Couples who meet in their 30s or 40s are less likely to use condoms than younger counterparts, a study suggests.

University College London researchers found two thirds of men and women in their late teens used a condom when they first had sex with a new partner.

But only a third of men and women aged 35 to 44 in new relationships did so.

Experts said the International Journal of Epidemiology study showed a worrying trend, and said people should practise safe sex at any age.

The UK’s Health Protection Agency has said rates of sexually transmitted infections (STIs) are on the increase.

It reported a rise of 6% in the total number of new STIs diagnosed in 2007 compared with 2006.

Other research from the West Midlands, published this year, found STI diagnoses in people aged 45 more than doubled between 1996 and 2003.

Men have sex ‘sooner’

The researchers interviewed more than 11,100 adults as part of the second British National Survey of Sexual Attitudes and Lifestyles.

People were asked a range of questions about their partnerships over the last 12 months including how they met, when they first had sex, what the age gap was and if they used condoms.

Increasing rates of STIs diagnosed among those in their 30s and 40s suggest that interventions that promote consistent condom use with new partners are urgently required Dr Catherine Mercer, University College London

Just under 9,600 people reported having 15,488 partners in the preceding year.

A higher proportion of men’s partnerships were described as “not regular” – 39% compared with 20% of women’s partnerships.

In addition, a higher proportion of women’s partnerships were marriages or cohabitations – 55% versus 39% of men’s partnerships.

Men had sex sooner after first meeting a partner than women, with one in five men reporting sex within 24 hours of meeting their partner, compared with one in 10 women.

And men who had sex within 24 hours of meeting their partner were more likely to report using a condom than those who waited longer than a day.

Overall, half of all new partnerships involved condom use at first sex, but this declined with age.

In partnerships where there was an age difference of five or more years, condom use is particularly low – especially in relationships between younger women and older men.

And condom use at the end of a relationship was lower than at the beginning.

Just 37% of men had used a condom on the final occasion they had sex with a partner, while the figure was 28% for women.

Advice ‘urgent’

Dr Catherine Mercer, of the Centre for Sexual Health and HIV Research, University College London, said: “Our finding that condom use at first sex declined with increasing age is of concern.

“Although a disproportionate amount of partnerships are formed among people in their teens and 20s, the fact is that about 45% of marriages are now expected to end in divorce, which means that the ‘population attributable risk’ of partnership formation by those in their 30s and 40s will increase.

“Indeed, increasing rates of STIs diagnosed among those in their 30s and 40s suggest that interventions that promote consistent condom use with new partners are urgently required, not just for young people as has been the focus recently, but for people in their 30s and 40s and older who are increasingly forming new partnerships.”

Julie Bentley, chief executive of the Family Planning Association, said: “This research shows that no matter what age you are, or what type of relationship you are in, sexual health messages still apply.”

Lisa Power, of the Terrence Higgins Trust, said: “STIs are no respecter of age and although most media portrayals of sexual relationships involve young people, these figures show that it’s important to support people to have a healthy sex life at every age.

Condoms are usually made of latex or polyurethane. If possible you should use a latex condom, as they are slightly more reliable, and in most countries they are most readily available.

Latex condoms can only be used with water based lubricants, not oil based lubricants such as Vaseline or cold cream as they break down the latex. A small number of people have an allergic reaction to latex and can use polyurethane condoms instead.

Polyurethane condoms are made of a type of plastic. They are thinner than latex condoms, and so they increase sensitivity and are more agreeable in feel and appearance to some users. They are more expensive than latex condoms and slightly less flexible so more lubrication may be needed. However both oil and water based lubricants can be used with them.

It’s not clear whether latex or polyurethane condoms are stronger – there are studies suggesting that either is less likely to break. With both types however, the likelihood of breakages is very small if used correctly.

The lubrication on condoms also varies. Some condoms are not lubricated at all, some are lubricated with a silicone substance, and some condoms have a water-based lubricant. The lubrication on condoms aims to make the condom easier to put on and more comfortable to use. It can also help prevent condom breakage.

The female condom is a thin sheath or pouch worn by a woman during sex. It entirely lines the vagina and helps to prevent pregnancy and sexually transmitted diseases (STDs) including HIV. Two types of female condom are available.

Open the package carefully. Choose a position that is comfortable for insertion – squat, raise one leg, sit or lie down. Make sure the condom is lubricated enough.

If you are using the FC or FC2 female condom, make sure the inner ring is at the closed end of the sheath, and hold the sheath with the open end hanging down. Squeeze the inner ring with thumb and middle finger (so it becomes long and narrow), and then insert the inner ring and sheath into the vaginal opening. Gently insert the inner ring into the vagina and feel it go up. Place the index finger inside the condom and push the inner ring as far as it will go. Make sure the condom is inserted straight, and is not twisted inside the vagina. The outer ring should remain on the outside of the vagina.

To begin inserting the VA, hold the sponge and frame close together and place the closed end in front of the vagina. Use two fingers to push the closed end containing the sponge inside the vagina as far as it will go. Make sure the sponge is opened up flat once it has been inserted. The frame should remain on the outside of the vagina.

The penis should be guided into the condom in order to ensure that the penis does not slip into the vagina outside the condom. Use enough lubricant so that the condom stays in place during sex. The female condom should not be used at the same time as a male condom because the friction between the two condoms may cause the condoms to break.

If the condom slips during intercourse, or if it enters the vagina, then you should stop immediately and take the female condom out. Then insert a new one and add extra lubricant to the opening of the sheath or on the penis.

To remove the condom, twist the outer ring or frame gently and then pull the condom out keeping the sperm inside. Wrap the condom in the package or in tissue and throw it away. Do not put it into the toilet. It is generally recommended that the female condom should not be reused.

The female condom may feel unfamiliar at first. The female condom may feel different and some people find it difficult to insert. Some women find that with time and practice using the female condom becomes easier and easier.