How Short Will You Shrink? Study Identifies Factors that Predict Your Future Height
Your height is still in your hands, according to new research. But instead of growing taller, the choices you make in adulthood may play a role in determining how much you shrink as you age.
American and Chinese researchers looked at data from a new longitudinal survey of 17,708 Chinese adults beginning at age 45 and found for the first time that lifestyle choices in adulthood really can influence how tall we stand as we age.
"Had we only examined the correlations between measured height and health, we would have missed this important insight," John Strauss, professor of economics at USC, and an investigator on a study published in the April 2013 issue of the American Economic Journal: Applied Economics, said in a statement. "The evidence shows that it is not only early-life events that are associated with how we age, but health decisions in later life as well."
Previous studies also looked at the connection between height and health in childhood and adulthood, but the latest research is the first to reveal factors that can influence height in aging.
The findings reveal that the loss of height over time is an important indicator for other health issues as people age, regardless of their maximum height. For instance, the study revealed a strong relationship between height loss and cognitive health. Researchers found that people who had lost more height were also significantly more likely to perform poorly on standardized cognitive tests on short-term memory, ability to perform basic math and awareness of the date.
The study also found that people who lived in cities has significantly less height loss than those in rural areas. Men who have complete primary school experience on average 0.9 cm less height shrinkage compared to their illiterate counterparts. Researchers found that completing high school also meant an additional 1 cm less in shrinkage. Researchers said these differences are rather large, given the fact that the overall average height loss in men is 3.3 cm.
Researchers found that in women, having completed primary school was the difference in 0.6 of shrinkage compared to average overall height decrease of 3.8 cm.
"Height has been recognized as an acceptable proxy for childhood health conditions, but there are complications there," co-researcher Geert Ridder, an economist at USC, said in a statement. "Some of adult health might be determined by childhood circumstances, but people shrink differentially, and that shrinkage is also a measure of adult health conditions."
Researchers explain that physical changes associated with aging include an increase in body fat and decrease in bone mass. However, a decrease in height can by further exacerbated by arthritis, inflammation of spine joints or osteoporosis, which have previously been linked to lifestyle choices such as diet, exercise and smoking.