Using strong painkiller opioids doubles the risk of hip fracture among people with Alzheimer's disease, according to a new study.

This could be because opioids are known to increase the risk of falls which, in turn, may lead to hip fracture in older people, said researchers from the University of Eastern Finland. The study showed that use of weak opioids, such as codeine and tramadol was not associated with the risk of hip fracture. 

However, moderately strong opioids such as buprenorphine were associated with a two-fold risk and strong opioids such as oxycodone and fentanyl were linked to almost a three-fold risk compared with non-use. For the study, published in the journal PAIN, the team included 23,100 persons diagnosed with Alzheimer's. 

From this sample, new opioid users were identified and matched with opioid non-users. The findings also showed that the risk was highest in the first two months of opioid use and attenuated after that. Further research is needed to find out whether the risk of injurious falls is avoidable by slow titration of opioid doses in the beginning of the treatment.

Opioids are used for the treatment of severe pain in cases where other painkillers fail to produce a sufficient response. But opioid abuse and addiction is a serious public health problem and may cause attentional impairment or drowsiness.