Based on 3420 pairs of middle-aged and older Chinese couples of a national representative ageing cohort, we found that almost one third of study participants developed at least one chronic disease over 4 years of follow-up. Moreover. After adjustment for baseline confounders, husbands whose wives had a chronic disease at baseline had an increased risk of chronic disease development over time, but this risk was not significant for wives conversely.
Our study contributes to the literature of spousal health concordance by investigating the development of chronic disease over four years conditional on spousal chronic diseases, stratified by gender and adjusted for covariates of both couples. Few studies previously had investigated spousal concordance in chronic disease development, which mainly focused on concurrent association of health status [6, 10, 36] and health behaviors [6, 37, 38]. Our finding of the spouse-dependent onset of chronic diseases was consistent with recent studies about the spousal concordance in obesity development [28], changes in biomarker and subjective well-being [31], and mental health and self-reported health trajectories [29]. We extended the evidence in a Chinese community-based setting, with lifestyle data directly collected from both couples, and health status defined by multiple chronic disease status that were more common in older adults [39].
In view of the inconsistent findings on gender variation [29, 30], we further advanced the literature by investigating spousal health concordance gender-specifically. In general, previous studies of married couples have shown that the health benefits of marriage and the health detriments of marital dissolution differ by gender [6, 40, 41]. Our study showed that the influence of the spouse’s health on the other was only evident in husbands but not wives. This finding was in line with previous findings that husbands but not wives experienced declines in self-reported health after their spouse’s onset of chronic diseases [29], and husbands’ but not wives’ obesity development was associated with their spouses’ diabetes status [28]. Yet our finding was different from other findings that wives were more likely to be impacted by their spouses’ chronic status psychologically and physically compared to husbands [30, 32].
Possible reasons for our gender-specific finding may result from as follows. Wives paly a predominant role of caregiver in the family under greater socialisation factors [42], which is practically true under the traditional Chinese gendered social role, namely ‘breadwinning men and homemaking women’ [39, 43]. Husbands may be more dependent on their spouses regarding lifestyles and health management, such that husbands whose spouse with chronic diseases may suffer more chronic disease risk than their female counterparts. Moreover, as suggested by literature men tend to maintain intimate relationships with fewer people and receive social support primarily from their spouses [44, 45], while women are more likely to have broader social support other than that of their spouses [44, 46]. Chinese retired women are more socially-engaged than their male counterparts, actively participating in social- and physical- group activities, such as square-dancing [47]. While wives’ lifestyle can be also influenced by their peers [47], their husbands’ health status may be mostly influenced by their wives’ lifestyle and lifestyle-related chronic disease status [48, 49].
These gender-specific association of chronic disease development was largely independent of sociodemographic and lifestyle factors included. Possible reasons for these non-significant adjustments may result from limited variations in our participants’ retirement status, education and exercise levels that may be underpowered to detect a statistically-significant adjustment for the given sample size. Moreover, variations in lifestyles were further reduced as we only included baseline measures, which were likely to change as participants aged and be influenced by the older couples’ health status [50].
Given the greater frequency of chronic diseases and increased dependency that occur in later life [51], our finding shows that for chronic disease prevention in China, spousal concordance in the development of chronic disease could inform prevention advice that shifts the focus from optimising prevention efforts for the individual patient alone to optimising couple-based interventions. Moreover, spousal concordance could also be used for earlier detection of chronic diseases to make people recognise and respond to health problems earlier and be more willing to undergo treatment [15, 52]. Our finding of gender specificity also indicates that the diagnosis of a chronic disease in one spouse may warrant increased surveillance in his/her partner, because a husband whose wife has a chronic disease may obtain benefit from such increased surveillance.
With a prospective dyadic design stratified by gender, our study explored gender specificity in the spousal concordance of chronic disease development over 4 years based on a population-representative sample of middle-aged and older Chinese couples. Several limitations warrant notice. First, our study used baseline lifestyles to obtain their clear temporal relationship with the incidence of chronic disease during the follow-up period, which overlooked lifestyle changes over time. Further studies are needed to better understand the dynamics between lifestyle and chronic disease development with age. Second, we defined chronic disease status in a purely qualitative manner (i.e. at least one of nine chronic diseases) rather than by quantity or specified disease. Metabolic and cardiovascular diseases may be more susceptible to influence from lifestyle than other chronic diseases, and multiple chronic diseases and single chronic diseases should be discussed separately. Thus, further investigation of specified disease type and quantity is needed. In addition, our study primarily used self-reported measures and lacked an eating behaviour measure. To reduce information bias and recall bias, eating behaviour measures, objective measures such as biomarkers, and physician verification of chronic disease status would improve the accuracy of the findings.