Difficulty buttoning your pants or jeans? Do not solely blame the fat on the stomach because it could be your hip bones are enlarged. The new study shows that human pelvic bones are still growing until the age of 80 years.

Most people are not increased height after the age of 20 years. But a recent study published in the Journal of Orthopaedic Research found evidence that the pelvic or hip bone continues to spread or grow in both men and women until about age 80 years, long after the framework is considered to have stopped growing.

“Although not many people realize that a wider waist size at the age of 40 or 60 years than at 20 years. This is due to the additional width was considered to result from increases in body fat,” explained Dr. Laurence E. Dahners, the study’s lead author and professor at the University of North Carolina School of Medicine, as reported by ABC News .

Dr. Dahners and his research team stumbled phenomenon of ‘widening hips’ is now studying the results of X-rays of patients in other studies that are not related.

“It seems the older the more width you pelvis, which seemed absurd. It is contrary to all we’ve ever heard, that the young people a bigger and more powerful than the older generation,” said Dr. Dahners.

The research team finally decided to investigate further, review the CT scans of 246 randomly selected patients, including about 20 men and 20 women in each group with age range is 10 years, between ages 20-29 years and 70-79 years.

Researchers measured the distance between the hip joint, the width of the hip joint, pelvic inlet width (road opening was born in the middle of the pelvis) and the height and width of the spine L4, to ensure patients are not bigger and taller.

And the researchers found that all patients showed similar results, namely the size of the hip bone will be more wide with age, at least until the age of 80 years.

The width of the pelvis in the oldest patient on average almost 1 inch wider than the youngest patients. Also found that there is an increasing waist size about 3 inches from age 20 to 79 years.

“Say you’re using pants with waist sizes 30 inches at the age of 20 years, then at the age of 80 years the size of your pants should be 33 inches, even if your abdominal fat is not increased,” explained Dr. Dahners.