Osteoporosis, a silent epidemic with no symptoms, is becoming more of a threat to the health of China's increasingly ageing population, say medical experts.

With World Osteoporosis Day 2005 tomorrow, the Chinese Osteoporosis Foundation and Roche Pharmaceuticals are planning free diagnostic services in some big hospitals in Beijing and Shanghai to make the public become more aware of the long-neglected disease.

According to the fifth national census in 2000, about 88,260,000 people suffer from primary osteoporosis, making China the country with the highest number of osteoporosis patients in the world. The annual medical cost for the group of people affected by the disease is estimated to be about 15 billion yuan (US$1.84 billion), not to mention the major strain it causes on the national healthcare programme.

Osteoporosis is a progressive disease that causes bones to become thin and brittle, and may result in broken bones.

Nowadays, more orthopaedists recognize osteoporosis as a serious challenge to their clinical treatment.

"In the past, we did not give too much attention to osteoporosis. But more and more clinical experiences proved that osteoporosis-related bone fractures were much harder for us to fix," said Dang Gengting, director of the Orthopaedics Department of the Third Hospital of the Peking University.

"The new bones grew slowly and prolonged the time of recovery, which would finally expose the patients to more risks of complications," Dang said.

The overall prevalence of broken bones is higher in women, according to Meng Xunwu, director of the endocrine department of Peking Union Medical College Hospital.

One in three women over 50 will experience osteoporotic fractures. In women over 45 years of age, osteoporosis accounts for more days spent in hospital than many other diseases, including diabetes, heart attacks and breast cancer.

"The accumulated bone thickness of women is lower than men," Meng said. "For postmenopausal women, the significant decrease in estrogen could cause a rapid loss of bone. So older women are more apt to have osteoporosis."

However, people's awareness about the "silent killer," in the long run, is very weak, according to medical experts. Patients' common misconception about osteoporosis is it is a normal phenomenon of ageing.

In Shanghai, three-fourths of the osteoporosis patients never visit a doctor, and only 2 per cent of the patients undertake treatment, according to Zhu Hanmin, director of the Osteoporosis Prevention and Treatment Centre in Huadong Hospital in Shanghai.

Commonly, the fracture occurs in the spine, wrist and hip. Hip fractures are the most serious ones. According to Meng, 20 per cent of hip fracture patients die of complications and about half become disabled during later years.

"If osteoporosis is not found and treated in time, it will be highly possible to lead to a physical disability," Meng said.

Disease prevention

Medical experts said they believe that a routine bone mineral density test to screen for osteoporosis holds the same importance as measuring the blood pressure and blood fat for people aged 60 and older.

However, there are only about 400 bone mineral density test machines around the country, so a "One Minute Risk Test" can be another effective tool to evaluate the bone health. The test only needs the respondents to answer nine questions. If all or part of their answers were "yes," they would be recommended to receive a bone mineral density test.

Between October 15 and November 15 in 37 hospitals in Beijing and Shanghai, 400,000 leaflets of the "One Minute Risk Test" will be distributed to people for a fast and convenient osteoporosis risk evaluation.

Old age, low body weight, smoking and a high intake of alcohol make people more likely to have osteoporosis, according to Meng.

Experts recommend prevention through better nutrition and more exercise.

Calcium and vitamin D supplementation, and higher dietary protein and lower salt intake reduce rates of bone loss and also fracture rates in older male and female adults. A higher level of physical activities is also associated with a significantly reduced risk for osteoporosis.