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Sexual Behaviour and Risks of HIV Infection

 | 
Michel Hubert

II. Qualitative and Quantitative Data Collection Methods in the Study of Sexual Behaviour

Self-Administered Anonymous Questionnaires in Sexual Behaviour Research: the Norwegian Experience

Jon M. Sundet, Per Magnus, Ingcla L. Kvalem and Leiv S. Bakketeig

Full text

1There are two different problem complexes involved in the area of sexual behaviour and HIV infection. On the one hand, it is important to estimate the speed and pattern of HIV spread in a population. On the other hand, it is important to change sexual behaviour in populations and sub-populations to limit and possibly stop the epidemic.

2These two problems imply quite different approaches to sexual behaviour studies. To estimate the speed and pattern of HIV spread, it is necessary to obtain quite precise estimates of the prevalence of different kinds of sexual behaviour in populations actually or potentially at risk. This necessitates representative population-based studies of different kinds of sexual behaviour. Such knowledge, together with knowledge about HIV prevalence and HIV transmission rates, makes it feasible, by means of mathematical modelling, to obtain reasonable forecasts with respect to HIV spread in a population.

3The preventive task implied in the effort to change sexual behaviour must be based on knowledge about what types of interventions may be useful and effective in this respect. This calls for investigations of the causal mechanisms involved in sexual conduct, especially causal relationships that may be manipulable on the population or sub-population level, and thereby be potentially useful in preventive work. We think that in-depth studies of possibly quite small groups are the best way to obtain knowledge of this kind.

I. Relevant efforts in Norway

4Norway has a population of approximately 4.5 million. As of March 1989 we have registered about 750 HIV positive persons, mainly among homosexual males and IV drug users, but the proportion of drug-free heterosexuals seems to be increasing. It is estimated that about 2,000-4,000 people are actually HIV positive. The total number of AIDS patients is about 110, of whom about 70 have already died.

5The Norwegian effort concerning the HIV epidemic has concentrated partly on prevention work and partly on research. The preventive work has concentrated on information through the mass media, folders and the like. The Norwegian government has spent considerable sums of money on this effort. Besides this, quite a lot of work on sexual behaviour information has been done in schools and with some sub-groups, especially homosexual males.

6The work we shall concentrate on in this context is the Norwegian effort to estimate the pattern and speed of the spread of HIV in the population. This work contains two elements:

  • Investigations of the prevalence of different kinds of sexual behaviour in the Norwegian population.

  • Mathematical modelling, based on the results of the sexual behaviour studies.

II. The Norwegian sexual behaviour study

7The purpose of this study was to map the prevalence of different kinds of sexual behaviour in the Norwegian population (for some main results, see Sundet et al., 1988). The usual way to do this has been by interviews (Kinsey et al., 1948, 1953) or a combination of interviewing and questionnaires to be filled in with the interviewer waiting (Zetterberg, 1969). We decided to use an anonymous, self-administered questionnaire. This is an inexpensive method (approximately £40,000, excluding salaries), and the data comes in quite quickly. Thus, we had all our data computerised only two months after sending out the questionnaires.

A. The design and content of the questionnaire

8The main philosophy behind the questionnaire’s construction was that it should be short, concrete, attractive (differents parts of the questionnaire were printed in different colours; this also made the questionnaire more easy to answer) and oriented towards behaviour. Thus, the respondents had to answer at most about 50 questions, most of them on a forced choice basis. Openended questions were avoided. We did not ask about feelings or attitudes. The main reason for this is that HIV, of course, is transmitted through sexual acts, but also because it is difficult to get reliable and valid information about feelings and altitudes by means of a self-administered questionnaire. For such purposes the interview technique is probably better suited. We intentionally avoided using terms denoting sexual inclinations, like "homosexual", "heterosexual" and the like. Thus, to get information about homosexual acts, we termed the questions in terms of sexual activity with persons of the same gender (e.g. "Did you ever engage in sexual acts with a person of the same gender as you?"). Likewise, we asked specific questions about all types of sexual activity, e.g. anal sex, oral sex, with an explanation of critical terms where we felt it to be necessary. (An English version may be found in the appendix).

9The questions were of two main kinds:

  • Sociodemographic variables, like age, gender, marital status, education, profession and place of residence, as well as the population density of their place of residence.

  • Sexual behaviour questions.

10The part concerned with sociodemographic variables and some of the sexual behaviour questions, such as age at first sexual intercourse, homosexual activity, number of sexual partners during whole life, and anal sexual activity, were to be answered by all respondents. The rest of the questionnaire was divided in two parts, one to be answered by those currently married or living together with a partner, and one for those currently single. Married and cohabiting subjects were asked about sexual activity within marriage/cohabitation, together with a few questions about their present spouse, like gender, age and the duration of present marriage/cohabitation. The sexual behaviour questions were concerned both with the frequency of intercourse and the type of intercourse as well as use of condoms within marriage or cohabitation. Those with extramarital partners were asked about number of extramarital partners during their present marriage/cohabitation, during the last three years, the last year and the last month, and about type and frequency of intercourse and condom use with their last extramarital partner. In addition, they were asked about some characteristics of their last partner, such as nationality, age and marital status, and whether she/he was a prostitute. Very similar questions were asked of the singles.

11Before deciding on the final questionnaire, different versions of it were tested on about 200 persons of both genders, different ages and of different sexual inclinations. Altogether, about 10 persons were involved in designing the questionnaire for some six months before the final version was accepted.

12Each questionnaire was followed by a cover letter (actually the first page of the questionnaire), where it was emphasized that the respondents should be careful not to write their names or other information through which they might be identified (like their personal identification number). This, together with avoiding questions that might directly or indirectly serve to identify persons, ensured the respondents' anonymity. In addition, it was stressed that those who answered the questionnaire made a contribution to the prevention of HIV/AIDS in Norway. We feel that this may have contributed to the response rate.

B. The sample

13Of course, the overriding consideration in a prevalence study is that the sample is representative of the relevant population. In our study, we defined the population of interest as all Norwegians between 18 and 60 years of age. The upper and lower limits of the age interval are, admittedly, somewhat arbitrary. The lower age limit (18 years of age) was chosen mainly on the basis of legal considerations. In Norway you cannot ask younger persons about certain things without parental consent. In this way we certainly lose information about a sexually quite active segment of the population. However, this may not be a serious limitation. All the respondents were asked to give relevant information on their whole sexual histories; hopefully the histories of the youngest persons among the respondents are not too different from the sexual activity of those at present younger than 18 years of age. The upper age limit of 60 years does not reflect the opinion that persons older than 60 years have no sexual life; rather it is a supposition that their sexual activity is of relatively little interest relative to the HIV epidemic.

14We decided upon a sample size of 10,000, which represents about 0.5% of the Norwegian population in the relevant age group. This rather large-scale sample size was chosen to ensure statistically reliable detection of low-frequency sexual practices such as homosexual practices. The sample was picked by simple random sampling from the Population Registry by the Norwegian Central Bureau of Statistics. With hindsight we have speculated that some kind of stratification of the sample might have been a better procedure, because the frequencies in some of the subgroups were rather small in the respondent group, rendering point estimates rather unreliable. A still larger sample is also a possible strategy. We plan to replicate the study in 1990 and will then probably do the sampling differently with regard to either sample size or sampling methods.

C. Distribution and reminder routines

15The questionnaire was sent by ordinary postal service to the subjects in the sample in November 1987. Two reminders were sent. The first one, sent out after about 14 days, contained only a reminder letter. After another 14 days another reminder was sent, this time containing both a letter and a questionnaire. Due to the anonymity of the responses, the reminders were sent to all persons in the original sample. There is, thus, a possibility that some persons may have answered the questionnaire twice, although it was emphasized in the letter that those who had already answered it should disregard the new questionnaire.

III. Response

16At least one of the three mailings was returned due to unknown address for 176 persons in the original sample. They were excluded from the sample. Thus, the final sample totalled 9,824 persons. Of these, 6,159 returned filled-in questionnaires. Four of those were rejected because of incomplete answering, leaving a total of 6,155 respondents. This is 62.7% of the final sample. Considering the intimate nature of the questionnaire, this is a rather high response rate. Researchers from other countries have commented that they would expect a lower response rate in their countries. Maybe the Norwegian population is special in this respect, but the fact that we launched a media campaign in the weeks before we sent out the questionnaire may have influenced the response rate. Thus, we sent press announcements to local newspapers, and most of them printed the announcements. In addition, we got some coverage on radio and television. It seems that most of the population knew about the investigation, so the questionnaire did not come as a big surprise for most of those who got it.

A. Validity and reliability problems

17The validity problem is a tricky one. Answers not in total agreement with the truth may have come about in several different ways. First, the formulation of the questions may not have adequately covered the area that was intended. Especially, the term "intercourse" may not be adequate for sexual activity among homosexuals. Further, we cannot be sure that terms like "anal" and "oral" sex were properly understood, even though we supplied an explanation of the terms in the questionnaire. Then, there is simple forgetting. Persons may have failed to report sexual acts simply because the time since they performed them have become rather long. This effect is probably roughly proportionate with age. Thus, we should expect a higher percentage of underreporting with increasing age. There may also be deliberate lying, such as some males boasting of more partners than they have actually had, or maybe some females underreporting on that point. This may seem to be an odd thing to do in an anonymous questionnaire, but in a culture where masculinity and feminity is so closely linked to certain patterns of sexual behaviour, it may well be the case that the respondents use this occasion to boost their self-image. In addition, we have well-known unconscious mechanisms, like repression, which also may lead to underreporting or overreporting, as the case may be. Thus, people may have repressed the memory of previous sexual acts of different kinds which are perceived as taboo. This may especially be the case with homosexual acts, and maybe also specific intercourse techniques like anal sex. Taboo sexual acts may also be redefined by the person such that they fall in a category of acceptable behaviour.

18There are some, admittedly quite weak, indirect ways to check validity issues. One is to check for internal consistency in each respondent's response pattern. For example, a person reporting more sexual partners during the last three years than during the whole life reports inconsistently. Such checks, which may also be considered a reliability check, reveal that about 3% of the respondents have response patterns that are more or less inconsistent. Another way is to check gender consistency. In a random sample we should expect that a number of parameters are about equal for females and males, e.g. frequency of intercourse and number of partners. The picture is quite encouraging with respect to the frequency of intercourse. Thus, married/cohabiting females and males report approximate the same intercourse frequency. Males do, however, generally report more partners than the females do. This may be due to overreporting and/or underreporting, or it may be wholly or partly due to many males having intercourse with relatively few females (prostitutes).

B. Representativity problems

19Representativity is, of course, a critical issue in such investigations. This is all the more so because the prevalence rates of different kinds of sexual habits are used directly in mathematical models to project the spread of HIV. Wrong prevalence rates will bias these estimates. The critical question is whether the 37% who did not answer have other types of sexual behaviour than the 63% who did answer. There is no direct evidence on this point, but we have some indirect information. Thus, we can find out if the respondent group is biased with respect to parameters like age, gender, marital status, education, and residential area, but it must be emphasised that these parameters are relevant only to the extent that they correlate with sexual behaviour. There are some quite typical biases in the gender and age response distribution. For example, females tend to be more willing to answer than males, and young persons more than old. The median age of the responders was 34 years with lower and upper quartiles of 25 and 44 years. It is somewhat reassuring that young persons have quite high response rates, as the most sexually active persons generally are found within these groups.

20In the respondent group, 57.3% reported to be currently married, 33.8% had never been married, 6.5% were separated/divorced, 1.2% were widowed, and 1.1% failed to answer the question about marital status. These numbers are very similar to the population parameters with respect to marital status. About 14% of the respondents were living together with a partner without being married. Thus, a total of 71% were living together with a partner, whereas about 29% were at present single. This is quite reassuring, since marital status certainly correlates with sexual behaviour parameters related to the risk of infection of HIV and other STDs (e.g., rate of partner change).

21The respondent group is clearly biased with respect to educational level. Respondents with high education are quite overrepresented. Thus, the percentage of persons with university education is twice as high as the corresponding percentage in the population.

22Respondents from cities that are small or middle-sized according to Norwegian standards (2,000 to 100,000 inhabitants) are slightly overrepresented relative to large cities and urban areas. This may not be too serious, because these two parameters (education and place of residence) seem to correlate rather weakly with sexual behaviour. Thus, multiple regression analyses reveal that these two parameters seen together account for between 4% (married/cohabitants) and 7% (singles) of the variance in the number of partners during the last three years. Other analyses show a similar pattern for other sexual behaviour parameters.

Conclusions

23We feel that self-administered anonymous questionnaires may be a satisfactory method to investigate the prevalence of sexual behaviour in a population. The data come in fast and the approach is far cheaper than personal interviews. However, we feel that this method is most suited to contexts where the theme is limited to the behavioural domain. Even then, the results are critically dependent upon carefully formulated questions. This strongly indicates that much work should be invested in the construction of the questionnaire, including pilot studies. The validity of the information certainly hinges on a good questionnaire, but the response rate will probably also rise if the questionnaire contains simple, easily answered questions. We also feel that the response rate may be improved by preparing the public, and appealing to their sense of responsibility. We understand that cultural factors may cause low response rates. Several of our foreign colleagues have commented that the response rate in their country probably would have been considerably lower than the one we achieved in Norway. If this is the case, this certainly is a serious objection to performing such studies in other countries.

Bibliography

References

Kinsey A.C., Pomeroy W.B. & Martin C.E. (1948), Sexual Behavior in the Human Male, Philadelphia, W.B. Saunders Company.

Kinsey A.C., Pomeroy W.B., Martin C.E. & Gebhard P.H. (1953), Sexual Behavior in the Human Female, Philadelphia, W.B. Saunders Company.

Sundet J.M., Kvalem I.L., Magnus P. & Bakketeig L.S. (1988), Prevalence of risk-prone sexual behaviour in the general population of Norway, in Fleming A.F. et al. (eds), The Global Impact of AIDS, N.Y., Alan R. Liss Inc.

Zetterberg H. (1969), Om sexuallivet i Sverige (On the sexual life in Sweden), Stockholm, SOU.

Annexes

Appendix: English version of the questionnaire of the Norwegian sexual behaviour study

Everyone answers question 1 to 13. After question 13 there will be a new instruction telling you how to continue.

1. Sex

( ) Male

( ) Female

2. Year of birth

19( )

3. Marital status

( ) Married

( ) Not married

( ) Divorced

( ) Widow / widower

4. Do you live together with a partner?

( ) No

( ) Yes

5. How many children do you have?

( ) None

( ) Please state the number

6. What kind of education have you completed? (please mark the highest level of education)

…………. (different national educational levels)

7. What kind of occupational training have you completed?

( ) None

( ) Vocational training

( ) Commercial school

( ) University

( ) Other kinds of training

8. What is your present occupational status?

( ) Employed (more than 15 hours / week)

( ) Unemployed

( ) Student

( ) In military service

( ) Living on pension / social security

( ) Housewife

( ) Other

9. If you are employed, what kind of occupation do you have?

……………………………………………………………..

10. What kind of area do you live in?

( ) Rural area

( ) Small community

( ) Large community

( ) Small town

( ) Large town

11. In what county (of Norway) do you live?

……………………………………………………………...

12. Have you ever had intercourse?

( ) No

( ) Yes

13. Have you ever had sexual partners of your own sex?

( ) No

( ) Yes. Please state number of partners

( )

If you answer is "NO" both on questions 12 and 13, you have now completed the questionnaire. Thank you very much for your help!

If your answer is "yes” on either question 12 or 13, or both, please proceed to fill in the questionnaire until the next instruction.

14. At what age did you have your first intercourse?

( ) years

15. Approximately how many sexual partners have you had during your

whole life? (including a possible current spouse / cohabitant). Please state number ( )

16. Have you taken a HIV/AIDS-test?

( ) No

( ) Yes

( ) Don't know

17. If you have answered "yes", have you taken the test in connection with a blood donation?

( ) No

( ) Yes

If you are married or cohabiting, please continue to answer questions 18 to 55.

If you are not married or cohabiting, please continue to answer from question 56.

The following questions are only to be answered if you are married or cohabiting

18. What year did you and your spouse / cohabitant get married / move together?

19 ( )

19. Are your spouse / cohabitant male or female?

( ) Male

( ) Female

20. How old are your current spouse / cohabitant?

( ) years

21. Have you been married before?

( ) No

( ) Yes. Please state number of previous marriages

( )

22. Have you been cohabiting before?

( ) No

( ) Yes. Please state number of previous cohabitants

( )

23. Approximately how many days / year are you away from home because of your work?

( ) days

24. Approximately how many days / year are your spouse / cohabitant away from home because of his / her work?

( ) days

25. How long is it since you and your spouse / cohabitant had intercourse?

( ) less than 1 month

( ) less than 6 months

( ) less than 1 year

( ) more than 1 year

26. How often did you and your spouse / cohabitant have intercourse during the last month?

( ) several times / day. Please state the number

( )

( ) daily

( ) 5-6 times a week

( ) 3-4 times a week

( ) 1-2 times a week

( ) once every fortnight

( ) more seldom

( ) never

27. How often is this compared with your usual frequency during the last 12 months?

( ) more often

( ) about the same

( ) more seldom

28. Was a condom used as a protection during your last intercourse?

( ) No

( ) Yes

29. Did you practise oral sex during your last intercourse?

( ) No

( ) Yes.

Were you the one which had the partner's penis in your mouth? (this part of the question is relevant only for men)

( ) No

( ) Yes

( ) We both had the partner's penis in our mouth

30. Did you practise anal sex during your last intercourse?

( ) No

( ) Yes.

Were you the one which had the partner's penis in your rectum? (this part of the question is relevant only for men)

( ) No

( ) Yes

( ) We both had the partner's penis in our rectum

31. Have your spouse / cohabitant been HIV/AIDS-tested?

( ) No

( ) Yes

( ) Don't know

32. Approximately how many sexual partners did you have during the last 3 years before you married / moved together with your current partner?

( ) No

Please state the number of partners

( )

33. Have your ever had another sexual partner after you started the relationship with your current spouse / cohabitant?

( ) No

( ) Yes. Please state the number of partners

( )

If you have answered "NO" on question 33, you have now completed this questionnaire. Thank you very much for your help!

If you have answered "YES" on question 33, please continue

34. When did you last have intercourse with someone else than your current spouse / cohabitant?

( ) less than 1 month

( ) less than 6 months

( ) less than 1 year

( ) more than 1 year

35. How many times during the last month have you had intercourse with someone else than your current spouse / cohabitant?

( ) none

( ) once

( ) 2 times

( ) 3-4 times

( ) 5-10 times

( ) 11-20 times

( ) 21-30 times

( ) more than 30 times.

Please state the approximate number

( )

36. Were your last sexual partner (except current spouse / cohabitant) male or female?

( ) Male

( ) Female

37. How old were your last sexual partner? (except current spouse / cohabitant). Please state / estimate the age in years.

( ) years

38. Were your last sexual partner (except your current spouse / cohabitant) married or a cohabitant?

( ) No

( ) Yes

( ) Don't know

39. Was your last sexual partner a prostitute?

( ) No

( ) Yes

40. Were your last sexual partner a IV drug addict?

( ) No

( ) Yes

( ) Don’t know

41. How long did you and your last sexual partner (except your current spouse / cohabitant) know each other before your first intercourse?

( ) less than 1 week

( ) 1-4 weeks

( ) 1-5 months

( ) more than 6 months

42. For how long after your first intercourse did you and your last sexual partner (except current spouse / cohabitant) continue to meet each other?

( ) less than 1 week

( ) 1-4 weeks

( ) 1-5 months

( ) more than 6 months

( ) we are still meeting each other

43. Where did you meet your last sexual partner?

( ) at my residence

( ) during a travel in Norway

( ) abroad (please state which country) ………………………….

44. Was he / she a foreigner?

( ) No

( ) Yes (please state the nationality) …………………………….

45. Was a condom used as a protection during your last intercourse with someone else than your current spouse / cohabitant?

( ) No

( ) Yes

46. Did you practise oral sex during last intercourse? (with the exception of your current spouse / cohabitant)

( ) No

( ) Yes

Were you the one which had the partner's penis in your mouth? (this part of the question is relevant only for men)

( ) No

( ) Yes

( ) We both had the partner's penis in our mouth

47. Did you practise anal sex during your last intercourse? (with the exception of your current spouse / cohabitant)

( ) No

( ) Yes.

Were you the one which had the partner's penis in your rectum? (this part of the question is only relevant for men)

( ) No

( ) Yes

( ) We both had the partner's penis in the rectum

48. Were your last partner HIV/AIDS-tested?

( ) No

( ) Yes

( ) Don't know

49. Have you had anal sex with any sexual partner (except current spouse / cohabitant) during the last 3 years?

( ) No

( ) Yes. Please state the number of partners

( )

50. Have you had anal sex with any sexual partner (except current spouse / cohabitant) during the last 12 months?

( ) No

( ) Yes. Please state the number of partners

( )

51. What are the total number of sexual partners you have had during the last 3 years? (except current spouse / cohabitant)

( ) None

Please state the number

( )

52. What are the total number of sexual partners you have had during the last 12 months? (except current spouse / cohabitant)

( ) None

Please state the number

( )

53. What are the total number of sexual partners you have had during the last month? (except current spouse / cohabitant)

( ) None

Please state the number

( )

54. Have you had sexual partners of your own sex during the last 3 years?

( ) No

( ) Yes. Please state the number

( )

55. Have you had sexual partners of your own sex during the last 12 months?

( ) No

( ) Yes. Please state the number

( )

You have now completed the questionnaire. Thank you very much for your help!

The following questions are only to be answered if you are not married or cohabiting

56. How long is it since you last had intercourse?

( ) less than 1 month

( ) less than 6 months

( ) less than 1 year

( ) more than 1 year

57. How many times during the last month have you had intercourse?

( ) none

( ) once

( ) 2 times

( ) 3-4 times

( ) 5-10 times

( ) 11-20 times

( ) 21-30 times

( ) more than 30 times. Please state the approximate number ( )

58. Were your last sexual partner male or female?

( ) Male

( ) Female

59. How old were your last sexual partner?

Please state / estimate the age in years

( ) years

60. Were your last sexual partner married or a cohabitant?

( ) No

( ) Yes

( ) Don't know

61. Were your last sexual partner a prostitute?

( ) No

( ) Yes

62. Were your last sexual partner a drug addict?

( ) No

( ) Yes

( ) Don't know

63. How long had you and your last sexual partner know each other before your first intercourse?

( ) less than 1 week

( ) 1-4 weeks

( ) 1-5 months

( ) more than 6 months

64. How long after your first intercourse did you and your last sexual partner continue to meet each other?

( ) less than 1 week

( ) 1-4 weeks

( ) 1-5 months

( ) more than 6 months

( ) we are still meeting each other

65. Where did you meet your last sexual partner?

( ) at my residence

( ) during a travel in Norway

( ) abroad (please state which country)

……………………………………………………………

66. Was he / she a foreigner?

( ) No

( ) Yes (please state nationality)

…………………………………………………………….

67. Was a condom used as a protection during your last intercourse?

( ) No

( ) Yes

68. Did you practise oral sex during your last intercourse?

( ) No

( ) Yes.

Were you the one which had the partner's penis in your mouth? (this part of the question is only relevant for men)

( ) No

( ) Yes

( ) We both had the partner's penis in the mouth

69. Did you practise anal sex during the last intercourse?

( ) No

( ) Yes.

Were you the one which had the partner's penis in your rectum? (this part of the question is only relevant for men)

( ) No

( ) Yes

( ) We both had the partner's penis in the rectum

70. Were your last sexual partner HIV/AIDS-tested?

( ) No

( ) Yes

( ) Don't know

71. Did you have anal sex with any sexual partner during the last 3 years?

( ) No

( ) Yes. Please state the number of partners

( )

72. Did you have anal sex with any sexual partner during the last 12 months?

( ) No

( ) Yes. Please state the number of partners

( )

73. What are the total number of sexual partners you have had during the last 3 years?

( ) None

( ) Please state the number

( )

74. What are the total number of sexual partners you have had during the last 12 months?

( ) None

( ) Please state the number

( )

75. What are the total number of sexual partners you have had during the last month?

( ) None

( ) Please state the number

( )

76. Have you had sexual partners of your own sex during the last 3 years?

( ) No

( ) Yes. Please state the number

( )

77. Have you had sexual partners of your own sex during the last 12 months?

( ) No

( ) Yes. Please state the number

( )

You have now completed this questionnaire. Thank you very much for your help!

Author(s)

Department of Epidemiology, National Institute of Public Health, Oslo, Norway.

Department of Epidemiology, National Institute of Public Health, Oslo, Norway.

Department of Epidemiology, National Institute of Public Health, Oslo, Norway.

Department of Epidemiology, National Institute of Public Health, Oslo, Norway.

© Presses de l’Université Saint-Louis, 1990

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