Coping strategies and risk of cardiovascular disease incidence and mortality: the Japan Public Health Center-based prospective Study

Abstract

Aims

Coping strategies may be significantly associated with health outcomes. This is the first study to investigate the association between baseline coping strategies and cardiovascular disease (CVD) incidence and mortality in a general population cohort.

Methods and results

The Japan Public Health Center-based prospective Study asked questions on coping in its third follow-up survey (2000–04). Analyses on CVD incidence and mortality included 57 017 subjects aged 50–79 without a history of CVD and who provided complete answers on approach- and avoidance-oriented coping behaviours and strategies. Cox regression models, adjusted for confounders, were used to determine hazard ratios (HRs) according to coping style. Mean follow-up time was 7.9 years for incidence and 8.0 years for mortality.

The premorbid use of an approach-oriented coping strategy was inversely associated with incidence of stroke (HR = 0.85; 95% CI, 0.73–1.00) and CVD mortality (HR = 0.74; 95% CI, 0.55–0.99). Stroke subtype analyses revealed an inverse association between the approach-oriented coping strategy and incidence of ischaemic stroke (HR = 0.79; 95% CI, 0.64–0.98) and a positive association between the combined coping strategy and incidence of intra-parenchymal haemorrhage (HR = 2.03; 95% CI, 1.01–4.10). Utilizing an avoidance coping strategy was associated with increased mortality from ischaemic heart disease (IHD) only in hypertensive individuals (HR = 3.46; 95% CI, 1.07–11.18). The coping behaviours fantasizing and positive reappraisal were associated with increased risk of CVD incidence (HR = 1.24; 95% CI, 1.03–1.50) and reduced risk of IHD mortality (HR = 0.63; 95% CI, 0.40–0.99), respectively.

Conclusion

An approach-oriented coping strategy, i.e. proactively dealing with sources of stress, may be associated with significantly reduced stroke incidence and CVD mortality in a Japanese population-based cohort.

Coping, Mortality, Incidence, Myocardial infarction, Stroke, Cohort

Clinical perspectives

The findings in this study indicate that approach-oriented stress coping strategies reduce the risk of incident stroke and cardiovascular mortality, most likely due to the indirect influence of coping on cardiovascular disease (CVD) risk factors. Behavioural intervention and education that improves stress coping strategies may thus further reduce the risk of CVD mortality.

Introduction

Mental stress not only influences risk factors of cardiovascular disease (CVD)¹ but independently predicts CVD incidence and mortality.^2,3 Stress is a modifiable risk factor;⁴ sources of stress can be managed through the utilization of coping strategies or coping behaviours,⁵ which differs among individuals depending on their cognitive efforts and abilities. Coping is generally clustered into problem-focused and emotion-focused,⁵ attention and avoidance,⁶ or a combination of them.⁷ Whereas problem-focused and attention coping strategies tend to focus on the stressor and deal with the source of stress, avoidance and emotion-focused strategies are instead utilized either to avoid the stressor or to regulate the individual's own emotions regarding the stressor. Hence, the potential impact of stress on an individual's health could be directly related to the way stress is being dealt with, thereby allowing for coping styles that are favourable or detrimental with respect to health outcomes.⁸

Despite growing evidence on the associations between stress and coping, and between stress and CVD, no study has investigated the association between coping behaviours/strategies and CVD incidence or mortality. The major objective of the present study is, therefore, to assess the association between coping—both approach-oriented and avoidance-oriented—and CVD incidence and mortality in a large general population cohort.

Methods

The Japan Public Health Center-based prospective study (JPHC Study) was started in 1990 and conducted in two cohorts: one initiated in 1990 (cohort I) and the other in 1993 (cohort II). The study design has been described in detail elsewhere.⁹

Surveys of the cohort participants were conducted on three occasions with 5-year intervals starting in 1990–94. The third survey (2000–04) included questions on coping behaviours and information on lifestyle factors, thereby making it the starting point in the present study. Participants were individuals who responded to the self-administered 10-year follow-up questionnaire at age 50–79 years.

A total of 57 017 individuals were eligible for inclusion in the present study (for methodological details, see Supplementary material online). The study was approved by the institutional review board of the National Cancer Center (approval number: 13-021) and The University of Tokyo (approval number: 10508).

Follow-up and identification of cause of death

All participants in this study, irrespective of endpoint, were followed from starting point until 31 December 2009. Information on the cause of death for deceased participants was obtained from death certificates, on which the cause of death is defined according to the International Statistical Classification of Diseases and Related Health Problems, tenth revision (ICD-10).¹⁰ The endpoints of the current study were mortality from ischaemic heart disease (IHD) (ICD-10: I20–I25) and cerebrovascular disease (ICD-10: I60–I69), as well as combined mortality from IHD and cerebrovascular disease (hereafter ‘CVD mortality’).

Identification of disease

For incidence analyses, the endpoints in the current study were myocardial infarction (MI), stroke, and combined incidence of MI and stroke (hereafter ‘CVD incidence’). The medical records were reviewed by hospital physicians, public health centre (PHC) physicians, or research physicians. Myocardial infarction was confirmed and diagnosed according to the criteria of the MONICA project,¹¹ whereas stroke was diagnosed by computed tomography scan and/or magnetic resonance imaging according to the National Survey of Stroke criteria.¹² Subtypes of stroke were classified as haemorrhagic (intra-parenchymal or sub-arachnoid) or ischaemic.

Coping behaviours and coping strategies

Coping was evaluated using the validated Japanese version of the Stress and Coping Inventory.¹³ Six coping behaviours (planning, consulting someone, positive reappraisal, fantasizing, avoidance, and self-blame) were assessed through one question, ‘How do you handle various problems and events that you experience daily?’ These behaviours were further used to define the coping strategy utilized to solve problems; those who used at least two out of three approach-oriented behaviours (planning, consulting someone, or positive reappraisal) or avoidance-oriented behaviours (fantasizing, avoidance, or self-blame) were considered to adopt approach-oriented or avoidance-oriented coping strategies, respectively. Individuals who failed to meet these criteria were considered not to use any specific strategy, and those who met criteria for both strategies were considered to use a combination of approach- and avoidance-oriented coping (combined coping). A network graph (Figure 1) shows the correlation structure between the different coping behaviours.

Figure 1

Network graph representing correlations between the different coping behaviours. Green nodes represent behaviours related to the approach coping strategy and pink nodes behaviours related to the avoidance strategy.

Statistical analysis

Person-years of follow-up were calculated for each participant from starting point to the date of disease diagnosis (for incidence analysis), the date of death (for mortality analysis), moving out of the study area, or end of follow-up period (31 December 2009), whichever occurred first. For individuals who withdrew from the study or were lost to follow-up, the date of censoring was set as the date of withdrawal or the last confirmed date of presence in the study. For individuals with multiple diagnoses, only the first recorded event during follow-up was considered.

Hazard ratios and 95% CI were used to characterize the relative risk of incidence of MI, stroke, or CVD, or mortality associated with coping strategies and coping behaviours. Cox proportional hazard models were used to estimate HR while controlling for potential confounders. All analyses were stratified on study area with minimally adjusted models adjusted for age (continuous), and gender at starting point. Multivariate models were additionally adjusted for alcohol consumption (none or occasional, <150, and ≥150 g ethanol/week), smoking (never, former smoker, or current smoker), a self-reported history of diabetes (yes/no), total physical activity [leisure time and occupational activity measured in metabolic equivalent (MET) in kcal/kg/h (continuous variable)], self-reported use of any prescribed medications by a physician (yes/no), unemployment (yes/no), having undergone screening examination (for men and women: blood pressure, blood test, electrocardiography, fundoscopy, chest radiograph, sputum cytology, gastric photofluorography, gastric endoscopy, faecal occult blood test, barium enema, or colonoscopy; for women: mammography or Papanicolau smear), and living arrangements [living alone (yes/no), living with a spouse (yes/no), living with children (yes/no), living with parents (yes/no), or living with other (yes/no)]. Missing data were addressed through the construction of dummy variables. Separate multivariate models were constructed for coping strategies and coping behaviours.

Cancer screening examinations were included in our multivariate model as they have the potential to independently serve as indicators of general health awareness and health conscious behaviour among participants. Interactions were considered between significant coping behaviours/strategies and the relevant demographic variables gender and age. Global tests for proportionality were conducted for main analyses and stroke subtype analyses and did not reveal any significant deviation from the proportional hazards assumption. As overweight/obesity and blood pressure could be considered possible mediators for the association between coping styles and CVD,^14,15 additional subgroup analyses were conducted according to body mass index (BMI) (<25 or ≥25 kg/m²) and hypertension (systolic blood pressure ≥140 or diastolic blood pressure ≥90). Statistical analyses were performed using SAS (SAS software version 9.3; SAS Institute Inc., Cary, NC, USA) and the R statistical software (version 3.1.1; R Development Core Team, 2014). The significance level was set as P < 0.05.

Adjusted survival curves for CVD incidence and CVD mortality (Figure 2) were obtained by a conditional approach.¹⁶ Using a Cox regression model stratified on coping strategy and including the same variables as Model 2, each subject's covariate values were used to generate several predicted survival curves, one for each coping strategy. Then, the predicted survival curves were averaged by strategy.

Figure 2

Raw and adjusted coping strategy-specific survival curves for incidence of and mortality from cardiovascular diseases. Left panels: Kaplan–Meier estimate for the whole study population (blue line) and raw Kaplan–Meier estimates for each coping strategy; Right panels: Kaplan–Meier estimate for the study population (blue line) and coping strategy-specific survival curves adjusted for the variables included in the fully adjusted model (Model 2).

Results

When comparing excluded (persons from Tokyo/Osaka and non-responders to questions on coping) with included individuals, excluded individuals were more likely to be older, women, hypertensive, unemployed, take medications, live alone, drink less, smoke less, and were less likely to have undergone a health screening examination (data not shown).

The majority of included individuals (84.2%) did not adopt any particular coping strategy. The coping strategy most frequently used by participants was the approach-oriented coping strategy (13.3%) followed by the avoidance coping strategy (1.6%) and a combination of strategies (0.9%) (Table 1). The coping behaviours of positive reappraisal and planning were used by 21.8 and 19.9% of participants, respectively, but only 3.9% of respondents actively utilized avoidance. The majority of those who used planning (53.3%) were men, whereas the highest proportion of women was seen for consulting someone (69.0%). The approach coping, avoidance coping, and combined coping strategies were all used by the majority of women.

Table 1

Characteristics at starting point for subjects according to coping strategies and specific coping behaviours

Variable	Coping strategies				Coping behaviours
	No particular strategy	Approach coping	Avoidance coping	Combined coping	Planning		Consulting someone		Positive reappraisal		Fantasizing		Avoidance		Self-blame
					Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No
Number of subjects	47 991	7565	929	532	11 355	45 662	4732	52 285	12 405	44 612	3915	53 102	2225	54 792	2642	54 375
Proportion of total population (%)	84.2	13.3	1.6	0.9	19.9	80.1	8.3	91.7	21.8	78.2	6.9	93.1	3.9	96.1	4.6	95.4
Person-years of follow-up	376 689	60 454	7333	4184	90 280	358 380	37 381	411 280	99 032	349 628	30 776	417 885	17 551	431 110	20 901	427 759
Men (%)	47.4	48.5	34.7	35.7	53.3	45.7	31.1	48.7	46.1	47.6	36.7	48.0	40.5	47.5	38.2	47.7
Age [mean (years ± SD)]	60.4 ± 7.5	59.7 ± 7.2	59.4 ± 7.2	60.1 ± 7.4	60.0 ± 7.2	60.4 ± 7.5	59.8 ± 7.5	60.3 ± 7.4	59.8 ± 7.2	60.4 ± 7.5	59.4 ± 7.3	60.4 ± 7.4	60.6 ± 7.5	60.3 ± 7.4	59.3 ± 7.1	60.3 ± 7.4
Smoking status (%)
Never	63.1	62.7	69.2	74.0	60.0	64.1	74.0	62.3	64.2	63.0	69.0	62.9	66.4	63.2	69.6	63.0
Past	14.3	15.8	11.3	9.7	16.9	13.7	10.6	14.7	14.8	14.3	10.7	14.6	13.1	14.4	11.7	14.5
Current	22.6	21.6	19.6	16.4	23.1	22.2	15.5	23.0	21.1	22.7	20.3	22.5	20.6	22.4	18.7	22.5
Alcohol consumption (%)
None/occasional	62.7	59.5	66.8	67.1	57.7	63.6	70.9	61.6	61.5	62.6	65.4	62.2	65.1	62.3	66.0	62.2
<150 g ethanol/week	12.5	14.2	11.5	11.2	14.4	12.2	12.5	12.7	13.7	12.4	13.0	12.6	12.0	12.7	12.0	12.7
≥150 g ethanol/week	24.8	26.3	21.8	21.8	28.0	24.2	16.6	25.7	24.8	25.0	21.6	25.2	22.9	25.0	22.0	25.1
PAa mean (MET-hours/day ± SD)	40.8 ± 7.2	41.2 ± 7.0	41.7 ± 7.7	41.5 ± 7.7	41.1 ± 7.1	40.8 ± 7.2	40.6 ± 6.9	40.9 ± 7.2	41.3 ± 7.0	40.8 ± 7.2	41.3 ± 7.3	40.9 ± 7.2	41.3 ± 7.5	40.9 ± 7.2	41.5 ± 7.5	40.9 ± 7.2
BMI (%)
≤18.5 kg/m2	3.3	3.3	5.5	3.6	3.2	3.4	3.9	3.3	3.0	3.5	4.6	3.3	3.9	3.4	4.4	3.3
18.5–23 kg/m2	40.0	39.7	43.3	35.7	39.8	40.0	41.0	39.8	39.3	40.1	40.1	39.9	39.4	40.0	41.3	39.9
23–25 kg/m2	25.7	26.7	20.8	26.0	26.7	25.5	25.2	25.8	26.7	25.5	23.7	25.9	24.0	25.8	23.6	25.9
≥25 kg/m2	31.0	30.3	30.5	34.7	30.4	31.1	30.0	31.0	31.1	30.9	31.7	30.9	32.7	30.9	30.7	30.9
Hypertensionb (%)	36.4	32.0	37.9	35.4	33.7	36.3	32.7	36.1	32.8	36.7	34.6	35.9	36.4	35.7	35.6	35.8
Unemployment (%)	14.0	11.5	13.7	12.0	12.5	13.9	12.1	13.8	11.2	14.3	12.5	13.7	15.2	13.6	12.8	13.7
Screening examination (%)	86.4	89.6	86.1	88.4	89.1	86.2	90.4	86.5	88.8	86.2	87.3	86.8	85.2	86.9	87.4	86.8
History of diabetes disease (%)	5.9	5.6	7.2	7.3	5.9	5.9	5.3	5.9	5.6	6.0	6.5	5.8	5.7	5.9	6.4	5.9
Use of prescribed medications (%)	40.6	39.6	45.0	43.2	40.1	40.7	44.4	40.2	38.6	41.1	41.9	40.5	40.1	40.6	44.0	40.4
Living arrangements (%)
Living alone	6.0	6.2	7.9	6.8	6.0	6.1	6.5	6.1	6.1	6.1	6.7	6.1	7.9	6.0	7.0	6.1
Living with spouse	76.7	80.1	72.4	71.6	80.6	76.2	76.1	77.1	79.3	76.4	75.4	77.2	72.7	77.2	75.1	77.1
Living with children	53.3	52.5	53.5	53.4	52.4	53.4	55.9	52.9	53.0	53.2	55.2	53.0	53.6	53.2	51.9	53.2
Living with parents	15.6	16.0	15.1	13.7	16.1	15.5	15.9	15.6	15.7	15.6	15.7	15.6	13.5	15.7	15.3	15.7
Living with other	11.1	12.0	12.3	11.5	11.2	11.3	13.7	11.0	11.5	11.2	11.6	11.2	12.8	11.2	11.0	11.2

^aTotal physical activity.

^bHypertension defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90mm Hg.

Utilizers of the approach coping strategy had the lowest proportion overweight, hypertensive, unemployed, prescribed medication, and history of diabetes. They were also more likely to attend screening examinations. Similar results were seen when comparing active users with non-users of the approach- and avoidance-oriented coping behaviours.

Incidence of myocardial infarction and stroke

Mean follow-up time for incidence was 7.9 years. During follow-up, there were 304 MI and 1565 strokes among the 57 017 subjects. The 5-year cumulative probabilities of MI and stroke occurrence were estimated at 0.34 and 1.64%, respectively. Following multivariate adjustment, the approach-oriented coping strategy remained inversely associated with incidence of stroke (HR = 0.85; 95% CI, 0.73–1.00) (Table 2) but was no longer associated with CVD incidence (Figure 2). The coping behaviour fantasizing was positively associated with CVD incidence (HR = 1.24; 95% CI, 1.03–1.50).

Table 2

Cox proportional hazard models for the association between coping strategies/coping behaviours and incidence of cardiovascular disease, myocardial infarction, and stroke

Variable	Person-years	CVD			MI			Stroke
		Cases	Model 1a	Model 2b	Cases	Model 1a	Model 2b	Cases	Model1a	Model2b
			HR (95% CI)	HR (95% CI)		HR (95% CI)	HR (95% CI)		HR (95% CI)	HR (95% CI)
Coping strategies
No particular coping strategy	376 689	1610	Reference	Reference	258	Reference	Reference	1353	Reference	Reference
Approach coping	60 454	214	0.85* (0.74–0.99)	0.88 (0.76–1.02)	41	1.00 (0.72–1.39)	1.04 (0.74–1.44)	173	0.83* (0.71–0.97)	0.85* (0.73–1.00)
Avoidance coping	7333	26	0.97 (0.66–1.43)	0.92 (0.62–1.35)	4	1.02 (0.38–2.74)	0.97 (0.36–2.61)	22	0.96 (0.63–1.46)	0.91 (0.60–1.38)
Combined coping	4184	18	1.11 (0.69–1.76)	1.10 (0.69–1.75)	1	0.41 (0.06–2.94)	0.40 (0.06–2.88)	17	1.22 (0.76–1.98)	1.22 (0.76–1.97)
Coping behaviours
Planning
Yes	90 280	349	0.90 (0.79–1.03)	0.92 (0.81–1.05)	65	0.97 (0.71–1.32)	0.99 (0.72–1.35)	284	0.89 (0.77–1.03)	0.91 (0.79–1.05)
No	358 380	1519	Reference	Reference	239	Reference	Reference	1281	Reference	Reference
Consulting someone
Yes	37 381	138	1.03 (0.86–1.24)	1.03 (0.86–1.23)	23	1.11 (0.71–1.73)	1.10 (0.71–1.72)	115	1.02 (0.84–1.24)	1.01 (0.83–1.24)
No	411 280	1730	Reference	Reference	281	Reference	Reference	1450	Reference	Reference
Positive reappraisal
Yes	99 032	372	0.93 (0.82–1.06)	0.96 (0.85–1.10)	68	1.03 (0.76–1.41)	1.08 (0.79–1.48)	304	0.91 (0.79–1.05)	0.94 (0.82–1.09)
No	349 628	1496	Reference	Reference	236	Reference	Reference	1261	Reference	Reference
Fantasizing
Yes	30 776	134	1.28** (1.06–1.55)	1.24* (1.03–1.50)	23	1.41 (0.90–2.22)	1.36 (0.86–2.14)	111	1.26* (1.02–1.55)	1.22 (0.99–1.49)
No	417 885	1734	Reference	Reference	281	Reference	Reference	1454	Reference	Reference
Avoidance
Yes	17 551	69	0.94 (0.73–1.20)	0.92 (0.72–1.17)	7	0.55 (0.26–1.19)	0.54 (0.25–1.16)	62	1.01 (0.78–1.31)	0.99 (0.76–1.29)
No	431 110	1799	Reference	Reference	297	Reference	Reference	1503	Reference	Reference
Self-blame
Yes	20 901	77	0.96 (0.76–1.21)	0.95 (0.75–1.20)	12	0.96 (0.53–1.74)	0.95 (0.52–1.72)	65	0.96 (0.74–1.24)	0.95 (0.73–1.23)
No	427 759	1791	Reference	Reference	292	Reference	Reference	1500	Reference	Reference

Values in bold indicate significant results: *P < 0.05; **P < 0.01.

^aModel 1 is adjusted for age and gender.

^bModel 2 is additionally adjusted for alcohol consumption, smoking status, history of diabetes, total physical activity, prescribed medication use, unemployment, screening examination, living arrangements, and either (i) coping strategies or (ii) all coping behaviours.

Sub-analyses on incidence of stroke subtypes (see Supplementary material online, Table S1) indicated that an approach-oriented coping strategy was inversely associated with ischaemic stroke (HR = 0.79; 95% CI, 0.64–0.98) and inversely associated (albeit non-significantly) with sub-arachnoid haemorrhage while the combined coping strategy was associated with intra-parenchymal haemorrhage (HR = 2.03; 95% CI, 1.01–4.10). A planning behaviour was inversely associated with ischaemic stroke (HR = 0.82; 95% CI, 0.68–0.99).

Mortality

Mean follow-up time for mortality was 8.0 years. During this time there were 191 and 331 deaths from IHD and cerebrovascular disease, respectively. The 5-year cumulative probabilities of death from IHD and cerebrovascular disease were estimated, respectively, at 0.20 and 0.33%. In the multivariate analysis, those who used the approach coping strategy had a significantly reduced risk of CVD mortality (HR = 0.74; 95% CI, 0.55–0.99) (Table 3 and Figure 2). Positive reappraisal was inversely associated with IHD mortality (HR = 0.63; 95% CI, 0.40–0.99). Coping behaviours/strategies were not associated with mortality from cerebrovascular disease or any of the stroke subtypes (see Supplementary material online, Table S2).

Table 3

Cox-proportional hazard models for the association between coping strategies/coping behaviours and mortality from cardiovascular disease, ischaemic heart disease, and cerebrovascular disease

Variable	Person-years	CVD			IHD			Cerebrovascular disease
		Cases	Model 1a	Model2b	Cases	Model1a	Model2b	Cases	Model1a	Model2b
			HR (95% CI)	HR (95% CI)		HR (95% CI)	HR (95% CI)		HR (95% CI)	HR (95% CI)
Coping strategies
No particular coping strategy	382 010	461	Reference	Reference	168	Reference	Reference	293	Reference	Reference
Approach coping	61 219	50	0.70* (0.52–0.94)	0.74* (0.55–0.99)	17	0.66 (0.40–1.08)	0.70 (0.42–1.16)	33	0.73 (0.51–1.04)	0.76 (0.53–1.10)
Avoidance coping	7390	6	0.81 (0.36–1.81)	0.75 (0.33–1.67)	4	1.60 (0.59–4.31)	1.47 (0.54–3.96)	2	0.41 (0.10–1.63)	0.37 (0.09–1.49)
Combined coping	4262	5	1.08 (0.45–2.62)	1.06 (0.44–2.57)	2	1.29 (0.32–5.22)	1.25 (0.31–5.04)	3	0.98 (0.31–3.05)	0.97 (0.31–3.03)
Coping behaviours
Planning
Yes	91 505	86	0.85 (0.70–1.10)	0.89 (0.69–1.15)	35	1.08 (0.72–1.63)	1.13 (0.75–1.70)	51	0.74 (0.53–1.03)	0.77 (0.55–1.07)
No	363 376	436	Reference	Reference	156	Reference	Reference	280	Reference	Reference
Consulting someone
Yes	37 873	38	1.11 (0.79–1.57)	1.11 (0.78–1.56)	9	0.73 (0.37–1.45)	0.73 (0.37–1.46)	29	1.34 (0.90–1.99)	1.33 (0.89–1.98)
No	417 007	484	Reference	Reference	182	Reference	Reference	302	Reference	Reference
Positive reappraisal
Yes	100 310	85	0.75* (0.58–0.98)	0.79 (0.61–1.03)	27	0.59* (0.38–0.94)	0.63* (0.40–0.99)	58	0.85 (0.62–1.17)	0.90 (0.65–1.24)
No	354 570	437	Reference	Reference	164	Reference	Reference	273	Reference	Reference
Fantasizing
Yes	31 265	31	1.12 (0.76–1.64)	1.07 (0.73–1.57)	10	1.07 (0.55–2.11)	1.02 (0.52–2.01)	21	1.14 (0.71–1.82)	1.09 (0.68–1.74)
No	423 616	491	Reference	Reference	181	Reference	Reference	310	Reference	Reference
Avoidance
Yes	17 757	25	1.37 (0.91–2.07)	1.31 (0.86–1.98)	9	1.44 (0.72–2.87)	1.37 (0.69–2.74)	16	1.34 (0.80–2.25)	1.26 (0.75–2.11)
No	437 124	497	Reference	Reference	182	Reference	Reference	315	Reference	Reference
Self-blame
Yes	21 161	17	0.79 (0.48–1.31)	0.77 (0.47–1.27)	7	1.02 (0.47–2.24)	1.02 (0.47–2.24)	10	0.68 (0.35–1.30)	0.66 (0.35–1.26)
No	433 719	505	Reference	Reference	184	Reference	Reference	321	Reference	Reference

Values in bold indicate significant results: *P < 0.05.

^aModel 1 is adjusted for age and gender.

^bModel 2 is additionally adjusted for alcohol consumption, smoking status, history of diabetes, total physical activity, prescribed medication use, unemployment, screening examination, living arrangements, and either (i) coping strategies or (ii) all coping behaviours.

Interactions

Gender interacted significantly with coping strategy for the CVD mortality endpoint. In further gender-stratified analyses, the approach coping strategy was inversely associated with CVD mortality in men (HR = 0.57; 95% CI, 0.38–0.85) but not in women (data not shown).

Subgroup analyses

The behaviour of consulting someone was associated with an increased risk of mortality from cerebrovascular disease (HR = 1.69; 95% CI, 1.09–2.60) among those with BMI <25 kg/m². For individuals with BMI ≥25 kg/m², an approach coping strategy was inversely associated with both CVD incidence (HR = 0.62; 95% CI, 0.47–0.82) and stroke (HR = 0.56; 95% CI, 0.41–0.77) while a fantasizing behaviour was associated with cerebrovascular disease mortality (HR = 2.12; 95% CI, 1.04–4.32) (data not shown).

Normotensive individuals who utilized the behaviour of consulting someone were at an increased risk of cerebrovascular disease mortality (HR = 2.18; 95% CI, 1.22–3.88) and CVD mortality (HR = 1.70; 95% CI, 1.03–2.82). Utilizing an avoidance-oriented coping strategy was associated with IHD mortality only in hypertensive (HR = 3.46; 95% CI, 1.07–11.18) (data not shown).

Discussion

Our study is the first of its kind to address the association of premorbid baseline coping styles with CVD outcomes in a general population cohort. We have found that an approach-oriented coping strategy was associated with significantly reduced incidence of stroke and reduced CVD mortality. The specific coping behaviours fantasizing and positive reappraisal are associated with CVD incidence and reduced IHD mortality, respectively.

Possible interrelations between covariates and their relation to cardiovascular events in premorbid individuals are presented in Supplementary material online, Figure S1. Our findings of an inverse association between approach-oriented coping and mortality can, however, be explained without inferring any direct causality, in particular, when considering a number of important aspects. First, those who have been diagnosed with a disease must relate to additional behavioural variables influencing mortality, such as attending follow-up visits, accepting advice from health-care professionals, and complying with treatment. In fact, increased compliance with clinical appointments in newly diagnosed patients is significantly related to survival independent of severity of illness.¹⁷ Second, it is important to take into account the contextual nature of coping.^5,18 In the wake of a traumatic experience such as stroke, MI, or diagnosis of cancer, coping strategies and behaviours may change over time.¹⁹ Such changes could potentially be beneficial and lead to post-traumatic growth and improved lifestyle habits.²⁰ Patients with active coping styles seem to have a healthier emotional adjustment to their illness,²¹ and a proactive coping style has been shown to correlate with patient information-seeking and medical decision-making.²² Attitude towards medical care has already been suggested as a reason for decreased mortality among optimists,²³ and may possibly explain the reduced mortality with an approach-oriented coping strategy seen in our study.

The use of an approach-oriented coping strategy was associated only with reduced incidence of stroke. A reason why these associations were not found for MI or CVD incidence could be that we have adjusted for several behaviours known to be associated with disease initiation, all of which can also be considered as indirect measures of coping. In accordance with previous studies where coping was found to be associated with blood pressure^15,24 and overweight/obesity,¹⁴ two known risk factors and potential mediators of coping for cardiovascular events, the present study found that approach-oriented copers were less likely to be overweight, hypertensive, have a history of diabetes, or use any medications. Although our study is the first to report an association between coping strategies and CVD mortality, previous research has highlighted the importance of coping mechanisms for blood pressure control through its influence on lifestyle factors.²⁴ Indeed, in subgroup analyses, the use of an avoidance coping strategy was associated with an increased risk of IHD mortality among hypertensive individuals, whereas overweight/obese individuals utilizing an approach coping strategy were at reduced risk of both CVD incidence and stroke.

An important covariate to consider for disease prevention is the attendance of screening examinations, which is central for the detection of disease at an early phase. When adjusting for all the variables included in our analyses, the approach-oriented coping strategy and all three approach-oriented behaviours were significantly associated with attending screening examinations (data not shown). This suggests that a proactive individual is also more likely to participate in general health check-ups. Thus, in a generally healthy population, coping styles, unlike stress that is known to both directly and indirectly affect CVD risk,²⁵ exert an indirect influence on CVD risk factors.^14,15

Gender, age, and cultural differences may all influence the association between coping styles and cardiovascular outcomes. Our significant interaction between gender and coping strategy for CVD mortality is in accordance with previous studies that suggest a different role of coping in men and women's cardiovascular functioning.¹⁵ Future studies on the association between coping and CVD endpoints should therefore, when possible, consider gender-stratified analyses. Age may potentially also influence the impact of coping on health outcomes, although we found no significant interactions between age and coping in our study. However, compared with younger people, older individuals use problem-focused coping in perceived controllable situations²⁶ and may therefore possibly adopt approach-oriented coping on perceivably controllable health determinants, e.g. weight loss during overweight/obesity. Finally, there are ethnic differences in coping styles.^27,28 In our study, the avoidance coping strategy was associated with IHD mortality only among hypertensive individuals, which indicates that avoidance coping among Japanese not necessarily equates to maladaptive coping unless coupled with a pre-existing CVD risk factor. Future studies conducted on different populations would allow for comparisons of potential intercultural differences in coping with stress and the importance of these for cardiovascular outcomes.

There are several limitations in the present study. First, we must consider possible random misclassification; coping is a dynamic variable, but was estimated at only one point. In addition, participants have been assigned to specific dichotomous coping behaviours with the ensuing possibility of underestimating our findings. We may also have underestimated individuals who utilize the avoidance coping strategy or specific avoidance behaviours as they may be over-represented among those who were excluded due to non-response on coping questions.²⁹ Second, we have been unable to adjust for education or socioeconomic level, two important variables which can influence the coping repertoire. However, when including information on education available only for participants from cohort I of this study, associations between coping strategies and our endpoints were not substantially changed, but they were attenuated due to loss of statistical power owing to a low number of cases. Third, we have been unable to adjust for treatment-related factors (for mortality analyses). Fourth, we have excluded individuals from Tokyo and Osaka, and extrapolation of results to urban areas should be considered with caution. Crude stroke incidence density in the present study is, however, comparable to other Japanese cohorts such as the Circulatory Risk in Communities Study.³⁰ Finally, results may not be generalizable to other ethnicities.

Despite such limitations, this study is the first study on the association between coping behaviours/strategies and CVD incidence and mortality with a number of strengths. The JPHC study is the largest study in Japan to collect incident CVD data, has a large number of endpoints, and uses a validated coping questionnaire. Moreover, we have focused on baseline coping in healthy individuals while adjusting for a large number of confounders associated with incidence and mortality from IHD and stroke.

Conclusion

In a healthy general population, an approach-oriented coping style is significantly associated with reduced incidence of stroke and reduced mortality from CVDs. A likely explanation for the found associations is the indirect influence of coping strategies on CVD risk factors, indicating that improved education on stress management and coping strategies may improve lifestyle habits, participation rates in screening programmes, and compliance with treatment.

Supplementary material

Supplementary material is available at European Heart Journal online.

Authors’ contributions

T.S. and H.C. performed statistical analysis. M.I. and S.T. handled funding and supervision. M.I., N.S., K.Y., I.S., H.I., and S.T. acquired the data. T.S., M.I., N.K., and S.T. conceived and designed the research. T.S. drafted the manuscript; and M.I., N.S., K.Y., H.C., I.S., Y.K., H.I., N.K., K.S., M.M., and S.T. made critical revision of the manuscript for key intellectual content.

Funding

This study was supported by National Cancer Center Research and Development Fund (23-A-31[toku] and 26-A-2) (since 2011) and a Grant-in-Aid for Cancer Research from the Ministry of Health, Labour and Welfare of Japan (from 1989 to 2010). M.I. is the beneficiary of a financial contribution from the AXA Research fund as a chair holder on the AXA Department of Health and Human Security, Graduate School of Medicine, The University of Tokyo. The AXA Research Fund had no role in the design, data collection, analysis, interpretation or manuscript drafting, or in the decision to submit the manuscript for publication.

Conflict of interest: none declared.

Acknowledgements

T.S. is a Research Fellow of Japan Society for the Promotion of Science (JSPS). M.I. had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Appendix

Members of the Japan Public Health Center-based prospective Study (JPHC Study, principal investigator: S. Tsugane) Group are: S. Tsugane, N. Sawada, M. Iwasaki, S. Sasazuki, T. Shimazu, T. Yamaji, and T. Hanaoka, National Cancer Center, Tokyo, Japan; J. Ogata, S. Baba, T. Mannami, A. Okayama, and Y. Kokubo, National Cerebral and Cardiovascular Center, Osaka, Japan; K. Miyakawa, F. Saito, A. Koizumi, Y. Sano, I. Hashimoto, T. Ikuta, Y. Tanaba, H. Sato, Y. Roppongi, and T. Takashima, Iwate Prefectural Ninohe Public Health Center, Iwate, Japan; Y. Miyajima, N. Suzuki, S. Nagasawa, Y. Furusugi, N. Nagai, Y. Ito, S. Komatsu, and T. Minamizono, Akita Prefectural Yokote Public Health Center, Akita, Japan; H. Sanada, Y. Hatayama, F. Kobayashi, H. Uchino, Y. Shirai, T. Kondo, R. Sasaki, Y. Watanabe, Y. Miyagawa, Y. Kobayashi, M. Machida, K. Kobayashi, and M. Tsukada, Nagano Prefectural Saku Public Health Center, Nagano, Japan; Y. Kishimoto, E. Takara, T. Fukuyama, M. Kinjo, M. Irei, and H. Sakiyama, Okinawa Prefectural Chubu Public Health Center, Okinawa, Japan; K. Imoto, H. Yazawa, T. Seo, A. Seiko, F. Ito, F. Shoji, and R. Saito, Katsushika Public Health Center, Tokyo, Japan; A. Murata, K. Minato, K. Motegi, T. Fujieda, and S. Yamato, Ibaraki Prefectural Mito Public Health Center, Ibaraki, Japan; K. Matsui, T. Abe, M. Katagiri, M. Suzuki, and K. Matsui, Niigata Prefectural Kashiwazaki and Nagaoka Public Health Center, Niigata, Japan; M. Doi, A. Terao, Y. Ishikawa, and T. Tagami, Kochi Prefectural Chuo-higashi Public Health Center, Kochi, Japan; H. Sueta, H. Doi, M. Urata, N. Okamoto, F. Ide, and H. Goto, Nagasaki Prefectural Kamigoto Public Health Center, Nagasaki, Japan; H. Sakiyama, N. Onga, H. Takaesu, M. Uehara, T. Nakasone, and M. Yamakawa, Okinawa Prefectural Miyako Public Health Center, Okinawa, Japan; F. Horii, I. Asano, H. Yamaguchi, K. Aoki, S. Maruyama, M. Ichii, and M. Takano, Osaka Prefectural Suita Public Health Center, Osaka, Japan; Y. Tsubono, Tohoku University, Miyagi, Japan; K. Suzuki, Research Institute for Brain and Blood Vessels Akita, Akita, Japan; Y. Honda, K. Yamagishi, S. Sakurai, and N. Tsuchiya, University of Tsukuba, Ibaraki, Japan; M. Kabuto, National Institute for Environmental Studies, Ibaraki, Japan; M. Yamaguchi, Y. Matsumura, S. Sasaki, and S. Watanabe, National Institute of Health and Nutrition, Tokyo, Japan; M. Akabane, Tokyo University of Agriculture, Tokyo, Japan; T. Kadowaki and M. Inoue, The University of Tokyo, Tokyo, Japan; M. Noda and T. Mizoue, National Center for Global Health and Medicine, Tokyo, Japan; Y. Kawaguchi, Tokyo Medical and Dental University, Tokyo, Japan; Y. Takashima and Y. Yoshida, Kyorin University, Tokyo, Japan; K. Nakamura and R. Takachi, Niigata University, Niigata, Japan; J. Ishihara, Sagami Women's University, Kanagawa, Japan; S. Matsushima and S. Natsukawa, Saku General Hospital, Nagano, Japan; H. Shimizu, Sakihae Institute, Gifu, Japan; H. Sugimura, Hamamatsu University School of Medicine, Shizuoka, Japan; S. Tominaga, Aichi Cancer Center, Aichi, Japan; N. Hamajima, Nagoya University, Aichi, Japan; H. Iso and T. Sobue, Osaka University, Osaka, Japan; M. Iida, W. Ajiki, and A. Ioka, Osaka Medical Center for Cancer and Cardiovascular Disease, Osaka, Japan; S. Sato, Chiba Prefectural Institute of Public Health, Chiba, Japan; E. Maruyama, Kobe University, Hyogo, Japan; M. Konishi, K. Okada, and I. Saito, Ehime University, Ehime, Japan; N. Yasuda, Kochi University, Kochi, Japan; S. Kono, Kyushu University, Fukuoka, Japan; and S. Akiba, Kagoshima University, Kagoshima, Japan.

Author notes

†

Study group members are listed in Appendix.