Perception of Offspring Risk for Type 2 Diabetes Among Patients With Type 2 Diabetes and Their Adult Offspring

Subjects in the present study comprised 164 pairs of type 2 diabetic patients (aged <75 years) receiving treatment at a general hospital's diabetes clinic located in the suburbs of Tokyo, Japan, and their offspring (aged ≥20 but <50 years with no diabetes or glucose intolerance). After obtaining written informed consent to participate in the study, the patient and offspring completed an anonymous questionnaire separately, with a unique ID to identify each parent/offspring pair. The present study was conducted from October to December 2005. The ethical committee of the University of Tokyo approved all study protocols.

The perception of offspring risk for type 2 diabetes was assessed among both patients and offspring as “the likelihood of your offspring/you developing diabetes in comparison to the general Japanese population.” The likelihood was evaluated from three perspectives: risk due to current lifestyle, risk due to family history, and overall risk. Response categories for each ranged from 1 (“very likely”) to 5 (“very unlikely”). Results were tabulated; then, interperspective comparison in each group and pairwise comparison in each parent/offspring pair for risk perception were conducted.

Backgrounds of subjects were as follows: male ratio in patients and offspring 54.3 and 40.2% (P = 0.01, χ² test), respectively; mean ± SD age 64.0 ± 6.5 and 33.4 ± 7.6 years; mean BMI 24.0 ± 3.6 and 22.9 ± 3.8 kg/m² (P < 0.01, t test); mean educational years 12.6 ± 2.6 and 14.3 ± 1.9 years; and 58.5% of pairs were living together. Among patients, 23.2% were receiving insulin therapy, and 26.2% reported diabetes-related complications.

About 40% of patients stated that their offspring were more likely to develop diabetes from the perspective of lifestyle habits and about one-half from the perspective of family history and an overall view. No interperspective differences in risk perception were seen. Among offspring, about one-half recognized that they were at higher risk for diabetes compared with the general population from the perspective of lifestyle habits and 63.5% from an overall view. A higher risk from the perspective of family history was recognized by 74% of offspring, representing significantly higher risk perception compared with the other two perspectives (vs. lifestyle, P < 0.001; vs. overall view, P < 0.01; Steel-Dwass test for multiple comparisons) (Table 1).

Pairwise comparison showed that offsprings’ perception of their risk related to family history and their overall risk was significantly higher than their parents’ (P < 0.001, Wilcoxon's sign-rank sum test), but no difference was found in perception of lifestyle-related risk.

In the present study, perceptions of risk for diabetes among offspring were higher compared with previous research involving both patients and offspring (7–9). Two possible causes may contribute to this higher risk perception. First, optimistic biases about risk perception and cross-cultural variations might exist between current and previous research. Many studies have described people underestimating risks of unfavorable events, representing optimistic bias (10). In addition, some research has shown cultural variations in optimism, with Western people more optimistic than Oriental people (11). These factors were related to lower risk perception in previous Western research. However, a previous study in Korea showed much lower risk perception than that seen in the present research (12), suggesting that the present subjects still display relatively high risk perception even after considering possible pessimistic trends in Asian countries. Secondly, an increasing awareness of diabetes may have affected this result. The present results are comparable with figures obtained from patients educated about genetic risks (13). In Japan, studies on genetic predispositions for diabetes have been conducted as part of national projects since 2000 (4,14), and the mass media has been actively reporting lifestyle diseases such as metabolic syndrome. The present results could indicate that these national projects have successfully raised awareness of diabetes among the Japanese population.

This study also clarified marked differences in risk perception between diabetic parents and offspring from both quantitative and qualitative perspectives. Offspring displayed greater recognition of diabetes risks than parents, contradicting a perception by health care professionals that offspring view diabetes as something that does not concern them (15). More interestingly, interperspective differences were found between patients and offspring as qualitative differences in risk perception. Patients perceived diabetes risks for offspring as equally low for lifestyle-related and hereditary risk, whereas offspring perceive hereditary risk as much higher than lifestyle-related risk. This may reflect self-serving thinking among both patients and offspring. Parents would feel guilty about passing susceptibility for a disease to their children (16), thus probably downplaying hereditary risk to reduce feelings of guilt about genetic predisposition toward diabetes. Conversely, offspring downplay their own responsibility by emphasizing hereditary risks more than lifestyle-related risks. These findings have some implications: if patients are to inform their offspring about disease risks more effectively, their own potential feelings of guilt need to be tackled first. If offspring are to take a more active stance toward prevention, realization of the importance of their own actions is particularly important in terms of risk.

Whether these findings are specific to Japanese diabetic patients and their offspring remains unclear, due to a limitation of this study: not containing a control group of nondiabetic adults. Further research investigating risk perceptions in the Japanese general population is needed to confirm and clarify these findings.