An increasing number of older people are contracting sexually transmitted infections such as chlamydia and genital warts, according to England’s Chief Medical Officer.

STI diagnoses in people aged between 50 and 70 have risen by more than a third over the last decade, found Dame Sally Davies in a new report into the health of the baby boomer generation.

In 2010, sexual health clinics recorded 11,366 new infections among this age group, which rose to 15,726 in 2014 – an increase of 38 per cent.

“These data may underestimate the true extent of the problem, as older people may either be unwilling to seek treatment or seek treatment options elsewhere to avoid the stigma” of attending sexual health clinics, the report warned.

Dr David Lee, who wrote the report’s chapter on sexual health, told The Independent a number of societal factors could be behind the change.

He said it was possible that rising divorce rates, meeting new partners later in life, and foregoing condoms if there is no risk of unwanted pregnancy had contributed to the increasing incidence of STIs in people over 50.

“It could be to do with older people breaking relationships then repartnering again. From a demographic perspective, we know that has happened over the last decade,” he said.

“There may just be more activity going on in terms of new partners, and having multiple partners in older age.”

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He added: “Thinking about the baby boomer generation, growing up in the 60s, one would argue perhaps they were exposed to more liberal attitudes to sexuality. Have they carried that forward?”

While the incidence of STIs among the over 50s remains small compared to younger age groups – less than five per cent of all infections – the report called for better communication between GPs and sexual health services and older patients.

“Health promotion messages give the impression that condoms and concerns about STIs are applicable to young people only,” it warned.

The most commonly diagnosed STIs in 2014 among those aged 50 to 70 were warts, chlamydia, herpes and gonorrhoea.

HIV cases have also risen among 50 to 70-year-olds and now account for 16 per cent of all new STI cases, the report found.

More than half, 54 per cent, of men and women in the 50 to 70 age bracket said they have intercourse at least twice a month, according to a 2012 study quoted in the report.

And 48 per cent of men and 17 per cent of women said they masturbate twice a month or more.

The report also examined other health issues among 50 to 70-year-olds, warning that diabetes is becoming a growing problem.

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Levels of obesity have also “significantly increased in baby-boomers compared with adults of the same age 20 years earlier”. A “staggering” 80% of men and 92% of women have a too-high waist circumference, it said.