You might not have noticed yet, but you're probably shrinking.
About four out of five people lose height as they get older, usually beginning in their 40s. For most of us, the loss is small and gradual, about a fifth-to-a-half inch per decade. Men are taller on average than women, but they typically lose less height as they age.
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Still, while height loss is common, it's worth your attention (and your doctor's). Mounting evidence indicates that more rapid shrinkage could be a sign of more serious medical concerns. According to a series of recent studies, the greater one's height loss, the greater the risk of hip fracture, heart disease and even cognitive decline.
Several factors lead to height loss with age. The discs between the spine's vertebrae can dry out and flatten. Or osteoporosis, the bone-thinning disease, can lead to small compression fractures of the vertebrae, which may not prompt pain or other symptoms. Other contributing factors include muscle weakening, changes in posture and spinal deformities.
"Height loss is a really simple way of saying, 'Yeah, you're probably losing bone, you're probably losing water,'" says Marian Hannan, an associate professor of epidemiology at the Harvard School of Public Health and a senior scientist at the Institute for Aging Research at Hebrew Senior Life in Boston. Hannan is the lead author of a recent study, one of the first of its kind, which examined the relationship over time between height loss and eventual hip fractures in both men and women.
The 1,300 men and 1,800 women in Hannan's study were participants in the ongoing landmark Framingham Heart Study. Their height was measured every other year for 24 years. During that time the men lost an average of 1.06 inches and the women 1.12. The researchers were able to link consistent, long-term height loss to later hip fractures only in men. But more recent and pronounced shrinkage was associated with an increased risk of hip fractures in both men and women. Being taller has often been linked to an increased risk of hip fracture in general, but Hannan's team found that height lost, not original height, was more closely tied to the fracture risk.
The Connection Between Height and Poor Health
In a 2006 study, British researchers tracked the change in height of approximately 4,200 men between age 40 and 60 over 20 years, then followed their health outcomes for an average of six additional years. They discovered that men who lost at least 1.2 inches were more likely to have died or had a diagnosis of coronary heart disease than those who shrunk less, even after accounting for such factors as age and pre-existing heart conditions.
While our genes play the primary role in determining our eventual peak height, loss of height is more a reflection of our health and lifestyle choices later in life. We know that shrinkage can be exacerbated by arthritis, joint inflammation or osteoporosis, but in many cases those conditions can be linked to poor diet, lack of exercise and smoking. Alcohol may also spur height loss, because it can reduce your calcium levels and accelerate the decline of bone density. "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," says John Strauss, an economics professor at the University of Southern California.
Strauss recently co-authored a major study that discovered shrinkage in midlife and beyond appears to reflect our socioeconomic status as well as our health. The longitudinal study of nearly 18,000 Chinese men and women 45 and older by researchers from China and the United States found that men and women with lower education and income experienced greater height loss than wealthier, more educated subjects. Men who completed high school, for example, lost 0.39 inches less than illiterate males during the study.
Researchers should expect to find a similar relationship between height loss and education, income and health in a study of U.S. residents, Strauss says.
Loss of height among subjects in the study was also strongly associated with cognitive skills. Adults who lost the most height were much more likely to perform poorly on standard tests of short-term memory and mathematical ability. The connection between height loss and cognitive decline isn't clear, however. "Shrinkage is a marker of bad health outcomes," Strauss says. "We cannot tell with our data which ones exactly cause the relationships we see. That is for future research."
What You Can Do
You can't restore lost height, though you can take steps to delay or slow the loss by exercising regularly and eating a healthy diet. Even if you are shrinking, it's not a cause for panic. "It doesn't mean something bad is definitely going to happen to you," Hannan says.
Still, it should be taken as a warning. If your height hasn't been measured since the days your parents marked it on a wall, make sure your doctor begins tracking it at every checkup. If you detect height loss, consider a bone density test — Medicare will cover it if you're 65 or older — and if you have osteoporosis, take steps to treat it. Finally, since falling at home is the leading cause of hip fractures, we can all take steps to limit our risk by securing rugs and cords and putting non-skid mats on bathroom floors.