Impact of communicating familial risk of diabetes on illness perceptions and self-reported behavioural outcomes: A randomized controlled trial

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1 Diabetes Care Publish Ahead of Print, published online January 8, 2009 Impact of communicating familial risk of diabetes Impact of communicating familial risk of diabetes on illness perceptions and self-reported behavioural outcomes: A randomized controlled trial Miranda Pijl, MSc 1,2 ; Danielle R.M. Timmermans, PhD 1,2 ; Liesbeth Claassen, MSc 1,2 ; A. Cecile J.W. Janssens, PhD 3 ; Giel Nijpels, MD, PhD 1,4 ; Jacqueline M. Dekker, PhD 2 ; Theresa M. Marteau, PhD 5 ; Lidewij Henneman, PhD 1,2 1 Department of Public and Occupational Health, VU University Medical Center, Amsterdam, The Netherlands 2 EMGO Institute, VU University Medical Center, Amsterdam, The Netherlands 3 Department of Public Health, Erasmus University Medical Center, Rotterdam, The Netherlands 4 Department of General Practice, VU University Medical Center, Amsterdam, The Netherlands 5 Psychology and Genetics Research Group, King s College, London, United Kingdom Corresponding author: Miranda Pijl. m.pijl@vumc.nl Additional information for this article can be found in an online appendix at Clinical trial reg. no. ISRCTN , Submitted 9 June 2008 and accepted 30 December This is an uncopyedited electronic version of an article accepted for publication in Diabetes Care. The American Diabetes Association, publisher of Diabetes Care, is not responsible for any errors or omissions in this version of the manuscript or any version derived from it by third parties. The definitive publisherauthenticated version will be available in a future issue of Diabetes Care in print and online at Copyright American Diabetes Association, Inc., 2009

2 Objective: To assess the potential effectiveness of communicating familial risk of diabetes on illness perceptions and self-reported behavioural outcomes. Research design and methods: Individuals with a family history of diabetes were randomized to receive risk information based on familial and general risk factors (n=59) or general risk factors alone (n=59). Outcomes were assessed using questionnaires at baseline, 1-week, and 3-months. Results: Compared to those receiving general risk information, those receiving familial risk information perceived heredity to be a more important cause of diabetes (p<0.01) at 1-week follow-up, and perceived greater control over preventing diabetes (p<0.05) and reported having eaten more healthily (p=0.01) after three months. Behavioural intentions did not differ between the groups. Conclusions: Communicating familial risk increased personal control and thus did not result in fatalism. Although the intervention did not influence intentions to change behaviour, there was some evidence to suggest it increases healthy behaviour. Trial registered as: ISRCTN

3 P revention of type 2 diabetes is especially important for people with a positive family history of diabetes, since this is one of the strongest risk factors (1). Individuals with a positive family history have difficulty understanding the causes of diabetes (2), underestimate their risk (3), and are less likely than those without a family history to believe that diabetes is preventable (4). Family history information might be used to raise awareness of individual risk and thereby positively influence preventive behaviours to reduce the risk (5). However, the belief that diabetes is determined mainly by genetic predisposition may prevent individuals from engaging in risk-reducing behaviour as a result of fatalism (2, 6, 7). The aim of this study was to assess the potential effectiveness of communicating familial risk of diabetes on illness perceptions and selfreported behavioural outcomes. RESEARCH DESIGN AND METHODS In 2007, a randomized trial was conducted among individuals at risk for diabetes who had participated in a diabetes screening program five years earlier (8). People (aged 75 years) with self-reported family history ( 1 first-degree relative) and highest diabetes risk scores on a symptom risk questionnaire (8) were invited (n=233). Exclusion criteria were: being diagnosed with diabetes and not understanding Dutch. The VU University Medical Center Ethical Committee approved the protocol. Participants were randomized by computerized and concealed block randomization and received risk information based on familial risk and general risk factors, or based on general risk factors alone during a personal consultation with a researcher (MP) at a Diabetes Research Centre. Five-year diabetes risk was estimated using a validated Diabetes Risk Test (9) and communicated to each participant using a graphical bar chart. In the intervention group alone, a family tree was constructed, familial risk was discussed, and the multifactorial character of diabetes was explained, indicating the nature of the risk in the bar chart. All participants received information on diabetes, including preventive measures. Sample size calculation was performed on intention to change behaviour (diet, physical activity, diabetes testing). With a mean difference of 2.00 in the intervention group compared to 1.00 in the control group, for 80% power (SD 1.6, P<0.05), 41 individuals per group were needed. Outcome measures were assessed at baseline, 1-weekand 3-month follow-up, including behavioural intentions, self-reported behaviours, illness perceptions (causal beliefs, perceived consequences of diabetes, personal control over preventing diabetes), perceived susceptibility to diabetes, diabetes risk worry, and psychological well-being (for detailed description see table1). The effect of the intervention on outcome measures was investigated using analysis of covariance (ANCOVA) for follow-up measurements with baseline measures as covariates. RESULTS Of 233 participants invited, 187 (80%) responded to the invitation, and 118 (51%) agreed to participate and were randomized: n=59 in each group (see Figure A1 available in the online appendix at Ten individuals did not receive the consultation and were excluded. Participants were Dutch Caucasian. Mean age at baseline was 67.1 years (SD 5.3); 43% were men; 5% completed higher vocational training or university; mean body mass index (kg/m 2 ) was 28.3 (SD 4.3); 52% and 31% reported having high blood pressure and high cholesterol, respectively. The median number of first-degree relatives was one (range 1-7). At baseline there were no 3

4 significant differences between the groups for participant characteristics. For all variables used in our analyses, 10% and 18% of the data were missing at 1- week- and 3-month follow-up, respectively. There were no differences at baseline in outcome variables between participants with missing data at follow-up and those for whom complete data were obtained. The intervention had no effect on behavioural intentions (table1). People who had received the intervention reported having eaten more healthily than those in the control group in the previous three months (p=0.01). Being more physically active showed a marginal significant difference (p=0.08). There was a significant increase in perceiving heredity as a cause of diabetes in the intervention group at 1-week (p<0.01) compared to the control group. Perceived consequences of diabetes increased in the control group and slightly decreased in the intervention group at 1-week (p=0.02). The intervention group perceived greater personal control over preventing diabetes than the control group at 3-month follow-up (p=0.03), an effect that was of borderline significance after one week (p=0.06). Communicating familial risk information did not affect perceived susceptibility, worry, or psychological well-being. CONCLUSIONS Our study shows that an intervention in which familial risk of diabetes is communicated did not result in fatalism, and actually led to increased perceived control over preventing diabetes. While at one week both groups had increased their intentions to change their health behaviour, participants receiving familial risk information reported having eaten more healthily three months after the consultation. A possible explanation might be that familial risk information, being more novel and more personally relevant, was better retained. In line with a recent crosssectional study (10), our study suggests that informing people of their risk of diabetes attributable to their family history could increase their engagement in risk-reducing behaviours. In addition, our results and others (11) show that discussing familial diabetes risk does not adversely affect psychological well-being. Although an earlier theory-based behavioural intervention aimed at increasing physical activity of people at familial risk of diabetes was no more effective than information given in an advice leaflet (12), it is promising that some positive results of communicating familial risk in our minimal design were found. Both groups received a personal consultation differing only in the type of risk information (familial versus general risk information) that was given. This study, though small, is one of the first to examine this issue. Since measures of behaviour and personal control were based on single items and the measures of behaviour were self-reported, the effects of the intervention must be considered tentative. Additionally, participants were recruited from a previous diabetes screening study, thereby limiting generalization. More robust trials are needed to confirm these findings, using objective measures of health-related behaviour in larger samples. Additionally, more research is needed in the area of risk communication and fatalistic attitudes, particularly with the introduction of more genetic information available in addition to family history. ACKNOWLEDGEMENTS This study was supported by the Centre for Medical Systems Biology (CMSB) in the framework of the Netherlands Genomics Initiative (NGI). 4

5 REFERENCES 1. Valdez R, Yoon PW, Liu T, Khoury MJ: Family history and prevalence of diabetes in the U.S. population: the 6-year results from the National Health and Nutrition Examination Survey ( ). Diabetes Care 30: , Pijl M, Henneman L, Claassen L, Detmar SB, Nijpels G, Timmermans DRM: Family history of diabetes: exploring perceptions of individuals at risk. Prev Chronic Dis in press 3. Adriaanse MC, Snoek FJ, Dekker JM, Spijkerman AM, Nijpels G, van der Ploeg HM, Heine RJ: Perceived risk for type 2 diabetes in participants in a stepwise population-screening programme. Diabetic Med 20: , Harwell TS, Dettori N, Flook BN, Priest L, Williamson DF, Helgerson SD, Gohdes D: Preventing type 2 diabetes: perceptions about risk and prevention in a population-based sample of adults > or =45 years of age. Diabetes Care 24: , Yoon PW, Scheuner MT, Khoury MJ: Research priorities for evaluating family history in the prevention of common chronic diseases. Am J Prev Med 24: , Marteau TM, Lerman C: Genetic risk and behavioural change. BMJ 322: , Shiloh S, Rashuk-Rosenthal D, Benyamini Y Illness causal attributions: An exploratory study of their structure and associations with other illness cognitions and perceptions of control. J Behav Med 25: Spijkerman AM, Adriaanse MC, Dekker JM, Nijpels G, Stehouwer CD, Bouter LM, Heine RJ: Diabetic patients detected by population-based stepwise screening already have a diabetic cardiovascular risk profile. Diabetes Care 25: , Alssema M, Feskens EJM, Bakker SJL, Gansevoort RT, Boer JMA, Heine RJ, Nijpels G, Stehouwer CDA, Kraan M van der, Dekker JM: Finnish questionnaire reasonably good predictor of the incidence of diabetes in the Netherlands. Ned Tijdschr Geneeskd 152: , Qureshi N, Kai J: Informing patients of familial diabetes mellitus risk: how do they respond? A cross-sectional survey. BMC Health Serv Res 8:37, Pierce M, Ridout D, Harding D, Keen H, Bradley C: More good than harm: a randomised controlled trial of the effect of education about familial risk of diabetes on psychological outcomes. Br J Gen Pract 50: , Kinmonth AL, Wareham NJ, Hardeman W, Sutton S, Prevost AT, Fanshawe T, Williams KM, Ekelund U, Spiegelhalter D, Griffin SJ: Efficacy of a theory-based behavioural intervention to increase physical activity in an at-risk group in primary care (ProActive UK): a randomised trial. Lancet 371:41-48, Moss-Morris R, Weinman JA, Petrie K, Horne R, Cameron L, Buick D: The revised illness perception questionnaire (IPQ-R). Psychology and Health 17:1-16, Watson D, Clark LA, Tellegen A: Development and validation of brief measures of positive and negative affect: the PANAS scales. J.Pers.Soc.Psychol. 54: , van der Bij AK, de Weerd S, Cikot RJ, Steegers EA, Braspenning JC: Validation of the dutch short form of the state scale of the Spielberger State-Trait Anxiety Inventory: considerations for usage in screening outcomes. Community Genet. 6:84-87,

6 Table 1. Outcomes of the ANCOVA analyses at baseline, 1-week- and 3-month follow-up * Intervention group Control group baseline 1-week 3-month baseline 1-week 3-month p-value p-value mean (sd) mean (sd) mean (sd) mean (sd) mean (sd) mean (sd) baseline and baseline and N = 54 N = 53 N = 46 N = 53 N = 48 N = 47 1-week 3-month Behavioural intentions (scale 1 7) healthy diet 2.9 (2.0) 4.3 (2.4) (1.8) 4.3 (2.3) physical activity 3.3 (2.2) 4.1 (2.2) (1.9) 4.2 (2.2) test for diabetes 3.7 (2.3) 4.1 (2.3) (2.4) 4.4 (2.1) Health behaviour (scale 1 7) healthy diet 3.6 (2.2) (1.7) 3.9 (1.9) (2.2) -.01 physical activity 3.9 (2.1) (1.8) 3.6 (1.9) (2.2) -.08 Causal beliefs (scale 1 5) heredity 4.0 (0.8) 4.4 (0.6) 4.0 (0.9) 3.7 (1.0) 4.0 (0.7) 3.8 (0.8) lifestyle 3.9 (0.8) 4.6 (0.6) 4.1 (0.9) 3.7 (0.9) 4.3 (0.8) 3.8 (0.9) Perceived consequences (scale 1 5) # 2.9 (0.7) 2.8 (0.7) 2.7 (0.7) 2.7 (0.8) 3.0 (0.6) 3.0 (0.6) Personal control (scale 1 5) ** 3.7 (0.8) 4.2 (0.6) 4.0 (0.6) 3.8 (1.0) 3.9 (0.8) 3.7 (0.8) Perceived susceptibility (scale 1 7) 3.3 (1.3) 4.0 (1.2) 3.2 (1.3) 3.1 (1.3) 3.6 (1.3) 3.3 (1.4) Diabetes risk worry (scale 1 7) 2.7 (1.4) 3.0 (1.5) 2.4 (1.4) 2.7 (1.7) 3.2 (1.8) 2.8 (1.6) Psychological well-being (scale 1 5) PANAS positive 3.1 (0.7) 3.2 (0.7) 3.2 (0.7) 3.0 (0.7) 3.1 (0.6) 3.1 (0.8) PANAS negative 1.7 (0.6) 1.6 (0.6) 1.6 (0.5) 1.8 (0.6) 1.7 (0.7) 1.7 (0.6) STAI 1.9 (0.6) 1.9 (0.6) 1.9 (0.6) 2.0 (0.6) 1.9 (0.6) 1.8 (0.5) * Unadjusted analyses are presented, since predefined variables did not affect the outcome of the trial. Baseline measures were unavailable for one person in the control group. P-values based on analyses of covariance (ANCOVA). Intention to eat more healthily (at least 2 pieces of fruit and 200 grams of vegetables a day and low saturated fat nutrition) or to increase physical activity (at least 30 minutes of moderate activity at least 5 days a week) within the following month were assessed (completely applicable to me (1) completely inapplicable to me (7)). Participants were asked to indicate whether they had changed their behaviour in the previous 3 months (completely disagree (1) completely agree (7)). Participants were asked to indicate the extent to which they believed that a given cause could be a cause of diabetes (definitely not (1) definitely (5)), based on the Revised Illness Perception Questionnaire (IPQ-R) (13). A heredity sub-scale was comprised of two items: heredity, diabetes runs in the family and predisposition (α =.62). A lifestyle sub-scale was comprised of three items: unhealthy diet or eating habit, lack of physical activity, and being overweight (α =.75). 6

7 # Perceived consequences was assessed using a 6-item scale (α =.86), based on the IPQ-R (13). ** Personal control over developing diabetes was assessed using a single item There is a lot I can do to prevent getting diabetes (completely disagree (1) completely agree (5)), based on the IPQ-R (13). Perceived susceptibility was assessed using the mean score of three items (α =.88): How likely do you think it is that you will get diabetes within the next 5 years? (very likely (1) very unlikely (7)), Based on your feelings, how big is the chance of you getting diabetes within the next 5 years (very low (1) very high (7)), and In your opinion, what is the chance of you getting diabetes compared to an average man/woman your age? (a lot lower (1) a lot higher (7)). Participants were asked to indicate their feelings when thinking about their chance of getting diabetes using a 7-point rating scale for two worry items (fear, worry) (α =.86). The Positive (α =.88) and Negative Affect scale (α =.84) (PANAS) (14) was used to assess general mood states, and the Dutch short form of the State-Trait Anxiety Inventory (STAI) (15) (α =.87) was used to assess anxiety at the time of assessment. 7

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