Americans, for nearly two centuries, lived as the world's tallest human beings. Averaging 172 centimeters in the year 1750, American men towered over English and Norwegians by seven centimeters, Austrians by six, and Swedes by five.
But, somehow, things changed. Young Dutchmen, once among the shortest in Europe, today lead the pack at 183 centimeters, or just over six feet tall, while Americans, who gained just four centimeters in the last 250 years, are shorter than all of them.
The statistics are intriguing, but are they meaningful? Is the relative shrinking of Americans cause for concern? The answers lie in the emerging science of auxology, or the study of human growth, which suggests that average height reflects the overall health of a population-its diet, wealth, quality of housing, levels of pollution, disease, and stress-particularly for infants and adolescents.
Richard Steckel '66 is an auxologist and professor of economics and anthropology at The Ohio State University, where he has been studying height since his doctoral years in the mid-1970s. In March, he was among three faculty members named Joan N. Huber Faculty Fellows, a program designed to reward the strongest scholars in the College of Social and Behavioral Sciences.
Steckel says that traditional measures of standard of living-gross national product or per capita income-don't reflect the total picture because they leave out other variables such as crime, congestion, workload, or the amount of leisure time afforded to a population. Height also has a direct relationship to longevity; research suggests that the height of a child at age 12 has a direct correlation with life expectancy as an adult. Per capita income can't make the same claim.
"Americans have not grown in 25 years," Steckel said. "Our loss of international leadership in stature should be a warning to those who think this country provides its citizens with widespread access to the basic necessities of life."
The study of auxology is a cross-disciplinary field involving historians, economists, biologists, anthropologists, and physicians who accept that height is a response to both nature and nurture. Genetic differences aside, changes in living conditions cause dramatic changes in average height. "If you look around the world at well-nourished populations today, whether in Africa, Japan, the U.S., Europe, or South America, the children are all about the same height within 1/2 inch," Steckel said. "I'm not saying there are no genetic differences across large populations, but I think they are small relative to what the environment does."
Steckel's research is derived in part from historical height data recorded on slave manifests of those shipped in the coastwide trade after 1807 and military muster roles from major wars. "Among the things we learned is that slave children were dreadfully small, among the smallest populations ever measured, but recovered substantially as teenagers," Steckel said. "Pregnant slave women had an arduous work routine, and their children as infants had a limited rate of breast feedings. Women were back in the fields within six weeks of giving birth, and the children left behind in the nursery were receiving a contaminated, low protein diet until age 10.
"Once the young adolescent slaves started working, however, they received regular allocations of meat and their growth caught up. This proved to be economically productive for slave owners. They had no incentive to improve the diets of young children nor to improve their health or welfare."
From a medical point of view, the findings make sense, Steckel said. Under periods of extreme physical stress, our bodies give up on growth and marshal whatever resources they have on survival. Later, during times of less stress, the body makes up for what's lost-a phenomenon known as catch-up growth.
"Stress and poor environmental conditions can depress growth rates down to zero," he said. "Diet, minus work and minus disease (and basic metabolism) equals net nutrition. How tall one becomes is a function of net nutrition during periods of growth. Average height is not adept in distinguishing between degrees of opulence, but is good at distinguishing between degrees of deprivation. In other words, it's a measure of one's consumption of basic needs."
In the early 1700s soldiers in the United States were the tallest in the world, attributed, most likely, to a healthy diet and an abundance of farmlands. "Americans experienced the best of the old and the new world foods at that time, and also had low population density, few epidemics, and a reasonably even distribution of wealth," Steckel said.
Average height for Americans peaked in the 1830s, then sharply declined toward a new low in 1880 (Chart 1). "Americans lost 1-1/2 to 2 inches in height despite an improving economy and increases in income," Steckel said. "But we also had a greater spread of communicable disease as the United States urbanized. The transportation revolution in the 1820s and '30s brought steamboats, canals, and railroads. People moved and migrated, taking disease with them: cholera, scarlet fever, whooping cough. Wealth inequality was also on the rise and the poor were more exposed by business downturns. Things didn't get better until the end of the century with the purification of water, removal of waste, emphasis on personal hygiene, and use of antiseptics, after which point we saw an increase of eight centimeters in height in the next three-quarters of a century."
Many Europeans, whose heights once lagged several centimeters behind Americans, caught up, eventually surpassed, and continued rising. In the United States, however, height began levelling off in the mid-1900s, and, in the last 25 years, experienced no increase at all. This is a warning, says Steckel, since the majority of growth occurs in early childhood and adolescence. He believes it highly probable that a significant number of our country's children face some type of impaired health. And because an average height difference of just a few centimeters across countries can have a significant effect on life expectancy, the longevity of our population is at risk.
What Steckel hasn't studied yet is the question of why Americans are falling behind-the trend is still too recent-and if there are current pockets of populations within the United States that experience different rates of growth. Union Army records from the Civil War suggest that the midwest and border states at that time produced the tallest soldiers; the northeast and urban areas, the shortest.
An educated guess as to our loss in stature might allude to malnutrition and meager access to health care that occur today in inner-cities and scattered rural areas-places where basic biological needs are not being met.
In Europe and Asia, heights have continued to grow very quickly and people are starting to ask why. The topic was explored in an October 1996 TIME magazine cover story, in which Steckel and other auxologists examined the impact on various European populations. Is there an ideal height? Is there a limit to how tall humans can grow? Can shorter populations catch up?
"The Dutch are currently tallest, measuring about two inches taller than Americans," Steckel said. "Why? They have very high income levels, they have perhaps the best pre-natal and post-natal care in the world, and they have a relatively equal distribution of income."
Height research conducted with European populations seems to mimic those of the Americans. A study of nearly 10,000 5-to-11-year-old English and Scottish children found a clear connection between a child's height and whether the father had a job. In each social class group, children with unemployed fathers were shorter.
In Norway a survey by professor Hans Waaler revealed that tall people live longer: women aged 40 to 44 who measured between 145 and 149 centimeters had a mortality rate double that of women between 165 and 169 centimeters. Norwegian men aged 55 to 59 who measured 150 to 155 centimeters had double the mortality rate of those whose height was 185 to 189 centimeters.
Even the Japanese, who were the smallest in height of any industrialized country in 1950, have increased their height by about eight centimeters in the last 50 years. "If you're in Asia today, the intergenerational differences in height are striking," Steckel said.
The growth of our European and Asian neighbors suggests positive change, yet the trend is leading to unique challenges for manufacturing industries. Changes have been so dramatic that clothing, cars, furniture, and tools need to be redesigned, and the architecture of homes, schools, and offices must be adapted for these larger physiques.
How high can we go? "The Norwegians did a study 20 years ago on height, weight, and longevity and found that mortality rates as a function of height were U shaped. People who are very, very tall die at much higher rates," Steckel said. "But the truth is, we just don't know.
"I do think the longevity and health of elderly people in the future will be much greater than we expect. Old people today grew up in a time when stature was far lower than it is now. People who will be old 20 to 40 years from now grew up in the mid-1950s when average height was much higher. This has very important implications for social security and pension systems. The number of old people who will be around is vastly underestimated."
The auxologists' theory has had its share of dissenters, especially within the first decade of research, but height studies were helped by economists in the 1970s who were looking beyond gross national product as a measure of the quality of life. "There are all kinds of social urban problems the GNP doesn't capture very well, so people were willing to listen," Steckel said.
Hirschel Kasper, Oberlin professor of economics, says that many scholars, especially those outside of the field, think economists place too much emphasis on monetary measures of life. "Even Amartya Sen, who won the Nobel Prize in economics last year, thinks economists should use more non-monetary measures, such as capability, to analyze how societies fare," Kasper said.
"Yet, non-monetary measures are so amorphous and difficult to calculate. Can progress and understanding actually move in that direction? Most economists are curious, tolerant, and hopeful, but not persuaded. Rick's attempts to tie the measurable (whether height or bone density) to broader indicators such as quality of life have earned him a place at the table. I, and most economists, I believe, find Rick's research fascinating, intriguing, amazing, and potentially enormously significant."
Steckel, who considers Kasper among his most memorable professors, discovered the height data as a doctoral student studying the demography of slaves at the University of Chicago with economist and future Nobel Prize recipient Robert Fogel. "I found the height data very intriguing and was convinced early on that it had tremendous promise. It was a matter of convincing other economists and historians that it had merit."
The National Archives in Washington, D.C., stored the slave manifests, which identified individual slaves shipped in the coastwide trade by name, age, gender, height, and color. Fogel had microfilmed some of these records to study the age and gender of slave migrants. Steckel took the films with him to Ohio State in 1975 and began a teaching career, never deviating far from his height studies. Within the past 24 years, his work has generated hundreds of articles, publications, and presentations written and conducted around the world.
Today Steckel is chair of the University Research Committee, serves on the University Senate and Fiscal Committee, and was nominated for Ohio State's prestigious Distinguished Scholar Award, to be presented this spring. He and his wife and daughters spent their spring break in Mexico, working ten-hour days and living in tents to build simple houses for the poor under the direction of Amor Ministries.
The professor is quick to credit his liberal arts education at Oberlin for encouraging him to think broadly and to welcome interdisciplinary work. "I was not a conformist, which was one reason why Oberlin appealed to me. It was the diversity of people and opinions. Where others might question an idea or have a gut reaction to negate something, I would consider it.
"Americans tend to think that height is genetically determined," Steckel continued. "And the people who believe that often lack a strong liberal arts background that includes some study in the sciences. We know that environment can cause five- or six-inch differences in height. I've heard physical anthropologists say that even the African pygmies would catch up to modern heights over three or four generations if they had good net nutrition."
Steckel is convinced that Americans have something to learn by studying other countries and suggests that we regularly measure our children to help monitor health conditions. It's cheap, it's easy, and it's effective.
"I've asked geneticists how long it will be before we can estimate the genetic potential for growth of particular individuals. We can take a blood sample or a mouth swab, get your DNA, determine your height, and conclude how tall you should end up. If we know each person's growth potential and discover that they're falling below that, then we know something is wrong.
"Then we can design personal diets for people: you need extra protein, I need more iodine, she needs additional iron to grow adequately," he said. "This would revolutionize pediatrics, and the technology should be available in five to ten years. We know that health in early childhood is a predictor of longevity, so this is the time to intervene."
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