A growing number of Hongkongers are at risk of developing a condition doctors call 'iPhone syndrome' by overusing their smartphones. Dr Sophia Ng Mo-tack, of the Hong Kong Chiropractors' Association, said practitioners were seeing more and more cases of people with a range of symptoms which they believe could be caused by bad posture while using smartphones and handheld game devices. Many cases involve people in their 30s, sometimes younger, suffering aches and pains normally associated with middle and old age. Symptoms of iPhone syndrome include pain and numbness in the neck, wrist, fingers and thumbs, which if ignored could lead to muscle strain, recurring episodes of pain, and in the long-term irreversible damage, arthritis and bone spurs which require surgery. 'These are degenerative conditions previously associated with people in their 40s and 50s, but we are now seeing an increasing number of cases among people in their 30s and even younger,' Ng said. 'We are calling it iPhone syndrome.' The problem occurs because of bad posture commonly adopted by people while using smartphones and handheld games, she said. 'You see people on the MTR using their iPhone, texting and playing apps while the train is moving and often they are holding the rail,' she said. 'Their heads are always bent and their shoulders hunched in a curve. This is bad posture.' In addition they often hold the device in one hand and type with the thumb on the same hand, which puts the thumb in an unnatural position leading to muscle and tendon strain. 'The first thing people might find is that the muscles tire in their neck and shoulders. If they don't correct this bad posture, they will start to have pain which in the long term could lead to degenerative arthritis. 'If you use two hands it will lead to pain in the one holding the phone as constant pressure is put on the wrist by the pushing on the keys with the fingers of the other hand. 'If you use one hand and key in with the thumb on the same hand, it will also affect the thumb.' Josephine Ip Wing-yuk, an associate professor of the Department of Orthopaedics and Traumatology at the University of Hong Kong, said about 10-20 per cent of the people she sees with problems caused by muscle overuse had smartphones. 'These sorts of overuse problems are on the increase, and usually it is a result of a combined computer and smartphone use,' she said. 'In the past few years, we have started to see people coming with just one problem, especially the thumb, which is caused by using the thumb to type rather than the fingers. 'Once you have an overuse problem, it can take weeks to recover, and during this time your working capacity will be decreased. 'If you don't manage it properly and if there is an inflammatory response, and your body heals with fibrosis, you have an increased chance of repeated episodes of pain. 'You may need conservative treatment such as physiotherapy, or an injection to control the inflammation, or in the worst scenario you may need an operation.' Dr Ip said it was important people realised pains associated with overuse of equipment should not be ignored. 'My advice to anyone using a smartphone is to keep an upright posture [and it] is better to touch the screen with your fingers.' Apple did not respond to e-mailed questions from the Sunday Morning Post on posture problems.