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Psychoneuroendocrinology (2008) 33, 601–611

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Psychological coping styles and cortisolover the day in healthy older adults

Katie O’Donnella, Ellena Badrickb, Meena Kumarib, Andrew Steptoea,�

aPsychobiology Group, Department of Epidemiology and Public Health, University College London,1-19 Torrington Place, London WC1E 6BT, UKbWhitehall Group, Department of Epidemiology and Public Health, University College London,1-19 Torrington Place, London WC1E 6BT, UK

Received 26 October 2007; received in revised form 25 January 2008; accepted 30 January 2008

KEYWORDSCortisol;Stress;Coping;Cortisol awakeningresponse

nt matter & 2008uen.2008.01.015

thor. Tel.: +44 207

.steptoe@ucl.ac.u

SummaryPatterns of psychological coping are associated with a variety of health outcomes but theunderlying pathways are not yet established. The purpose of this study was to assess therelationship between salivary cortisol output over the course of a day and coping style.Data were available from 350 men and 192 women with an average age of 60.9 years.Participants were drawn from the Whitehall II cohort, and had no history of cardiovasculardisease. Individuals who were taking medication that might affect cortisol levels were alsoexcluded. Saliva samples were provided on waking, then 0.5, 2.5, 8 and 12 h after waking,and just before the participant went to sleep. Coping style was measured with a standardinstrument, the COPE, and data were factor analysed to generate three factors: seekingsocial support, problem engagement and problem avoidance. The relationships betweenthese factors and the cortisol awakening response (CAR), the slope of cortisol change overthe day and total cortisol output over the day (excluding the waking period) were assessedusing multiple linear regression. Cortisol output over the day was inversely associated withcoping with stress by seeking social support (p ¼ 0.034) and by problem engagement(p ¼ 0.003), independently of age, gender, body mass index, smoking, depression,self-rated health, time of waking and income. Individuals who coped by problemengagement and seeking support had lower cortisol levels. Additionally, gender, BMI,smoking, self-rated health and time of waking were independently related to cortisoloutput over the day. There were no significant associations between coping and the CAR orcortisol slope over the day. The results indicate that adaptive coping styles are related tolow levels of cortisol over the day, suggesting that neuroendocrine pathways may partlymediate relationships between psychological coping and health.& 2008 Elsevier Ltd. All rights reserved.

Elsevier Ltd. All rights reserved.

679 1804; fax: +44 207 916 8542.

k (A. Steptoe).

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K. O’Donnell et al.602

1. Introduction

Psychological coping can be defined as the thoughts andbehaviours used to manage the internal and externaldemands of situations that are appraised as stressful(Folkman and Moskowitz, 2004). Patterns of psychologicalcoping are associated with a variety of health outcomes, andare fundamental to an understanding of how stress affectspeople. Much coping research in the past has focussed onexamining how different coping styles relate to mentalhealth, but a number of studies have also attempted torelate different coping styles with physical health outcomes.These have produced varied results (Stanton et al., 2007).Penley et al. (2002) meta-analysed 34 studies, nine of whichexamined coping in relation to mainly self-reported physicalhealth outcomes. Although some did report a relationshipbetween coping and physical health, there were others whodid not. Results were heterogeneous, but in generalemotion-focused strategies such as distancing and avoidancewere negatively associated with health outcomes, whileproblem-focused strategies were more adaptive. Seekingsocial support had mixed effects. This analysis was limitedto studies which assessed coping via the Revised Ways ofCoping Questionnaire (Folkman and Lazarus, 1988a) or theWays of Coping Checklist (Vitaliano et al., 1985), but thereare other questionnaires widely used to assess copingmethods including the COPE scale (Carver et al., 1989).

Investigations in clinical populations indicate that copingstrategies can be linked to future outcomes. For example,Billings et al. (2000) demonstrated that social coping incaregivers predicted lower levels of physical symptoms inHIV/AIDs patients, while avoidant coping predicted moresymptoms. Additionally, emotionally expressive copingstrategies in cancer patients have been linked to fewermedical appointments and enhanced self-rated physicalhealth and vigour measured three months later (Stantonet al., 2000).

Many investigators have sought to explain relationshipsbetween coping and health in terms of behavioural inter-mediary responses. Lazarus (1991) suggested that denial/avoidance may cause people to delay medical treatment orparticipate in hazardous behaviour. On the other hand activecoping could lead people to seek medical help earlier andalso be more likely to adhere to medical regimes.

It is possible, however, that the relationship betweencoping and health is mediated by more direct psychobio-logical pathways (Biondi and Picardi, 1999). Vickers (1988)argued that the construct of ‘effective defence’, developedin the 1960s in studies of the parents of terminally illchildren, is associated with lower cortisol output. Personalmastery and sense of control have been related to greaterdecline in cortisol output over the day (Sjogren et al., 2006),and to lower overall secretion over the day (Vedhara et al.,2006). Evidence concerning specific coping strategies ismore limited. Rosenberger et al. (2004) examined copingstrategies and their relation to pain and knee functionfollowing arthroscopic knee surgery. Higher serum cortisollevels were related to both using high levels of avoidantcoping and poorer functioning in the early stages aftersurgery. The authors suggest that avoidant coping couldinfluence postoperative outcomes by affecting the bodies’hormonal balance.

Nicolson (1992) studied the role of coping responses tospecific stressors in everyday life by evaluating methods ofcoping with three different examination stress situations.Coping did not affect the magnitude of the cortisol responsebut it was related to the return of cortisol levels to baselinemeasures. Higher cortisol levels after the exam were relatedto ‘distraction’ and ‘comforting cognitions’ and lower levelsof cortisol following the exam were related to problem-oriented coping. Other studies have found inconsistentassociations between coping strategies and cortisol re-sponses to acute laboratory stressors (Bossert et al., 1988;Bohnen et al., 1991; van Eck et al., 1996).

Although cortisol activity has been postulated to reflectthe effectiveness of coping strategies (Nicolson, 1992), todate few studies have examined how general coping stylesrelate to overall cortisol levels in everyday settings. Cortisolhas a natural circadian rhythm with a sharp increase shortlyafter waking (the cortisol awakening response or CAR) anddecreasing levels over the day leading to a trough at night-time. These two features of cortisol output are regulateddifferently and are associated with different psychosocialfeatures (Wust et al., 2000; Steptoe, 2007).

The objective of this study was to examine whethergeneral psychological coping styles are related to the CAR orto cortisol levels over the course of a typical day (excludingthe waking period) in healthy middle-aged and older adults.We predicted that coping by active engagement withproblems would be associated with lower cortisol, whileavoidant coping would be correlated with elevated cortisol.At present, the optimal level of cortisol through the day isnot established, particularly for salivary values. But it isknown that both very high and very low cortisol outputs aredamaging to humans, as in Cushing’s and Addison’s diseases(Newell-Price et al., 2006). Some conditions such asfibromyalgia, chronic fatigue and posttraumatic stressdisorder are associated with hypocortisolism (Raison andMiller, 2003). There is also considerable evidence thatheightened corticosteroid levels raise risk for both centralnervous system and systemic pathology, and may contributeto impaired cognition, damage to the hippocampus, abdom-inal obesity, hypertension, coronary heart disease andimmune dysfunction (Herbert et al., 2006; Dhabhar andMcEwen, 2007; McEwen, 2007). We based our study there-fore on the notion that even modestly elevated cortisol ineveryday life may be indicative of chronic low levelactivation and increased risk of future disease.

The study excluded individuals with a history of cardio-vascular disease or those who were taking medications thatmight influence cortisol levels. Nevertheless, it is concei-vable that associations between cortisol and coping could besecondary to the heath status of participants, or could bedue to underlying associations of both coping and cortisolwith depressed mood. Self-rated health is a consistentpredictor of mortality and morbidity after conventional riskfactors and measures of health status have been taken intoaccount (Idler and Benyamini, 1997; Singh-Manoux et al.,2006). We therefore included self-ratings of health and astandard measure of depression as covariates in theanalyses.

There is evidence that patterns of coping change aspeople age. Socioemotional selectivity theory suggests thatthere is an adaptive narrowing of the social world of older

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Coping styles and cortisol over the day 603

people and a decreasing investment in activities and socialrelationships, coupled with a prioritisation of emotion overproblem-focused coping (Lockenhoff and Carstensen, 2004).It has also been argued that people accommodate to loss ofcontrol in particular domains with increasing age by down-scaling the value of the goal domain (Brandtstadter andRothermund, 1994). However, active coping may continue tobe adaptive in older age if challenges are potentiallymanageable. Thus, Wrosch et al. (2007) showed in a studyof community dwelling men and women aged 72 on averagethat health engagement control strategies (active copingresponses focused on health care) were associated withlower cortisol output over the day among individuals withself-reported health problems. Nevertheless, it is possiblethat associations between cortisol and coping stylesmight change with age. Consequently, we tested for inter-actions between coping styles and age in relation to cortisolin this study.

2. Methods

2.1. Study sample

The data were collected from a sub-sample of participantsfrom the Whitehall II epidemiological cohort. This wasoriginally set up in 1985 to investigate the social gradient ofhealth and disease, and involved 10,308 civil servants agedbetween 35 and 55 and based in London (Marmot et al.,1991). The participants are given a health screeningapproximately every five years and this sample wasrecruited during the 2003–2004 screening, which involvedextensive clinical, cognitive, physiological and question-naire measurements (see Marmot and Brunner, 2005, fordetails). 4609 (90.1%) of those asked to carry out cortisolsampling did so, and of these 748 out of 860 (86.9%)completed an additional coping questionnaire, administeredin the context of a study of heat shock proteins thatis not discussed here (Shamaei-Tousi et al., 2007). Ethicalapproval for the study was granted by the Joint Univer-sity College London/University College London HospitalsEthics Committee, and all participants gave informedconsent.

2.2. Cortisol sampling

Cortisol sampling was explained and practised during thehealth screening and participants were given a pack of sixsalivettes (Sarstedt, Leicester, UK) which they were asked touse over the course of a day to collect saliva. Saliva sampleswere to be collected without delay after waking followed bya salivette half an hour, two and a half hours, eight hoursand twelve hours after waking, with a final sample beingobtained just before bedtime. Time of waking was recordedalong with the actual times the saliva samples werecollected. Participants were asked to store salivettes indomestic refrigerators before posting them back to thelaboratory where they were frozen at �80 1C. The sampleswere subsequently sent to the University of Dresden to beanalysed by a time-resolved immunoassay with fluorescencedetection. Inter- and intra-assay coefficients of variance(CVs) were o8%.

2.3. Coping measure

The questionnaire was adapted from the COPE scale (Carveret al., 1989) and consisted of the four items from each ofthe following five scales: positive re-interpretation andgrowth, planning, seeking social support for instrumentalreasons, seeking social support for emotional reasons anddenial scales. Three of the four items from the mentaldisengagement scale were also included. One item ‘I sleepmore than usual’ was replaced with another item ‘I try toget away from the situation and not think about it’. Eachitem was scored on a 4-point scale (from 0 never to 3always). The danger of overburdening participants in theWhitehall II study with questionnaires prevented us fromincluding other scales from the COPE.

2.4. Other measures

Height and weight were both assessed using standardprocedures. Current smoking status and household incomewere assessed by questionnaire. Participants indicated thetotal income their household had received in the previous 12months on an 8-point scale and the responses weresubsequently split into three categories: less than £25,000,£25,00 to £69,999 and £70,000 and over. Income was used asan indicator of socioeconomic status. Depressed mood wasmeasured using the Center for Epidemiologic StudiesDepression (CES-D) scale, a widely used self-report ques-tionnaire (Radloff, 1977). Scores can range from 0 to 60,with higher scores indicating more depressed mood. Self-rated health was measured with a commonly used singleitem ‘In general, would you say your health is: excellent,very good, good, fair, or poor’ that has consistently beenshown to predict adverse health outcomes (Idler andBenyamini, 1997).

2.5. Statistical analysis

2.5.1. Factor analysisThe sub-scales of the COPE are known to cluster into higherorder coping factors (Carver et al., 1989; Zautra et al.,1996). The relationships between the 24 coping question-naire items were therefore examined by principal compo-nent analysis using varimax rotation. Examination of thescree plot revealed the presence of three factors that, takentogether, accounted for 47.37% of the variance in theoriginal data. The factor loadings (Table 1) revealed thatfactor one comprised the eight questions from the seekingsocial support for instrumental reasons and seeking socialsupport for emotional reasons sub-scales and was labelled‘seeking social support’. Factor loadings ranged from 0.56 to0.86. The second factor was composed of the eight itemsfrom the planning and positive reinterpretation and growthsub-scales and was labelled ‘problem engagement’. Factorloadings ranged from 0.62 to 0.77. The third factor wascomposed of seven items from the denial and mentaldisengagement sub-scales and was labelled ‘avoidant cop-ing’. Factor loadings ranged from 0.48 to 0.72. One item‘I turn to work or other activities to take my mind off things’had a factor loading of 0.32 and was not included in thefollowing analyses. Cronbach’s alphas for the three factors

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Table 1 Results of principal component analysis of the COPE scales.

Cope questionnaire sub-scale and items Factor

Seeking socialsupport

Problemengagement

Avoidantcoping

Seeking social support for instrumental reasonsI ask people who have had similar experiences what they did 0.56I try to get advice from someone about what to do 0.68I talk to someone to find out more about the situation 0.62I talk to someone who could do something concrete about the problem 0.67

Seeking social support for emotional reasonsI talk to someone about how I feel 0.86I try to get emotional support from friends or relatives 0.72I discuss my feelings with someone 0.80I get sympathy and understanding from someone 0.66

PlanningI try to come up with a strategy about what to do 0.77I make a plan of action 0.71I think hard about what steps to take 0.62I think about how I might best handle the problem 0.65

Positive re-interpretation and growthI look for something good in what is happening 0.63I try to see it in a different light, to make it seem more positive 0.70I learn something from the experience 0.68I try to grow as a person as a result of the experience 0.66

DenialI refuse to believe that it has happened 0.70I pretend it has not really happened 0.72I act as though it has not really happened 0.71I say to myself ‘this is not real’ 0.64

Mental disengagementI go the cinema or watch TV, to think about it less 0.50I daydream about other things 0.48I try to get away from the situation and not think about it 0.64

Eigenvalues 5.90 3.09 2.38Reliability (Cronbach’s alpha) 0.86 0.85 0.74

ScoresLowest score recorded 0 0.38 0Highest score recorded 3 3 2Mean score7SD 1.3670.50 1.7570.52 0.4870.38

Factor loadings above 0.40 are displayed.

K. O’Donnell et al.604

ranged from 0.74 for ‘avoidant coping’ to 0.86 for ‘seekingsocial support’ (Table 1). Scores for the three factors werecomputed by averaging responses on the relevant items. Thescores for each factor had a possible range of between 0 and3 and Table 1 demonstrates the range of scores actuallyrecorded for each factor. Analysis of variance followed byBonferroni comparisons demonstrated the avoidant copingfactor had a lower mean than either of the other two factors:t(747) ¼ 36.86; po0.001 and t(747) ¼ 51.25; po0.001 forthe seeking social support and problem engagement factors,respectively. There were no associations between scores onany of the coping factors and age. Scores on the seekingsocial support and problem engagement scales were positive

correlated (r ¼ 0.41, po0.001), but neither was significantlyassociated with avoidant coping scores.

2.5.2. Cortisol analysisAs part of the Whitehall II assessment programme, partici-pants underwent a thorough clinical screening (Marmot andBrunner, 2005). Participants who were taking medicationswhich could affect cortisol levels or who had a history ofcardiovascular disease were excluded from this study, so 630were available for cortisol analyses. Of these, 65 had nomeasurable cortisol on any sample, primarily due to failuresof collection or storage. Four aspects of the cortisol profile

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Coping styles and cortisol over the day 605

over the day were assessed: cortisol on waking, the CAR,cortisol output over the day and evening, and the slope ofcortisol decline between waking and evening. The CAR wasassessed by calculating the difference between the wakingsample and the sample 30min after waking (Clow et al.,2004). Of the 565 individuals with any cortisol samples, 547had cortisol data on both waking and 30min later. However,the CAR is affected by delays after waking in performing thefirst sample (Kunz-Ebrecht et al., 2004; Dockray et al., 2008),so 72 participants with a delay of more than 15min afterwaking, or for whom waking times and time of sample onewere not available, were excluded from the CAR analysis,leaving 475 individuals. The cortisol level on waking wasanalysed in 496 participants. Cortisol output over the day wasanalysed by calculating the area under the curve of the foursamples obtained between 2.5 h after waking and bedtime,using the procedure described by Pruessner et al. (2003).Twenty-two participants had one or more missing values, andone had excessively high values, so analysis of cortisol overthe day was carried out on 542 participants. The cortisolslope of change over the day was computed as the decreasein ouptut per hour between waking and bedtime values, andwas analysed in 479 individuals.

Separate multiple linear regressions were used to assessthe relationship between the three coping factors and thecortisol measures. Age, gender, body mass index, smokingstatus, time of awakening, income, CES-D depression andself-rated health were included as covariates. To testwhether the associations between coping and cortisol variedwith age, participants were divided into two categoriesaround the median age (61 years), and interaction termsrelating age with each of the coping factors were computedand entered into the regression models. The vast majority(89.5%) of the sample was of white European origin, so therewere insufficient numbers to analyse ethnic groups sepa-rately. All analyses were carried out using SPSS 14.0.

3. Results

3.1. Characteristics of the participants

Table 2 summarises the characteristics of the participantsincluded in the analysis of cortisol over the day. Reflecting

Table 2 Characteristics of study participants.

Men (N ¼ 350

Age (years) 61.1575.61Smoking status (current smokers) 30 (8.6%)BMI (kg/m2) 26.2573.82CES-D depression 7.9677.8Self-rated health (1–5) 2.3970.84

Incomeo£25,000 30.0%£25,000–£69,999 55.0%X£70,000 15.0%Wake up time 06:40761min

Mean7SD and n (%).

the overall demographics of the Whitehall II cohort, moremen than women were involved in this analysis with 65% ofthe participants being male and 35% female. The 462 (89.5%)were of white European origin. There were no significantdifferences in gender for age, BMI or smoking status. Theproportion of smokers was relatively low at 8.7%. Depressionratings were higher in women than men (po0.001) and self-rated health was worse (po0.001). Time of waking wastypical for this cohort with the average time of waking06:40 h (758min), and did not differ between men andwomen. Women had a lower household income than menwith 47.4% of women with a household income of less than£25,000 compared with 30.0% of men. Comparisons ofparticipants with partial and complete cortisol data overthe day revealed no differences on any of the variablesincluded in these analyses.

3.2. Cortisol profiles

Figure 1 demonstrates the average cortisol levels that wereproduced for each sample throughout the day. The expectedprofile was produced with cortisol levels rising on average by8.19711.43 nmol/l in the first half-hour after waking andthen decreasing throughout the rest of the day. Cortisolsamples throughout the day were taken 2 h 40min(719min), 8 h 17min (737min), 12 h 17min (743min)and 16 h 28min (766min) after waking, corresponding tothe average times indicated in Figure 1, indicating goodadherence to the timetable. Cortisol output over the day,computed as the area under the curse for readings 3–6,averaged 4945.172531.6 nmol/l, and was higher in menthan women (po0.001). The cortisol slope between wakingand bedtime averaged 0.8570.50 nmol/l/h.

3.3. CAR and cortisol levels on waking

The results of the multiple linear regressions on the CAR aresummarised in Table 3. None of the three coping factorswere related to the CAR. Smoking status and time of wakingwere both significant predictors of the CAR. The total R2 forthese models were 0.045, 0.049 and 0.045 for the seekingsocial support, problem engagement and avoidant copingfactors, respectively. As can be seen from Table 3, the CAR

) Women (N ¼ 192) p-Value

60.6275.54 0.2917 (8.9%) 0.9126.0074.87 0.5311.14710.0 0.0012.6670.90 0.001

47.4% 0.00148.5%4.1%06:41751min 0.75

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K. O’Donnell et al.606

was significantly larger in participants who smoked, and inthose who woke earlier in the morning. Additional controlfor waking cortisol levels did not alter these results, andthere were no interactions between coping scores and age.Nor was the cortisol level on waking itself associated withcoping by seeking social support (B ¼ �0.55, 95% C.I. �2.06to 0.95, p ¼ 0.47), problem engagement (B ¼ �0.95, C.I.�2.50 to 0.59, p ¼ 0.23), or avoidant coping (B ¼ �0.54,C.I. �2.79 to 1.70, p ¼ 0.64).

3.4. Cortisol output over the day and cortisol slope

Table 4 summarises the regressions on the cortisol outputover the day. Seeking social support had an inverserelationship with cortisol output over the day (p ¼ 0.034),independently of age, gender, BMI, smoking status, depres-sion, self-rated health, time of waking in the morning, and

Table 3 Regressions on cortisol awakening response.

Factor Regression coefficient (95%C.I.)

1Seeking social support 0.542 (�1.596 to 2.680)Age 0.054 (�0.156 to 0.264)Gender �0.925 (�3.238 to 1.387)BMI 0.091 (�0.169 to 0.351)Smoking status 5.461 (1.751 to 9.171)Depression �0.034 (�0.170 to 0.102)Self-rated health �0.609 (�2.014 to –0.795)Wake up time �0.026 (�0.045 to �0.006)Household income 0.576 (�1.339 to 2.491)

2Problem engagement 1.418 (�0.772 to 3.607)Complete model

3Avoidant coping 0.003 (�3.169 to 3.175)Complete model

Regression coefficients for covariates are not shown in models 2 anavailable on request).

0

5

10

15

20

25

30

06:44Average time of sample

Cor

tisol

leve

l nm

ol/l

07:15 09:21 14:57 18:58 23:08

Figure 1 Mean salivary cortisol over the six samples of the day.Standard errors of the mean (error bars) range from 0.12 to0.48 nmol/l for the different time points.

household income. The complete model accounted for 13.1%of the variance. Participants in the lowest quartile of copingby seeking social support had an average cortisol outputover the day of 5604.072889.2 nmol/l, compared with4947.872244.5 nmol/l for those in the highest quartile,after adjustment for covariates. This represents a 13.3%difference. Coping by problem engagement also had aninverse relationship with cortisol output over the dayindependently of covariates (p ¼ 0.003). The mean outputadjusted for covariates averaged 5831.773314.7 nmol/l and4816.171779.3 nmol/l in the lowest and highest problemengagement quartiles, a 21.1% difference. The total R2 forthis model was 0.140. Avoidant coping was not a significantpredictor of cortisol levels over the day. In all threeregressions on cortisol output over the day, gender, BMI,smoking status, wake up time and self-rated health weresignificant predictors. Women had lower cortisol levels overthe day than men, while smokers had higher levels ofcortisol over the day. Participants with greater BMIs andpoorer self-rated health had higher cortisol outputs over theday, and cortisol levels were also greater in individuals whowoke earlier in the morning. When all three coping factorswere entered in the same regression model, coping byproblem engagement remained a significant independentpredictor of cortisol output over the day, while coping byeliciting social support was not.

There were no significant interactions between ageor gender and coping styles in the analyses of cortisoloutput over the day. The slope of cortisol decline over theday was not associated with any of the factors included inthese models, or with coping by seeking social support(B ¼ �0.04, C.I. �0.14 to 0.06, p ¼ 0.43), problem engage-ment (B ¼ �0.03, C.I. �0.13 to 0.07, p ¼ 0.51), or avoidantcoping (B ¼ 0.01, 95% C.I. �0.14 to 0.15, p ¼ 0.96).

Standardisedregression coefficient

t-Test p Adjus-ted R2

0.024 0.50 0.620.027 0.51 0.61�0.040 �0.79 0.430.034 0.69 0.490.142 2.89 0.004�0.027 �0.50 0.62�0.048 �0.85 0.39�0.145 �2.92 0.0040.033 0.59 0.55 0.045

0.064 1.27 0.200.049

0.001 0.01 0.990.045

d 3, since they are similar to those in model 1 (complete data

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Table 4 Regressions on cortisol levels over the day.

Factor Regression coefficient (95% C.I.) Standardisedregressioncoefficient

t-Test P Adjus-ted R2

1Seeking social support �455.9 (�858.6 to �33.22) �0.093 �2.12 0.034Age 27.60 (�13.59 to 68.79) 0.064 1.32 0.19Gender �784.39 (�1238.3 to �330.48) �0.154 �3.39 0.001BMI �79.79 (�130.76 to �28.82) �0.138 �3.08 0.002Smoking status 1412.76 (665.95 to 2159.6) 0.164 3.72 0.001Depression �15.69 (�42.54 to 11.17) �0.057 �1.15 0.25Self-rated health 350.43 (74.34 to 626.52) 0.127 2.49 0.013Wake up time �0.166 (�0.227 to �0.105) �0.238 �5.38 0.001Household income 202.73 (�174.28 to 579.75) 0.054 1.06 0.29 0.131

2Problem engagement �647.44 (�1067.11 to �227.77) �0.135 �3.03 0.003Complete model 0.140

3Avoidant coping �435.35 (�1053.80 to 183.11) �0.065 �1.38 0.17Complete model 0.126

Regression coefficients for covariates are not shown in models 2 and 3, since they are similar to those in model 1 (complete dataavailable on request).

Coping styles and cortisol over the day 607

4. Discussion

The purpose of this study was to assess whether psycholo-gical coping styles are related to cortisol levels in everydaylife. Factor analysis of 24 items from the COPE scalerevealed the presence of three factors: problem engage-ment, seeking social support and avoidant coping. Indivi-duals who scored higher in either problem engagement orseeking social support had lower average cortisol outputover the day. The relationship was independent of gender,age, socioeconomic status, BMI, smoking status, depressionand self-rated health. Avoidant coping did not demonstratea significant relationship with cortisol levels. Additionally,neither the CAR nor slope of change in cortisol across theday were associated with any of the coping strategiesexamined.

We measured coping style in this study using a shortenedversion of the COPE (Carver et al., 1989). The COPE consistsof 13–15 scales (in different versions) describing a range ofmethods people might mobilise in response to stressfulexperiences in their lives. It has previously been used tostudy coping with a variety of issues including healthproblems like allergic illness, multiple sclerosis and hearttransplantation (Burker et al., 2005; Knibb and Horton,2008; Lode et al., 2007). We selected six scales thataddressed a range of coping options, and further reducedthese by factor analysis to three. Skinner et al. (2003) haveargued that common distinctions such as those betweenproblem and emotion-focused coping, or approach versusavoidance do not adequately summarise the richness ofcoping, and that a larger number of core ‘families’ of copingresponse can be identified. The three factors emerging fromthe factor analysis in this study (problem engagement,seeking social support and avoidant coping) are among the

core elements described in Skinner’s taxonomy. The factorsare similar to those defined in the Coping StrategiesIndicator (Amirkhan, 1990), and in previous higher orderfactor analyses of the COPE (Carver et al., 1989; Zautraet al., 1996).

As noted in the Introduction, the literature relatingcortisol with coping styles is limited. A number ofinvestigators have described associations between lack ofcontrol and cortisol, but this is more likely to reflect afailure of effective coping rather than the deployment ofany particular coping strategy (Adam et al., 2006; Sjogrenet al., 2006; Vedhara et al., 2006).

Our prediction that coping by problem engagement wouldbe associated with lower cortisol was confirmed. This resultcomplements other studies which have found a relationshipbeen adaptive coping strategies and cortisol reactivity andrecovery (Dienstbier, 1989; Bohnen et al., 1991; Nicolson,1992) and with decline of cortisol over the day (Sjogrenet al., 2006; Vedhara et al., 2006; Wrosch et al., 2007).

There is little research at present which examines seekingsocial support as a coping response and cortisol levels.Research which has looked at seeking social support andmental and physical health has found both positive andnegative outcomes, making it uncertain whether seekingsocial support is adaptive (Billings et al., 2000; Penley et al.,2002). Billings et al. (2000) suggest in the short term,eliciting social support can cause negative responses, butthat there are long term benefits of seeking social supportwhich could overshadow the short term costs. The designused here examining typical coping strategies may havebeen more likely to reflect long term benefits.

The lack of a relationship between avoidant coping andcortisol was not predicted and is somewhat inconsistent withprevious literature. For example, Nicolson (1992) found that

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K. O’Donnell et al.608

distraction techniques were correlated with a slowerdecline of cortisol levels after a stressor and Rosenbergeret al. (2004) demonstrated a positive relationship betweenhigh scores on avoidant coping and greater cortisolresponses to knee surgery. In our study, the scores on theavoidant factor were lower on average and had a smallerrange than either the problem engagement or seeking socialsupport scales, indicating that few participants reportedgreat use of this method of coping. This could explain thelack of any associations with cortisol.

We tested whether the relationships between copingstyles and cortisol might change with age. It has been arguedthat old age is associated with reduced reliance on socialrelationships and problem solving, and a prioritisation ofemotional regulation through methods such as distancingand avoidance (Blanchard-Fields et al., 2004; Lockenhoffand Carstensen, 2004). However, we did not detect anysignificant relationships between age and the use ofdifferent coping styles, or interactions between age andcoping styles in relation to cortisol. The reason may be thatmany of the changes in coping priorities with age have beenfound in samples that are several years older on averagethan the group we studied (Folkman and Lazarus, 1988b;Rothermund and Brandtstadter, 2003; Blanchard-Fieldset al., 2004).

The finding that coping strategies are associated withaverage cortisol levels over the day but not to wakingcortisol or the CAR is perhaps not surprising. Previous studieshave shown that these two aspects of the diurnal cortisolrhythm are regulated differently (Wust et al., 2000;Steptoe, 2007), and are subject to different psychosocialinfluences (Schmidt-Reinwald et al., 1999; Evans et al.,2007). We applied a rigorous timing criterion to the CARdata, so individuals who reported delaying more than 15minbetween waking and taking the waking sample wereexcluded from the analysis. This criterion was based onprevious experience with self-reported and objectiveindicators of waking in our laboratory (Kunz-Ebrecht et al.,2004; Dockray et al., 2008). As a result, a substantialnumber of participants were excluded from the CARanalysis. The mean CAR recorded in this study was8.43 nmol/l, equivalent to an increase of 51% which isconsistent with previous literature (Pruessner et al., 1997;Wust et al., 2000; Clow et al., 2004). Taken together, thesefactors indicate that the lack of a relationship between theCAR and coping methods is unlikely to be due to noncom-pliance with instructions. By contrast, cortisol output overthe day may be related to the ongoing demands andexperiences of the day (Adam et al., 2006), and theresponse to these events is likely to be affected by copingstyles.

We did not observe any associations between copingstyles and the slope of cortisol decline over the day.Although the slope over the day was calculated as differencebetween waking levels and values measured in the finalsample of the day, similar results were observed withmeasures based on regression coefficients for change overthe day. Flatter cortisol slopes have previously beenassociated with lower socioeconomic status (Cohen et al.,2006), greater tension and anger over the day (Adam et al.,2006), posttraumatic stress disorder (Aardal-Erikssonet al., 2001), and poor marital relationship quality in both

younger and older adults (Adam and Gunnar, 2001; Barnettet al., 2005). In another study, our group recently found norelationship between positive affect, psychological wellbeing and the slope of cortisol decline over the day (Steptoeet al., 2007). It is possible that cortisol slopes are morestrongly related to negative than protective psychosocialfactors.

Use of the COPE scale relies on self-report and does notallow verification of participants’ responses in times ofstress or an assessment of how effective their responsesactually are. What it does allow is an analysis of distinctcoping styles reported by the participants and their relationto a marker of HPA activity in a natural setting. Copingmeasures have been used as both state and trait measures(Folkman and Moskowitz, 2004). In this study subjects wererequired to indicate how they would typically respond in astressful situation and this may have caused their responsesto differ from those that would have been elicited if theyhad been asked to recall a specific stressful event and reporthow they coped at that time. Although retrospective reportsof coping strategies can be subject to recall bias, Folkmanand Moskowitz (2004) suggest that one advantage is theycan sometimes predict future outcomes more accuratelythan contemporary assessments of coping strategies. Inaddition, although trait measures are less robust when usedas predictors of cortisol levels in a specific situation(Nicolson, 1992), this study demonstrates that typical copingstrategies can be predictive of average cortisol output overa typical day.

Several other factors were associated with greater cortisoloutput over the day in this study, including smoking, BMI,self-rated health and time of waking. The association withsmoking has previously been described in an analysis of alarger sample from the Whitehall study (Badrick et al., 2007).Relationships with body mass have been inconsistent,depending on fat distribution, the method of assessingcortisol and on the time of day of assessments (Ljunget al., 2000; Duclos et al., 2005; Therrien et al., 2007). Theobservation that cortisol output over the day was higheramong participants who rated their health as poorer meritsfurther investigation. Previous studies have related self-ratedhealth with distinctive patterns of acute cortisol stressresponsivity (Adler et al., 2000; Kristenson et al., 2005),and Sjogren et al. (2006) found that the cortisol decreaseover the day was greater in individuals with better reportedhealth on a measure that incorporated the self-rated healthscale. Self-rated health problems were associated withelevated cortisol over the day in older adults, but only inthose who failed to cope with health difficulties using activeproblem solving methods (Wrosch et al., 2007). The associa-tion between cortisol output over the day and time of wakingis in part a product of the sample timing protocol. Sincesamples were collected at fixed intervals after waking,individuals who woke earlier also took samples over the dayat earlier time points. The circadian rhythm of cortisol outputis partly independent of time of waking (Wilhelm et al.,2007), the saliva samples of such individuals will typically beearlier in the day when cortisol levels are greater.

There were a number of limitations to the design of thisstudy. The sample was relatively homogeneous; all of theparticipants were civil servants, aged 51–72 years, 64% weremale and the vast majority were white. Therefore, it is not

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known if the results are extendable to other populations.The study was cross-sectional, so no causal conclusions canbe drawn. Compliance with the sampling times was assessedby self-report and it was not possible to assess the reliabilityof these reports objectively. Cortisol measures wereprovided over the course of a single day. Several investiga-tors have reported moderately consistent responses overdays, but repeated sampling over additional days wouldhave provided more information about the stability ofaverage cortisol production over the day (Kirschbaum andHellhammer, 2007). Additionally, we did not include severalother types of psychological coping such as coping byinformation seeking, delegation, proactive coping, andreligious coping.

The study also has several strengths. The sample sizewas large, with data collected from 542 participants, incomparison with much of the research in this field, adding tothe confidence with which the results can be viewed.Compared with studies that measured cortisol at one timepoint in blood or urine samples in clinics or laboratories(Vickers, 1988; Rosenberger et al., 2004), the more detailedmethod of obtaining several saliva samples meant that theprofile of cortisol output over a typical day could bemeasured. This allowed us to identify the correlates ofcoping both over the day and in the period immediatelyafter waking. Additionally, the inclusion of healthy indivi-duals in coping research is particularly important. If onlyindividuals with a health problem are examined, this mightmean that the physical challenges faced by participantscould mask any difference made to health by copingstrategies. Many physical health problems are related todisruption of the HPA axis (and therefore cortisol produc-tion) again effectively rendering any difference made bycoping strategy at this time difficult to identify.

The differences in cortisol output relating to psychologi-cal coping styles were small. This was expected, since thereare a number of other influences on cortisol levels includinggenetic, clinical, biological and psychosocial factors (Biondiand Picardi, 1999; Kirschbaum and Hellhammer, 2007).Coping style is just one element in a broader set ofdeterminants of cortisol levels. However, it is notable thatindividuals in the highest and lowest quartiles on thesecoping styles showed differences of 13.3% and 21.1% incortisol output over the day. Additionally, small differencesin everyday life that persist over months or years may havelong term consequences for adaptation to stress. Elevatedcortisol is implicated in a range of health problems includingabdominal adiposity and insulin resistance, cardiovasculardisease, diabetes, alcohol abuse and memory problems(Ehlert et al., 2001; Brown et al., 2004; Lupien et al., 2005).Follow-up of the participants in this study through continu-ing monitoring of the Whitehall II sample will determinewhether or not the elevated cortisol associated with lowlevels of coping by problem engagement and eliciting socialsupport predict adverse health outcomes in the future.

Role of the funding source

The funders of this research had no involvement with thedesign, execution or analysis of this study, or with thedrafting or approval of this article.

Conflict of interest statement

None declared.

Acknowledgements

This research was supported by the British Heart Founda-tion, the Medical Research Council and the Economic andSocial Research Council. We are grateful to the participantsof the Whitehall II cohort, Bev Murray and Ann Donald andher team for help with data collection and ClemensKirschbaum for carrying out the cortisol analyses.

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