UK rates of transgender identity have risen at least 5-fold since 2000, with the highest rise observed among 16 to 29-year-olds, although the overall numbers are still small, suggests an analysis of nearly 20 years of anonymised general practice records in BMJ Medicine.

Rates of people identifying as transgender were more than twice as high in the most socially and economically deprived areas as they were in less deprived areas, the analysis of data from 2000 to 2018 shows. This puzzled the researchers. “Transgender individuals in wealthier areas may be more able to afford specialist gender care privately, which can be accessed entirely independently of NHS primary care. This trend may be increasing with longer NHS waiting lists. Therefore, individuals from a wealthier background might bypass NHS services entirely,” they suggest.

Transgender statistics are essential for appropriate service design, resource allocation, and staff training. But there’s little in the way of recent good quality data; the last UK primary care records study that attempted to estimate these figures was published in 1998.

In a bid to strengthen the evidence base, the researchers analysed the diagnostic codes recorded in anonymised general practice medical records from the start of 2000 to the end of 2018 to track changes over time in the proportion of transgender 10 to 99-year-olds seen at 649 general practices across the UK. The analysis included more than 7 million people with at least one full calendar year of medical records information during the study period.

Overall, newly recorded transgender identity codes increased five-fold between 2000 and 2018: roughly 1 person in every 70,000 was newly identified as transgender in 2000; by 2018, this had risen to around 1 in every 13,000 people.

But the proportion of people with recorded transgender identity differed by age group. It was highest in 16 to 17-year-olds (about 1 in 4300 people) and in 18 to 29-year-olds (about 1 in 3700 people).

Over time, the largest increase occurred in 16 to 17-year-olds, among whom the rate of newly recorded trans identity rose from zero and 4 per 100,000 people in 2000, respectively, to 78 per 100,000 people in 2018. Similar patterns were evident among 18 to 29-year-olds.

In 2018, the proportion of people identifying as transgender, and coded as such in their medical records, had reached roughly 1 in 600 among 16 to 17-year-olds and around 1 in 800 among 18 to 29 year olds.

The data also only go up to 2018: recording rates of transgender identity in general practice may very well have changed since then, they add.