University College London researchers questioned more than 11,000 men and women about their condom use in the previous 12 months.
Just 38% of men and 28% of women aged 35-44 used a condom the first time they had sex with a new partner, compared to almost 70% of 16-19 year-olds, the researchers said online in the International Journal of Epidemiology.
The authors said the study findings were of ‘great concern’ and that condom use and health promotion messages need target all age groups, not just young people.
Catherine Mercer, a lecturer in UCL’s Centre for Sexual Health and HIV Research, said: ‘To the best of our knowledge this is the first research to take account of all heterosexual partnerships and not just people’s most recent partnerships, which tend to be more established partnerships such as marriages and cohabitations.
‘Our study ensures accurate representation of casual partnerships, which are known to be important in the transmission of STIs. People with large numbers of partners contribute disproportionately to STI transmission in populations,’ she added.