Between- and Within-Couple Concordance for Health Behaviors Among Japanese Older Married Couples: Examining the Moderating Role of Working Time.

Background: Although previous studies report spousal concordance for health behaviors at between-couple levels, concordance at within-couple levels remains unconfirmed. To clarify the behavioral mechanisms of spousal concordance for health behaviors among older couples at both levels, it is necessary to examine the moderators (effect modifiers) of spousal concordance. This study examined (1) whether spousal concordance for dietary variety, exercise behavior, and TV viewing behavior was observed at both the between-couple and the within-couple levels and (2) whether this spousal concordance was moderated by working time among older Japanese couples.

Method: This study analyzed data obtained from a questionnaire-based, three-wave longitudinal survey (baseline, 1-year follow-up, 3-year follow-up) among 210 Japanese older couples. Each spouse's dietary variety, exercise time, TV viewing time, the couple's working time, and demographic factors were investigated by multi-level analyses.

Results: One spouse's dietary variety and TV viewing time, but not exercise time, were significantly associated with the other spouse's corresponding behaviors at both levels. The regressions of the wife's TV viewing time on the husband's TV viewing time were moderated by working time at the within-couple level; the regressive effects of wife's TV viewing time on husband's TV viewing time were more relevant as working time was lower.

Conclusion: This study found that spousal concordance for dietary variety and TV viewing was observed at within-couple and between-couple levels among older Japanese couples. In addition, shorter working time partly moderates the wife's influence on the husband's TV viewing among older couples at the within-couple level.