Occupational Physical Activity and Lung Cancer Risk: A Systematic Review and Meta-Analysis

Re: Cillekens B, Huysmans MA, Holtermann A, van Mechelen W, Straker L, Krause N, van der Beek AJ, Coenen P. Physical activity at work may not be health enhancing. A systematic review with meta-analysis on the association between occupational physical activity and cardiovascular disease mortality covering 23 studies with 655 892 participants. Scand J Work Environ Health. 2022;48(2):86-98. doi:10.5271/sjweh.3993

Objectives

Emerging evidence suggests contrasting health effects for leisure-time and occupational physical activity. In this systematic review, we synthesized and described the epidemiological evidence regarding the association between occupational physical activity and cardiovascular disease (CVD) mortality.

Methods

A literature search was performed in PubMed, Embase, CINAHL, PsycINFO and Evidence-Based Medicine Reviews, from database inception to 17 April 2020. Articles were included if they described original observational prospective research, assessing the association between occupational physical activity and CVD mortality among adult workers. Reviews were included if they controlled for age and gender and at least one other relevant variable. We performed meta-analyses on the associations between occupational physical activity and CVD mortality.

Results

We screened 3345 unique articles, and 31 articles (from 23 studies) were described in this review. In the meta-analysis, occupational physical activity showed no significant association with overall CVD mortality for both males [hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.84–1.12] and females (HR 0.97, 95% CI 0.82–1.15). Additional analysis showed that higher levels of occupational physical activity were non-significantly associated with a 9% increase in studies reporting on the outcome ischemic heart disease mortality (HR 1.09, 95% CI 0.82–1.43).

Conclusions

While the beneficial association between leisure-time physical activity and CVD mortality has been widely documented, occupational physical activity was not found to have a beneficial association with CVD mortality. This observation may have implications for our appreciation of the association between physical activity and health for workers in physically demanding jobs, as occupational physical activity may not be health enhancing.

An Exploratory Study on the Physical Activity Health Paradox-Musculoskeletal Pain and Cardiovascular Load during Work and Leisure in Construction and Healthcare Workers

Using a novel approach, this exploratory study investigated whether the physical activity (PA) paradox extends to cardiovascular load and musculoskeletal pain. At baseline, 1–2 days of 24 h heart rate was assessed in 72 workers from construction and healthcare. Workers then reported pain intensity in 9 body regions (scale 0–3) every 6 months for two years. The 2 year average of musculoskeletal pain (sum of 9 pain scores; scale 0–27) was regressed on time spent during work and leisure above three thresholds of percentage heart rate reserve (%HRR), i.e., ≥20 %HRR, ≥30 %HRR, and ≥40 %HRR, using a novel ilr structure in compositional data analysis. Analyses were stratified for several important variables. Workers spending more time in physical activity at work had higher pain, while workers with more time in physical activity during leisure had less pain (i.e., the PA paradox), but none of the associations were statistically significant. Higher aerobic capacity and lower body mass index lowered the pain score among those with higher physical activity at work. This exploratory study suggests that the PA paradox may apply to musculoskeletal pain and future studies with larger sample sizes and additional exposure analyses are needed to explain why this occurs.

Association of Balance Function With All-Cause and Cause-Specific Mortality Among US Adults

Importance

Difficulty maintaining balance is common among individuals aged 40 years or older and increases the risk of falls. However, little is known about the association of balance function with long-term mortality outcomes in adults.

Objective

To investigate the association of balance function with all-cause and cause-specific mortality among US adults.

Design, Setting, and Participants

A prospective, population-based cohort study of a nationally representative sample of 5816 adults (weighted population, 92 260 641) from the US National Health and Nutrition Examination Survey was conducted from 1999 to 2004. Individuals aged 40 years or older who completed the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces were included. Participants were linked to mortality data from the test date through December 31, 2015. Data analysis was conducted from February 1 to June 1, 2020.

Exposures

The modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces was used to measure balance function and define balance disorder according to sensory input.

Main Outcomes and Measures

Mortality associated with all causes, cardiovascular disease (CVD), and cancer.

Results

A total of 5816 adults (weighted mean [SE] age, 53.6 [0.2] years; 2897 [49.8%] women) were included in this cohort study. During up to 16.8 years of follow-up (median, 12.5 years; 68 919 person-years), 1530 deaths occurred, including 342 associated with CVD and 364 associated with cancer. Participants with balance disorder were at a higher risk of death from all causes, CVD, and cancer. After adjusting for sociodemographic characteristics, lifestyle factors, and chronic conditions, the hazard ratios (HRs) among participants with balance disorder compared with those without balance disorder were 1.44 (95% CI, 1.23-1.69) for all-cause mortality, 1.65 (95% CI, 1.17-2.31) for CVD mortality, and 1.37 (95% CI, 1.03-1.83) for cancer mortality. Furthermore, vestibular balance disorder was associated with increased mortality from all causes (HR, 1.31; 95% CI, 1.08-1.58), CVD (HR, 1.59; 95% CI, 1.12-2.27), and cancer (HR, 1.39; 95% CI, 1.04-1.86).

Conclusions and Relevance

In this nationally representative sample of US adults, balance disorder was associated with an increased risk of all-cause, CVD, and cancer mortality. Further studies are needed to confirm these findings and evaluate whether the observed associations represent a causal biological phenomenon and, if so, whether the effect is modifiable with a multicomponent exercise program.