Ronald Klein was biking around his neighborhood in North Wales, Pa., in 2006 and tried to jump a curb. “But I was going too slow — I didn’t have enough momentum,” he recalled.

As the bike toppled, he thrust out his left arm to break the fall. It didn’t seem like a serious accident, yet “I couldn’t get up.”

At the emergency room, X-rays showed that he had fractured both his hip, which required surgical repair, and his shoulder. Dr. Klein, a dentist, went back to work in three weeks, using a cane. After about six months and plenty of physical therapy, he felt fine.

But he wondered about the damage the fall had caused. “A 52-year-old is not supposed to break a hip and a shoulder,” he said. At a follow-up visit with his orthopedist, “I said, ‘Maybe I should have a bone density scan.’”

As he suspected, the test showed that he had developed osteoporosis, a progressive condition, increasing sharply with age, that thins and weakens bones and can lead to serious fractures. Dr. Klein immediately began a drug regimen and, now 70, remains on one.

Osteoporosis occurs so much more commonly in women, for whom medical guidelines recommend universal screening after age 65, that a man who was not a health care professional might not have thought about a scan. The orthopedist didn’t raise the prospect.