Wednesday March 10 2010
Birds do it, bees do it, even OAPs do it: sex is not just for the young
“If you want good sex, you better get down the gym and tuck into your fruit and veg,” says the Daily Mirror. The newspaper reports that a “big-bang theory” has found a link between sexual activity and general health.
The news is based on two US surveys that looked at more than 6,000 people aged 25 to 85. It found that a satisfactory sex life is positively associated with health in middle age and later life. It also noted that between the ages of 75 to 85, 39% of men were sexually active compared to just 17% of women.
The study has also introduced the idea of a new health measure, called "sexually active life expectancy", which can denote the average remaining years of sexually active life. The research showed that men aged 55 could expect another 15 years of sexual activity, but despite their longer life spans, women the same age could expect fewer than 11 years.
While the accuracy of self-reported sexual activity is often questioned in this type of sexuality research, it seems likely that the sexually active life expectancies estimated in this study are accurate.
Where did the story come from?
The research was conducted by Professor Stacy Tessler Lindau and Natalia Gavrilova from the University of Chicago in the US. The study was funded by the Center on Demography and Economics of Aging in Chicago and a grant from the US National Institutes of Health/National Institute on Aging. The study was published in the peer-reviewed British Medical Journal.
Other newspapers, including The Times, report this study. The coverage is accurate, commenting on other issues for older people, including use of drugs such as Viagra, sexual problems and the use of condoms.
What kind of research was this?
This research set out to examine the links between health and sexuality in a cross-sectional analysis. The researchers also wanted to estimate the number of sexually active years that middle-aged and older adults had remaining, and how this varied in groups people of different gender and health status.
The research provides a snapshot of sexual activity in the US through data from two surveys conducted in 1995-96 and 2005-06. These surveys asked members of the public about their sexual activity, quality of sexual life and interest in sex. They calculated a new measure for various ages: the average remaining years of sexually active life, referred to as “sexually active life expectancy”.
This was observational research that relied on self-reported health measures and responses to personal questions asked by questionnaire. Rates of non-response to questions on sexuality was higher among women and older people, although 84% of all respondents returned the questionnaires. The accuracy of responses is a problem for sexuality research, but good response rates and study design suggest that inaccuracy is unlikely to account for the large differences seen in the elderly groups.
What did the research involve?
The researchers had data from two large, nationally representative, population surveys: the National Survey of Midlife Development in the US (MIDUS, or midlife cohort) and the National Social Life, Health and Aging Project (NSHAP). The two surveys asked similar questions on sexuality and had sufficient numbers of older people to allow for assessments of sexuality in age groups of up to 85 years old.
In the 1995-96 MIDUS survey, telephone numbers were used to randomly select adults aged 25 to 74 from the English-speaking population of 48 US states. The participants completed both a telephone interview and a postal questionnaire. The response rate was 60.8%, with 3,032 respondents (1,561 women, 1,471 men) providing responses to both parts of the survey.
For the 2005-06 NSHAP survey, the process was slightly different. In this survey, the age range followed was marginally older (57 to 85) and the sample was generated from households previously screened in 2004. In order to closely analyse certain populations the researchers recruited disproportionately large numbers of people from some ethnicities minorities (such as African-Americans, Latinos) and from other subgroups including males and very old people. Participant interviews were conducted at home by professional English and Spanish-speaking interviewers. For this survey there were 3,005 respondents, equating to a response rate of 75.5%.
The two studies featured several similar questions and recorded comparable datasets on factors such as age, partnership/relationship status (married, co-habiting, single with partner or without), sexual activity (defined as sexual activity within six months in one survey and within 12 months in the other) and frequency of sex. Quality of sex and interest in sex was rated on a scale from 1 to 10 for the MIDUS study.
The researchers used standard mathematical modelling techniques to report the likelihood of being sexually active, having a good quality sex life and being interested in sex among those of a particular age or health status when compared with those in a baseline category.
They calculated sexually active life expectancy using publicly available data on life expectancy for various ages and matched these to the people in the same age groups in their study. They also adjusted for the fact that a substantial proportion of the older population live in institutions.
What were the basic results?
Men were more likely than women to be sexually active, report a good quality sex life, and be interested in sex. Among the 75 to 85-year-olds, 38.9% of men and 16.8% of women were sexually active.
Men and women reporting very good or excellent health were about twice as likely to be sexually active compared with similarly aged people in poor or fair health. When broken down by gender and study:
- Men with good/excellent health were around 2.2 times more likely than less healthy men to be sexually active in the MIDUS mid-life study.
- Women with good/excellent health were around 1.6 times more likely than less healthy women to be sexually active in the MIDUS mid-life study.
- Men with good/excellent health were around 4.6 times more likely than less healthy men to be sexually active in the NSHAP older-life study.
- Women with good/excellent health were around 2.8 times more likely than less healthy women to be sexually active in the NSHAP older-life study.
At the age of 30, sexually active life expectancy (active years remaining) was 34.7 years for men and 30.7 years for women, compared with about 15 years for men and 10.6 years for women at age 55. This difference in sexually active life expectancy was smaller for people with a spouse or other intimate partner.
How did the researchers interpret the results?
Researchers say that sexual partnership, frequency of sexual activity, a good quality sex life, and interest in sex are positively associated with health among middle-aged and older adults in the US. Since 2000 they say, interest in sex among middle-aged and older men in the US has increased.
The researchers say that men lose more years of sexually active life as a result of poor health than women. They claim that the estimation of ‘sexually active life expectancy’ is a new life expectancy tool that can be used in the arena of sexual health planning and treatment.
This observational cross-sectional study has provided a detailed and interesting body of new information on the sexual life of different age groups in America. It has the following strengths:
- The data was collected by large population surveys using broadly similar measures of sexuality. The size of the sample increases confidence in the results.
- The numbers of people in the groups for partnership, sexual activity, sexual frequency and good quality sex life were similar in both surveys and similar rates of activity have been reported in other international reports, suggesting that the sampling was representative.
- There was a low non-response rate to items in both surveys, although older respondents and women were more likely than others to refuse to answer questions on sexuality. It is not clear how these refusals would affect the results.
The authors note that as this data was not collected over time, it is not possible to say if regular good health facilitates a good sex life or if the opposite may be true, that being sexually active contributes to good health. The researchers also say that because of the study population, their findings may not be relevant to non-Western cultures or for people who are lesbian, gay or who do not identify as heterosexual.
Overall, despite the fact that self-reported sexual activity might be inaccurately reported, it seems likely that the large differences in sexually active life expectancy shown between the sexes in this study are genuine.