Liesbeth Claassen

Using family history information to promote healthy lifestyles and prevent diseases; a discussion of the evidence.

BackgroundA family history, reflecting genetic susceptibility as well as shared environmental and behavioral factors, is an important risk factor for common chronic multifactorial diseases such as cardiovascular diseases, type 2 diabetes and many cancers.DiscussionThe purpose of the present paper is to discuss the evidence for the use of family history as a tool for primary prevention of common chronic diseases, in particular for tailored interventions aimed at promoting healthy lifestyles. The following questions are addressed: (1) What is the value of family history information as a determinant of personal disease risk?; (2)How can family history information be used to motivate at-risk individuals to adopt and maintain healthy lifestyles in order to prevent disease?; and (3) What additional studies are needed to assess the potential value of family history information as a tool to promote a healthy lifestyle?SummaryIn addition to risk assessment, family history information can be used to personalize health messages, which are potentially more effective in promoting healthy lifestyles than standardized health messages. More research is needed on the evidence for the effectiveness of such a tool.

Perceived risk and representations of cardiovascular disease and preventive behaviour in people diagnosed with familial hypercholesterolemia a cross-sectional questionnaire study

Perceived risk and representations of cardiovascular disease (CVD), and preventive behaviour of people diagnosed with Familial Hypercholesterolemia by DNA testing (N = 81) were assessed. In general, participants perceived their own CVD risk as being relatively low. While participants reported almost optimal medication adherence (99%), only 49 per cent reported following recommendations concerning diet and physical activity. Family history of CVD was associated with both risk perception and the adoption of a healthy lifestyle. In their communications with FH-screened positives, health professionals should be aware that people may underestimate CVD risk, and should stress how behaviour change can reduce the risk.

Impact of Communicating Familial Risk of Diabetes on Illness Perceptions and Self-Reported Behavioral Outcomes A randomized controlled trial

OBJECTIVE To assess the potential effectiveness of communicating familial risk of diabetes on illness perceptions and self-reported behavioral 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 with individuals 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, perceived greater control over preventing diabetes (P < 0.05), and reported having eaten more healthily (P = 0.01) after 3 months. Behavioral 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 behavior, there was some evidence to suggest it increases healthy behavior.

Public attitudes towards genetic testing revisited: comparing opinions between 2002 and 2010

Ten years after the Human Genome Project, medicine is still waiting for many of the promised benefits, and experts have tempered their high expectations. Public opinion on genetic testing has generally been favourable but is this still the case? The aim of this study is to compare public experiences, beliefs and expectations concerning genetic testing over the years (2002 vs 2010). A cross-sectional questionnaire survey was conducted using the Dutch Health Care Consumer Panel in 2002 and 2010. Responses to questions in identical wording were compared. In 2002 and 2010, 817 (63%) and 978 (70%) members responded, respectively. Awareness and reported use of genetic tests remained stable over time. In 2010, more respondents expected genetic testing to become more widely applied, believed that knowledge about the genetic background of disease helps people live longer, and that testing should be promoted more intensively. In 2010, they were also more interested in their own genetic make-up. On the one hand, the concern that a dichotomy would emerge between people with ‘good genes’ and ‘bad genes’ was higher. On the other hand, respondents thought that insurance companies would be less likely to demand a genetic test in order to calculate health insurance premiums. In conclusion, the results suggest that in 8 years, expectations of benefits and potential use of genetic testing have been raised among the public, resulting in more positive opinions. Worries on inequity remain, although worries about premium differentiation by insurance companies have decreased.

Fatalistic responses to different types of genetic risk information: exploring the role of self-malleability

Providing people with genetic risk information may induce a sense of fatalism, the belief that little can be done to reduce the risk. We postulated that fatalism is a function of health risk information and individual differences in self-perception. DNA-based risk information was hypothesised to generate more fatalism than risk information based on family history or non-genetic risk information. Moreover, people who view themselves as more rather than less able to change self-attributes were hypothesised to respond least fatalistically. Factor analyses in separate samples were used to construct a five-item ‘Malleability of self’ measure. Predictive validity of the measure was tested using a within-subjects analogue design. Participants responded to three scenario vignettes in which they were informed of an increased risk of cardiovascular disease (CVD). In Scenario 1, risk was ascertained by DNA testing, family history and cholesterol testing; in Scenario 2, it was ascertained by family history and cholesterol testing; in Scenario 3, risk was ascertained by cholesterol testing alone. Scenario 1 was associated with least perceived control over cholesterol level and CVD risk. People who viewed themselves as more able to change self-attributes experienced more control in all three scenarios.

Being at risk for cardiovascular disease: Perceptions and preventive behavior in people with and without a known genetic predisposition

This study compares and explains differences in perceptions of cardiovascular disease (CVD) risk and preventive behaviors in people with and without a known genetic predisposition to CVD. A cross-sectional study using two samples was performed. The first sample (genetic predisposition; n = 51) consisted of individuals recently diagnosed with familial hypercholesterolemia (FH) through DNA testing. The second sample (no genetic predisposition; n = 49) was recruited among patients with CVD-risk profiles based on family history of CVD, cholesterol levels, and blood pressure, registered at general practices. Participants filled out a postal questionnaire asking about their perceived risk, causal attributions (i.e. genetic and lifestyle), and about perceived efficacy and adoption of preventive behavior (i.e. medication adherence and adoption of a healthy diet and being sufficiently active). Perceived comparative risk, genetic attributions of CVD, and perceived efficacy of medication were higher in the “genetic predisposition” sample than in the “no genetic predisposition” sample. The samples did not differ on lifestyle attributions, efficacy of a healthy lifestyle, or preventive behavior. Individual differences in perceived risk, genetic attributions, perceived efficacy of medication, and adoption of a healthy lifestyle were best explained by family history of CVD. Our findings suggest that in people diagnosed with a single gene disorder characterized by a family disease history such as FH, family disease history may be more important than DNA information in explaining perceptions of and responses to risk.

Health responses to a new high-voltage power line route: design of a quasi-experimental prospective field study in the Netherlands

BackgroundNew high-voltage power transmission lines will be introduced due to increasing demand for reliable and renewable energy supplies. Some residents associate non-specific health complaints with exposure to electromagnetic fields from nearby power lines. This study protocol describes the design and rationale of a prospective study investigating whether the introduction of a new power line triggers health responses in residents living nearby.Methods/DesignThe study is designed as a quasi-experimental field study with two pretests during the construction of a new power line route, and two posttests after it has been put into operation. Key outcomes are self-reported non-specific somatic and cognitive health complaints, and attribution of these health complaints to a power line. The main determinant is proximity to the new power line route. One member of every household (n = 2379) residing in close proximity (0-500 meters) to the overhead parts of a new power line route in the Netherlands is invited to participate, as well as a sample of household members (n = 2382) residing farther away (500-2000 meters). Multilevel analysis will be employed to test whether an increase in key outcome measures is related to proximity to the line. Longitudinal structural equation models will be applied to test to what extent health responses are mediated by psychosocial health mechanisms and moderated by negative oriented personality traits.DiscussionThis is the first study to investigate health responses to a new power line route in a prospective manner. The results will provide theoretical insight into psychosocial mechanisms operating during the introduction of an environmental health risk, and may offer suggestions to policymakers and other stakeholders for minimizing adverse health responses when introducing new high-voltage power lines.

Symptom reporting after the introduction of a new high-voltage power line: A prospective field study

BACKGROUND There is public concern about the potential health effects of exposure to extremely low frequency electromagnetic fields (ELF-EMF) of high-voltage power lines (HVPLs). Some residents living near HVPLs believe ELF-EMF might cause non-specific health complaints. OBJECTIVES The present study is the first to prospectively investigate whether self-reported health complaints and causal beliefs increase after the construction of a new power line. METHODS We used a quasi-experimental design with two pretests before and two posttests after a new HVPL was put into operation. Residents living near (0-300m, n=229; 300-500m, n=489) and farther away (500-2000m, n=536) participated in the study. Linear mixed models were fitted to test whether symptom reports and beliefs that power lines caused health complaints increased more in residents living close to the new line compared to residents living farther away. RESULTS A significantly (p<.05) larger increase from baseline in symptom reports and causal beliefs was found in residents living within 300m from the new power line when compared to residents living farther away. While symptom reports did not differ at baseline, the belief that a power line could cause these symptoms was at baseline already stronger for residents living close compared to residents living farther away. CONCLUSIONS We found a negative impact of a new HVPL on health perceptions of nearby residents, even before the line was put into operation.

Nocebo responses to high-voltage power lines: Evidence from a prospective field study.

BACKGROUND Experimental studies suggest that nocebo responses might occur after exposure to equipment emitting electromagnetic fields such as high voltage power lines (HVPLs) or mobile phone base stations. OBJECTIVES The present study investigates to what extent health responses to a new HVPL can be explained by beliefs of residents regarding the health effects of HVPLs. METHODS We used a quasi-experimental prospective field study design with two pretests during the construction of a new HVPL, and two posttests after it has been put into operation. Residents living near (0-300 m, n=229; 300-500 m, n=489) and farther away (500-2000 m, n=536) filled out questionnaires about their health and their beliefs about the negative health effects of power lines. Longitudinal mediation models were applied to investigate to what extent these beliefs could explain a change in reported symptoms after the new line was put into operation. RESULTS Significant (p<.01) indirect effects were found for proximity on the increase in reported cognitive (R(2)=0.41) and somatic (R(2)=0.79) symptoms after the power line was put into operation through an increase in the belief that power lines causes health effects. The direct effects of proximity on an increase in reported symptoms were not significant. CONCLUSIONS Our findings suggest that increases in reported health complaints after a new HVPL has been put into operation can be explained by nocebo mechanisms. Future field studies are needed to know whether our findings extend to other environmental health issues in a community.

People’s responses to risks of electromagnetic fields and trust in government policy: the role of perceived risk, benefits and control

Trust in government policy affects the way people perceive and handle risks. In our study, we investigated the relationships between trust in government policy regarding electromagnetic fields (EMF), perceived risk and perceived benefits of public and personal EMF sources, perceived control over exposure to EMF and responses to the possible EMF health risk (e.g. protest against placement of mobile phone base stations or power lines, or taking own measures against EMF exposure). Previous research indicated that perceived risk and benefits mediate the relationship between trust and people’s risk responses. Additionally, we suggest that perceived control over EMF exposure affects the relation between trust in government policy and perceived risk, and, consequently, the risk responses. We performed a survey among the Dutch population (n = 1009), which contained questions about risk responses to EMF, perceived risk and benefits of several EMF sources, trust in government policy and perceived control over EMF exposure. Comparing public EMF sources, i.e. power lines and mobile phone base stations, to personal EMF sources, i.e. microwave ovens and cordless and mobile phones, we tested our hypotheses. Variations in risk responses to both public and personal EMF sources were mainly explained by risk perception. In addition, perceived risk partially mediated the relationship between trust in government policy and risk responses. For public sources, perceived control over exposure weakened the negative relationship between trust and perceived risk. We conclude that, especially in people with low perceived control, a lack of trust in government policy may enhance perceptions of health risks, thereby increasing their inclination for risk responses.