ارتباط میان درگیری خانواده و سلامت روحی در میان بزرگسالان میانسال در ژاپن

• Mental health is negatively associated with family caregiving.• Family caregiving is more stressful than poverty and unemployment.• Caring for mothers-in-laws amplifies female caregivers' distress.It is widely known that the mental health of middle-aged adults is closely associated with involvement in family caregiving, as well as socioeconomic and sociodemographic factors. However, most studies focusing on mental health in adulthood have not fully controlled for time-invariant factors. Moreover, the relative importance of factors associated with mental health has remained largely understudied. In the current study, we employed fixed-effects regression models to examine the manner in which middle-aged adults' mental health is associated with involvement in family caregiving and socioeconomic and sociodemographic factors, after controlling for time-invariant factors. Using data from a population-based, six-year panel survey in Japan, we focused on the evolution of the Kessler 6 (K6) scores (range: 0–24) for 26,522 individuals (12,646 men and 13,876 women) aged 50–59 years in 2005 over the subsequent five years. We found that men and women experienced 0.54 (95% CI 0.44–0.64) and 0.57 (95% CI 0.49–0.66) unit increases in their K6 scores, respectively, when they became involved in care provision for any family member. This magnitude of distress exceeded that associated with any socioeconomic or sociodemographic factor examined in this study. Furthermore, we found that care provision to a mother-in-law had an additional, negative association with mental health for female caregivers, as opposed to men. These findings suggest that more panel studies are needed to examine the correlates of mental health among middle-aged adults.

It is widely known that family care provision is closely associated with mental health in adulthood. Previous studies have found that family members' involvement in nursing care tends to adversely affect their psychological well-being (e.g., Amirkhanyan and Wolf, 2006, Bookwala, 2009, Ennis and Bunting, 2003 and Sugihara et al., 2004). An aging population and declining fertility are likely to increase the risks of psychological distress associated with individuals' provision of care to their elderly parents and parents-in-law, unless public nursing services and/or support for family caregiving are sufficiently provided. Middle-aged adults also contend with many socioeconomic and sociodemographic factors that could negatively affect their mental health. Among others, household income, employment status, marital status, co-residence with family members, and participation in social activities have been found to closely correlate with psychological distress (e.g., Butterworth et al., 2009, Kaplan et al., 2008, Lorant et al., 2007 and Sareen et al., 2011). In recent years, an increasing number of studies on mental health in adulthood have utilized panel, rather than cross-sectional data. Even with the use of longitudinal information, however, most studies have relied heavily on the analysis of the data over two time points (baseline and follow-up years) without fully controlling for time-invariant confounders, especially unobserved ones. This probably led to biased estimation results. In the current study, we sought to validate previous findings on the correlates of mental health in adulthood by removing the effects of time-invariant factors. There are two types of time-invariant factors: observed and unobserved. Observed time-invariant variables include gender and educational background (as far as the analysis focuses on middle-aged adults), which are usually observed from a survey. Unobserved time-invariant factors are not observable from a survey. In the current study, personality traits, intelligence quotient (IQ), and other inherent individual attributes, which did not appear on the dataset of the survey, were regarded as potential time-invariant factors. We employed fixed-effects regression models to examine the manner in which the mental health of middle-aged adults was associated with involvement in family caregiving, as well as socioeconomic and sociodemographic factors, after controlling for both observed and unobserved time-invariant factors. To this end, we utilized data from a six-year nationwide survey in Japan. It included 26,522 individuals (12,646 men and 13,876 women) aged between 50 and 59 years in 2005; the study tracked developments in the participants' mental health, involvement in family caregiving, and socioeconomic and sociodemographic factors over the subsequent five years.

This study demonstrated that the mental health of middle-aged Japanese adults is negatively associated with involvement in family caregiving. The study used data obtained from a nationwide, population-based, six-year survey, with time-invariant factors controlled for. Psychological distress was more significantly associated with family caregiving than any socioeconomic and sociodemographic factor that the respondents were exposed to in midlife. Care provision to a mother-in-law had an additional, negative association with mental health for female caregivers, as opposed to men. These findings suggest that more panel studies are needed to examine the correlates of mental health among middle-aged adults.