What Does a Low White Blood Cell Count Mean?

What Does a Low White Blood Cell Count Mean?
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Since white blood cell count is a sign of systemic inflammation, it’s no surprise that those with lower white blood cell counts live longer.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

If you took a drop of blood and smeared it between two pieces of glass and looked at it under a microscope, it might look something like this: a whole bunch of little round red blood cells and then this big white blood cell. Red blood cells carry oxygen, and white blood cells are our immune system foot soldiers. We may churn out 50 billion new ones a day. In response to inflammation or infection, that number can shoot up to 100 billion or more. In fact, that’s what pus is largely composed of: millions and millions of white blood cells.

One of the most common laboratory tests that doctors order is the white blood cell count, which tests how many white blood cells we have at any given time. We order it hundreds of millions of times a year. So, for example, if you end up in the emergency room with abdominal pain, having a white blood cell count above about 10 billion per quart of blood may be a sign you have appendicitis. Most Americans fall between 4.5 and 10, but most Americans are unhealthy. Just because 4.5 to 10 is normal, doesn’t mean it’s ideal. It’s like having a normal cholesterol level in a society where it’s normal to die of heart disease. The average American is overweight; so, if your weight is “normal,” that’s a bad thing.

In fact, having excess fat itself causes inflammation within the body. So, no surprise those who are obese walk around with 2 billion more white cells per quart of blood. So, maybe obese individuals “should…have their own ‘normal values?'” So, someone with a 47-inch waist walking into the ER with a white count of 12, 13, 14 may not have appendicitis, or an infection—that may just be their baseline, normal level, given all the inflammation they have in their body from the excess fat. So, normal levels are not necessarily healthy levels.

It’s like smoking. If you take identical twins and one smokes but the other doesn’t, the smoker is going to end up with a significantly higher white cell count. In Japan, for example, as smoking rates have steadily dropped, so has the normal white count range, such that about 8% of never smoking men would now be flagged as having abnormally low white counts if you used a cutoff like 4. But, that’s because most people were smoking before, when they set that cutoff. So, maybe 3 would be a better lower limit. The inflammation caused by smoking may actually be one of the reasons cigarettes increase the risk of heart attacks, strokes, and other inflammatory diseases. So, do people who have lower white counts have less heart disease, cancer, and overall mortality? Yes, yes, and yes. People with lower white blood cell counts live longer. “Even within the normal range,” every one point drop may be associated with a 20% drop in the risk of premature death.

This is a log scale; so, there’s an exponential increase in risk as white count goes up, even within the so-called normal range. This is for men; the same is found for women. The white blood cell count is a “widely available and inexpensive measure of systemic inflammation.” At around age 85 in this study, half of women who started out with white counts under 5.6 were still alive, whereas 80% of those that started out over 7 were dead. And, 7, 8, 9, or 10 would be considered normal. Being at the high normal range may place one at 3 times the risk of dying from heart disease compared to being at the lower end.

Same link found for African-American men and women. Same in middle age. Same at age 75. Same at age 85. Same even in our 20s and 30s: a 17% increase in coronary artery disease incidence for each single point higher.

The higher your white count, the worse your arterial function and the stiffer your arteries; so, no wonder white blood cell count, “WBC count is a useful predictor of…artery disease” in your heart, brain, legs, and neck, and of high blood pressure. Even diabetes? Even diabetes, according to a compilation of 20 different studies. Everything from fatty liver disease to having an enlarged prostate. And, having a higher white blood cell count is associated with an increased risk of dying from cancer as well. And, these are all within the normal range. So, what would the ideal range be? I’ll cover that, next.

Please consider volunteering to help out on the site.

Images by Reytan, Bobjgalindo, Keith Chambers, Ed Uthman, and Mate Marschalko.

Motion graphics by Avocado Video

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

If you took a drop of blood and smeared it between two pieces of glass and looked at it under a microscope, it might look something like this: a whole bunch of little round red blood cells and then this big white blood cell. Red blood cells carry oxygen, and white blood cells are our immune system foot soldiers. We may churn out 50 billion new ones a day. In response to inflammation or infection, that number can shoot up to 100 billion or more. In fact, that’s what pus is largely composed of: millions and millions of white blood cells.

One of the most common laboratory tests that doctors order is the white blood cell count, which tests how many white blood cells we have at any given time. We order it hundreds of millions of times a year. So, for example, if you end up in the emergency room with abdominal pain, having a white blood cell count above about 10 billion per quart of blood may be a sign you have appendicitis. Most Americans fall between 4.5 and 10, but most Americans are unhealthy. Just because 4.5 to 10 is normal, doesn’t mean it’s ideal. It’s like having a normal cholesterol level in a society where it’s normal to die of heart disease. The average American is overweight; so, if your weight is “normal,” that’s a bad thing.

In fact, having excess fat itself causes inflammation within the body. So, no surprise those who are obese walk around with 2 billion more white cells per quart of blood. So, maybe obese individuals “should…have their own ‘normal values?'” So, someone with a 47-inch waist walking into the ER with a white count of 12, 13, 14 may not have appendicitis, or an infection—that may just be their baseline, normal level, given all the inflammation they have in their body from the excess fat. So, normal levels are not necessarily healthy levels.

It’s like smoking. If you take identical twins and one smokes but the other doesn’t, the smoker is going to end up with a significantly higher white cell count. In Japan, for example, as smoking rates have steadily dropped, so has the normal white count range, such that about 8% of never smoking men would now be flagged as having abnormally low white counts if you used a cutoff like 4. But, that’s because most people were smoking before, when they set that cutoff. So, maybe 3 would be a better lower limit. The inflammation caused by smoking may actually be one of the reasons cigarettes increase the risk of heart attacks, strokes, and other inflammatory diseases. So, do people who have lower white counts have less heart disease, cancer, and overall mortality? Yes, yes, and yes. People with lower white blood cell counts live longer. “Even within the normal range,” every one point drop may be associated with a 20% drop in the risk of premature death.

This is a log scale; so, there’s an exponential increase in risk as white count goes up, even within the so-called normal range. This is for men; the same is found for women. The white blood cell count is a “widely available and inexpensive measure of systemic inflammation.” At around age 85 in this study, half of women who started out with white counts under 5.6 were still alive, whereas 80% of those that started out over 7 were dead. And, 7, 8, 9, or 10 would be considered normal. Being at the high normal range may place one at 3 times the risk of dying from heart disease compared to being at the lower end.

Same link found for African-American men and women. Same in middle age. Same at age 75. Same at age 85. Same even in our 20s and 30s: a 17% increase in coronary artery disease incidence for each single point higher.

The higher your white count, the worse your arterial function and the stiffer your arteries; so, no wonder white blood cell count, “WBC count is a useful predictor of…artery disease” in your heart, brain, legs, and neck, and of high blood pressure. Even diabetes? Even diabetes, according to a compilation of 20 different studies. Everything from fatty liver disease to having an enlarged prostate. And, having a higher white blood cell count is associated with an increased risk of dying from cancer as well. And, these are all within the normal range. So, what would the ideal range be? I’ll cover that, next.

Please consider volunteering to help out on the site.

Images by Reytan, Bobjgalindo, Keith Chambers, Ed Uthman, and Mate Marschalko.

Motion graphics by Avocado Video

Doctor's Note

This concept of the risks of being normal in a sick society is explored further in my video When Low-Risk Means High-Risk.

Stay tuned next for What Is the Ideal White Blood Cell Count?.

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