It probably comes as no surprise that people find themselves to be wider at the age of 40 or 60 than they were at the age of 20. What may surprise us is why. A study published by the Journal of Orthopaedic Research shows that hip bones continue to grow with age—in both women and men. By age 20, most people have achieved their maximum height. But researchers at the University of North Carolina at Chapel Hill School of Medicine have now found that while people don’t grow taller after age 20, they do grow wider—well into their 70s. This growth is not fueled simply by an increase in body fat, as was previously thought.
The researchers randomly selected 246 male and female patients in various age groups ranging from age 20 to age 79. Using CT scans, they determined that the width of people’s pelvises continued to grow after skeletal maturity was reached at age 20. Specifically, the pelvic inlet widened–evidence of actual pelvic growth.
The results: on average, the pelvic width of the oldest people in the study was nearly 2.5 cm larger than the youngest patients. This one-inch increase in pelvic diameter could lead to an approximately 7.6 cm increase in waist size from age 20 to age 79, whether or not body fat increases.
While it’s nice to be able to blame expanding girth on your bones, it is still important to maintain a healthy weight through diet and exercise. We can’t stop our pelvises from growing, but we can prevent an unhealthy increase in body fat. Excess body fat raises the risk for illnesses ranging from diabetes to heart disease.
Berger AA, May R, Renner JB, Viradia N, Dahners LE. Surprising evidence of pelvic growth (widening) after skeletal maturity. Journal of Orthopaedic Research. 29(11):1719-23.