The challenge of unravelling family resemblance related to illness behaviour.

Background: Efforts to promote health or prevent disease may conflict with patients’ habits at home. Irrespective of the national setting, families are important social contexts in which illness occurs and resolves. Family members resemble each other in their illness behaviour, even across generations. To optimize the effect of health promotion strategies the challenge is to unravel family resemblances related to health. The underlying mechanism of family resemblance has not been studied before. The aim of this study is to evaluate whether family resemblance is caused by having determinants in common as a result of (i) shared circumstances, (ii) socialization, or (iii) similarity in background characteristics. Methods Data: were used from the second Dutch national survey of general practice. In 2001 all consultations were recorded (electronic medical data) in 104 general practices in The Netherlands. We selected for analysis 41 431 families with children up to 18 years of age and formulated eight hypotheses related to the three abovementioned mechanisms. Data were analysed using multilevel analysis with three levels: individual, family, and practice. Family resemblance in contact frequencies with general practice was set as the dependent variable. Results: In relation to health, mothers still are key figures, but the fathers’ role is also important. All in all, we were able to show that having determinants of frequencies of contact in common through socialization and shared circumstances can explain similarities in contact frequencies within families, although not all hypotheses could be confirmed. Regarding shared circumstances family resemblance was best explained by conjoint contacts of mothers with children. Related to socialization resemblance was best explained by spending more time together. Conclusions: The concepts of shared circumstances, socialization and homogeneous background characteristics can serve as a framework for a family case history. A family case history may shed a different light on strategies for health promotion. In countries with free access to specialists, general practitioners may have fewer opportunities to gain insight into family patterns which may lead to less effective treatment strategies. (aut.ref.