The shorter they get, the harder they fall

Height loss is strongly associated with risk of osteoporosis

By Brian Hoyle

As a young woman, Ruth Simpson was a tall beauty who frequently modelled for department store catalogues. Now the 72-year-old struggles to maintain a stylish appearance despite having shrunk 7cm since her modelling days. She also wasn't sure how she was going to pass off the cast on her fractured hip as a fashion statement. Interestingly, Ms Simpson's two style trials, height and bone-density loss, may not be unrelated, according to a recent report published in the spring issue of the Journal of Clinical Densitometry.

According to the study of over 2,000 women, age-related height loss in elderly women may increase their chances of developing bone-weakening osteoporosis, and consequently raise their risk of fracturing a hip. The findings have lead the Ohio State University Medical Center researchers who conducted the study to recommend that family doctors routinely screen their elderly female patients for height loss and target screening for osteoporosis to women who've become more vertically challenged.

"Our findings suggest that a very simple test for all patients — current height compared to peak adult height — can predict the need for a bone mineral density scan to check for osteoporosis," said Dr Seth Kantor, the study's lead author, in an interview with Science Daily News.

Dr Kantor and his colleagues statistically analyzed bone-density scans obtained from 2,108 women who averaged 60 years of age. They wanted to see if height loss was associated with decreased mineral density of the femur. In osteoporosis, mineral replacement can be outstripped by mineral loss, ending with a bone that's liable to crack or break.

In the Ohio State University study, the self-reported maximum adult height of the women was compared to their current measured height and to their current hipbone mineral density. The researchers also examined the medical records of the women to see who had developed osteoporosis. The height change and osteoporosis numbers were crunched using a mathematical technique known as multinomial logistic regression modelling — a fancy term for a method used to determine if any cause-and-effect relationship exists between two variables. As well, more statistical analysis was done to take into account confounding factors like age, weight and maximum adult height.

The results showed that height loss could point the way to hip trouble. Shrinkage toward terra firma of 5-8cm increased the odds of developing osteoporosis of the hip by 4.4 times, compared to women who were within a few centimetres of their peak adult height. Women who had lost more than 7cm in height were almost 10 times more likely to develop hip fragility than their counterparts who had shrunk by only a couple of centimetres.

"We didn't necessarily try to define the best model for predicting hip osteoporosis," Dr Kantor told Science Daily News. "Instead, we wanted to illuminate the relationship between height loss and osteoporosis by ruling out other factors that might affect this relationship."

The clear relationship between the two "implies that a simple evaluation of height can help physicians in an outpatient clinic setting decide whether a patient should undergo a bone-density scan," said Dr Kantor.

The scan could become a routine examination of menopausal women. Even men, whose bone-density also decreases with age, could benefit from this precautionary look-see.

In Canada, one in four women and one in eight men aged 50 or older have osteoporosis. The findings of this study may make it easier for family physicians to figure out who has a high risk of bone-density loss. So not only the 1.4 million Canadians known to suffer from the disease, but the untold numbers of undiagnosed people could stand to benefit from the new research.