It’s clear that body weight influences the risk of developing certain health problems. For example, obesity is linked with a greater risk for type 2 diabetes, heart disease, gallbladder disease, high blood pressure, sleep apnea, gout, chronic kidney disease, non-alcoholic fatty liver, osteoarthritis, Alzheimer’s disease and some types of cancer. That’s why there’s so much concern about the growing rate of obesity.
Yet, how much you weigh is only one aspect of your body composition. Human beings come in various heights from very short to supermodel tall. That’s what makes the world such an interesting place, right? But what implications does this have for health?
Height and Health
If instinct tells you that height plays a role in the risk of certain diseases, you’re right. According to a new study, how tall you are influences the risk of developing three of the most common chronic diseases that impact health – heart disease, type 2 diabetes, and cancer.
How do we know this? Researchers in Germany in collaboration with researchers at the Harvard School of Public Health studied this issue. According to their findings, tall people enjoy a lower risk of heart disease, the leading cause of death in the U.S., and type 2 diabetes. Unfortunately, being taller was also linked with a greater risk of cancer, especially breast and colon cancer.
In contrast, shorter people appear to be less prone to cancer but have a modestly higher risk of developing coronary artery disease and type 2 diabetes. This association held even when the researchers carefully controlled for factors like body weight.
This isn’t the first study to show a link between height and health risks. It seems that circumstances that play a role in how tall you are also influencing the growth of cells and factors that alter your metabolic health.
How Height Impacts Your Risk of Cancer
The link between being taller and a greater risk for developing cancer is an intriguing one. How can you explain such an association? One theory is that taller people consume higher levels of calories during critical growth phases, going back to early childhood. Some studies even show a link between growth rates in the womb and a higher risk for health problems.
Another hormone-like molecule that likely plays a role is a growth factor called IGF-1. People who are taller tend to have a higher baseline level of IGF-1, a hormone-like compound produced by the liver in response to growth hormone.
A number of studies have linked higher levels of IGF-1 with a greater risk for cancers, including breast and colorectal cancer. In fact, a study involving almost 33,000 nurses showed those with the highest level of IGF-1 had a 2.5 times greater risk of colon cancer. The same held true for men as well. Growth factors like IGF-1 play in important role in bone, tissue, and cell growth during childhood, but if you have too much hanging around at an older age stimulating cells to grow, it creates ideal conditions for a cancer-causing mutation to occur.
An epidemiologist at Albert Einstein College has another explanation as to how height increases cancer risk. Based on the results of three studies, Geoffrey Kabat, Ph.D., found that women in the highest quartile of height (5’10” and over) were 35% more likely to develop some types of cancer, including breast, colon, thyroid, kidney cancer, and melanoma, relative to women 5’2″ and under.
According to Dr. Kabat, taller women have more cells. Having more cells increases the risk of one of them mutating to form cancer. He also acknowledges the role that higher level growth factors play in increasing cancer risk in taller women. One factor that increases IGF-1 is overconsumption of calories. Higher levels of IGF-1 may partially explain why people who are obese are at greater risk for some types of cancer.
Heart Disease and Height
While being tall may not lower your risk of cancer, it does offer modest protection against heart disease. In a study published in the New England Journal of Medicine, a woman’s chance of developing heart disease was almost 30% lower at 5’8″ compared to 5’3″. But here’s some good news. If you’re short, 5’2″ and under and at healthy body weight, your risk of developing a blood clot is lower than that of a taller person.
How does height protect against heart disease? According to a study published in the journal Circulation, IGF-1, the same growth factor that stimulates cell proliferation, may protect against blood dysfunction and plaque formation inside the walls of arteries. It also seems to protect against metabolic syndrome, a risk factor for heart disease and type 2 diabetes.
On the other hand, there may be other factors that explain why heart disease risk is lower in taller people since some studies show IGF-1 has the opposite effect, it may increase the risk for heart disease. How can you explain these discrepancies? It may have to do with WHEN over the course of a lifetime, your heart and blood vessels are exposed to higher levels of IGF-1.
Height and Longevity
Cancer, heart disease, blood clots, and diabetes are one thing, but the bigger question is whether height impacts longevity. According to scientist Thomas Samaras who studies the association, when you compare shorter people to taller people in every population, shorter people live longer on average.
While that might not be music to your ears if you tower over most of your friends, factors other than height play a stronger role in how long you live. The type of diet you eat, whether or not you smoke or drink alcohol, and whether you exercise are ultimately more important than your height for determining your risk of cancer, heart disease, and type 2 diabetes.
The Bottom Line
The association between height, longevity, and health problems is an intriguing one, but lifestyle trumps these factors. Keep eating a healthy diet and exercising and your risk for many health problems will go down
References:
Harvard T.H. Chan School of Public Health. “Obesity Prevention Source”
Eurekalert.org. “Height Influences Risk of Cardiovascular Disease, Diabetes, and Cancer”
Prevention. “6 Things Your Height Says About Your Health”
Harvard University Gazette. “Growth Factor Raises Cancer Risk”
Discover. “Is Being Tall Hazardous to Your Health?”
Circulation. 2004; 110: 2260-2265 doi: 10.1161/01.CIR.0000144309.87183.FB.
J Gerontol A Biol Sci Med Sci (2012) 67A (6): 626-639.
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How Birthweight Affects Your Risk for Obesity
Studies find that taller people have lower, the same or higher risk of coronary heart disease (CHD). However, most do show taller people have lower CHD. Findings that shorter people have more CHD mortality is challenged by many findings, including some involving millions of deceased subjects. For example, a US government report of CHD mortality by ethnic groups shows that the shortest groups have the lowest mortality. The Asians have the lowest and Whites and Blacks the highest (almost 100% difference). Latinos and Native Americans are in-between these two extremes in both height and CHD mortality. This finding matches data from Western Europe which shows that the shortest countries have the lowest CHD mortality and the tallest the highest.
Another problem with most studies is that they don’t explain why many short populations had no CHD or stroke during the middle of the 20th century. These include Solomon Islands, Papua New Guinea, Kalahari Bushmen, Congo pygmies and Kitavans. Average male height ranges from less than 5 feet to about 5 feet 5 inches. Unfortunately, changes in diet and lifestyle have increased CHD substantially in most of these populations.
Of course women are shorter than men and have less CHD. In addition, in 1900, CHD was much lower than today but the people in 1900 were a few inches shorter. Researchers also tell us that pre-western people are generally free of CHD and stroke until they adopt a Western type diet. For example, as S. Koreans became Westernized, they changed their dietary habits to some extent, grew taller (now males are 5’8.5″) and increased their CHD mortality by 2.5 times what it was when they were 5’5″ in the 1930s. (Contemporary studies have not found a difference in CHD between taller and shorter people in S. Korea. This probably due to taller people being in a higher socioeconomic position. Hi income status is protective against all-cause and CHD mortality.)