Descomposición de salarios de (Machado & Mata, 2005)

The final analysis was a multiple linear regression, entering variables in blocks as discussed in Chapter 4. This analysis was used to explore whether there were any differences in the correlates of intention to have a genetic test.

Table 5.5 Linear regression of intention onto psychological and demographic

Regression of intent onto psychological variables

Men Women

Step Final Beta R2 Adjusted

R2

R2 change (sign)

Final Beta R2 Adjusted

R2 R2 change (sign) 1 Attitude Subjective Norm 0.379*** 0.227** 0.601 0.593 0.334*** 0.174** 0.487 0.482 2 Perceived Behavioural Control ■0.161* 0.606 0.595 0.005ns 0.019 0.489 0.482 0.002ns 3 Anticipated Negative

Affect if decided not to have test Anticipated Negative Affect if positive result Anticipated Negative Affect if negative result Anticipated Positive Affect if negative result ■0.061 ■0.002 0.002 0.085 0.619 0.593 0.013ns 0.071 ■0.01 -0.023 0.021 0.506 0.491 0.017ns 4 Perceived Benefits Perceived Barriers Perceived Susceptibility Perceived Severity 0.151* 0.198* ■0.015 ■0.129* 0.676 0.639 0.057** 0.055 0.204*** 0.063 ■0.055 0.534 0.513 0.029** 5 Uncertainty 0.24** 0.711 0.675 0.035*** 0.208*** 0.56 0.538 0.026*** 6 Cancer Worry Anticipated Reassurance GT compared with FOB Anticipated Reassurance GT compared with colonoscopy 0.054 0.037 ■0.085 0.716 0.67 0.005ns ■0.077 ■0.108* 0.079 0.572 0.545 0.012ns 7 age N° children Risk group 0.03 -0.004 0.074 0.712 0.665 0.005ns -0.009 0.092* -0.153*** 0.599 0.567 0.027** ***p<0.001 **p<0.01 *p<0.05

Chapter 5:Gender and Genetic Testing

The linear regression models which emerged explained more of the variance in intention in males (Adj = 0.665) than in females (Adj = 0.567). Both models were highly significant. Examinations of the residuals and Cook’s distance indicated that there were no cases that had undue influence on the regression equation. In the final equation, the standardised regression coefficients (P) for attitudes was 0.379 and for women 0.334. At the same step, the beta values for subjective normative beliefs were 0.227 and 0.174 respectively. Both variables were positively related to intention. At the second block perceived behavioural control explained no additional variance in intent in women. In men there was a significant negative standardised regression coefficient when perceived behavioural control was entered into the equation and in the final analysis. This indicates that this is a suppressor variable, and has a higher correlation with the residual than the predicted value of intent. Examination of the univariate correlation co-efficient between perceived behavioural control and intent confirmed that this was a non­ significant correlation in men (r=0.013 p=0.89). Anticipated affect did not explain additional variance in either the men or the women when entered at the third step of the analysis and was not significant in the final equation.

Variables composing the health belief model (benefits, barriers, susceptibility and severity) were entered at the next step. In women the only variable to emerge in the final equation with a significant beta value was perceived barriers (P = 0.204), this block explained a significant additional 2.9% of the variance in intent. In men the standardised regression coefficients for perceived benefits (p = 0.151), perceived barriers(P = 0.198) and perceived severity (p = -0.129) were all significant in the final equation; the block explained an additional 5.7% of the variance in intent. An examination of the correlation of perceived severity with intent showed that contrary to that predicted and the correlation in the whole sample, lower perceived severity was associated with higher intent (r=-0.083) in men.

Attitude towards medical uncertainty, entered at the 5^^ step, remained significant in the final equation for both men and women, explaining an additional 3.5% of the variance in intent in men and 2.6% of the variance in intent in women. This was the last variable to add significantly to the variance in intent for men. In women anticipated re-assurance of genetic testing compared with FOB testing was significant in the final equation (p =-

Chapter 5:Gender and Genetic Testing

0.108), but the block as a whole was not. The final block entered for women did explain significant additional variance in intent (2.7%), with number of children and clinical risk group having significant beta values at this stage (P = 0.092 and p =-0.153 respectively). Clinical risk, although just positively correlated with intent, here is negatively correlated; again indicating that this is acting as a suppressor variable.

In the final equation to predict intent in men, the order of the standardised regression coefficients (which is an indicator of the likely importance) was:- attitudes, attitude towards medical uncertainty, subjective norms, perceived barriers, perceived behavioural control (suppressor), perceived benefits and perceived severity. In women the order was slightly different:- attitudes, attitude towards medical uncertainty, perceived barriers, subjective norms, clinical risk (suppressor), anticipated reassurance of genetic testing compared to FOB testing and number of children.

The unstandardised regression co-efficients were then compared between men and women. These analyses indicated that there was no significant difference between men and women in the relative strengths of the predictors.

5.6 Discussion

The exploration of gender issues with respect to genetic testing for colon cancer has revealed some important differences between men and women. The first finding was that, there were no significant differences between men and women in the main correlates of intent (as found in Chapter 4) to have a genetic test - attitudes, subjective norms, perceived benefits, perceived barriers and attitude towards uncertainty. Although this cannot be interpreted as indicating that intent was formed in the same way in both men and women, it does show that on these important correlates there is no difference. The issue of the process by which intent may be formed will be explored in more detail below.

Despite the lack of difference on these measures, there were significant differences on other factors. Compared with men, women did anticipate more negative emotional reactions whether the test result was positive or negative. They also anticipated more positive emotions if the test was negative, showing that they were at no more than

Chapter 5:Gender and Genetic Testing

population risk of colon cancer. Women also reported that they currently worry more about cancer, and they indicated a higher score on the anxiety sub-scale of the HADS than men did. Taken together these findings indicate that women are currently experiencing, and are anticipating more emotional responses to the prospect of both being at risk of cancer (cancer worry) and receiving a genetic test result. This indicates that the finding that men anticipate different emotional reactions to the prospect of genetic testing for breast cancer (Struewing et al 1995b) may not just be a fimction of their different risk status with respect to developing breast cancer, but may be due in part to a more fundamental gender difference.

Gender differences with respect to anticipated emotional reactions to genetic testing were explored in more detail. The first question participants were asked was their anticipated reaction if they decided not to have a genetic test. The only differences between men and women was that women anticipated feeling more relieved, but also more worried. The higher levels of anticipated relief in women is an interesting finding, as it may indicate that at one level they may actually be happier then men if they did not actually discover their genetic makeup. The high levels of anticipated worry in women, are likely to be for the same reasons as their higher current cancer worry, these two variables are highly correlated (r=0.37, p<0.001).

When considering their anticipated reaction if a genetic test was positive (showing that they carried a gene leading to susceptibility to colon cancer), women anticipated feeling more depressed, worried and angry than men did. The higher anticipated depression in women compared to men is similar to that found by Struewing et al (1995b). In that study 46.2% of women and 16.7% of men anticipated depression if they knew they carried a gene mutation, whereas in this study 44.1% of women, and 28.2% of men anticipated feeling fairly or extremely depressed. Men in this study anticipate less depression than the women in this study, but whereas the women in this study anticipate similar levels of depression as those in Struewing’s study, men in this study anticipate considerably higher levels of depression than those anticipating testing for breast cancer gene carrier status. In an analogous finding looking at the related concepts of anxiety and worry, women in this study anticipate experiencing more worry and in Struewing’s study anticipate more anxiety than the men do, but levels of worry in men in this study are considerably higher than levels of anxiety in men in Struewing’s study. These

Chapter 5:Gender and Genetic Testing

associations indicate that there are genuine differences between the two genders in terms of their anticipated responses to genetic testing for cancer, but in Struewing’s study the difference was in part due to the differential impact of the gene mutation on the men’s risk of developing breast cancer. The higher levels of anticipated anger if the test is positive in women again indicate that the decision to have a genetic test may be associated with mixed feelings for women more than men.

In response to a negative (low risk) genetic test result women believe that they will still worry more than men do. The mean overall levels of anticipated worry in both groups are quite low, so worrying after receiving a low risk result is unlikely to prove problematic to either men or women.

These analyses have shown that there are differences between men and women on measures related to genetic testing for colon cancer, and that men and women anticipate different emotional reactions. This difference in anticipation of emotional responses may not translate into actual differences in response, as it may be difficult for people to imagine how they will feel. The differences in anticipated affect between the genders may not be due to actual differences in emotional response that would emerge at testing, but rather one gender may be more accurate in anticipating how they will feel. In addition it has frequently been reported that women are more willing to report their emotional state than men, this may mean that men do anticipate similar reactions to women, but are unwilling to report them. These issues will need to be examined in a longitudinal analysis of the emotional reactions to testing.

Despite all these results, the unresolved issue is whether, although there is no difference in intent between men and women, is there a difference in the correlates of intention?

For both men and women attitudes and attitude towards uncertainty are the most important correlates of intent. Other than these factors, in men, subjective norms, perceived benefits, perceived barriers and perceived severity were associated with intent. Contrary to the established theory, perceived severity of colon cancer was inversely related to intent in men. It may be that men are more willing to consider genetic testing if they perceive colon cancer to be less severe. Perhaps those men who perceive colon cancer to be more severe would rather not have a genetic test because

Chapter 5:Gender and Genetic Testing

then they would need to confront the disease. The importance of social-cognition variables in the regression equation predicting intent means that all these factors are likely to be important in making their decision, rather than the more limited list which emerged when the entire population was considered together. In men these variables together explain a large proportion of the variation in intent.

In women a different picture emerges, with only perceived barriers and subjective norms emerging as additional social- cognition factors. Other significant correlates of intent are anticipated reassurance of genetic testing compared to FOB testing and the number of children a woman has. Women are considering factors outside of those usually considered in social cognition models when deciding whether to have a genetic test. Screening and the likely benefits for children are additional factors that explain variation in intent. In women these variables also explain less variation in intent than it was possible to explain in the male population. These findings raise important questions, not only about which other factors may explain women’s intent to have genetic testing for colon cancer, but also whether for other behaviours social cognition variables explain a greater proportion of intent and behaviour in men than in women.

When the regression models were compared the moderated regression analyses would appear to indicate that there are no differences that would suggest that men and women consider different factors when forming their intention regarding genetic testing for colon cancer.

5.7 Conclusion and Next Study

The previous studies have established the correlates of intent to have a genetic test for colon cancer, and factors associated with this decision in asymptomatic individuals (Chapter 4) and the different nature of the decision in men and women (this chapter). The next study will examine the stability of these models over time, and examine whether it is possible to determine the causal direction of the theory of reasoned action in the case of genetic testing for colon cancer.

Chapter 6: One Year Follow-up

Chapter 6