increases in CRP can occur due to infections, injuries, or other acute inflammatory conditions, so it is often recommended to repeat the test after a period of stability if an initial high reading is observed.

Connection to Diseases

High levels of hs-CRP in the blood indicate that there is inflammation somewhere in the body. Chronic inflammation is linked to several diseases:

1. Cardiovascular Diseases: People with high hs-CRP levels are at greater risk of heart attacks and strokes. For example, levels above 3 mg/L are associated with a higher risk of these events.
2. Diabetes: Inflammation can lead to insulin resistance, a condition where the body's cells don't respond well to insulin, making it harder to control blood sugar levels.
3. Cancer: Chronic inflammation has been linked to the development and progression of some cancers. High hs-CRP levels can be an indicator of increased cancer risk.
4. Autoimmune Disorders: Diseases like rheumatoid arthritis and lupus, where the immune system attacks the body's own tissues, are often associated with elevated hs-CRP levels.

Relevance of hs-CRP for Longevity

hs-CRP levels provide valuable insights into long-term health and potential lifespan. Here’s how this marker connects to longevity:

Inflammation and Aging

Chronic inflammation is a key factor in the aging process, often referred to as "inflammaging." Persistent low-grade inflammation accelerates aging and contributes to age-related diseases. Studies have shown that individuals with lower hs-CRP levels tend to age more healthily and have longer lifespans. For example, a study published in the Journal of the American Medical Association found that older adults with lower hs-CRP levels had a reduced risk of mortality over a 5-year period.

Disease Prevention and Management

By measuring hs-CRP levels, individuals and healthcare providers can implement early interventions to prevent or manage diseases associated with inflammation. This includes:

1. Cardiovascular Health: Regular monitoring of hs-CRP can help identify individuals at risk of heart disease. Proactive measures, such as improving diet, increasing physical activity, and possibly taking medications, can lower inflammation and reduce the risk of heart attacks and strokes.
2. Metabolic Health: Elevated hs-CRP levels are linked to insulin resistance and type 2 diabetes. Interventions to lower hs-CRP can improve insulin sensitivity and help manage blood sugar levels, reducing the long-term complications of diabetes.

Case Studies

Heart Disease Prevention:

• A 50-year-old man with no history of heart disease but an hs-CRP level of 4.5 mg/L was advised to make lifestyle changes and start statin therapy. After six months, his hs-CRP level dropped to 1.8 mg/L, significantly lowering his risk of heart disease.

Managing Diabetes:

• A 40-year-old woman with type 2 diabetes had an hs-CRP level of 5 mg/L. Her doctor recommended a low-carb diet and regular exercise. After a year, her hs-CRP level decreased to 2 mg/L, and her blood sugar levels were better controlled.

Lifestyle Interventions

Specific lifestyle changes can significantly impact hs-CRP levels and, consequently, longevity:

Diet and Nutrition

• Eat Anti-Inflammatory Foods:
  • Fruits and Vegetables: These are rich in antioxidants and phytochemicals that reduce inflammation. Aim for at least 5 servings per day. Berries, leafy greens, and cruciferous vegetables like broccoli are particularly beneficial.
  • Whole Grains: Foods like brown rice, quinoa, and oats contain fiber and nutrients that help lower inflammation.
  • Healthy Fats: Omega-3 fatty acids found in fatty fish (like salmon and mackerel), flaxseeds, and walnuts are known to reduce inflammation. Incorporate these into your diet regularly.
  • Nuts and Seeds: Almonds, chia seeds, and other nuts and seeds are excellent sources of anti-inflammatory nutrients.
• Avoid Pro-Inflammatory Foods:
  • Sugary Foods and Beverages: High sugar intake is linked to increased inflammation. Reduce consumption of sweets, sodas, and sugary snacks.
  • Processed Foods: Foods high in trans fats, like fast food and packaged snacks, can raise inflammation levels. Opt for whole, unprocessed foods whenever possible.
  • Refined Carbohydrates: White bread, pastries, and other refined carbs can spike blood sugar and increase inflammation. Choose whole grain alternatives.

Exercise

• Regular Physical Activity:
  • Aerobic Exercise: Activities like walking, running, cycling, and swimming can significantly reduce inflammation. Aim for at least 150 minutes of moderate aerobic exercise per week.
  • Strength Training: Incorporate resistance exercises, such as lifting weights or using resistance bands, at least twice a week to build muscle and reduce inflammation.
  • Flexibility and Balance: Activities like yoga and tai chi can reduce stress and inflammation. Try to include these in your routine a few times a week.

Lifestyle Changes

• Maintain a Healthy Weight:
  • Excess body fat, particularly around the abdomen, is associated with higher inflammation levels. Losing even a small percentage of body weight (5-10%) can lower hs-CRP levels.
• Quit Smoking:
  • Smoking increases inflammation and hs-CRP levels. Quitting smoking can significantly reduce these levels and improve overall health.
• Manage Stress:
  • Chronic stress can lead to increased inflammation. Practice stress-reducing techniques such as mindfulness meditation, deep breathing exercises, and spending time in nature.

Sleep

• Prioritize Quality Sleep:
  • Poor sleep is linked to higher inflammation. Aim for 7-9 hours of quality sleep per night. Establish a regular sleep schedule, create a restful environment, and avoid screens before bedtime.

Supplements

• Consider Anti-Inflammatory Supplements:
  • Omega-3 Fatty Acids: Fish oil supplements can help reduce inflammation.
  • Turmeric/Curcumin: This spice contains curcumin, a compound with strong anti-inflammatory properties. Supplements can be taken if dietary intake is insufficient.
  • Vitamin D: Adequate levels of vitamin D are essential for immune function and inflammation control. Consider supplements if you have low levels.

Hydration

• Stay Hydrated:
  • Drinking plenty of water helps maintain overall health and can aid in reducing inflammation. Aim for at least 8 cups (64 ounces) of water a day, or more if you are physically active or live in a hot climate.

Alcohol Consumption

• Moderate Alcohol Intake:
  • Excessive alcohol consumption can increase inflammation. If you drink, do so in moderation (up to one drink per day for women and up to two drinks per day for men).

Cost of Testing

For those in Canada, testing for hs-CRP is not usually covered by provincial insurances such as OHIP. Fortunately, it’s relatively inexpensive and should only cost between $10 to $20 depending on the lab provider. Hs-CRP is one of the biomarkers we test for as part of our longevity panel.

Disclaimer: This blog post is intended for educational purposes only and should not be taken as medical advice. Always consult your healthcare provider for personal health concerns.