“Most people are aware of the connection between being overweight and the risk of cardiovascular disease, but up to now too few people know about the link between being underweight and weak bones,” says Dr. Wolfgang Orthuber, a mathematician and orthodontist at the University of Kiel in Germany.

Dr. Orthuber began to consciously lead a healthy lifestyle at the age of 18. For over twenty five years he practiced intensive endurance exercises at home on his bicycle ergometer, on average about one hour each day, and took care to eat healthy foods and maintain an adequate intake of calcium and vitamin D. Feeling very fit and confident about his health status, he remained unconcerned when friends or doctors occasionally made general comments about his thinness. Yet without realizing it, he had, through years of intensive exercise and calorie restriction, become dangerously underweight. His Body Mass Index (BMI) – a measure of body fat based on height and weight - had decreased to between 17 and 18, a level considered underweight and below the recommended normal range of 18.5 to 24.9.

osteoporotic compression fractures: a) of August 2005 in the thoracic spine; b) of November 2005 in the lumbar spine.

He suffered a nasty shock when, aged 44, he was diagnosed with severe osteoporosis after suffering two spontaneous vertebral compression fractures. DXA testing showed T-scores of -2.2 at the femur total, and -4.6 in the spine at the first lumbar vertebra L1. Clinical examinations determined that there was no underlying endocrine disorder or other secondary causes, other than the underweight status.

By taking the prescribed treatment (a bisphosphonate and calcium-vitamin D supplements), correcting his exercise regimen, and increasing his caloric intake, Dr Orthuber was able to make significant gains in his BMD. DXA testing indicated that within 3 years and 2 months his BMD at the hip (femur total) had increased from 0,799 g/cm2 to 1,039 g/cm2 (T-score from -2.2 to -0.4), and at the spine at L1 had increased from 0,614 g/cm2 to 0,894 g/cm2 (T-score from -4.6 to -2.2).

He attributes these remarkable gains not just to the medical therapy, but in large part to his new exercise regimen. He performed one hour of slow but intensive full body strength training two times per week and reduced endurance training to ½ hour two other times per week. The new training regimen and greater caloric intake led to an increase in BMI to 22 within one year.

“There was a setback when I spontaneously fractured my left leg while jogging (see image, left) . Since I had been doing leg presses and increasing the weight resistance I assumed that jogging would be safe. However unlike leg presses, which are done slowly and in a controlled manner, the impact of jogging resulted in traumatic force peaks.” After surgical intervention the leg healed well and Dr. Orthuber resumed his safe exercise regimen. He states, “My personal experience confirms the conclusions of many research studies which show, on the one hand, the danger of long-term underweight status for bones, and on the other, the benefits of controlled strength training. People with osteoporosis should engage in targeted strength training, according to their physical abilities and, ideally, in a safe, medically supervised environment.”

By sharing his personal story Dr. Orthuber hopes to raise awareness of this dangerous link between being underweight and osteoporosis. “Like me, many young athletes who practice endurance sports may be at risk of osteoporosis”, he says. He urges people of all ages who are underweight and who practice endurance sports to keep their bone health in mind and possibly take a DXA exam. If measurements show low BMD, a change of lifestyle would be indicated, preventing a possible future of painful fractures.

Read more stories about people with osteoporosis