continuous variables. Secondly, the variables were entered in a forward stepwise multiple logistic regression analysis in the order of descending magnitude of ...
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J Med Screen 1999;6:82–88
Psychosocial predictors of first attendance for organised mammography screening Arja R Aro, Harry J de Koning, Pilvikki Absetz, Marjut Schreck
Health Education Research Unit, Department of Epidemiology and Health Promotion, National Public Health Institute, Helsinki, Finland A R Aro, senior researcher, psychologist P Absetz, psychologist, researcher M Schreck, data manager Department of Public Health, Faculty of Medicine, Erasmus University Rotterdam, The Netherlands A R Aro H J de Koning, associate professor Netherlands Institute for Health Sciences Rotterdam, The Netherlands A R Aro H J de Koning Correspondence to Dr Arja R Aro, Department of Epidemiology and Health Promotion, Health Education Research Unit, National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland. Accepted for publication 8 March 1999
Abstract Objective—To study psychosocial predictors of attendance at an organised breast cancer screening programme. Setting—Finnish screening programme based on personal first round invitations in 1992–94, and with 90% attendance rate. Methods—Attenders (n=946) belonged to a 10% random sample (n=1680 women, age 50, response rate 64%) of the target population (n=16 886), non-attenders (n=641, 38%) came from the whole target population. Predictors were measured one month before the screening invitation. Measures included items for social and behavioural factors, Breast Cancer Susceptibility Scale, Illness Attitude Scale, Health Locus of Control Scale, Anxiety Inventory, and Depression Inventory. Univariate and multivariate logistic regression analyses were used to predict attendance. Results—Those most likely to attend were working, middle income, and averagely educated women, who had not had a mass mammogram recently, but who regularly visited gynaecologists, attended for Pap smear screening, practised breast self examination, and who did not smoke. Low confidence in their own capabilities in breast cancer prevention, overoptimism about the sensitivity of mammography, and perception of breast cancer risk as moderate were also predictive of attendance. Expectation of pain at mammography was predictive of non-attendance. Conclusion—Mammography screening organised as a public health service was well accepted. A recent mammogram, high reliance on self control of breast cancer, and an expectation of pain at mammography deterred attendance at screening. Further information about these factors and health information on screening are needed. (J Med Screen 1999;6:82–88) Keywords: mammography; attendance; psychosocial factors
High quality mammographic screening of women aged 50–74 may significantly reduce breast cancer mortality.1 In Finland screening has been carried out since 1987 as a public health policy, with personal invitations sent to women aged between 50 and 59 every two years. Uptake is around 90%,2 close to the Swedish figures3 and higher than in many other countries with similar services.
Several reports have looked at the diVerences between attenders and non-attenders.4 Only a few studies, however, have used a prospective design in which background characteristics were monitored before the invitation to the first screening round, and participation was verified at the screening registry afterwards. Married, healthy women, interested in their health, especially health check-ups, who perceived their risk of breast cancer to be high and believed in the benefit of screening, were more likely to attend.5–7 Sociodemographic factors—for example, level of education or social class, were not predictive.5–7 Nonattendance may be partly explained by recent mammography elsewhere.3 7 8 It has been suggested that emotional factors, such as anxiety and depression, may aVect attendance,9 but no study has included standardised, prospective measures. This study aimed at determining the influence of psychosocial factors, cognitive factors, health behaviour, and aVective factors on first time attendance at mammography screening. A prospective design was used, in which predictors were measured before invitation and participation was verified from the screening registry. Subjects and methods Subjects comprised a random sample (every 10th woman) of 50 year old Finnish speaking women, invited by a personal invitation from the health authorities to their first mammography screening in Finland in 1992–93, from a target population of 16 886. Data were gathered by a postal questionnaire one month before the screening invitations were sent out; reminders were sent a week after the first mailing. The attendance rate (confirmed later) in the sample was 88% (1479/1680). A total of 946/1479 (64%) attended for screening and responded to the questionnaire—they comprised the attenders study group. The nonattenders comprised 641 (38%) respondents of 1695 non-attenders of the target population (fig 1). Subjects whose questionnaires were returned after the invitations for screening had Target population (n = 16 886) Random sample (n = 1680)
Attenders (n = 1479) Response rate 64% (n = 946)
Figure 1
Non-attenders (n = 1695) Response rate 38% (n = 641)
Flow diagram showing the design of the study.
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Attendance for mammography screening
been sent out, or whose answers were incomplete, were excluded from the study, leaving a total of 871 attenders and 587 non-attenders for analysis. Questionnaires, which had been piloted in a sample of 139 middle aged women participating in mammography screening in southern Finland, covered the following areas: 1 Sociodemographic and social factors: Municipality, marital status, number of household members, number of children, total years of education, profession, income, working status. Social support was measured as the number of friends, frequency of meeting friends, given and received support, and satisfaction with support. 2 Personal history and health: Life events, history of severe illnesses, and experience with breast cancer in a close relative, friend, or acquaintance. 3 Cognitive factors: (a) Knowledge of breast cancer and mammography: Incidence and curability of, and risk by age for breast cancer, possible malignancy of breast lumps, sensitivity of mammography, partly using questions of Fallowfield et al.10 (b) Perceptions: Value of health, risk factors and early warning signs of breast cancer, importance of and confidence in breast self examination, perceived breast cancer risk, confidence in own capabilities in breast cancer prevention, and expectations of pain and discomfort in mammography. (c) Breast cancer beliefs: Beliefs were measured with the Breast Cancer Susceptibility Scale (BCS Scale),10–12 further developed and validated in the random sample of the study to comprise 11 items (range 1–4) on three subscales (perceived susceptibility, severity of breast cancer, and barriers to early detection of breast cancer) derived by maximum likelihood method, varimax rotation. The number of factors was based on eigenvalues >1 and on a scree plot. The BCS Scale had reasonable general reliability13: whole scale 0.72 (subscale reliabilities can be obtained from the authors). (d) Perceptions of controllability of health: Health Locus of Control Scale,14 27 items (range 1–4) with three subscales (chance health outcomes, provider control, and own control) derived in the random sample, general reliability of the whole scale was 0.84. (e) Attitudes towards illness: Illness Attitudes Scale,15 29 items, 27 of which (range 0–4) belong to eight subscales (concern about pain, eVects of symptoms, fear of death, health habits, worry about illness, treatment experience, fear of illness, bodily preoccupation) derived in the random sample. The general reliability of the whole scale was 0.92. 4 Perceived health and health behaviour: Smoking, drinking, exercise, stress, visits to doctor, number of days sick, and diagnosed illnesses, measured according to the annual Finnish Health Behaviour among Adults Study. Questions about the uptake of mam-
mography, Pap smear screening, frequency of breast self examination, and number of visits to the gynaecologist were also asked. 5 AVective factors: (a) Anxiety was measured by the State Trait Anxiety Inventory,16 which contains 20+20 items (range 1–4), and was used as a unidimensional sum score (range 20–80). General reliability in the random sample was 0.96 for the state version, and 0.92 for the trait version. (b) Depression was measured by Beck Depression Inventory,17 a scale with 21 items (range 0–3), which is mostly used as a unidimensional sum score (range 0–63) depicting the severity of depression. The general reliability of the scale in the random sample was 0.91. STATISTICAL METHODS
Levels of education were: low 8 to 11 years, according to the continuous variable years of education classification. The annual total household income was classified as: low $20 000 to $40 000. The reliability of the scales was calculated using the general reliability coeYcient,13 and the construct validity of the multidimensional scales was checked by maximum likelihood factor analysis for the structure. Statistical diVerences between distributions were calculated by the ÷2 test, and between means by two sided t tests, and univariate and multivariate logistic regression analysis with odds ratios for attendance (with 95% confidence limits) was used to study predictors of attendance. For the logistic regression analyses new design variables were formed from the variables not measured by an interval scale. For marital status the reference category was “not married”, for area it was “rural”. For the remaining variables the most prevalent, the correct option, or the recommended practice was taken as the reference category (in brackets) as follows: income and education (middle level); working status (working); visits to gynaecologist (annually); breast self examination (monthly); Pap smear (at least once in the past five years), previous mammography (no); and perceived risk (low). For the three multi-item scale means—of perceived breast cancer susceptibility, concern about pain, and worry about illness—a change of one unit (1 to 2, etc) was used as the basis of calculation. Firstly, univariate logistic regression analysis was performed on all variables significant at the level of p
