Abstract
Marital status is associated with cardiovascular disease (CVD) incidence and overall mortality, yet limited research on this topic in elderly individuals is available. Our aim was to comprehensively assess the impact of marital status and other family factors on CVD incidence and long-term mortality among elderly people.
Data from the Chinese Longitudinal Healthy Longevity Survey (2002/2005/2008–2018) for participants aged ≥60 years were analysed. A cross-sectional study initially examined the correlation between spouses, offspring, living arrangements, and CVD using logistic regression. Subsequently, a retrospective cohort study investigated the long-term associations of these factors with overall mortality via Kaplan–Meier and Cox regression analyses.
The study involved 48 510 subjects (average age: 87 years). The cross-sectional analysis revealed a correlation between living with a spouse and an increased incidence of heart disease (adjusted OR 1.27, 95% CI 1.04–1.55) and cerebrovascular disease/stroke (adjusted OR 1.26, 95% CI 1.11–1.42). According to the retrospective cohort analysis, living with a spouse significantly reduced overall mortality (adjusted HR 0.84, 95% CI 0.80–0.87), irrespective of marital relationship quality. Conversely, living with offspring (adjusted HR 1.12, 95% CI 1.08–1.16), having more children (adjusted Pnonlinearity = 0.427) or cohabitants (adjusted Pnonlinearity < 0.0001) were associated with increased overall mortality.
In the elderly population, being married and living with a spouse were not significantly associated with a decrease in CVD incidence but were associated with a reduction in long-term overall mortality. Living with offspring, having more children, or having a larger family size did not replicate the protective effect but indicated greater overall mortality.
What is already known on this topic
Being married is associated with a decrease in cardiovascular disease (CVD) and overall mortality in the general population.
What this study adds
Among the elderly, living with a spouse was associated with lower long-term mortality rates but not with the occurrence of CVD. Conversely, living with offspring, having more children, or a larger family size did not provide the same protective effect and instead indicated higher overall mortality.
How this study might affect research, practice, or policy
Cohabiting with a spouse might contribute to extending the lifespan of elderly people. For widowed or divorced elderly individuals, remarriage could be beneficial.
Introduction
The aging of populations worldwide has emerged as a critical challenge for healthcare systems and social support structures in both developed and developing countries [1]. This demographic shift underscores the need to address the unique health challenges faced by elderly people, including the increasing prevalence of cardiovascular disease (CVD), and to develop effective strategies for promoting healthy aging [2].
Extensive research has delved into the potential cardiovascular and survival benefits associated with marriage and spousal relationships [3, 4]. A meta-analysis investigating the relationship between marriage and cardiovascular diseases demonstrated a decreased risk of coronary heart disease (CHD) and mortality from CHD and stroke among married individuals in the general population [5]. Similarly, another meta-analysis, drawing from evidence from twenty-one studies involving 7 891 623 individuals, highlighted a significant association between being unmarried and elevated all-cause mortality [3]. However, existing research has focused predominantly on the general population, creating a gap in understanding the impact of marriage on elderly people, particularly the very elderly. Furthermore, previous studies have primarily emphasized the influence of the spouse while overlooking the potential effects of other family members. A debate has arisen regarding whether “living with someone” should replace “being married”, underscoring the need for a comprehensive understanding of marital status and other family factors influencing CVD and overall mortality in later life [6, 7].
Given these gaps and discussions in the literature, our study aimed to comprehensively elucidate the associations between various family factors and the prevalence of cardiovascular outcomes and long-term overall mortality among older adults. We will investigate a wide spectrum of family factors, including marital status, the role of cohabiting partners, the number of offspring ever born, and family size. Through this comprehensive examination, we aim to provide a nuanced understanding of the interplay between marital status and other familial factors and CVD and overall mortality in later life, with significant implications for public health interventions.
Methods
Study design and data availability
We conducted a cross-sectional analysis and retrospective cohort study to investigate the relationships between household factors and CVD and overall mortality, respectively. Data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were utilized, representing the largest sample of oldest-old individuals in China and the first nationally longitudinal survey focusing on determinants of healthy aging [8, 9]. The study incorporated three waves of data from 2002/2005/2008 to 2018. The average attrition rates per wave were 4.67%, 6.24%, and 6.99%, respectively (Fig. S1). The research complied with all relevant national regulations and institutional policies, following the principles outlined in the Helsinki Declaration.
Flow chart of the study population.
Exposure and outcome ascertainment
Exposure variables were collected at baseline in 2002, 2005, and 2008. We assessed information on marital status and satisfaction with the marital relationship using the following questions:
1) Marital status: How would you describe your current marital status?
2) Marital relationship: Are you getting along well with your spouse in this marriage (the quality of the marital relationship)?
Responses to the first question were grouped into five categories: married and cohabiting, married but not cohabiting, divorced, widowed, and never married. In our study, individuals who were married and cohabiting with their spouse were categorized as the exposure group, while the remaining participants were classified as the comparison group. Marital relationship quality was determined based on responses to the second question: “good” indicated a high-quality marriage, while “just so so” or “bad” indicated low to moderate quality.
We obtained information on living arrangements with offspring, the number of children ever born, and family size (the number of cohabitants) using the following questions: (i) Living with the offspring: what is the relationship between you and the person you are currently living with?, (ii) The number of children ever born: how many children have you ever had? and (iii) Family size: how many people live with you (excluding yourself) if you live with family members?
In this cross-sectional study, we comprehensively analysed the relationships between family factors (living arrangements, marital relationship quality, number of children and cohabitants) and the incidence of CVD, including hypertension, heart disease, and cerebrovascular disease or stroke. Those with an average of two measurements of resting blood pressure meeting the diagnostic criteria for hypertension (systolic blood pressure [SBP] ≥ 140 mmHg and/or diastolic blood pressure [DBP] ≥ 90 mmHg) were also identified as hypertensive patients.
In the cohort analysis, we conducted a follow-up study spanning more than 10 years to examine the long-term impact of consistent family factors on overall mortality. Data on deaths were obtained from close family members of deceased participants between data collection waves. Survival time was measured from cohort entry to the year of death or the end of the follow-up period in 2018. A quality assessment of the death data indicated satisfactory reliability [10].
Covariates
All detailed baseline information and covariates used in our analysis are available in the supplementary file. Following prior research on CVD risk factors and mortality predictors [11–14], we included critical covariates such as age, sex, frequency of exercise and social activities, smoking and drinking status, dietary habits, economic status, and chronic illness burden. In the analysis of hypertension, we adjusted for diabetes as a chronic illness covariate; While for heart disease and cerebrovascular disease or stroke analysis, we adjusted for hypertension and diabetes. In the long-term cohort study, chronic illness covariate was the number of major chronic internal diseases, including hypertension, heart disease, cerebrovascular disease or stroke, diabetes, lung diseases (bronchitis, emphysema, pneumonia, and asthma), and gastric or duodenal ulcers. Information on these critical covariates was extracted from reports provided by elderly people or their proxies in the CLHLS.
Statistical analysis
Baseline variables were compared among responders based on various marital status categories. These categories included individuals who were married and living with a spouse, both in low-moderate and high-quality marriages, as well as individuals living without a spouse (including those who were previously married but separated). We used Pearson’s chi-squared test for categorical variables and the Wilcoxon rank-sum test for continuous variables to assess the differences among the groups.
Cross-sectional analysis
Logistic regression models were employed to compute odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for hypertension, heart disease, and cerebrovascular disease or stroke. These analyses aimed to explore the associations between various family factors and health conditions, including: (i) living with a spouse versus living without a spouse; (ii) high-quality marital relationships versus low to moderate quality marital relationships; (iii) living with children versus living without children; (iv) number of children ever born; and (v) count of cohabitants.
Long-term cohort analysis
To assess differences in survival curves among different groups, Kaplan–Meier (KM) survival analysis was conducted using the log-rank method. This analysis aimed to compare survival experiences between individuals who were married and living with spouses versus those who were not, individuals with a high-quality marital relationship compared to those with a low-moderate quality marital relationship, and individuals living with children versus those who were not. Crude and adjusted Cox proportional hazard ratios (HRs) and their corresponding 95% CIs were estimated for the categorized groups. To address violations of the proportional hazards assumption, a time-segmented Cox regression model was employed, allowing for the incorporation of time-dependent effects of the covariates. In the analysis examining the association between living with a spouse and CVD, as well as overall mortality, the control groups consisted of individuals without a spouse companion. Additionally, we compared the impact of living with a spouse to individuals living without a spouse but with other cohabitants to investigate whether the role of the spouse could be fulfilled by other family members.
The associations of the number of offspring and cohabitants with the risk of all-cause death were modelled using restricted cubic splines (RCSs) with four knots. The Cox proportional hazards model was also employed for this analysis. A deletion strategy was utilized to handle missing data for the variables included in our analysis, involving the exclusion of individuals with missing data for any of the analysed variables from the final sample used in the statistical analyses. All the statistical analyses and data visualization were performed using R software (version 4.2.3).
Results
The study included 48 510 participants with a median age of 88 years (average age was 87 years), ranging from 77 to 96 years (Figure 1). Table 1 and Table S1 (detailed information) provide baseline characteristics stratified by marital status. Among those living without a spouse (n = 33 865), the majority had cohabitants, while a few individuals (n = 8292, 24.5%) did not report detailed information or lived alone (n = 2, 0.006%). Participants who were married and living with spouses tended to be younger and had a greater proportion of urban residents, smokers, and alcohol drinkers. They also reported higher rates of regular exercise and social activity participation, despite having more comorbidities.
Baseline characteristics according to marital status classification.
| Variables | [ALL] | Single status or did not cohabit with the spouse | Married with high-quality relationship | Married with low-moderate quality relationship | P value |
|---|---|---|---|---|---|
| N = 48 510 | N = 33 865 | N = 13 150 | N = 1495 | ||
| Age, years | 88.0 [77.0;96.0] | 92.0 [84.0;100] | 76.0 [70.0;84.0] | 75.0 [69.0;83.0] | 0.000 |
| Sex, n(%) | 0.000 | ||||
| Male | 20 672(42.6%) | 10 828(32.0%) | 8875(67.5%) | 969(64.8%) | |
| Female | 27 838(57.4%) | 23 037(68.0%) | 4275(32.5%) | 526(35.2%) | |
| Marital status, n(%) | 0.000 | ||||
| Married and living with spouse | 14 645(30.2%) | 0(0.00%) | 13 150(100%) | 1495(100%) | |
| Living separately | 871(1.80%) | 871(2.57%) | 0(0.00%) | 0(0.00%) | |
| Divorced | 203(0.42%) | 203(0.60%) | 0(0.00%) | 0(0.00%) | |
| Widowed | 32 296(66.6%) | 32 296(95.4%) | 0(0.00%) | 0(0.00%) | |
| Never married | 495(1.02%) | 495(1.46%) | 0(0.00%) | 0(0.00%) | |
| Remarried in the later years, n(%) | / | 778(2.30%) | / | / | . |
| Number of cohabiting individuals, n(%) | 2.00[1.00;4.00] | 3.00[2.00;4.00] | 1.00[1.00;3.00] | 1.00[1.00;4.00] | 0.000 |
| Living with offspring, n(%) | 19 096(47.7%) | 13 668(53.6%) | 4837(37.1%) | 591(40.1%) | 0.000 |
| Experienced divorce in later years, n(%) | 1059(2.18%) | 707(2.09%) | 318(2.42%) | 34(2.27%) | 0.086 |
| Category of residence, n (%) | <0.001 | ||||
| City | 11 056(22.8%) | 7402(21.9%) | 3439(26.2%) | 215(14.4%) | |
| Town | 9937(20.5%) | 7010(20.7%) | 2619(19.9%) | 308(20.6%) | |
| Rural | 27 517(56.7%) | 19 453(57.4%) | 7092(53.9%) | 972(65.0%) | |
| Physical examination | |||||
| SBP, mmHg | 130[120;143] | 130[120;143] | 130[120;144] | 130[120;140] | 0.045 |
| DBP, mmHg | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 0.011 |
| Heart rate, beats/minute | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 0.709 |
| Weight, kg | 48.0[41.0;56.0] | 45.0[40.0;53.0] | 55.0[48.0;62.0] | 51.0[45.0;60.0] | 0.000 |
| Economic condition, n(%) | <0.001 | ||||
| Very rich | 601(1.24%) | 381(1.13%) | 211(1.61%) | 9(0.60%) | |
| Rich | 6899(14.3%) | 4634(13.8%) | 2129(16.2%) | 136(9.10%) | |
| Moderate | 32 468(67.2%) | 22 551(67.0%) | 8942(68.1%) | 975(65.2%) | |
| Poor | 6866(14.2%) | 4976(14.8%) | 1586(12.1%) | 304(20.3%) | |
| Very poor | 1464(3.03%) | 1133(3.36%) | 260(1.98%) | 71(4.75%) | |
| Self-reported diseases | |||||
| Hypertension, n(%) | 8518(18.3%) | 5470(16.9%) | 2784(21.8%) | 264(18.4%) | <0.001 |
| Diabetes, n(%) | 1216(2.62%) | 664(2.05%) | 515(4.05%) | 37(2.58%) | <0.001 |
| Heart diseases, n(%) | 4320(9.27%) | 2661(8.21%) | 1531(12.0%) | 128(8.90%) | <0.001 |
| Cerebrovascular disease or stroke, n(%) | 2710(5.81%) | 1634(5.03%) | 978(7.67%) | 98(6.84%) | <0.001 |
| Count of major CID, n(%) | . | ||||
| 0 | 27 862(60.6%) | 20 209(63.3%) | 6838(54.0%) | 815(57.4%) | |
| 1 | 12 689(27.6%) | 8403(26.3%) | 3862(30.5%) | 424(29.9%) | |
| 2 | 3999(8.69%) | 2477(7.76%) | 1381(10.9%) | 141(9.93%) | |
| 3 | 1345(2.92%) | 784(2.46%) | 526(4.16%) | 35(2.46%) | |
| 4 | 113(0.25%) | 57(0.18%) | 51(0.40%) | 5(0.35%) | |
| Access to adequate medical service, n(%) | <0.001 | ||||
| Yes | 43 618(89.9%) | 30 045(88.7%) | 12 301(93.6%) | 1272(85.1%) | |
| No | 4890(10.1%) | 3819(11.3%) | 848(6.45%) | 223(14.9%) | |
| Frequency of social activities, n(%) | <0.001 | ||||
| Almost everyday | 1162(2.40%) | 546(1.61%) | 582(4.43%) | 34(2.27%) | |
| Once for a week | 1043(2.15%) | 518(1.53%) | 487(3.70%) | 38(2.54%) | |
| At least once for a month | 1346(2.77%) | 674(1.99%) | 622(4.73%) | 50(3.34%) | |
| Sometimes | 2765(5.70%) | 1410(4.16%) | 1246(9.48%) | 109(7.29%) | |
| never | 42 192(87.0%) | 30 716(90.7%) | 10 212(77.7%) | 1264(84.5%) | |
| Diet quality score, n(%) | <0.001 | ||||
| Low (score < 8) | 1189(2.45%) | 946(2.80%) | 201(1.53%) | 42(2.81%) | |
| Moderate (score: 8–12) | 14 970(30.9%) | 11 013(32.5%) | 3388(25.8%) | 569(38.1%) | |
| High (score ≥ 12) | 32 323(66.7%) | 21 885(64.7%) | 9554(72.7%) | 884(59.1%) | |
| Smoking status, n(%) | 0.000 | ||||
| Never | 31 755(65.5%) | 24 169(71.5%) | 6818(51.9%) | 768(51.4%) | |
| Former smoker | 8860(18.3%) | 4810(14.2%) | 3595(27.3%) | 455(30.4%) | |
| Current smoker | 7831(16.2%) | 4826(14.3%) | 2733(20.8%) | 272(18.2%) | |
| Drinking status, n(%) | <0.001 | ||||
| Never | 32 662(67.4%) | 23 966(70.9%) | 7794(59.3%) | 902(60.3%) | |
| Former drinker | 9286(19.2%) | 5566(16.5%) | 3350(25.5%) | 370(24.7%) | |
| Current drinker | 6482(13.4%) | 4259(12.6%) | 2000(15.2%) | 223(14.9%) | |
| Regular exercise, n(%) | 14 441(29.8%) | 8643(25.5%) | 5358(40.8%) | 440(29.4%) | <0.001 |
| Variables | [ALL] | Single status or did not cohabit with the spouse | Married with high-quality relationship | Married with low-moderate quality relationship | P value |
|---|---|---|---|---|---|
| N = 48 510 | N = 33 865 | N = 13 150 | N = 1495 | ||
| Age, years | 88.0 [77.0;96.0] | 92.0 [84.0;100] | 76.0 [70.0;84.0] | 75.0 [69.0;83.0] | 0.000 |
| Sex, n(%) | 0.000 | ||||
| Male | 20 672(42.6%) | 10 828(32.0%) | 8875(67.5%) | 969(64.8%) | |
| Female | 27 838(57.4%) | 23 037(68.0%) | 4275(32.5%) | 526(35.2%) | |
| Marital status, n(%) | 0.000 | ||||
| Married and living with spouse | 14 645(30.2%) | 0(0.00%) | 13 150(100%) | 1495(100%) | |
| Living separately | 871(1.80%) | 871(2.57%) | 0(0.00%) | 0(0.00%) | |
| Divorced | 203(0.42%) | 203(0.60%) | 0(0.00%) | 0(0.00%) | |
| Widowed | 32 296(66.6%) | 32 296(95.4%) | 0(0.00%) | 0(0.00%) | |
| Never married | 495(1.02%) | 495(1.46%) | 0(0.00%) | 0(0.00%) | |
| Remarried in the later years, n(%) | / | 778(2.30%) | / | / | . |
| Number of cohabiting individuals, n(%) | 2.00[1.00;4.00] | 3.00[2.00;4.00] | 1.00[1.00;3.00] | 1.00[1.00;4.00] | 0.000 |
| Living with offspring, n(%) | 19 096(47.7%) | 13 668(53.6%) | 4837(37.1%) | 591(40.1%) | 0.000 |
| Experienced divorce in later years, n(%) | 1059(2.18%) | 707(2.09%) | 318(2.42%) | 34(2.27%) | 0.086 |
| Category of residence, n (%) | <0.001 | ||||
| City | 11 056(22.8%) | 7402(21.9%) | 3439(26.2%) | 215(14.4%) | |
| Town | 9937(20.5%) | 7010(20.7%) | 2619(19.9%) | 308(20.6%) | |
| Rural | 27 517(56.7%) | 19 453(57.4%) | 7092(53.9%) | 972(65.0%) | |
| Physical examination | |||||
| SBP, mmHg | 130[120;143] | 130[120;143] | 130[120;144] | 130[120;140] | 0.045 |
| DBP, mmHg | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 0.011 |
| Heart rate, beats/minute | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 0.709 |
| Weight, kg | 48.0[41.0;56.0] | 45.0[40.0;53.0] | 55.0[48.0;62.0] | 51.0[45.0;60.0] | 0.000 |
| Economic condition, n(%) | <0.001 | ||||
| Very rich | 601(1.24%) | 381(1.13%) | 211(1.61%) | 9(0.60%) | |
| Rich | 6899(14.3%) | 4634(13.8%) | 2129(16.2%) | 136(9.10%) | |
| Moderate | 32 468(67.2%) | 22 551(67.0%) | 8942(68.1%) | 975(65.2%) | |
| Poor | 6866(14.2%) | 4976(14.8%) | 1586(12.1%) | 304(20.3%) | |
| Very poor | 1464(3.03%) | 1133(3.36%) | 260(1.98%) | 71(4.75%) | |
| Self-reported diseases | |||||
| Hypertension, n(%) | 8518(18.3%) | 5470(16.9%) | 2784(21.8%) | 264(18.4%) | <0.001 |
| Diabetes, n(%) | 1216(2.62%) | 664(2.05%) | 515(4.05%) | 37(2.58%) | <0.001 |
| Heart diseases, n(%) | 4320(9.27%) | 2661(8.21%) | 1531(12.0%) | 128(8.90%) | <0.001 |
| Cerebrovascular disease or stroke, n(%) | 2710(5.81%) | 1634(5.03%) | 978(7.67%) | 98(6.84%) | <0.001 |
| Count of major CID, n(%) | . | ||||
| 0 | 27 862(60.6%) | 20 209(63.3%) | 6838(54.0%) | 815(57.4%) | |
| 1 | 12 689(27.6%) | 8403(26.3%) | 3862(30.5%) | 424(29.9%) | |
| 2 | 3999(8.69%) | 2477(7.76%) | 1381(10.9%) | 141(9.93%) | |
| 3 | 1345(2.92%) | 784(2.46%) | 526(4.16%) | 35(2.46%) | |
| 4 | 113(0.25%) | 57(0.18%) | 51(0.40%) | 5(0.35%) | |
| Access to adequate medical service, n(%) | <0.001 | ||||
| Yes | 43 618(89.9%) | 30 045(88.7%) | 12 301(93.6%) | 1272(85.1%) | |
| No | 4890(10.1%) | 3819(11.3%) | 848(6.45%) | 223(14.9%) | |
| Frequency of social activities, n(%) | <0.001 | ||||
| Almost everyday | 1162(2.40%) | 546(1.61%) | 582(4.43%) | 34(2.27%) | |
| Once for a week | 1043(2.15%) | 518(1.53%) | 487(3.70%) | 38(2.54%) | |
| At least once for a month | 1346(2.77%) | 674(1.99%) | 622(4.73%) | 50(3.34%) | |
| Sometimes | 2765(5.70%) | 1410(4.16%) | 1246(9.48%) | 109(7.29%) | |
| never | 42 192(87.0%) | 30 716(90.7%) | 10 212(77.7%) | 1264(84.5%) | |
| Diet quality score, n(%) | <0.001 | ||||
| Low (score < 8) | 1189(2.45%) | 946(2.80%) | 201(1.53%) | 42(2.81%) | |
| Moderate (score: 8–12) | 14 970(30.9%) | 11 013(32.5%) | 3388(25.8%) | 569(38.1%) | |
| High (score ≥ 12) | 32 323(66.7%) | 21 885(64.7%) | 9554(72.7%) | 884(59.1%) | |
| Smoking status, n(%) | 0.000 | ||||
| Never | 31 755(65.5%) | 24 169(71.5%) | 6818(51.9%) | 768(51.4%) | |
| Former smoker | 8860(18.3%) | 4810(14.2%) | 3595(27.3%) | 455(30.4%) | |
| Current smoker | 7831(16.2%) | 4826(14.3%) | 2733(20.8%) | 272(18.2%) | |
| Drinking status, n(%) | <0.001 | ||||
| Never | 32 662(67.4%) | 23 966(70.9%) | 7794(59.3%) | 902(60.3%) | |
| Former drinker | 9286(19.2%) | 5566(16.5%) | 3350(25.5%) | 370(24.7%) | |
| Current drinker | 6482(13.4%) | 4259(12.6%) | 2000(15.2%) | 223(14.9%) | |
| Regular exercise, n(%) | 14 441(29.8%) | 8643(25.5%) | 5358(40.8%) | 440(29.4%) | <0.001 |
SP: Systolic Pressure; BP: Diastolic Pressure; mmHg: Millimetres of Mercury; n: Number. CID: Chronic Internal Disease; Major CID: Hypertension, Heart Disease, Cerebrovascular Disease or Stroke, Diabetes, Lung Diseases (such as Bronchitis, Emphysema, Pneumonia, and Asthma), and Gastric or Duodenal Ulcers.
Baseline characteristics according to marital status classification.
| Variables | [ALL] | Single status or did not cohabit with the spouse | Married with high-quality relationship | Married with low-moderate quality relationship | P value |
|---|---|---|---|---|---|
| N = 48 510 | N = 33 865 | N = 13 150 | N = 1495 | ||
| Age, years | 88.0 [77.0;96.0] | 92.0 [84.0;100] | 76.0 [70.0;84.0] | 75.0 [69.0;83.0] | 0.000 |
| Sex, n(%) | 0.000 | ||||
| Male | 20 672(42.6%) | 10 828(32.0%) | 8875(67.5%) | 969(64.8%) | |
| Female | 27 838(57.4%) | 23 037(68.0%) | 4275(32.5%) | 526(35.2%) | |
| Marital status, n(%) | 0.000 | ||||
| Married and living with spouse | 14 645(30.2%) | 0(0.00%) | 13 150(100%) | 1495(100%) | |
| Living separately | 871(1.80%) | 871(2.57%) | 0(0.00%) | 0(0.00%) | |
| Divorced | 203(0.42%) | 203(0.60%) | 0(0.00%) | 0(0.00%) | |
| Widowed | 32 296(66.6%) | 32 296(95.4%) | 0(0.00%) | 0(0.00%) | |
| Never married | 495(1.02%) | 495(1.46%) | 0(0.00%) | 0(0.00%) | |
| Remarried in the later years, n(%) | / | 778(2.30%) | / | / | . |
| Number of cohabiting individuals, n(%) | 2.00[1.00;4.00] | 3.00[2.00;4.00] | 1.00[1.00;3.00] | 1.00[1.00;4.00] | 0.000 |
| Living with offspring, n(%) | 19 096(47.7%) | 13 668(53.6%) | 4837(37.1%) | 591(40.1%) | 0.000 |
| Experienced divorce in later years, n(%) | 1059(2.18%) | 707(2.09%) | 318(2.42%) | 34(2.27%) | 0.086 |
| Category of residence, n (%) | <0.001 | ||||
| City | 11 056(22.8%) | 7402(21.9%) | 3439(26.2%) | 215(14.4%) | |
| Town | 9937(20.5%) | 7010(20.7%) | 2619(19.9%) | 308(20.6%) | |
| Rural | 27 517(56.7%) | 19 453(57.4%) | 7092(53.9%) | 972(65.0%) | |
| Physical examination | |||||
| SBP, mmHg | 130[120;143] | 130[120;143] | 130[120;144] | 130[120;140] | 0.045 |
| DBP, mmHg | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 0.011 |
| Heart rate, beats/minute | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 0.709 |
| Weight, kg | 48.0[41.0;56.0] | 45.0[40.0;53.0] | 55.0[48.0;62.0] | 51.0[45.0;60.0] | 0.000 |
| Economic condition, n(%) | <0.001 | ||||
| Very rich | 601(1.24%) | 381(1.13%) | 211(1.61%) | 9(0.60%) | |
| Rich | 6899(14.3%) | 4634(13.8%) | 2129(16.2%) | 136(9.10%) | |
| Moderate | 32 468(67.2%) | 22 551(67.0%) | 8942(68.1%) | 975(65.2%) | |
| Poor | 6866(14.2%) | 4976(14.8%) | 1586(12.1%) | 304(20.3%) | |
| Very poor | 1464(3.03%) | 1133(3.36%) | 260(1.98%) | 71(4.75%) | |
| Self-reported diseases | |||||
| Hypertension, n(%) | 8518(18.3%) | 5470(16.9%) | 2784(21.8%) | 264(18.4%) | <0.001 |
| Diabetes, n(%) | 1216(2.62%) | 664(2.05%) | 515(4.05%) | 37(2.58%) | <0.001 |
| Heart diseases, n(%) | 4320(9.27%) | 2661(8.21%) | 1531(12.0%) | 128(8.90%) | <0.001 |
| Cerebrovascular disease or stroke, n(%) | 2710(5.81%) | 1634(5.03%) | 978(7.67%) | 98(6.84%) | <0.001 |
| Count of major CID, n(%) | . | ||||
| 0 | 27 862(60.6%) | 20 209(63.3%) | 6838(54.0%) | 815(57.4%) | |
| 1 | 12 689(27.6%) | 8403(26.3%) | 3862(30.5%) | 424(29.9%) | |
| 2 | 3999(8.69%) | 2477(7.76%) | 1381(10.9%) | 141(9.93%) | |
| 3 | 1345(2.92%) | 784(2.46%) | 526(4.16%) | 35(2.46%) | |
| 4 | 113(0.25%) | 57(0.18%) | 51(0.40%) | 5(0.35%) | |
| Access to adequate medical service, n(%) | <0.001 | ||||
| Yes | 43 618(89.9%) | 30 045(88.7%) | 12 301(93.6%) | 1272(85.1%) | |
| No | 4890(10.1%) | 3819(11.3%) | 848(6.45%) | 223(14.9%) | |
| Frequency of social activities, n(%) | <0.001 | ||||
| Almost everyday | 1162(2.40%) | 546(1.61%) | 582(4.43%) | 34(2.27%) | |
| Once for a week | 1043(2.15%) | 518(1.53%) | 487(3.70%) | 38(2.54%) | |
| At least once for a month | 1346(2.77%) | 674(1.99%) | 622(4.73%) | 50(3.34%) | |
| Sometimes | 2765(5.70%) | 1410(4.16%) | 1246(9.48%) | 109(7.29%) | |
| never | 42 192(87.0%) | 30 716(90.7%) | 10 212(77.7%) | 1264(84.5%) | |
| Diet quality score, n(%) | <0.001 | ||||
| Low (score < 8) | 1189(2.45%) | 946(2.80%) | 201(1.53%) | 42(2.81%) | |
| Moderate (score: 8–12) | 14 970(30.9%) | 11 013(32.5%) | 3388(25.8%) | 569(38.1%) | |
| High (score ≥ 12) | 32 323(66.7%) | 21 885(64.7%) | 9554(72.7%) | 884(59.1%) | |
| Smoking status, n(%) | 0.000 | ||||
| Never | 31 755(65.5%) | 24 169(71.5%) | 6818(51.9%) | 768(51.4%) | |
| Former smoker | 8860(18.3%) | 4810(14.2%) | 3595(27.3%) | 455(30.4%) | |
| Current smoker | 7831(16.2%) | 4826(14.3%) | 2733(20.8%) | 272(18.2%) | |
| Drinking status, n(%) | <0.001 | ||||
| Never | 32 662(67.4%) | 23 966(70.9%) | 7794(59.3%) | 902(60.3%) | |
| Former drinker | 9286(19.2%) | 5566(16.5%) | 3350(25.5%) | 370(24.7%) | |
| Current drinker | 6482(13.4%) | 4259(12.6%) | 2000(15.2%) | 223(14.9%) | |
| Regular exercise, n(%) | 14 441(29.8%) | 8643(25.5%) | 5358(40.8%) | 440(29.4%) | <0.001 |
| Variables | [ALL] | Single status or did not cohabit with the spouse | Married with high-quality relationship | Married with low-moderate quality relationship | P value |
|---|---|---|---|---|---|
| N = 48 510 | N = 33 865 | N = 13 150 | N = 1495 | ||
| Age, years | 88.0 [77.0;96.0] | 92.0 [84.0;100] | 76.0 [70.0;84.0] | 75.0 [69.0;83.0] | 0.000 |
| Sex, n(%) | 0.000 | ||||
| Male | 20 672(42.6%) | 10 828(32.0%) | 8875(67.5%) | 969(64.8%) | |
| Female | 27 838(57.4%) | 23 037(68.0%) | 4275(32.5%) | 526(35.2%) | |
| Marital status, n(%) | 0.000 | ||||
| Married and living with spouse | 14 645(30.2%) | 0(0.00%) | 13 150(100%) | 1495(100%) | |
| Living separately | 871(1.80%) | 871(2.57%) | 0(0.00%) | 0(0.00%) | |
| Divorced | 203(0.42%) | 203(0.60%) | 0(0.00%) | 0(0.00%) | |
| Widowed | 32 296(66.6%) | 32 296(95.4%) | 0(0.00%) | 0(0.00%) | |
| Never married | 495(1.02%) | 495(1.46%) | 0(0.00%) | 0(0.00%) | |
| Remarried in the later years, n(%) | / | 778(2.30%) | / | / | . |
| Number of cohabiting individuals, n(%) | 2.00[1.00;4.00] | 3.00[2.00;4.00] | 1.00[1.00;3.00] | 1.00[1.00;4.00] | 0.000 |
| Living with offspring, n(%) | 19 096(47.7%) | 13 668(53.6%) | 4837(37.1%) | 591(40.1%) | 0.000 |
| Experienced divorce in later years, n(%) | 1059(2.18%) | 707(2.09%) | 318(2.42%) | 34(2.27%) | 0.086 |
| Category of residence, n (%) | <0.001 | ||||
| City | 11 056(22.8%) | 7402(21.9%) | 3439(26.2%) | 215(14.4%) | |
| Town | 9937(20.5%) | 7010(20.7%) | 2619(19.9%) | 308(20.6%) | |
| Rural | 27 517(56.7%) | 19 453(57.4%) | 7092(53.9%) | 972(65.0%) | |
| Physical examination | |||||
| SBP, mmHg | 130[120;143] | 130[120;143] | 130[120;144] | 130[120;140] | 0.045 |
| DBP, mmHg | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 80.0[75.0;90.0] | 0.011 |
| Heart rate, beats/minute | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 72.0[68.0;78.0] | 0.709 |
| Weight, kg | 48.0[41.0;56.0] | 45.0[40.0;53.0] | 55.0[48.0;62.0] | 51.0[45.0;60.0] | 0.000 |
| Economic condition, n(%) | <0.001 | ||||
| Very rich | 601(1.24%) | 381(1.13%) | 211(1.61%) | 9(0.60%) | |
| Rich | 6899(14.3%) | 4634(13.8%) | 2129(16.2%) | 136(9.10%) | |
| Moderate | 32 468(67.2%) | 22 551(67.0%) | 8942(68.1%) | 975(65.2%) | |
| Poor | 6866(14.2%) | 4976(14.8%) | 1586(12.1%) | 304(20.3%) | |
| Very poor | 1464(3.03%) | 1133(3.36%) | 260(1.98%) | 71(4.75%) | |
| Self-reported diseases | |||||
| Hypertension, n(%) | 8518(18.3%) | 5470(16.9%) | 2784(21.8%) | 264(18.4%) | <0.001 |
| Diabetes, n(%) | 1216(2.62%) | 664(2.05%) | 515(4.05%) | 37(2.58%) | <0.001 |
| Heart diseases, n(%) | 4320(9.27%) | 2661(8.21%) | 1531(12.0%) | 128(8.90%) | <0.001 |
| Cerebrovascular disease or stroke, n(%) | 2710(5.81%) | 1634(5.03%) | 978(7.67%) | 98(6.84%) | <0.001 |
| Count of major CID, n(%) | . | ||||
| 0 | 27 862(60.6%) | 20 209(63.3%) | 6838(54.0%) | 815(57.4%) | |
| 1 | 12 689(27.6%) | 8403(26.3%) | 3862(30.5%) | 424(29.9%) | |
| 2 | 3999(8.69%) | 2477(7.76%) | 1381(10.9%) | 141(9.93%) | |
| 3 | 1345(2.92%) | 784(2.46%) | 526(4.16%) | 35(2.46%) | |
| 4 | 113(0.25%) | 57(0.18%) | 51(0.40%) | 5(0.35%) | |
| Access to adequate medical service, n(%) | <0.001 | ||||
| Yes | 43 618(89.9%) | 30 045(88.7%) | 12 301(93.6%) | 1272(85.1%) | |
| No | 4890(10.1%) | 3819(11.3%) | 848(6.45%) | 223(14.9%) | |
| Frequency of social activities, n(%) | <0.001 | ||||
| Almost everyday | 1162(2.40%) | 546(1.61%) | 582(4.43%) | 34(2.27%) | |
| Once for a week | 1043(2.15%) | 518(1.53%) | 487(3.70%) | 38(2.54%) | |
| At least once for a month | 1346(2.77%) | 674(1.99%) | 622(4.73%) | 50(3.34%) | |
| Sometimes | 2765(5.70%) | 1410(4.16%) | 1246(9.48%) | 109(7.29%) | |
| never | 42 192(87.0%) | 30 716(90.7%) | 10 212(77.7%) | 1264(84.5%) | |
| Diet quality score, n(%) | <0.001 | ||||
| Low (score < 8) | 1189(2.45%) | 946(2.80%) | 201(1.53%) | 42(2.81%) | |
| Moderate (score: 8–12) | 14 970(30.9%) | 11 013(32.5%) | 3388(25.8%) | 569(38.1%) | |
| High (score ≥ 12) | 32 323(66.7%) | 21 885(64.7%) | 9554(72.7%) | 884(59.1%) | |
| Smoking status, n(%) | 0.000 | ||||
| Never | 31 755(65.5%) | 24 169(71.5%) | 6818(51.9%) | 768(51.4%) | |
| Former smoker | 8860(18.3%) | 4810(14.2%) | 3595(27.3%) | 455(30.4%) | |
| Current smoker | 7831(16.2%) | 4826(14.3%) | 2733(20.8%) | 272(18.2%) | |
| Drinking status, n(%) | <0.001 | ||||
| Never | 32 662(67.4%) | 23 966(70.9%) | 7794(59.3%) | 902(60.3%) | |
| Former drinker | 9286(19.2%) | 5566(16.5%) | 3350(25.5%) | 370(24.7%) | |
| Current drinker | 6482(13.4%) | 4259(12.6%) | 2000(15.2%) | 223(14.9%) | |
| Regular exercise, n(%) | 14 441(29.8%) | 8643(25.5%) | 5358(40.8%) | 440(29.4%) | <0.001 |
SP: Systolic Pressure; BP: Diastolic Pressure; mmHg: Millimetres of Mercury; n: Number. CID: Chronic Internal Disease; Major CID: Hypertension, Heart Disease, Cerebrovascular Disease or Stroke, Diabetes, Lung Diseases (such as Bronchitis, Emphysema, Pneumonia, and Asthma), and Gastric or Duodenal Ulcers.
Family factors and cardiovascular health
The cross-sectional analysis results in Table 2 reveal that, after adjusting for covariates, individuals living with a spouse did not exhibit a reduced incidence of hypertension (adjusted OR 1.01, 95% CI 0.95–1.07). However, these subjects had a greater incidence of heart disease (adjusted OR 1.18, 95% CI 1.06–1.31) and cerebrovascular disease or stroke (adjusted OR 1.26, 95% CI 1.11–1.42). Those in high-quality marriages reported more hypertension (adjusted OR 1.16, 95% CI 1.04–1.30). Additionally, individuals with more cohabitants had a lower incidence of heart disease (adjusted OR 0.91, 95% CI 0.89–0.93), while those living with children had a greater incidence of cerebrovascular disease or stroke (adjusted OR 1.16, 95% CI 1.05–1.29).
ORs (95% CIs) for CVD incidence according to various family factors.
| CVD | Model 1 | Model 2 |
|---|---|---|
| Hypertension | ||
| Be living with the spouse vs. without | 0.99 (0.94–1.04) | 1.01 (0.95–1.07) |
| High-quality vs. low-moderate marital relationship | 1.17 (1.05–1.31)a | 1.16 (1.04–1.30)a |
| Be living with the children vs. without | 1.02 (0.96–1.08) | 0.99 (0.94–1.04) |
| Count of children ever born | 0.99 (0.99–1.00) | 0.99 (0.99–1.00) |
| Count of cohabitants | 0.99 (0.98–1.00) | 0.99 (0.98–1.00) |
| Heart disease | ||
| Be living with the spouse vs. without | 1.27(1.17, 1.37)a | 1.18 (1.06–1.31)a |
| High-quality vs. low-moderate marital relationship | 1.41 (1.17–1.71)a | 1.27 (1.04–1.55)a |
| Be living with the children vs. without | 0.86 (0.80, 0.93)a | 0.92 (0.85–1.01) |
| Count of children ever born | 1.03 (1.01, 1.05)a | 1.01 (1.00–1.02) |
| Count of cohabitants | 0.90 (0.88–0.92)a | 0.91 (0.89–0.93)a |
| Cerebrovascular disease or stroke | ||
| Be living with the spouse vs. without | 1.25 (1.14, 1.38)a | 1.26 (1.11–1.42)a |
| High-quality vs. low-moderate marital relationship | 1.12 (0.90–1.39) | 1.11 (0.88–1.39) |
| Be living with the children vs. without | 1.03 (0.94, 1.13) | 1.16 (1.05–1.29)a |
| Count of children ever born | 1.02 (1.00, 1.05)a | 1.00 (0.99–1.02) |
| Count of cohabitants | 0.95 (0.93–0.98)a | 0.97 (0.95–1.00) |
| CVD | Model 1 | Model 2 |
|---|---|---|
| Hypertension | ||
| Be living with the spouse vs. without | 0.99 (0.94–1.04) | 1.01 (0.95–1.07) |
| High-quality vs. low-moderate marital relationship | 1.17 (1.05–1.31)a | 1.16 (1.04–1.30)a |
| Be living with the children vs. without | 1.02 (0.96–1.08) | 0.99 (0.94–1.04) |
| Count of children ever born | 0.99 (0.99–1.00) | 0.99 (0.99–1.00) |
| Count of cohabitants | 0.99 (0.98–1.00) | 0.99 (0.98–1.00) |
| Heart disease | ||
| Be living with the spouse vs. without | 1.27(1.17, 1.37)a | 1.18 (1.06–1.31)a |
| High-quality vs. low-moderate marital relationship | 1.41 (1.17–1.71)a | 1.27 (1.04–1.55)a |
| Be living with the children vs. without | 0.86 (0.80, 0.93)a | 0.92 (0.85–1.01) |
| Count of children ever born | 1.03 (1.01, 1.05)a | 1.01 (1.00–1.02) |
| Count of cohabitants | 0.90 (0.88–0.92)a | 0.91 (0.89–0.93)a |
| Cerebrovascular disease or stroke | ||
| Be living with the spouse vs. without | 1.25 (1.14, 1.38)a | 1.26 (1.11–1.42)a |
| High-quality vs. low-moderate marital relationship | 1.12 (0.90–1.39) | 1.11 (0.88–1.39) |
| Be living with the children vs. without | 1.03 (0.94, 1.13) | 1.16 (1.05–1.29)a |
| Count of children ever born | 1.02 (1.00, 1.05)a | 1.00 (0.99–1.02) |
| Count of cohabitants | 0.95 (0.93–0.98)a | 0.97 (0.95–1.00) |
Confidence intervals not including 1 indicate statistically significant associations (P < 0.05).
Model 1. ORs were adjusted for age and sex;
Model 2. Odds ratios for hypertension were adjusted for multiple confounders, including age, sex, frequency of exercise and social activities, smoking status, drinking status, dietary habits, economic status, access to adequate medical services, and diabetes. In the analysis of heart disease and cerebrovascular disease or stroke, adjusted factors included the incidence of hypertension in addition to the factors listed above. When assessing the effects of living with children or one’s spouse, the effect of the other was adjusted.
ORs (95% CIs) for CVD incidence according to various family factors.
| CVD | Model 1 | Model 2 |
|---|---|---|
| Hypertension | ||
| Be living with the spouse vs. without | 0.99 (0.94–1.04) | 1.01 (0.95–1.07) |
| High-quality vs. low-moderate marital relationship | 1.17 (1.05–1.31)a | 1.16 (1.04–1.30)a |
| Be living with the children vs. without | 1.02 (0.96–1.08) | 0.99 (0.94–1.04) |
| Count of children ever born | 0.99 (0.99–1.00) | 0.99 (0.99–1.00) |
| Count of cohabitants | 0.99 (0.98–1.00) | 0.99 (0.98–1.00) |
| Heart disease | ||
| Be living with the spouse vs. without | 1.27(1.17, 1.37)a | 1.18 (1.06–1.31)a |
| High-quality vs. low-moderate marital relationship | 1.41 (1.17–1.71)a | 1.27 (1.04–1.55)a |
| Be living with the children vs. without | 0.86 (0.80, 0.93)a | 0.92 (0.85–1.01) |
| Count of children ever born | 1.03 (1.01, 1.05)a | 1.01 (1.00–1.02) |
| Count of cohabitants | 0.90 (0.88–0.92)a | 0.91 (0.89–0.93)a |
| Cerebrovascular disease or stroke | ||
| Be living with the spouse vs. without | 1.25 (1.14, 1.38)a | 1.26 (1.11–1.42)a |
| High-quality vs. low-moderate marital relationship | 1.12 (0.90–1.39) | 1.11 (0.88–1.39) |
| Be living with the children vs. without | 1.03 (0.94, 1.13) | 1.16 (1.05–1.29)a |
| Count of children ever born | 1.02 (1.00, 1.05)a | 1.00 (0.99–1.02) |
| Count of cohabitants | 0.95 (0.93–0.98)a | 0.97 (0.95–1.00) |
| CVD | Model 1 | Model 2 |
|---|---|---|
| Hypertension | ||
| Be living with the spouse vs. without | 0.99 (0.94–1.04) | 1.01 (0.95–1.07) |
| High-quality vs. low-moderate marital relationship | 1.17 (1.05–1.31)a | 1.16 (1.04–1.30)a |
| Be living with the children vs. without | 1.02 (0.96–1.08) | 0.99 (0.94–1.04) |
| Count of children ever born | 0.99 (0.99–1.00) | 0.99 (0.99–1.00) |
| Count of cohabitants | 0.99 (0.98–1.00) | 0.99 (0.98–1.00) |
| Heart disease | ||
| Be living with the spouse vs. without | 1.27(1.17, 1.37)a | 1.18 (1.06–1.31)a |
| High-quality vs. low-moderate marital relationship | 1.41 (1.17–1.71)a | 1.27 (1.04–1.55)a |
| Be living with the children vs. without | 0.86 (0.80, 0.93)a | 0.92 (0.85–1.01) |
| Count of children ever born | 1.03 (1.01, 1.05)a | 1.01 (1.00–1.02) |
| Count of cohabitants | 0.90 (0.88–0.92)a | 0.91 (0.89–0.93)a |
| Cerebrovascular disease or stroke | ||
| Be living with the spouse vs. without | 1.25 (1.14, 1.38)a | 1.26 (1.11–1.42)a |
| High-quality vs. low-moderate marital relationship | 1.12 (0.90–1.39) | 1.11 (0.88–1.39) |
| Be living with the children vs. without | 1.03 (0.94, 1.13) | 1.16 (1.05–1.29)a |
| Count of children ever born | 1.02 (1.00, 1.05)a | 1.00 (0.99–1.02) |
| Count of cohabitants | 0.95 (0.93–0.98)a | 0.97 (0.95–1.00) |
Confidence intervals not including 1 indicate statistically significant associations (P < 0.05).
Model 1. ORs were adjusted for age and sex;
Model 2. Odds ratios for hypertension were adjusted for multiple confounders, including age, sex, frequency of exercise and social activities, smoking status, drinking status, dietary habits, economic status, access to adequate medical services, and diabetes. In the analysis of heart disease and cerebrovascular disease or stroke, adjusted factors included the incidence of hypertension in addition to the factors listed above. When assessing the effects of living with children or one’s spouse, the effect of the other was adjusted.
Additional analysis comparing participants without a spouse but with other cohabitants to those living with a spouse revealed consistent associations. Living with the spouse was associated with a greater incidence of heart disease (adjusted OR 1.20, 95% CI 1.07–1.35), while no significant associations were found for hypertension (adjusted OR 1.09, 95% CI 0.99–1.19), cerebrovascular disease or stroke (adjusted OR 1.07, 95% CI 0.95–1.21) (not presented in the table).
Family members/relationships and long-term overall mortality
In the retrospective cohort study, living with a married partner significantly reduced overall mortality (P < 0.001) (Fig. 2A). Survival curves comparing married individuals living with a spouse to those without a spouse but with other cohabitants exhibited similar patterns (Fig. S2). However, no significant differences were found in the survival curves between individuals with a high-quality marital relationship and those without (P = 0.410) (Fig. 2A). Elders living with offspring had significantly greater mortality than did those living without offspring (P < 0.001) (Fig. 2B), which was consistent after adjusting for confounding factors (Fig. 3A and 3B). Further analysis using a time-segmented Cox regression model showed that living with a spouse improved survival outcomes initially (adjusted HR 0.84, 95% CI 0.80–0.87), but this benefit diminished later (adjusted HR 1.22, 95% CI 0.95–1.58) (Fig. 3A). Conversely, living with offspring was initially associated with elevated mortality (adjusted HR 1.12, 95% CI 1.08–1.16), which decreased over time (adjusted HR 0.86, 95% CI 0.61–1.22) (Fig. 3B).
Among single cohort members at baseline, those who remarried and lived with spouses exhibited a significant survival benefit (P < 0.001) (Fig. 4). Due to the low divorce rate (Table 1), further analysis on the dynamic effect of divorce was not conducted.
Several factors showed interactive effects on the impact of marital status according to subgroup analyses and interaction tests (Fig. S3).
Subgroup analyses and interaction tests revealed interactive effects of several factors on the impact of marital status (Fig. S3).
The RCS curve in Fig. 5A indicates a linear increase in the risk of death with increasing number of children (adjusted Pnonlinearity = 0.331). The curve pattern remained consistent across sexes (Fig. S4). Figure 5B shows that as the number of cohabitants increased, respondent mortality also increased (adjusted Pnonlinearity < 0.0001).
A) Kaplan–Meier survival curves for the effect of marital status; B) Kaplan–Meier survival curves for the effect of living with children.
A) Adjusted survival curves illustrating the effect of marital status; B) adjusted survival curves illustrating the effect of living with children. The confounders adjusted for in the analysis included age, sex, frequency of exercise and social activities, smoking status, drinking status, dietary habits, economic status, access to adequate medical services, and the amount of major CID.
Adjusted survival curves illustrating the positive impact of remarriage on single individuals at the baseline survey. The factors adjusted remain consistent with those in Fig. 3.
Discussion
In the elderly, averaging 87 years old, a comprehensive evaluation was conducted to assess the association of marital status and other family factors with CVD and long-term all-cause mortality. The key findings are as follows: (i) Being married and living with spouses did not correlate with a reduced prevalence of CVD among elderly individuals in China, including hypertension, heart diseases, and cerebrovascular disease/stroke. Conversely, they exhibited a higher prevalence of heart diseases and cerebrovascular disease/stroke. (ii) The long-term cohort study highlighted the significant role of a spouse in reducing all-cause mortality. Compared to elderly individuals who remained single, those who remarried experienced improved survival rate. The role of a spouse could not be substituted by offspring or other residential occupants. Furthermore, living with children and having a larger number of children or household size were associated with increased overall mortality.
The analysis of the association between marital status and CVD risk did not reveal a positive impact of having a spouse on reducing morbidity among elderly people, which contrasts with findings from studies conducted in the general population [6]. The reasons for this difference may be complex, and it is crucial to carefully consider the distinctions between elderly and younger adults. Aging typically leads to reduced social activity and exercise but increased time spent with family, particularly one’s spouse. In this context, the shared cardiovascular risk factors, which are common among many couples, may be amplified [15–17]. The alignment of these risk factors among couples, especially those in ideal relationships, could contribute to cardiovascular health decline. However, it’s essential to acknowledge the limitations of cross-sectional studies and the necessity for further research to uncover the underlying mechanisms and potential confounding factors in this intricate relationship among the elderly.
According to our long-term cohort study, the benefits observed in the general population regarding marital status appeared to be consistent among the elderly [3, 18, 19]. Compared to individuals living with others but not their spouse, those cohabiting with a spouse still showed significantly reduced overall mortality, indicating that the specific role of a spouse could not be filled by the companionship of others. Additionally, the significantly decreased mortality observed in remarried elderly individuals further supports the positive effect that a marital partner could have. The substantial benefits that a spouse brings deserve serious consideration, especially considering that the elderly are often affected by age-related conditions such as frailty and disabilities [20]. Frailty, rather than organ disorders, has been identified as the leading factor contributing to mortality in advanced age [21]. Being unmarried and having single status have been identified as key factors increasing the risk of frailty in the elderly [22, 23]. The partial or complete loss of self-care ability significantly diminishes their quality of life and overall well-being. In this context, the presence of a spouse as a warm and supportive companion not only provides essential nutritional interventions but also serves as a vital source of emotional support. Furthermore, the close relationship allows for earlier recognition and response to warning symptoms and conditions, such as falls or fractures [24, 25]. No other family member can replace the role of a spouse, including adult children who have their own spouses and children to take care of. As our research demonstrated, living with children or other family members did not confer additional lifespan benefits. For elderly individuals who have lost their spouses due to various reasons, encouraging remarriage should be seen as a valuable option rather than an unorthodox behavior.
One notable discovery regarding offspring was their adverse impact on the overall mortality of the elderly. Firstly, the presence of offspring in the same household was associated with negative health outcomes. Even after adjusting for various factors, including marital status, older Chinese individuals residing with their children exhibited a 16% higher prevalence of cerebrovascular disease/stroke and a 12% elevated risk of death. These findings may stem from differences in lifestyle and perspectives between the elderly and younger adults, leading to conflicts detrimental to the mental health of the elderly. Additionally, in previous generations in China, elderly individuals typically had at least two children, leading to rotated living arrangements with offspring, linked to worse health conditions [26]. Secondly, contrary to traditional beliefs of children serving as a provision for old age and more offspring equating to better care in advanced years, our study, along with research by Peters et al. [27], supported a negative impact on survival outcomes associated with having more children. Metabolic changes post-childbirth among females and increased mental and economic stress from a larger family size may contribute to this negative impact, offsetting the happiness derived from having children [28–30].
Adjusted RCS curves depicting the relationship of the number of children (A) and cohabitants (B) with the long-term risk of all-cause death. The factors adjusted remain consistent with those in Fig. 3.
Strengths and limitations
Compared to previous studies focusing solely on the impact of marriage or offspring on health outcomes, our study offers a comprehensive assessment of how family members and living arrangements are associated with CVD and overall mortality in a large sample of elderly individuals. Through rigorous statistical analyses and adjustment for various confounding factors, we provide novel insights into the complex relationships between family factors and CVD as well as all-cause mortality in elderly people, contributing to a deeper understanding of healthy aging. However, our study has several limitations. First, the cross-sectional design restricts our ability to evaluate the impact of family factors on the incidence of CVD. Longitudinal studies could provide more reliable evidence in this regard. Second, reliance on self-reported information from participants introduces the possibility of unreliability. Third, there is potential for reverse causality in our observational study, as various socioeconomic factors may significantly influence the observed associations. Subgroup analyses and interaction tests revealed interactive effects of various factors on the impact of marital status. Finally, given that this research was conducted within a Chinese cohort, additional validation is necessary to extrapolate the findings to other populations worldwide.
Conclusion
Our findings among elderly people, with an average age of 87 years, suggested that being married and living with a spouse does not appear to decrease the prevalence of CVD. However, it significantly contributes to reducing long-term overall mortality. On the other hand, living with children, having more children, or residing in larger households do not consistently confer survival benefits. In fact, these factors indicate an increased risk of long-term mortality.
Acknowledgements
None.
Conflict of interest statement
None declared.
Funding
The Chinese Academy of Medical Science Innovation Fund for Medical Science (grant number 2021-CXGC08).
Data availability statement
Data are available in a public, open access repository. Researchers can download the datasets free of charge from the following website: https://opendata.pku.edu.cn and the Peking University Open Access Research Database.
Contributions
G.L., Y.Z., and J.Z. were involved in the conceptualization and design of the study; G.L., J.G., Y.H., M.L., L.H., and J.F. acquired and analysed the data; Y.Z. and J.Z. were involved in the supervision of the study; G.L. drafted the manuscript; and G.L., Y.H., Y.Z., and J.Z. revised the manuscript. All the authors were involved in the interpretation of the data. All authors approved the final version before submission.
Ethics statement
Patient consent for publication
Consent was obtained directly from the participants.
Ethics approval
The study protocol was approved by the Ethics Committee of Peking University (IRB00001052–13074), and written informed consent was obtained from all participants or their proxy respondents.
