A new study has shed light on how the number of sexual partners British people have changes as they age, and new findings have surprised researchers.
The study suggests that gay and bisexual men over 70 may continue to have a sex life with multiple partners, while straight women become less sexually active after the age of 50.
Researchers from the University of East Anglia (UEA), in collaboration with King’s College London and University College London, questioned more than 5,000 people aged 18 and older during the 2022 mpox – previously known as monkeypox – outbreak.
They wanted to analyse how sexual behaviour changes with age, so that mathematical models of sexually transmitted infections can be made more accurate.
Lead researcher Dr Julii Brainard, from UEA’s Norwich Medical School, said: “Before this study, many models about sexually transmitted diseases assumed that everyone over a certain age, say 40 or 65, stopped being sexually active, or at least stopped having multiple partners.
“Or there might be an assumption that young people have the most sex.
“But the answer is more nuanced, and it partly depends on people’s sexuality.”
Researchers questioned 5,164 British people, including 3,297 sampled from the general population and 1,036 men who have sex with men (MSM) recruited via Facebook and Instagram, between September 5 and October 6 last year.
A further 831 people responded to adverts on the gay dating app Grindr.
Women who have sex with women and other partnership types were not investigated because only a small number responded to the survey.
According to the findings, most people questioned had either zero or one sexual partner at any age in the preceding three weeks.
Some 65% of straight women reported having one partner in the last three weeks consistently until they were 50 – after which there was a steep climb in reporting no partners.
The survey also found that 79% of women aged 70 and older, who identified as heterosexual or had any male partners in the last three months, had had no male partners in the last three weeks.
Of the heterosexual men questioned (all age groups), half reported having one partner in the last three weeks.
But they were increasingly likely to report no partners as they got older.
Half of the men aged 70 or older who were heterosexual or had had sex with any women in the last three months, did not have a female partner in the most recent three weeks.
This was compared with just 44% of men having heterosexual sex who had no recent female partners when under the age of 70.
Partner concurrency – having more than one recent sex partner – was uncommon in the general population, but common among the social media samples.
Forty-two per cent of MSMs recruited on Facebook or Instagram and 52%of Grindr respondents had at least two recent male partners.
The study found that partner concurrency fell among older people, with the least decline among social media respondents.
Seventy-seven men of 70 and over who have sex with men answered the survey.
According to the findings, 17% of them reported more than one recent partner in the most recent three weeks.
And a quarter of the MSM aged 70 and over recruited via social media had concurrent partners.
Only 2% of straight people over 70 reported multiple partners.
Dr Brainard said: “Most people in our survey, regardless of their gender identity or sexuality, had zero or one recent partner at any age.
“We managed to collect a lot of data from MSM who practised partner concurrency.
“About 45% of them sustained partner concurrency from age 27 to 63.
“Even at age 65+ the respondents recruited via social media still tended to have more sexual contact than the general population sample at the same age.
“It would be interesting to see if these findings were replicated if we targeted heterosexuals most likely to practise partner concurrency.
“Models of disease spread shouldn’t assume that young people are necessarily most at risk or that having multiple partners just stops happening at a strict age threshold.”
Information about age profiles and sexual habits is useful because it helps to tailor safe sex messages at the right groups and using media channels that best reaches these people.
Research Fellow Dr Louise Smith at King’s College London co-ordinated the survey in autumn 2022 to collect information about public awareness of mpox and what public health messages might be most motivating for different sub-groups.
Dr Smith said: “This study underscores the importance of considering how data were collected.
“For instance, we can’t conclude from this survey that MSM who use social media are particularly likely to have concurrent partners.
“But it may be that the algorithms that Facebook or Instagram use to identify MSMs are also very good at finding that subset of people.
“At the time, mpox mostly affected gay and bisexual men so we focused recruitment on this group.
“Because we didn’t recruit very many lesbian and bisexual women, or members of the trans community, our statistical analyses would have been less reliable for these groups.
“Further research into other minority sexualities and gender identities could be beneficial to better understand the granularity of sexual behaviour and optimal public health messaging suited to different groups of people in the UK.”
This study, published in the Plos One journal, was funded by the National Institute for Health and Care Research.