Full research paper European Journal of Preventive Cardiology 2019, Vol. 26(17) 1877–1885 Exploring the interplay between job strain ! The European Society of Cardiology 2019 and different domains of physical activity Article reuse guidelines: sagepub.com/journals-permissions on the incidence of coronary heart disease DOI: 10.1177/2047487319852186 journals.sagepub.com/home/cpr in adult men

Marco M Ferrario1,2, Giovanni Veronesi1, Mattia Roncaioli3, Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 Andreas Holtermann4,5, Niklas Krause6, Els Clays7, Rossana Borchini1,2, Guido Grassi8 and Giancarlo Cesana9; on behalf of The Cohorts Collaborative Study in Northern Italy (CCSNI) Research Group

Abstract Aims: The aim of this study was to investigate the independent associations of occupational (OPA) and sport physical activity (SpPA) and job strain on the incidence of coronary heart disease (CHD) events, and to explore their interplay. Methods: The study sample included 3310 25–64-year-old employed men, free of CHD at baseline, recruited in three population-based and one factory-based cohorts. OPA and SpPA, and job strain were assessed by the Baecke and the Job Content Questionnaires, respectively. We estimated the associations between different domains of physical activity and job strain with CHD, adjusting for major risk factors using Cox models. Results: During follow-up (median¼14 years), 120 CHD events, fatal and non-fatal, occurred. In the entire sample, a higher CHD risk was found for high job strain (hazard ratio¼1.55, 95% confidence interval: 1.05–2.31). The joint effect of low OPA and high job strain was estimated as a hazard ratio of 2.53 (1.29–4.97; reference intermediate OPA with non-high strain). With respect to intermediate OPA workers, in stratified analysis when SpPA is none, low OPA workers had a hazard ratio of 2.13 (95% confidence interval: 1.19–3.81), increased to 3.95 (1.79–8.78) by the presence of high job strain. Low OPA–high job strain workers take great advantage from SpPA, reducing their risk up to 90%. In contrast, the protective effect of SpPA on CHD in other OPA–job strain categories was modest or even absent, in particular when OPA is high. Conclusions: Our study shows a protective effect of recommended and intermediate SpPA levels on CHD risk among sedentary male workers. When workers are jointly exposed to high job strain and sedentary work their risk further increases, but this group benefits most from regular sport physical activity.

Keywords Physical activity, job strain, coronary heart disease, preventive medicine, longitudinal studies

Received 11 February 2019; accepted 1 May 2019

1Research Centre in Epidemiology and Preventive Medicine, Department of Medicine and Surgery, School of Medicine, University of Insubria at 7 Varese, Italy Department of Public Health and Primary Care, Ghent University, 2 Belgium Occupational Medicine Unit, University Hospital of Varese, Italy 8 3School of Occupational Medicine, University of Insubria at Varese, Italy Clinic Medica, Department of Medicine and Surgery, University of 4 Milano-Bicocca, Milan, Italy The National Research Centre for Work Environment, Copenhagen, 9 Denmark Research Centre on Public Health, Department of Medicine and Surgery, 5Department of Sports Science and Clinical Biomechanics, University of University of Milano-Bicocca, Monza, Italy Southern Denmark, Odense, Denmark Corresponding author: 6Department of Environmental Health Sciences and Department of Marco M Ferrario, Research Centre on Epidemiology and Preventive Epidemiology, Fielding School of Public Health, and Southern California Medicine, Department of Medicine and Surgery, University of Insubria at NIOSH Education and Research Center, University of California Los Varese, Rossi building – Via O Rossi 9, 21100 Varese, Italy. Angeles, USA Email: [email protected] 1878 European Journal of Preventive Cardiology 26(17)

Introduction Methods In the late 1990s the WHO-MONICA Project docu- Study cohorts mented downward trends in the attack rates of myocar- dial infarction and stroke events in most Western We considered participants of three population-based Europe and attributed them to a reduced prevalence (the MONICA (Multinational Monitoring of Trends of major coronary heart disease (CHD) risk factors at and Determinants in Cardiovascular Disease) Brianza population level.1 Similar trends were later found in surveys II and III and the PAMELA (Pressioni selected East European countries as well.2 Arteriose Monitorate e Loro Associazioni) study) and Nevertheless in 2015 1.8 million CHD deaths were esti- one factory-based (the SEMM (Study of Employed in 3

mated to occur annually in Europe. These data bring the Municipality of Milan) study) prospective Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 attention to the efficacy of primary and secondary pre- cohorts.26–28 The study cohorts were recruited in the vention approaches, only the former capable of produ- same area (located north of Milan) over an eight-year cing effects on the population at large4 and in lower period (1989–1996) with baseline assessments carried socioeconomic strata where most events occur.5,6 In out by the same team of researchers and adopting the this context, the work environment may make a specific same standardized protocol.29 Participation rates and valuable contribution.7 ranged between 67% and 71% for population-based In 1991 Olsen and Kristensen estimated the aetio- cohorts, and were around 75% for the factory-based logic fractions for premature CVDs in Denmark due cohort. Local Ethical Committees of the University to exposures at the workplace to be 51% and 55%, in Hospital of Monza (MONICA-Brianza and men and women respectively, highlighting the major PAMELA) and Varese (SEMM study) approved contribution of stressful work conditions and physical these cohort studies. inactivity at work.8 Since then, perceived job stress as determined by the demand–control or the effort–reward Occupational and sport physical activity imbalance models has been consistently associated with CHD incidence.9–12 Consistent results document the We measured physical activity using the Baecke detrimental effects of sedentary work on CVD and Questionnaire,30 a reliable and valid tool31 to assess mortality.4,13 Meanwhile, evidence is emerging in sup- habitual occupational and sport physical activity in epi- port of the so-called health paradox of physical activity, demiological studies. Eight OPA items assess the par- indicating higher CVD rates among workers with ticipant’s main occupation: his/her self-rating of the intense physical activity at work.14–17 work’s vigour as compared with workers of the same The interplay between sport physical activity age; the frequency of sitting, standing, walking, lifting (SpPA) or leisure time physical activity (LTPA) and sweating at work; and the frequency of fatigue and occupational physical activity (OPA) on the risk after work. Each item score ranges from 1 to 5; the of CVDs has been re-evaluated,18–24 since more recent original OPA score is the average. We categorized the evidence is in support of a prominent protective effect OPA score into three classes according to sample ter- of SpPA among sedentary workers, but an opposite tiles, with cut-off values at 2.5 and 3.125. The four items effect was seen among workers with moderate and investigating sport activities during leisure time allowed strenuous levels of OPA, with an increment in risk the quantification of the absolute intensity based on from SpPA. metabolic equivalent of task32 as well as of the duration Finally, the interplay of different domains of phys- in ‘minutes per week’ of the activity. We derived a ical activity and work stress on the risk of CVD has three-class study variable24 based upon the American been poorly investigated. Kivima¨ ki et al., assessing the Heart Association (AHA) categories of none (0 min/ association between job stress and lifestyle factors in a week of activity); intermediate (1–149 min/week moder- North European large cohort pooled study, did find ate or 1–74 min/week vigorous or 1–149 min/week mod- an increased CHD risk in workers both exposed to erate plus vigorous activity); and recommended job strain and with poor LTPA.25 To tackle this lack (150 min/week moderate or 75 min/week vigorous of knowledge, the aim of our study is to investigate in or 150 moderate plus vigorous activity) sport physical a North Italian pooled cohorts study the independent activity.33 Given the complexity of studying the inter- associations of OPA and SpPA, as well as of job strain, play of OPA, SpPA and job strain, in survival analysis on the incidence of coronary heart disease events. the original variable was dichotomized as none versus A second aim is to explore the role of SpPA as effect intermediate/recommended SpPA. The association modifier for the associations of OPA, job strain and between the three-class OPA and SpPA variables with their combination on CHD risk. CHD has been previously published.24 Ferrario et al. 1879 Job strain leaving a final sample size of 3310 male workers. At baseline, the Job Content Questionnaire (JCQ)34 There was no difference in survival probability among was administered to all workers, using either the short included and excluded men (log-rank test MONICA-MOPSY35 in the MONICA-Brianza and p-value ¼ 0.8). We estimated the age-adjusted mean PAMELA cohorts or the extended version of JCQ36 (prevalence) of major CHD risk factors by OPA, job in the SEMM study. The two JCQ versions share the strain and SpPA categories from linear (logistic) regres- bulk of core items, each on a four-point scale ranging sion models, and tested differences among groups using from completely agree to completely disagree, which the Wald v2 test. A generalized logits model was used allow assessing equivalent ‘psychological job demand’ whenever the risk factor had more than two levels. To (PJD) and ‘decision latitude’ scores.37,38 We computed estimate the association of OPA, job strain and SpPA

PJD and decision latitude from the items satisfying a with the incidence of coronary events, we used Cox Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 preliminary construct validity assessment, as previously proportional hazards models, with age, cohort type described.11 We derived the standard four JCQ cate- (population vs. factory-based), educational level (low, gories (low strain, active, passive and high strain) intermediate and high) and major cardiovascular dis- based on the conventional quadrant approach using ease risk factors as potential confounders. Due to the sample medians as cut-off values for PJD and decision high collinearity between occupational classes and latitude. Given the complexity of studying the interplay OPA, we did not further adjust for occupation. With of a four-class job strain variable with OPA and SpPA, the same Cox regression approach, we estimated the in survival analysis low strain, passive and active were association between OPA and job strain with coronary combined with low strain into a unique non-high strain events according to SpPA levels, to investigate its category. The association between the four-class potential role as effect modifier. Finally, we explored job strain variable and CHD has been previously the combined effect of job strain and OPA by adding published.11 relevant OPA*job strain interaction terms in age and CHD risk factors-adjusted Cox regression models, and formally testing the presence of additive interaction on Assessment of other cardiovascular disease 2 risk factors at baseline the log(hazard ratio) scale with a Wald v test. This analysis was replicated stratifying according to SpPA Details on the risk factors included in this study (edu- levels. The analyses were performed using the Statistical cation, body mass index, blood lipids, systolic blood Analysis System (9.4 release; SAS Institute, Cary, pressure, current smoking, diabetes, alcohol intake) North Carolina, USA), while the figure was drawn have already been extensively published24,29,39 and are using R (version 3.1.3, 2015, The R Foundation for reported as Supplementary Material online. Statistical Computing, Wien, Austria).

Follow-up procedures and event definition Results The study endpoint was the first acute coronary event During a median follow-up time of 14 years (interquar- (fatal and non-fatal) as myocardial infarction, acute tile range 13–16 years), we observed 120 incident CHD coronary syndrome or coronary revascularization, events (fatal or non-fatal). Age-adjusted means and pro- whichever occurred first. Event ascertainment and adju- portions of demographic characteristics and CHD risk dication are described in the Supplementary Material. factor levels at baseline for OPA, job strain and SpPA Loss-to-follow-up rate was less than 4%, with no dif- categories are shown in Supplementary Tables S1, S2 ferences across study cohorts. and S3, respectively. As compared with the low OPA, workers in the high OPA category were more likely to be Statistical analysis in the high-strain class (p-value¼0.002) and less likely to meet SpPA recommended levels (p-value < 0.0001). Job The four study cohorts totalled 3991 and 6026 25–64- strain and SpPA were not associated. With respect to year-old men and women, respectively, who were free other established risk factors, OPA was positively asso- of cardiovascular disease and worked as salaried ciated with smoking, alcohol intake, high-density lipo- employees (executive, white and blue-collar workers) protein (HDL)-cholesterol. SpPA was positively related at baseline. Women were not included in these analyses to HDL-cholesterol and inversely to total cholesterol, due to the low number of events during follow-up body mass index and smoking. High job strain was (n ¼ 40). We excluded n ¼ 480 (12%) men due to miss- inversely associated with blood pressure. ing information on OPA or job strain, and a further Reciprocally-independent associations between OPA, n ¼ 201 (5%) for missing data in any CHD risk factor, SpPA and job strain with CHD are reported in Table 1, 1880 European Journal of Preventive Cardiology 26(17)

Table 1. Age-adjusted event rates and incrementally adjusted hazard ratios (with 95% confidence intervals) for incident coronary heart disease, by levels of occupational and sports physical activity and job strain.

n Events Rates Model 1 Model 2

Occupational physical activity Low 1264 60 2.91 1.56 (0.97; 2.53) 1.51 (0.93; 2.45) Intermediate 1036 25 1.93 Reference Reference High 1010 35 2.73 1.34 (0.79; 2.27) 1.43 (0.84; 2.44) p-value 0.19 0.22 Sport physical activity

None 2029 91 2.80 Reference Reference Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 Intermediate/recommended 1281 29 2.16 0.76 (0.50; 1.18) 0.91 (0.59; 1.40) p-value 0.22 0.67 Job strain Non-high strain 2367 81 2.22 Reference Reference High strain 943 39 3.43 1.55 (1.05; 2.29) 1.55 (1.05; 2.31) p-value 0.03 0.03

Rates ( 1000 person-years) are age-adjusted and estimated at the mean age of 40 years. Model 1: for each exposure variable, the model is adjusted for age, cohort, educational level, and the remaining two exposure variables. Model 2: Model 1 plus body mass index, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, current smoking, diabetes and alcohol intake. p-value: Wald heterogeneity v2 test (df equal to the number of categories minus 1).

Table 2. Age-adjusted event rates and incrementally adjusted hazard ratios (with 95% confidence intervals) for incident coronary heart disease, by occupational physical activity and job strain categories according to sport physical activity levels.

No SpPA Intermediate or recommended SpPA

n Events Ratesa HRb (95% CI) n Events Ratesa HRb (95% CI)

Occupational physical activity Low 740 49 4.31 2.13 (1.19; 3.81) 524 11 0.99 0.49 (0.17; 1.38) Intermediate 605 16 2.03 Reference 431 9 1.76 Reference High 684 26 2.96 1.42 (0.75; 2.69) 326 9 2.34 1.69 (0.55; 5.21) p-value 0.03 0.09 Job strain Non-high strain 1466 59 2.66 Reference 901 22 1.55 Reference High strain 563 32 4.54 1.78 (1.14; 2.78) 380 7 1.67 1.09 (0.42; 2.82) p-value 0.01 0.86 aAge-adjusted event rate ( 1000 person-years) at the age of 40 years. bAdjusted for: age, cohort type (population-based vs. factory-based), educational level, body mass index, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, current smoking, diabetes and alcohol intake. p-value: Wald heterogeneity v2 test (df equal to the number of categories minus 1). SpPA: sport physical activity; HR: hazard ratio; CI: confidence interval showing hazard ratios and 95% confidence intervals effect of SpPA attenuated when adjusting for CHD (CIs) adjusted for age, cohort and education and remain- risk factors. A CHD risk excess was found in high job ing two exposure categories in Model 1, and additionally strain workers, with a hazard ratio of 1.55 (1.05–2.29) adjusted for other major CHD risk factors in Model 2. when contrasted with the non-high job strain category. Keeping the intermediate OPA as the reference category, The association remained after the adjustment for major increased risks were found for both the low and high risk factors. OPA categories, although not statistically significant. Table 2 presents the results of the analysis of the Compared with no SpPA, intermediate or recommended association between OPA and job strain with the inci- levels of SpPA were associated with a 24% decrease in dence of CHD, stratified by the two SpPA categories of CHD risk, not statistically significant. The protective none and intermediate/recommended. When SpPA is Ferrario et al. 1881 none, low OPA workers showed an increased risk of 113% (hazard ratio¼2.13; CI 95% 1.19–3.81); and high strain workers had a hazard ratio of 1.78 (1.14–2.78) t smoking, (95% CI) when compared with the non-high strain category. b Both these risk excesses reduced or even disappeared HR in workers engaged in intermediate or recommended a

SpPA levels. However, among high OPA workers, g to the level of sport intermediate or recommended SpPA levels increased their CHD risk by 69%, although these estimates 29 were imprecise. The joint effects of OPA and job ¼

strain categories on CHD risk in the entire male Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 Events Rate sample and by SpPA levels are shown in Table 3 com-

pared with workers with intermediate OPA and non- 1281, CHD ¼ n high job strain. In the entire sample, high strain was Intermediate/recommended SpPA n consistently associated with increased risks of CHD across all OPA categories, highest and most precise risk estimates being found for workers with low OPA and high job strain (hazard ratio¼2.53, 95% CI: 1.29–

4.97). Among these workers, no SpPA exacerbates their (95% CI) b

risk further to a nearly four-fold increase (hazard HR ratio¼3.95, 95% CI 1.97–8.68).

Finally, as reported in Figure 1, for any combination a of OPA and job strain categories the age-adjusted CHD rates were lower for workers performing intermediate/ 91 recommended levels of SpPA, but this is more evident ¼ for low OPA and in particular for low OPA and high job strain workers. Among these two categories of Events Rate

workers, the age-adjusted rate ratios were 0.66 and 2029, CHD ¼ No SpPA n 0.1 (only the latter statistically significant), indicating n that the benefit in terms of CHD prevention is out- standing for sedentary workers and even larger when in addition they are exposed to high job strain. In con- trast, the protective effect of SpPA on CHD in other

OPA–job strain categories is absent, or the associations (95% CI) b are even reversed and become potentially harmful when HR 0.70 0.66 0.22 OPA is high. a Discussion 120

In this longitudinal cohort study based on North ¼ . factory-based), educational level, body mass index, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, curren

Italian working men, with respect to the intermediate vs OPA category, workers with low and high levels of Events Rate

OPA had an increased CHD risk of 51% and 43%, 3310, CHD respectively, although not statistically significant. ¼ All workers N – – – 0.13 – – – 0.03 – – – 0.28 n A recent meta-analysis17 reported similar results for the higher but not for the lower levels of OPA. The

higher CVD risk in sedentary people (mainly due to 1000 person-years) at the mean age of 40 years. the work component) was also found in some stu- c dies,40,41 but not in others,18,42 although differences in d -value endpoint definitions, in adopted methods to assess OPA p -value as well as the length of follow-up,24 may partly explain p the different results. Adjusted joint effect of occupational physical activity and job strain on incidence of coronary heart disease, among all workers (left) and accordin test (df 2). test (df 5). 2 2 v One finding of this paper is the 113% increased v CHD risk of sedentary work compared with intermedi- Wald Adjusted for: age, cohort type (population-based Wald Age-adjusted event rate ( Table 3. a b c d Interaction test diabetes and alcohol intake. physical activity (centre and right). OPA JS ate OPA in workers who are not engaged in SpPAs, LowLowIntermediateIntermediateHigh Non-high Non-highHigh High strain High strainHeterogeneity test 760 925 276 339 Non-high 16 40 High 20 9 strain 682 1.58 2.48 328 4.08 2.98 25 Reference 1.68 10 (0.93; 3.04) 2.53 2.12 (1.29; (0.92; 4.97) 4.87) 2.58 549 3.04 191 159 446 30 1.68 (0.88; 3.22) 19 10 2.22 6 (0.99; 4.97) 471 2.85 213 6.02 1.40 2.85 19 2.00 (0.97; 7 4.13) 3.95 (1.79; Reference 2.01 8.68) (0.72; 5.60) 2.51 376 148 2.73 117 10 1.68 (0.77; 314 3.66) 1 2.08 (0.78; 3 5.51) 211 6 1.87 115 0.59 6 3.33 1.14 (0.41; 3.20) 3 2.08 0.32 (0.04; 2.54 2.70) (0.62; 10.4) 2.98 Reference 4.25 1.89 (0.59; 6.05) 3.06 (0.74; 12.6) 1882 European Journal of Preventive Cardiology 26(17)

10 SpPA = none 10 SpPA = intermediate/recommended 4

8 rate ratio ( Age-adjusted 2

1 6 0.5

0.25

4 Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021

◊

0.10 )

2 Age-adjusted CHD rate (x 1000 p-y)

0.01 0 Non-hight JS High JS Non-high JSHigh JS Non-high JS High JS

Low OPA Inter OPA High OPA

Figure 1. Age-adjusted CHD event rates for none (grey bars) and intermediate/recommended sport physical activity levels (empty bars), and their rate ratios (diamonds), in non-high and in high job strain workers, according to occupational physical activity categories. Age-adjusted rate ratios: SpPA¼none as reference category. CHD: coronary heart disease; Inter: intermediate; JS: job strain; OPA: occupational physical activity; p-y: person years; SpPA: sport physical activity while this risk excess disappeared in workers engaging SpPA was confirmed.24 In addition, with the present in intermediate or recommended SpPA categories. analysis focusing on the combined effect of OPA and These results are consistent with the ones we recently job strain, we can recognize that we found a borderline published on the same cohorts,24 but in the current statistically significant excess incremental CHD risk of analyses the hazard ratios are also adjusted for job 122% in workers concurrently exposed to strenuous strain. For workers exposed to high strain we found work activities and job strain. In this category of work- in comparison with non-high strain an excess CHD ers, intermediate/recommended SpPA may actually risk of 55%. The adjustment for OPA and SpPA cate- exacerbate CHD risk, even if the low number of gories did not modify the CHD risk excess previously events requires caution in the interpretation of the found for high job strain,11 in support of the consist- results. Finally, a protective effect of regular SpPA in ency of the finding. leisure time on CHD has been extensively reported.32,33 Another finding of this study is the joint effect of What our study adds is the evidence that at least the OPA and job strain: when levels of OPA are low and intermediate AHA level of sport activities is able to job strain is high the CHD risk increases up to 153% in reduce the risk of CHD up to 90% among high-strain the entire sample, and up to 295% in the restricted sedentary workers, but apparently has minimal effects group of workers with no SpPA. These findings confirm in non-sedentary workers, whether exposed to job the higher CHD incidence rates found in a larger strain or not. If these findings are confirmed in larger pooled-cohort study,25 among people concurrently cohort studies, present CVD prevention guidelines4,33 exposed to job strain and unhealthy lifestyles, including may be revised considering personalized physical activ- LTPA. However, existing literature did not differentiate ity interventions tailored upon the workers’ exposure to between work and leisure time physical activity physical and psychosocial job conditions. domains, as we were able to do in the present study. The first limitation of this study is the small sample In fact when considering workers performing at least size, and the relatively small number of events (120 intermediate levels of SpPA, the risk excess in sedentary CHD first events). The second limitation, which follows workers with job strain disappeared. On the other from the first, is that we exclude women, due to the hand, the excess risk of physically strenuous work in even smaller number of CHD events (n ¼ 40), which combination with intermediate/recommended levels of further limited our ability to produce precise estimates Ferrario et al. 1883 of the interplay between OPA, SpPA and job strain. Author contribution Third, we do not have a reliable measure of working MMF originally conceived the research question, MMF, GV hours available for all the included cohorts. Another and MR drafted the manuscript and MMF and GV prepared limitation is the concurrent assessment of physical the revisions; MMF is the Principal Investigator (PI) of the activity and job strain, which does not allow us to dis- SEMM study, MMF and GC are co-PIs of the MONICA tinguish between the effect of SpPA on job strain, and Brianza cohorts and GG is PI for the PAMELA study. GV of job strain on SpPA. However, it has been shown in was responsible for the statistical analyses. AH, NK, EC, RB, prospective studies that performing sports in youth43 or GG and GC critically revised the text, with particular refer- sustained LTPA in adulthood44 can reduce job strain.45 ence to the introduction, the interpretation of results and the discussion sections. All gave final approval and agree to be These findings are supported by the results of studies accountable for all aspects of work ensuring integrity and showing positive effects of physical activity on depres- accuracy. Downloaded from https://academic.oup.com/eurjpc/article/26/17/1877/5925882 by guest on 28 September 2021 sion and anxiety as well as on psychosocial stress in healthy subjects and cardiovascular patients.46,47 On the other hand, some studies showed consistent Declaration of conflicting interests results in identifying subjects with poor job control The author(s) declared no potential conflicts of interest with and low rewards being at higher risk of no physical respect to the research, authorship, and/or publication of this activity during leisure time.45–51 So we can postulate article. circular feedbacks between no SpPA and high job strain to reinforce one another and as such determining Funding synergistic detrimental effects on CVD outcomes. The author(s) disclosed receipt of the following financial sup- Finally, job strain levels may have changed during port for the research, authorship, and/or publication of this follow-up upon modifications of the working condi- article: this work and the latest activities of the Brianza, tions or retirement. However, restricting the analyses PAMELA and SEMM cohorts have been funded by the to 24–50 years old (n ¼ 2654, CHD events ¼ 61), the Health Administration of the Lombardia Region (grants adjusted hazard ratio for high versus non-high job no. 17155/2004 and 10800/2009). The follow-up was partially strain did not change substantially. This is in agreement supported with grants from the Italian Ministry of Health with previous observations on long-term effects of job (grant 2012/597) and it was carried out in collaboration with the Department for Cardiovascular Dysmetabolic and strain on CVD risk.11 Ageing – Associated Diseases of the Istituto Superiore di In conclusion, our study conducted on North Sanita` in Rome. Italian male workers shows a prominent protective effect of AHA recommended and intermediate SpPA levels on CHD among sedentary workers, and an References opposite effect in individuals involved in physically 1. Kuulasmaa K, Tunstall-Pedoe H, Dobson A, et al.; for the demanding working tasks. Job strain is also associated WHO MONICA Project. Estimation of contribution of with an excess risk of CHD, but the joint condition of changes in classic risk factors to trends in coronary-event high job strain and sedentary work determined a con- rates across the WHO MONICA Project populations. Lancet 2000; 355: 675–687. siderable increase in risk. This group of workers may 2. De´ gano IR, Salomaa V, Veronesi, et al. Twenty-five-year benefit most from regular SpPA. Based on the evidence trends in myocardial infarction attack and mortality rates, of the protective effect of aerobic training on the Heart 52 and case-fatality, in six European populations. 2015; burden of atrial fibrillation and the recently pub- 101: 1413–1421. lished results of the association between job strain 3. Townsend N, Wilson L, Bhatnagar P, et al. 53 and the same disease, investigating the combined Cardiovascular disease in Europe: Epidemiological effect of different domains of physical activity and job update 2016. Eur Heart J 2016; 37: 3232–3245. strain with atrial fibrillation is of major interest for 4. Piepoli MF, Hoes AW, Agewall S, et al. 2016 European future studies. Due to the increasing number of seden- Guidelines on cardiovascular disease prevention in clinical tary workers in post-industrialized countries, interven- practice: The Sixth Joint Task Force of the European tions to promote SpPA in sedentary working male Society of Cardiology and Other Societies on populations could be an important factor to reduce Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of 10 societies and by the burden of CVDs. invited experts). Developed with the special contribution of the European Association for Cardiovascular Acknowledgements Prevention & Rehabilitation (EACPR). Eur Heart J This study was carried out under the coordination of The 2016; 37: 2315–2381. Cohorts Collaborative Study in Northern Italy (CCSNI) 5. Veronesi G, Ferrario MM, Kuulasmaa K, et al. Research Group. The authors are deeply grateful to col- Educational class inequalities in the incidence of coronary leagues who were involved in different study activities. heart disease in Europe. Heart 2016; 102: 958–65. 1884 European Journal of Preventive Cardiology 26(17)

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