Japanese version of the Quality of Relationship Inventory: its reliability and validity among women with recurrent spontaneous abortion.

Until now most of the research on social support has concentrated on general support in relationship to the whole group of people around each individual. In contrast, only a few studies have dealt with individual-specific support (i.e. social support from a particular individual relationship). The Quality of Relationship Inventory (QRI) is a recently developed questionnaire to measure individual-specific social support. We developed the Japanese version by means of back translation and ascertained its reliability and validity among the Japanese women who had had two recurrent spontaneous abortions without known organic etiologies. Factor analysis revealed that the Japanese QRI had a two-factor structure, representing supportive and conflictual aspects of a particular relationship (named Factor-S and Factor-C, respectively). Each factor showed satisfactory reliability with Cronbach's alphas of 0.95 and 0.89. When the QRI scores were compared with the scales from the Social Support Questionnaire, a measure of general social support, the Factor-C of the former with respect to the mother correlated negatively with the Social Support Satisfaction of the latter (r = - 0.40; 95% confidence interval (CI) - 0.64 to - 0.09). Childhood experiences with parents also showed expected correlations with the QRI: care received from the parent before age 16 years strongly predicted Factor-S with that parent (r = 0.50, 95% CI 0.21-0.71 in the case of the mother; r = 0.54, 95% CI 0.27-0.73 in the case of the father). Although we still need to examine the Japanese QRI with different populations, it appears to be a promising measure of individual-specific relationship for the Japanese population.