Acupuncture can ease chronic back pain – and a single course of treatment can bring benefits that last for a year, researchers have claimed.

In a major new study, the therapy, which involves inserting hair-fine needles painlessly into the skin at specific points, was trialled in older adults with long-term lower back problems.

Those given a full course of sessions reported less pain and disability than those who stuck with standard medical care alone – and the improvements were still measurable 12 months later.

Back pain is the world's leading cause of disability, with rates climbing as people get older.

In Britain, it is one of the most common reasons for seeing a GP – accounting for between three and seven million appointments a year.

NHS figures show musculoskeletal problems, which include back pain, make up almost a third of all GP consultations. Around four in ten people with chronic pain in England say it is their back that troubles them most.

Treatments usually focus on painkillers, spinal injections or even surgery.

But drugs often have only modest effects – and in older people can cause serious side-effects ranging from stomach bleeds and confusion to addiction.

The new research, published in JAMA Network Open, offers strong evidence that acupuncture – a drug-free option already widely available in private clinics and some NHS services – can help.

The study was led by Kaiser Permanente in Oregon and carried out across four major US health systems in California, Washington and New York, involving more than 50 licensed acupuncturists.

Patients in the trial were randomly assigned to three groups. One received 'usual medical care' – GP visits, painkillers and physiotherapy referrals, sometimes escalating to spinal injections or surgery.

Another group had a standard course of acupuncture: eight to 15 sessions spread across 12 weeks, on top of usual care. The third had the same course, followed by four to six 'maintenance' sessions over the next 12 weeks.

At the six-month mark – the main time point for the study – both acupuncture groups showed significantly greater improvements in back-pain disability scores than those on usual care alone.

On a 24-point scale used to measure how pain limits daily life, acupuncture patients were on average one to one-and-a-half points better off than those without it.

In their conclusion, the researchers wrote: 'Acupuncture provided greater improvements in back pain-related dysfunction at a six-month and 12-month follow-up compared with usual medical care alone, with the advantage of a low-risk profile.'

They added: 'Our resulting 1.0- to 1.5-point difference is clinically important, congruent with or larger than effects reported for other pain-related treatments, and shows more sustained benefit and substantially lower adverse effects than pharmacotherapy.'

Almost half of the patients who received acupuncture saw their symptoms improve by at least 30 per cent – compared with just three in ten in the usual care group.

Crucially, these benefits were not short-lived. They were still evident a year after the course of acupuncture began, even without further treatment.

Adding maintenance sessions gave a slight extra benefit on pain ratings but made little difference to overall disability.

Patients also reported feeling better when asked to rate their pain in general, and there were signs of reduced anxiety in those who had acupuncture compared with standard care.

Safety was another important finding. Serious adverse events were rare and occurred at similar rates in all groups.

Only one case – an infection in the leg, successfully treated with antibiotics – was judged possibly linked to acupuncture.

Minor problems such as brief soreness at the needle site affected fewer than one in ten patients.

Researchers said the results were comparable to earlier trials of acupuncture in mixed-age adults, suggesting the therapy could be useful at all ages, though the study was designed to answer the specific question of whether it works safely in pensioners.

Acupuncture is already recommended in clinical guidelines in the US and UK for managing long-term back pain, but the evidence in older people had been patchy.

This study, designed in part to inform Medicare funding decisions, is the first large randomised trial to focus solely on the over-65s.

With drug side-effects a growing concern for an ageing population, the authors said acupuncture offers a safe, accessible and non-pharmacological alternative.