High Occupational Physical Activity Research Articles

Occupational And Leisure-time Physical Activity And Risk Of Disability Pension

Objectives To prospectively investigate the association between occupational physical activity (OPA) and disability pension due to musculoskeletal cause, mental cause or any cause. We also examined the combined association of OPA and leisure-time physical activity (LTPA) with disability pension. Methods A population-based cohort study in Norway on 32 362 persons aged 20–65 years with questionnaire data on OPA and LTPA that were followed up for incident disability pension through the National Insurance Database. We used Cox regression to estimate adjusted HRs with 95% CIs. Results During a follow-up of 9.3 years, 3837 (12%) received disability pension. Compared with people with mostly sedentary work, those who performed much walking, much walking and lifting, and heavy physical work had HRs of 1.26 (95% CI 1.16 to 1.38), 1.44 (95% CI 1.32 to 1.58) and 1.48 (95% CI 1.33 to 1.70), respectively. These associations were stronger for disability pension due to musculoskeletal disorders, whereas there was no clear association between OPA and risk of disability pension due to mental disorders. People with high OPA and low LTPA had a HR of 1.77 (95% CI 1.58 to 1.98) for overall disability pension and HR of 2.56 (95% CI 2.10 to 3.11) for disability pension due to musculoskeletal disorders, versus low OPA and high LTPA. Conclusions We observed a positive association between OPA and risk of disability pension due to all causes and musculoskeletal disorders, but not for mental disorders. Physical activity during leisure time reduced some, but not all of the unfavourable effect of physically demanding work on risk of disability pension.

Does Aerobic Exercise Increase 24-Hour Ambulatory Blood Pressure Among Workers With High Occupational Physical Activity?-A RCT.

OBJECTIVEHigh occupational physical activity (OPA) increases cardiovascular risk and aerobic exercise has been recommended for reducing this risk. This paper investigates the effects of an aerobic exercise intervention on 24-hour ambulatory blood pressure (ABP) among cleaners with high OPA.METHODSHundred and sixteen cleaners between 18 and 65 years were randomized. During the 4-month intervention period, the aerobic exercise group (AE) (n = 57) performed worksite aerobic exercise (2 × 30 minutes/week), while the reference group (REF) (n = 59) attended lectures. Between-group differences in 4-month ABP changes were evaluated by intention-to-treat analysis using a repeated-measure 2 × 2 multiadjusted mixed-models design.RESULTSRelative to REF, 24-hour ABP significantly increased in AE: systolic 3.6 mm Hg (95% confidence interval (CI) 1.6–5.7) and diastolic 2.3 mm Hg (95% CI 0.9–3.8). Cleaners with high aerobic workload exhibited particularly high 24-hour ABP increases: systolic 6.0 mm Hg (95% CI 2.4–9.6), and diastolic 3.8 mm Hg (95% CI 1.3–6.4).CONCLUSIONAerobic exercise increased 24-hour ABP among cleaners. This adverse effect raises questions about the safety and intended benefits of aerobic exercise, especially among workers with high OPA and a demanding aerobic workload. http://www.controlled-trials.com/ISRCTN86682076. Unique identifier ISRCTN86682076.CLINICAL TRIAL REGISTRATIONTrial Number ISRCTN86682076.

Association of Occupational and Leisure-Time Physical Activity with Aerobic Capacity in a Working Population

IntroductionObjective data on the association of maximal aerobic capacity (VO2max) with work related physical activity are sparse. Thus, it is not clear whether occupational physical activity (OPA) contributes to an increase of VO2max. This study examined the association of VO2max with work and non-work related physical activity in a Swiss working population.MethodsIn this cross-sectional study, a total of 337 healthy and full-time employed adults were recruited. Demographic data, height, weight and BMI were recorded in all subjects. Participants were classified into nine occupational categories (ISCO-88) and merged into three groups with low, moderate, and high OPA. Physical activity was objectively measured by the SenseWear Mini Armband on seven consecutive days (23 hours per day). Participants were regarded as sufficiently active when accumulating ≥30 min of moderate-to-vigorous physical activity per day. VO2max was evaluated using the multistage 20-meter shuttle run test.ResultsData of 303 participants were considered for analysis (63% male, age 33 yrs, SD 12). Multiple linear regression analysis (adjusted R2 = 0.69) revealed significant positive associations of VO2max with leisure-time physical activity (LTPA) at vigorous intensity (β = 0.212) and sufficient moderate-to-vigorous physical activity (β = 0.100) on workdays. Female gender (β = -0.622), age (β = -0.264), BMI (β = -0.220), the ratio of maximum to resting heart rate (β = 0.192), occupational group (low vs. high OPA, β = -0.141), and smoking (β = -0.133) were also identified as independent predictors of VO2max.ConclusionsThe present results suggest that VO2max is positively associated with LTPA, but not with OPA on workdays. This finding emphasizes the need for employees to engage in sufficient high-intensity physical activity in recreation for maintaining or improving VO2max with regard to health benefits.

Long Term Effects on Risk Factors for Cardiovascular Disease after 12-Months of Aerobic Exercise Intervention - A Worksite RCT among Cleaners.

ObjectivesOccupational groups exposed to high occupational physical activity have an increased risk for cardiovascular disease (CVD). This may be explained by the high relative aerobic workload. Enhanced cardiorespiratory fitness reduces the relative aerobic workload. Thus, the aim was to evaluate the 12-months effects of worksite aerobic exercise on risk factors for CVD among cleaners.MethodsOne hundred and sixteen cleaners aged 18–65 years were randomized to a group performing aerobic exercise and a reference group receiving lectures. Outcomes were collected at baseline and after 12-months. A repeated measures 2×2 multi-adjusted mixed-model design was applied to compare the between-group differences using intention-to-treat analysis.ResultsBetween-group differences (p<0.05) were found favouring the aerobic exercise group: cardiorespiratory fitness 2.15 (SE 1.03) mlO2/min/kg, aerobic workload -2.15 (SE 1.06) %HRR, resting HR -5.31 (SE 1.61) beats/min, high sensitive C-reactive protein -0.65 (SE 0.24) μg/ml. The blood pressure was unaltered. Stratified analyses on relative aerobic workload at baseline revealed that those with relative aerobic workloads ≥30% of HRR seems to impose a notable adverse effect on resting and ambulatory blood pressure.ConclusionThis long-term worksite aerobic exercise intervention among cleaners led to several beneficial effects, but also potential adverse effects among those with high relative aerobic workloads.Trial RegistrationControlled-Trials.com ISRCTN86682076

Occupational physical activity, but not leisure-time physical activity increases the risk of atrial fibrillation: The Copenhagen City Heart Study.

Previous findings regarding physical activity and risk of incident atrial fibrillation (AF) are controversial, focusing on leisure-time physical activity (LTPA) and without distinguishing it from occupational physical activity (OPA). Our aim was to study the association between physical activity and risk of AF, with special attention to the possible divergent effects of OPA and LTPA. In a prospective, observational cohort study, 17,196 subjects were included from the Copenhagen Population Register. All participants had a physical examination, a 12-lead electrocardiogram (ECG), and answered a questionnaire regarding health and physical activity. Participants without previously diagnosed AF who answered adequately regarding OPA and LTPA were included. LTPA and OPA were each graded into four levels. Follow-up were carried out between 1981-1983, 1991-1994, and 2001-2003. Information regarding hospitalization and mortality was drawn from the National Patient Registry and the Registry of Causes of Death. Outcome was incident AF as determined by follow-up ECG or register diagnosis. In univariable Cox regression analysis all sub-groups of OPA had a significant higher risk of AF compared to moderate OPA. When adjusting for confounders, the risk remained significantly increased for high OPA (hazard ratio (HR) 1.21 (95% confidence interval (CI) 1.02-1.43), p = 0.028), and very high OPA (HR 1.39 (95% CI 1.03-1.88), p = 0.034). We found no significant association between LTPA and incident AF. High and very high OPA were associated with a significantly increased risk of incident AF. LTPA was not associated with risk of incident AF.

Effects of leisure-time and occupational physical activities on 20-year incidence of acute myocardial infarction: mediation and interaction

This study aimed to disentangle the interplay between occupational physical activity (OPA) and leisure-time physical activity (LTPA) in affecting cardiovascular health by examining: (i) interactions between OPA and LTPA and their combined effect on 20-year incidence of acute myocardial infarction (AMI) and (ii) the effect of OPA on AMI that is mediated through LTPA. We analyzed data on 1891 men, aged 42-60 years at baseline, from the prospective Kuopio Ischemic Heart Disease Risk Factor Study. OPA was measured as relative aerobic strain (RAS), accounting for workers' cardiorespiratory fitness. Averaged 12-month LTPA and potential confounders were assessed by questionnaires. Analyses were stratified by the presence of ischemic heart disease (IHD) at baseline. We found potential multiplicative, but not additive, interactions between OPA and LTPA among men with IHD. The multivariable Cox model, adjusted for age, education, smoking, alcohol consumption, psychosocial job factors, and participation in an unrelated drug trial, showed that high OPA positively predicted AMI at low LTPA levels for both men with and without IHD: hazard ratio (HR) 1.27 [95% confidence interval (95% CI) 0.96-1.68] and HR 1.59 (95% CI 0.99-1.68), respectively. The combination of high OPA and low LTPA constituted the group associated with the highest risk for AMI, irrespective of IHD status. LTPA was not independently predictive of AMI and did not mediate the impact of OPA on AMI. LTPA interacted with OPA on the multiplicative scale only. LTPA did not mediate the effect of OPA on AMI.

Midlife Occupational Physical Activity and Risk of Disability Later in Life: National Health and Aging Trends Study.

To determine whether midlife occupational physical activity (PA) is associated with disability in older adults and to test disease as a mediating variable. Cross-sectional study. National Health and Aging Trends Study. Individuals aged 65 and older (N = 7,307). Participants were classified as to occupational PA levels by linking information from the Occupational Information Network database using standard occupation codes. Disability outcomes and covariates were obtained through in-person interviews. Logistic regression models were used to examine the association between occupational PA and disability. Structural equation modeling (SEM) was fitted to examine the mediating effect of disease. Occupations with high physically demands were associated with greater decline in functional capacity later in life. Individuals with occupations with high and very high PA were less likely to be able to perform activities of daily living than those with occupations with low PA. SEM showed that occupational PA has a very strong direct effect on disability (P < .001) and has an indirect effect on disability through disease (P = .003). The population attributable fraction for high occupational PA was 11%. Higher midlife occupational PA levels were significantly associated with poorer ability to perform activities of daily living in older age. Performing the optimal level of occupational PA may be instrumental in reducing disability later in life.

Self-reported occupational physical activity and cardiorespiratory fitness: Importance for cardiovascular disease and all-cause mortality.

This study aimed to investigate whether workers with the combination of high occupational physical activity (OPA) and low cardiorespiratory fitness have an increased risk of cardiovascular disease (CVD) and all-cause mortality. Using multivariable Cox proportional hazards regression, we analyzed 2190 males and 2534 females from the Copenhagen City Heart Study, aged 20-67 years and with no known CVD at study entry in 1991-1994, for the risk of CVD and all-cause mortality from independent, stratified and combinations of self-reported OPA (ie, low, moderate and high) and cardiorespiratory fitness (low, same and higher as peers) at baseline. During a median follow-up of 18.5 years, 257 and 852 individuals died from CVD and any cause, respectively. In the fully-adjusted model, an increased risk for CVD mortality was found for those with low compared to high self-reported cardiorespiratory fitness [hazard ratio (HR) 2.17, 95% confidence interval (95% CI) 1.40-3.38), for those with high compared to low OPA (HR 1.45, 95% CI 1.05-2.00), and for those with high compared to low OPA within the strata of low self-reported cardiorespiratory fitness (HR 2.83, 95% CI 1.24-6.46). Moreover, those with the combination of high OPA and low self-reported cardiorespiratory fitness had an increased risk for CVD mortality compared to those with the combination of low OPA and high self-reported cardiorespiratory fitness (HR 6.22, 95% CI 2.67-14.49). Rather similar, but lower risk estimates were found for all-cause mortality. These findings may have important implications for CVD prevention among workers with excessive cardiovascular strain at work.

Leisure-time exercise, physical activity during work and commuting, and risk of metabolic syndrome.

Data are limited regarding effect of intensity of leisure-time physical activity on metabolic syndrome. Furthermore, no prospective data are available regarding effect of occupational and commuting physical activity on metabolic syndrome. We compared metabolic syndrome risk by intensity level of leisure-time exercise and by occupational and commuting physical activity in Japanese workers. We followed 22,383 participants, aged 30-64years, without metabolic syndrome until 2014 March (maximum, 5years of follow-up). Physical activity was self-reported. Metabolic syndrome was defined by the Joint Statement criteria. We used Cox regression models to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of metabolic syndrome. During a mean follow-up of 4.1years, 5361 workers developed metabolic syndrome. After adjustment for covariates, compared with engaging in no exercise, the HRs (95% CIs) for <7.5, 7.5 to <16.5, and ≥16.5 metabolic equivalent hours of exercise per week were 0.99 (0.90, 1.08), 0.99 (0.90, 1.10), and 0.95 (0.83, 1.08), respectively, among individuals engaging in moderate-intensity exercise alone; 0.93 (0.75, 1.14), 0.81 (0.64, 1.02), and 0.84 (0.66, 1.06), among individuals engaging in vigorous-intensity exercise alone; and 0.90 (0.70, 1.17), 0.74 (0.62, 0.89), and 0.81 (0.69, 0.96) among individuals engaging in the two intensities. Higher occupational physical activity was weakly but significantly associated with lower risk of metabolic syndrome. Walking to and from work was not associated with metabolic syndrome. Vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise and worksite intervention for physical activity may help prevent metabolic syndrome for Japanese workers.

High risk of fall, poor physical function, and low grip strength in men with fracture-the STRAMBO study.

BackgroundSeveral studies assessed the association of prevalent fractures with muscle mass, strength, and physical capacity in men. Clinical impact of these associations is not clear, and they could be influenced by confounders. Our aim was to assess the association of the prevalent fractures with muscle strength, physical function, and the risk of subsequent falls in older men after adjustment for muscle mass and potential confounders.MethodsIn a cohort of 890 men aged 50 and older, we assessed appendicular skeletal muscle mass (ASM) by DXA, grip strength, physical function (chair stands, static, and dynamic balance). Relative ASM (RASM) was calculated as ASM / (height)2. Then, 813 men aged 60 and over were followed up prospectively for 5 years and 144 sustained >1 incident falls. All the analyses were adjusted for lifestyle factors, co‐morbidities, and hormones known to influence muscle and physical function.ResultsLow leisure physical activity, very high occupational physical activity, Parkinson's disease, diabetes mellitus, low apparent free testosterone concentration (AFTC), as well as Grade 2 and 3 vertebral fractures and multiple fractures were associated with lower grip strength when adjusted for confounders including upper limb RASM. Low leisure physical activity, very high occupational physical activity, diabetes mellitus, prior stroke, low AFTC and 25‐hydroxycholecalciferol, high C‐reactive protein, vertebral fractures, and non‐vertebral fractures were associated with poor physical function (lowest quintile of the score of tests) when adjusted for confounders including lower limb RASM. Grade 2 and 3 and multiple vertebral fractures were associated with twofold higher risk of multiple falls after adjustment for confounders. Men having multiple fractures had a twofold higher risk of multiple falls after adjusting for confounders. In multivariable models, risk of falls increased proportionally to the increasing severity and number of vertebral fractures as well as to the increasing number of all fractures.ConclusionsIn older men, Grade 2 and 3 vertebral fractures and multiple vertebral and non‐vertebral fractures are associated with lower grip strength, poor physical function, and higher risk of multiple falls after adjustment for multiple confounders. This suggests a real direct association. One fracture can initiate a vicious circle leading to another fracture; thus, patients with fractures need physical therapy regardless of their general health status.

Effects of high occupational physical activity, aging, and exercise on heart rate variability among male workers.

ObjectivesEffects of aging and leisure time physical activity (LPA) might influence the effect of occupational physical activity (OPA) on risk for cardiovascular disease (CVD). This study was conducted to determine whether OPA affects CVD after controlling the effects of LPA and other risk factors for CVD such as job stress.MethodsParticipants were 131 male Korean manual workers. Tests for heart rate variability (HRV) were conducted for five minutes in the morning at work. We defined OPA as the combined concept of relative heart rate ratio (RHR), evaluated using a heart rate monitor.ResultsWhereas high OPA was not related to any HRV items in the younger age group, high OPA was associated with an increased number of low-value cases among all HRV items in older workers. Exercise had beneficial effects only in the younger group. After controlling for exercise and other risk factors, the odds ratios of the root-mean square of the difference of successive normal R-R intervals (rMSSD) and high frequency band power (HF) among the older age and high OPA group compared with the younger age and low OPA group were 64.0 and 18.5, respectively. Social support and shift work were independent risk factors in HRV.ConclusionsOPA in aging workers increases CVD risks. This study provides support for the need for protection of aging workers from physical work overload, and indicates the need for further study of optimal limits of OPA.

Time trends in physical activity from 1982 to 2012 in Finland.

The aim of this study was to examine population trends from 1982 to 2012 in Finland for leisure time physical activity (LTPA), commuting physical activity (CPA), occupational physical activity (OPA), and total physical activity. Furthermore, time trends in physical activity by educational levels and body mass index (BMI) categories were explored. Data were collected in independent cross-sectional population surveys, implemented every 5 years from 1982 to 2012. The data comprised 21,903 men and 24,311 women. Participants underwent a health examination and filled in questionnaires. Information on LTPA, CPA, and OPA was used both separately and combined to create an index of total physical activity. Between 1982 and 2012, high LTPA has increased in men (from 21% to 33%) and women (from 12% to 27%). High CPA and high OPA have decreased in men (from 17% to 12% and from 48% to 36%, respectively) and women (from 30% to 20% and from 26% to 21%, respectively). Total physical activity has remained fairly stable. Differences by education and BMI have increased, particularly for LTPA. Marked changes in physical activity have taken place over time. Differences in LTPA and OPA have grown wider across educational groups and BMI categories.

Does aerobic exercise improve or impair cardiorespiratory fitness and health among cleaners? A cluster randomized controlled trial.

It is unknown if aerobic exercise overloads or improves the cardiovascular system among workers with high occupational physical activity. This was investigated in a worksite randomized controlled trial (RCT) of aerobic exercise among cleaners. We randomized 116 cleaners between 18-65 years. The aerobic exercise group (N=57) performed worksite aerobic exercise (30 minutes twice a week) and the reference group (N=59) received lectures. Cardiorespiratory fitness, blood pressure (BP) and diurnal heart rate (HR) for measuring aerobic workload [% HR reserve (% HRR)] were collected at baseline and after four months. A repeated measure 2×2 multi-adjusted mixed-model design was applied to compare the between-group differences in an intention-to-treat analysis. Between-group differences (P<0.01) were found: cardiorespiratory fitness 2.2 [standard error (SE) 0.8] ml O 2 × min -1 × kg -1 [95% confidence interval (95% CI) 0.6-3.8], aerobic workload - 3.5 (SE 1.2) % HRR (95% CI - 5.9- -1.0), resting HR -3.8 (SE 1.2) bpm (95 % CI -6.1- - 1.4), sleeping HR -3.8 (SE 1.1) bpm (95% CI - 5.9- - 1.7), and systolic BP 3.6 (SE 1.3) mmHg (95% CI 1.1-6.0). Worksite aerobic exercise seems to improve cardiorespiratory fitness, aerobic workload, and resting and sleeping HR, but increase systolic BP among cleaners. Beneficial physiological cardiovascular effects are seen from aerobic exercise, but also a harmful effect is evident. Therefore, recommendations should take into consideration the potential cardiovascular overload from additional aerobic exercise on workers with high levels of occupational physical activity.

High occupational physical activity and risk of ischaemic heart disease in women: the interplay with physical activity during leisure time.

Recent studies indicate that physically demanding work is a risk factor for heart disease among men, especially those with low or moderate physical activity during leisure time. Among women, present evidence is inconclusive. The design was a prospective cohort study. This investigation in the Danish Nurse Cohort Study included 12,093 female nurses aged 45-64 years, who answered a self-report questionnaire on physical activity at work and during leisure time, known risk factors for ischaemic heart disease (IHD) and occupational factors at baseline in 1993. Information on the 15-year incidence of IHD was obtained by individual linkage in the National Register of Hospital Discharges to 2008. During follow-up 580 participants were hospitalised with IHD. A significant interaction between occupational and leisure time physical activity was found with the lowest risk of IHD among nurses with the combination of moderate physical activity at work and vigorous physical activity during leisure time. Compared to this group high physical activity at work was associated with a higher risk of IHD at all levels of physical activity during leisure time increasing from hazard ratio 1.75 (95% confidence interval (CI) 1.10-2.80) among nurses with vigorous physical activity during leisure time to 2.65 (95% CI 1.44-4.88) among nurses being sedentary during leisure time. This study among Danish nurses suggests that high physical activity at work is a risk factor for IHD among women. Vigorous physical activity during leisure time lowered but did not completely counteract the adverse effect of occupational physical activity on risk of IHD.

Rotating night shift work and physical activity of nurses and midwives in the cross-sectional study in Łódź, Poland

Shift work have been thought to restrict participation in leisure time activities, but the knowledge about physical activity in rotating night shift nurses has been limited so far. We investigated the associations between the rotating night shift work and physical activity using data from a cross-sectional study among nurses and midwives. This study included 354 nurses and midwives (aged 40–60) currently working rotating night shifts and 371 ones working days only. The information on the work characteristics and potential covariates was collected via a personal interview. Weight and height were measured and BMI was calculated. Physical activity was assessed according to the international questionnaire on physical activity – IPAQ, and four domains: leisure time, occupational, transport related and household were analyzed. Women who reported none leisure time activity were defined as recreationally “inactive”. The associations were examined with multiple linear or logistic regression models adjusted for age, season of the year, number of full term births, marital status and BMI. Total and occupational physical activity was significantly higher among nurses working rotating night shifts. However, leisure time activity was significantly affected among rotating night shift nurses and midwives, compared to women working during the days only, with increased odds ratio for recreational “inactivity” (OR = 1.57, 95% CI: 1.11–2.20). Rotating night shift work among nurses and midwives is associated with higher occupational physical activity but lower leisure time activity. Initiatives supporting exercising among night shift workers are recommended.

Effects of leisure-time and occupational physical activity on total mortality risk in NHANES III according to sex, ethnicity, central obesity, and age.

Associations of physical activity with all-cause mortality seem to be quite strong, but little is known about potential effect modifiers as sex, race/ethnicity, age, and obesity. Data of the Third National Health and Nutrition Examination Survey (NHANES III), conducted 1988-1994 with mortality follow-up until 2006, were used to compare mortality risk between different levels of leisure-time physical activity (LTPA) and occupational physical activity (OPA). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). LTPA (n = 15,307) was inversely associated with all-cause mortality (HR 0.75, 95% CI 0.64-0.88 for regular vs. no LTPA). There was a statistically significant interaction with age (P = .03), with participants over 60 years of age benefitting more from regular or irregular LTPA. OPA was positively associated with all-cause mortality (HR 1.25, 95% CI 0.85-1.84 for high vs. low OPA), particularly among Mexican-Americans (HR 2.28, 95% CI 1.23-4.22); statistically significant interactions were observed for obesity and gender. LTPA clearly predicts all-cause mortality. However, associations between OPA and all-cause mortality are unclear and need further research with special regard to ethnic differences.

The Combined Relationship of Occupational and Leisure-Time Physical Activity With All-Cause Mortality Among Men, Accounting for Physical Fitness

The aim of this study was to assess the combined relationship of occupational physical activity and leisure-time physical activity with all-cause mortality among men, while accounting for physical fitness. The prospective Belgian Physical Fitness Study included 1,456 male workers aged 40-55 years who were free of coronary heart disease at baseline. Baseline data were collected through questionnaires and clinical examinations from 1976 to 1978. To estimate physical fitness, a submaximal graded exercise test was performed on a bicycle ergometer. Total mortality was registered during a mean follow-up period of 16.9 years. Main results were obtained through Cox proportional hazards regression analysis. A total of 145 deaths were registered during follow-up. After adjustment for confounders, a significantly increased mortality rate was observed in workers who had low levels of both physical activity types (hazard ratio = 2.07, 95% confidence interval: 1.03, 4.19) but also in workers combining high occupational physical activity and low leisure-time physical activity (hazard ratio = 2.04, 95% confidence interval: 1.07, 3.91); the latter finding was particularly pronounced among workers with a low physical fitness level. The present results confirm the existence of a complex interplay among different physical activity settings and fitness levels in predicting mortality.

Abstract A47: Lifetime occupational physical activity and lung cancer risk in men and women

Abstract The majority of epidemiological studies investigating the relationship between physical activity (PA) and lung cancer risk support the role of recreational PA in lung cancer risk reduction. There have been fewer studies that have examined occupational PA in relation to lung cancer risk and inconclusive results have been reported with some evidence supporting a positive association. In most of these studies, the assessment of occupational PA was crude, based either on self-reported cross-sectional assessments or simple job title-based categorizations. Consideration of lifetime occupational PA and occupational PA accrued in different age windows may provide additional information regarding the direction and magnitude of the relationship, as well as the biologically relevant time window, between PA and lung cancer risk. Methods: The relationship between lifetime occupational PA and lung cancer risk was examined in a population-based case-control study of 1,136 incident lung cancer cases and 1,457 controls conducted in Montreal, Canada. Lifetime job history was collected via in-person interviews; for each job, the main tasks conducted were also obtained. The energy expenditure for each job-related task was determined via expert assessment by an industrial hygienist and an exercise physiologist in units of metabolic equivalent of task (MET). For each job, an average MET value was calculated by weighting the MET values of each job-related task by the hours per week spent in each task. The average lifetime occupational PA level was then computed by weighting the average MET value for each job by the duration spent in that job. The interview also elicited information on the subject's habitual recreational PA. Unconditional logistic regression was used to estimate adjusted odds ratios (OR) with 95% confidence intervals (CI) for lung cancer risk associated with average lifetime occupational PA and average occupational PA levels in different age windows while controlling for potential confounders. Specifically, average occupational PA in the age windows of 18-24, 24-44 and 45-64 years in relation to lung cancer risk was examined. Confounding was assessed by combining directed acyclic graphs and the change-in-estimate procedure as a novel approach for covariate selection. Effect modification by smoking, body mass index (BMI) and exposure to occupational carcinogens was also assessed. All analyses were conducted separately for men and women. Results: The OR (95% CI) between average lifetime occupational PA and lung cancer risk, comparing the highest versus lowest quartile, was 1.38 (0.88-2.16) in men and 1.01 (0.58-1.76) in women. These associations were not modified by smoking level, BMI or occupational carcinogen exposure. Occupational PA in men was not associated with lung cancer in any of the age windows in which exposure was examined. In women, the highest versus lowest quartile of occupational PA was associated with an increased risk of lung cancer in the age window of 18-24 years (OR=1.72: 1.00-2.94); in the age windows of 24-44 (OR=0.89: 0.53-1.48) and 45-64 years (OR=0.63: 0.38-1.02) no increase in lung cancer risk was observed. When analyses were adjusted for recreational PA, results did not differ appreciably. Conclusion: These results fail to support the previously reported protective effects of PA on lung cancer risk. To the limited extent that they show a deviation from the null hypothesis of no influence on risk, they actually suggest some increased risk of lung cancer with higher occupational PA, although this relationship was inconsistent between sexes and in different age windows. This research was funded by the Canadian Cancer Society and the Guzzo-SRC Chair in Environment and Cancer. Citation Format: Vikki Ho, Marie-Élise Parent, Javier Pintos, Michal Abrahamowicz, Lise Gauvin, Jack Siemiatycki, Anita Koushik. Lifetime occupational physical activity and lung cancer risk in men and women. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A47.

Occupational Versus Leisure-Time Physical Activity in Reducing Cardiovascular Risks and Mortality Among Ethnic Chinese Adults in Taiwan

The aim of the study was to investigate the associations of occupational physical activity (OPA) and leisure-time physical activity (LTPA) with the risk of cardiovascular disease (CVD) and mortality. Physical activity data from the Baeck questionnaire was available for 1706 participants. During a follow-up period, there were 215 cases of CVD and 438 deaths. With the lowest tertile as the reference, the hazard ratios (HRs) for CVD and mortality in the highest tertiles of LTPA were 0.65 (95% confidence interval [CI] = 0.46-0.92) and 0.73 (95% CI = 0.58-0.92). In contrast, the HRs for CVD and mortality in the highest tertiles of OPA were 1.75 (95% CI = 1.10-2.80) and 1.53 (95% CI = 1.06-2.22). The association between OPA and the risk of CVD and mortality was significant in men but not in women. Our findings suggest that high OPA imposes harmful effects on the risk of CVD and mortality, particularly among men.

Occupational heavy lifting and risk of ischemic heart disease and all-cause mortality

BackgroundOccupational heavy lifting is known to impose a high cardiovascular strain, but the risk of ischemic heart disease (IHD) from occupational heavy lifting is unknown. The objective was to investigate the association between occupational heavy lifting and risk of IHD and all-cause mortality, and the influence of occupational and leisure time physical activity on this association.MethodsData were analyzed from 1987, 1994, and 2000 from the Danish National Health Interview Surveys providing a sample of 6,692 working men and 5,921 working women aged 16–85 years without cardiovascular disease at baseline. Conventional risk factors for the outcomes IHD and all-cause mortality were controlled for in Cox analyses.ResultsAmong men, heavy lifting was associated with increased risk for IHD (hazard ratio (HR): 1.52, 95% Confidence interval (95% CI): 1.15, 2.02), while a decreased risk was associated with occupational (HR: 0.50, 95% CI: 0.37, 0.68) and leisure time (HR: 0.73, 95% CI: 0.56, 0.95) physical activity. Referencing men with high occupational physical activity and no heavy lifting, men with high occupational physical activity and heavy lifting did not have an increased risk (HR: 1.11, 95% CI:0.68, 1.82), while men with low occupational physical activity and heavy lifting had a substantial increased risk (HR: 2.56, 95% CI:1.52, 4.32). No significant associations were found for all-cause mortality or for females.ConclusionThese findings indicate an excessive risk for IHD from occupational heavy lifting among men, particularly among those with low occupational and leisure time physical activity.