Introduction

The work–family literature on “work–family conflict” has expanded steadily over the past few decades, along with an increase in dual-earner couples, single-parent families, and caregiving needs of elderly people.[1–4] Work–family conflict is generally defined as “a form of inter-role conflict in which the role pressures from the work and family domains are mutually incompatible in some respect.”[5] Importantly, there is growing evidence linking work–family conflict and various health outcomes such as psychiatric disorders,[6] mental disorders,[7] depression,[8, 9] psychological distress,[10] mental health,[11] health behaviors (e.g., smoking, unhealthy eating habits, and heavy alcohol consumption),[12] drinking behaviors,[8, 13] physical and mental functioning,[14] smoking,[15] sleep problems,[16] sleep medication,[17] and poor self-rated health.[18–21]

However, it is still unclear if there is a gender difference in the health effects of work–family conflict. In most societies, the household responsibilities of women persist despite more women entering and playing a greater role in the workforce.[22] The demands of household duties and responsibilities often increase work–family conflicts for women.[3] In line with this, a Swedish representative longitudinal study reported that women experienced work–family conflict slightly more often than men, and an increased risk for poor self-rated health existed only among women.[19] On the other hand, a cross-sectional study on self-rated health in the United Kingdom showed that work–family conflict associated with reporting poor self-rated health was equally observed among men and women.[18] Another cross-sectional study with municipal employees in Finland also identified that work-to-family and family-to-work conflicts were associated with poor self-rated health among both men and women.[20]

One of the salient features of Japanese society is the male breadwinner model: men work outside the home to provide an income for their family, while women stay at home as housewife, providing care for children and the elderly. This model persists to this day in Japanese society.[23] For example, the time spent by Japanese men on housework (less than 1 hour per week) has not changed substantially over the past two decades[24] despite an increase in women’s social participation in the workforce. Arguably then, Japanese working women may experience more conflicts than men, as the demands of their work role conflict with the demands of their family role.

Furthermore, a recent cross-sectional study among Brazilian civil servants have shown that the association between work–family conflict and self-rated health differed by educational level only among women.[21] While few studies have focused on how socioeconomic conditions affect work–family conflict and self-rated health,[21] the association between work–family conflict and self-rated health may differ by socioeconomic conditions. Thus, the impacts of work–family conflict on self-rated health would also differ by household income.

There is some evidence available on work–family conflict in Japan;[9–12, 14, 16] in these studies, Japanese workers with high work–family conflict reported poorer self-rated health. However, most of this evidence was derived from limited samples such as civil servants of local government,[11, 12, 14, 16] regularly employed information technology engineers,[9] and dual-earner couples in a metropolitan area.[10] No studies have been conducted for self-rated health with general community residents under various working conditions.

The objective of this study was to investigate the associations of work–family conflict and self-rated health among community residents in Japan. We aimed to answer the following specific research questions:

1. Are there any associations between work–family conflict and self-rated health among Japanese working men and women?
2. Are the associations noted above modified by socioeconomic conditions (i.e., household income level)?

Methods

Results

Table 1 shows sex-specific proportions of work–family conflict and demographic characteristics, stratified by self-rated health. A total of 1,065 (13.9%) men and 1,249 (17.7%) women rated their health as poor: gender difference in poor self-rated health (p <0.001). The proportion of high WF conflict was 36.6% for men and 28.4% for women, while those of high FW conflict were 36.4% for men and 56.8% for women. The proportions of men and women with high WF conflict and high FW conflict were 19.8% and 22.0%, respectively. High work–family conflict was more prevalent among those with poor self-rated health than those with good self-rated health. Of the 8 items of work–family conflict, the proportion of men who responded “often” to the question (iii), “Your work involves a lot of travel away from home,” was higher than that of women in the highest work–family conflict group. By contrast, the proportion of women who responded “often” to the question (vii), “Family activities stop you getting the amount of sleep you need to do your job well,” and (viii) “Family obligations reduce the time you need to relax or be yourself,” were higher than those of men (see S1 Table). Furthermore, men reporting poor self-rated health were more likely to be younger and had more domestic roles (married with children under 15 years old), whereas women reporting poor self-rated health were more likely to be less educated, to be regular workers, and to have fewer domestic roles. Both men and women who reported having lower social support and medical histories of hypertension, diabetes mellitus, and hypercholesterolemia were more likely to report poor self-rated health.

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Table 1. Sex specific work-family conflict and demographic characteristics according to self-rated health.

https://doi.org/10.1371/journal.pone.0169903.t001

Table 2 shows gender-specific adjusted odds ratios (ORs) for poor self-rated health associated with work–family conflict. We identified statistically significant associations between work–family conflict and poor self-rated health among both men and women. High WF conflict, as well as high FW conflict, was associated with poor self-rated health among both men and women. The adjusted ORs (95% confidence interval [CI]) for poor self-rated health in the high WF conflict and high FW conflict group were 2.46 (95% CI, 2.04–2.97) for men and 3.54 (95% CI 2.92–4.30) for women, with reference to the low WF conflict and low FW conflict group. The association between work–family conflict and poor self-rated health among women was relatively stronger than that among men (interaction for p = 0.02).

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Table 2. Odds ratios (OR) for poor self-rated health associated with work–family conflict, separately by gender.

https://doi.org/10.1371/journal.pone.0169903.t002

The subgroup analysis by household income showed that the association between work–family conflict and self-rated health was modified by household equivalent income only among women in Table 3 (interaction for p = 0.01). The adjusted ORs (95% CI) for poor self-rated health of the women who reported high WF conflict and high FW conflict with reference to those reporting low WF conflict and low FW conflict, were 4.63 (95% CI, 3.42–6.27) in the lowest household income group, 3.49 (95% CI, (2.45–4.99) in the intermediate household income group, and 2.45 (95% CI, 1.72–3.50) in the highest household income group. For men, no modification by household income was observed.

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Table 3. Odds ratios (OR) for poor self-rated health associated with work–family conflict, by household equivalent income.

https://doi.org/10.1371/journal.pone.0169903.t003

Discussion

The present study shows that higher WF conflict and higher FW conflict are associated with increased odds of having poor self-rated health among both men and women. The work–family conflict represented by a combination of WF conflict and FW conflict also showed a statistically significant association with self-rated health, which was more evident among women than men. Subgroup analysis by household income indicated that the associations between work–family conflict and self-rated health were modified only among women; a stronger association between work–family conflict and self-rated health was observed in the lower household income group among women, while no significant differences were identified among men.

Our results are in line with previous research showing harmful effects of higher work–family conflict on poor self-rated health.[18–21] There have been a limited number of studies on the health effects of work–family conflict among Japanese populations. One cross-sectional study indicated that higher work–family conflicts were associated with an increased probability of having poor self-rated mental health among both men and women.[11] Another study also showed that higher work–family conflict was associated with poorer psychological health.[9,10] It is suggested that increased inter-role conflict in which the role pressures from work and family domains can reduce time for sleep or leisure activities, and thus increase psychological stress, consequently affect physical health conditions.[3]

As we noted previously, the evidence for a gender difference in the effects of work–family conflict on self-rated health remains mixed.[18–21] In this study, we observed a significant gender difference in the effect of work–family conflict on self-rated health: the relatively stronger association between work–family conflict and self-rated health among women. While we did not examine the mechanisms underlying this gender difference, we did explore gender differences in the nature of the work–family conflict and found substantive gender-specific responses to the questions related to work–family conflict in our data; the proportion of men who responded “often” to the question about work-to-family conflict due to a lot of business travel was higher than that of women. By contrast, the proportion of women who responded “often” to the question about family-to-work conflict due to family activities and family obligations were higher than those of men (see S1 Table). Given the materially imbalanced household duties of men and women, women will arguably find it more challenging to juggle work- and family-related demands.[22] Thus, the dissimilarity in the nature of work–family conflict underlying normalized gendered roles in Japan may help explain the gender-based differences in the health effects of work–family conflict.

Contrary to our hypothesis, we found similar proportions of men and women who reported having high work–family conflict. However, we found that men had higher WF conflict, while women had higher FW conflict. Strong gendered social roles such as the male breadwinner model may affect these differences. Women tend to give priority to homemaker and maternal roles and thus may be more likely to feel FW conflict, while men tend to emphasize responsibilities in their breadwinner role and thus are more likely to experience WF conflict.

Furthermore, we showed higher effects of work–family conflict on self-rated health in the low income group, compared with those in the intermediate or high income group among women. One possible explanation is that women with low household incomes might bear much of the responsibility for their family due to the economic constrains. For example, the nationally representative surveys of Japan have shown that an unhealthy nutrient intake was associated with lower household expenditure.[30] In addition, despite a universal health care insurance system in Japan, people with low incomes are likely to have poorer access to outpatient care and more serious health conditions than people with high incomes.[31] Given Japan’s gendered social roles, there might be some possibility that Japanese women with low incomes prioritize needs of their families such as food and health issues. As a result, women perceived high work–family conflict in the low income group seem to have reported poorer health status. Further studies are needed to clarify how household income modifies the associations between work–family conflicts and self-rated health by taking into account food, medical access, and other residual confounders.

To our knowledge, this is the first study to examine the association between work–family conflict and self-rated health in the general Japanese population. However, several limitations should also be noted. First, we cannot exclude the possibility of reverse causation because of the cross-sectional design. To reduce this possibility, we excluded people who had medical histories of cancer, cardiovascular disease, stroke, and depression to avoid the possible effects of initial health status. Supplementary analysis conducted after further excluding people who had medical histories of hypertension, diabetes mellitus, and hypercholesterolemia did not change our conclusion. In addition, supplementary analysis limited items of work–family conflicts (see S2 Table) showed similar results to those in Table 2, although we obtained somewhat attenuated results among women. Second, we did not have information on work-related factors (e.g., working hours and job demands) that are considered relevant to work-to-family conflict,[3] and on the content or time spent on child caring and household work. It is likely that these work- and family-related factors vary by gender and income, and thus future studies are needed that take such work-related factors into account. Third, as both exposure and outcome variables were assessed by self-reported questionnaires, spurious correlations could have occurred if respondents answered questions consistently but not accurately. Although self-rated health has proved to be an independent predictor of mortality, over and above other health status indicators and other relevant covariates known to predict mortality,[25, 26] future prospective studies are needed to test the robustness of our study by using not subjective outcomes such as mobility or mortality. Furthermore, the possibility of missing bias cannot be ruled out due to self-reported assessment of both exposure and outcome. Excluded participants were likely to be older, have less household income compared to our study population but no significant difference in self-rated health. In our study, missing of work–family conflicts seemed to be non-differential to self-rated health, which may have attenuated the present results. Finally, we must generalize our results cautiously to other populations, because our sample was restricted to residents of one public center area in Japan and the response rate was not high (57%).

Conclusions

In this study, we showed that higher work–family conflict was associated with poor self-rated health among both men and women in the general Japanese population. These associations were stronger among women than among men, and in particular, among economically disadvantaged women. The present findings may help advance understanding of gender differences in the associations between work–family conflict and poor self-rated health.

Supporting information

Acknowledgments

The authors thank all staff members in Saku areas and in the central office for their extensive efforts to conduct the baseline survey. Members of the Japan Public Health Center-based Prospective Study for the NEXT generation (JPHC-NEXT Study, principal investigator: S. Tsugane) Group are: S. Tsugane, N. Sawada, M. Iwasaki, T. Shimazu, T. Yamaji, S. Sasazuki, A. Hidaka, and A. Goto, National Cancer Center, Tokyo; H. Iso*, Osaka University, Osaka; K. Yamagishi, University of Tsukuba, Ibaraki; N. Yasuda, Kochi University, Kochi; I. Saito, Ehime University, Ehime; K. Aoyagi, Nagasaki University, Nagasaki; K. Sakata, Iwate Medical University, Iwate; M. Tsukada and K. Kobayashi, Nagano Prefectural Saku Public Health Center, Nagano; Y. Kokubo, National Cerebral and Cardiovascular Center, Osaka; M. Inoue, The University of Tokyo, Tokyo; M. Noda, Saitama Medical University, Saitama; T. Mizoue, National Center for Global Health and Medicine, Tokyo; R. Takachi, Nara Women’s University, Nara; J. Ishihara, Sagami Women’s University, Kanagawa; H. Komatsu, Saku General Hospital, Nagano; K. Nakajima, Asama General Hospital, Nagano; N. Hamajima, Nagoya University, Aichi; T. Sobue, Osaka University, Osaka; S. Akiba, Kagoshima University, Kagoshima; T. Isobe, Keio University, Tokyo; Y. Sato, Tokyo Gakugei University, Tokyo.