Leslie Israel

Sedentary work, low physical job demand, and obesity in US workers

BACKGROUND Little is known about the role of low physical activity at work (sedentary work or low physical job demand) in the increasing prevalence of obesity of US workers. METHODS This cross-sectional and secondary data analysis included 1,001 male and 1,018 female workers (age range: 32-69) from the National Survey of Midlife Development in the United States (MIDUS) II study (2004-2006). Sedentary work and physical job demand were measured by questionnaire items. Total obesity (based on body mass index) and central obesity (based on waist circumference) were defined using WHO criteria. RESULTS After controlling for covariates (socio-demographic, psychosocial working conditions, health status, and health behaviors), sedentary work, low physical job demand, or their combination increased the risk for total and central obesity in male workers, particularly when they worked longer than 40 hr per week. Sedentary work marginally increased the risk for total and central obesity in female workers. CONCLUSIONS Low physical activity at work is a significant risk factor for total and central obesity in middle-aged US male workers.

Exploring Occupational and Health Behavioral Causes of Firefighter Obesity: A Qualitative Study

BACKGROUND Firefighters, as an occupational group, have one of the highest prevalence rates of obesity. A qualitative study investigated occupational and health behavioral determinants of obesity among firefighters. METHODS Four focus groups were conducted with firefighters of every rank as Phase I of the FORWARD study which was designed to assess health behavioral and occupational characteristics related to obesity in firefighters. RESULTS Analysis revealed five main themes of central importance to firefighters: (1) fire station eating culture; (2) night calls and sleep interruption; (3) supervisor leadership and physical fitness; (4) sedentary work; and (5) age and generational influences. CONCLUSION The results showed a strong interrelationship between occupational and health behavioral causes of obesity in firefighters. The relevance of these qualitative findings are discussed along with the implications for future obesity interventions with firefighters.

Exploring Occupational and Behavioral Risk Factors for Obesity in Firefighters: A Theoretical Framework and Study Design

Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US). However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupational and behavioral risk factors in the development of obesity in firefighters enrolled in the Orange County Fire Authority Wellness Fitness Program. The study plan will be described with emphasis on its methodological merits: adopting a participatory action research approach, developing a firefighter-specific work and health questionnaire, conducting both a cross-sectional epidemiological study using the questionnaire and a sub-study to assess the validity of the questionnaire with dietary intake and physical activity measures, and evaluating the strengths and weaknesses of the body mass index as an obesity measure in comparison to skinfold-based percent body fat. The study plan based on a theoretical framework can be an essential first step for establishing effective intervention programs for obesity among professional and voluntary firefighters.

Very Long (> 48 hours) Shifts and Cardiovascular Strain in Firefighters: a Theoretical Framework.

Shift work and overtime have been implicated as important work-related risk factors for cardiovascular disease (CVD). Many firefighters who contractually work on a 24-hr work schedule, often do overtime (additional 24-hr shifts) which can result in working multiple, consecutive 24-hr shifts. Very little research has been conducted on firefighters at work that examines the impact of performing consecutive 24-hr shifts on cardiovascular physiology. Also, there have been no standard field methods for assessing in firefighters the cardiovascular changes that result from 24-hr shifts, what we call “cardiovascular strain”. The objective of this study, as the first step toward elucidating the role of very long (> 48 hrs) shifts in the development of CVD in firefighters, is to develop and describe a theoretical framework for studying cardiovascular strain in firefighters on very long shifts (i.e., > 2 consecutive 24-hr shifts). The developed theoretical framework was built on an extensive literature review, our recently completed studies with firefighters in Southern California, e-mail and discussions with several firefighters on their experiences of consecutive shifts, and our recently conducted feasibility study in a small group of firefighters of several ambulatory cardiovascular strain biomarkers (heart rate, heart rate variability, blood pressure, salivary cortisol, and salivary C-reactive protein). The theoretical framework developed in this study will facilitate future field studies on consecutive 24-hr shifts and cardiovascular health in firefighters. Also it will increase our understanding of the mechanisms by which shift work or long work hours can affect CVD, particularly through CVD biological risk factors, and thereby inform policy about sustainable work and rest schedules for firefighters.

Short-term test–retest reliability of the Job Content Questionnaire and Effort–Reward Imbalance Questionnaire items and scales among professional firefighters

Relatively little is known about the short-term test–retest reliability of the Job Content Questionnaire (JCQ) and Effort–Reward Imbalance Questionnaire (ERIQ). Seventeen JCQ and six ERIQ items were qualitatively reviewed by 19 firefighters in focus groups. The items were then administered twice to 81 firefighters with a time interval of 1–8 weeks. The short-term reliability of the JCQ and ERIQ items and scales with the four-point Likert item responses was at least fair or moderate with several complementary statistical methods. It improved substantially when the four-point responses were simplified into the two (‘agree’ or ‘disagree’) responses. The JCQ psychological demands and the ERIQ effort scales were among the least reliable scales and their items were most frequently indicated by the firefighters to be clarified. The responses of professional firefighters to the JCQ and ERIQ items and scales were stable during an 8-week period, particularly when dichotomous item responses were used. Practitioner Summary: The little-known short-term reliability of the two most commonly used questionnaires for assessing psychosocial working conditions was investigated. This study indicates that the dichotomous (strongly agree/agree vs. strongly disagree/disagree) responses of firefighters to the JCQ and ERIQ items and scales are generally stable during an 8-week period.

High Levels of Polybrominated Diphenyl Ethers in Vacuum Cleaner Dust from California Fire Stations

Firefighters are exposed to chemicals during fire events and may also experience chemical exposure in their fire stations. Dust samples from used vacuum cleaner bags were collected from 20 fire stations in California and analyzed for polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) using gas chromatography-mass spectrometry. Median dust concentrations were higher for PBDEs (e.g., 47 000 ng/g for BDE-209) than for PAHs (e.g., 220 ng/g for benzo[a]pyrene) or PCBs (e.g., 9.3 ng/g for PCB-180). BDE-209 concentrations in dust from California fire stations were among the highest of any previously documented homes or occupational settings in the world. We examined factors such as the frequency of emergency responses, the number of fire vehicles on site, and building age, but we could not account for the high levels of BDE-209 observed in fire station dust. Based on the findings of our pilot study, we hypothesize that possible sources of BDE-209 in fire stations include contaminated ash tracked back from fire events via boots, clothing, and other equipment as well as specialized equipment treated with BDE-209, including turnout gear and fire vehicles. We suggest possible follow-up studies to confirm these hypotheses.

Exposures to environmental phenols in Southern California firefighters and findings of elevated urinary benzophenone-3 levels.

Firefighters are at increased risk for exposure to toxic chemicals compared to the general population, but few studies of this occupational group have included biomonitoring. We measured selected phenolic chemicals in urine collected from 101 Southern California firefighters. The analytes included bisphenol A (BPA), triclosan, benzophenone-3 (BP-3), and parabens, which are common ingredients in a range of consumer products. BP-3, BPA, triclosan, and methyl paraben were detected in almost all study subjects (94-100%). The BP-3 geometric mean for firefighters was approximately five times higher than for a comparable National Health and Nutrition Examination Survey (NHANES) subgroup. Demographic and exposure data were collected from medical records and via a questionnaire, and covariates were examined to assess associations with BP-3 levels. BP-3 levels were elevated across all firefighter age groups, with the highest levels observed in the 35 to 39year old group. Body fat percentage had a significant inverse association with BP-3 concentrations. Our results indicate pervasive exposure to BP-3, BPA, triclosan, and methyl paraben in this population of firefighters, consistent with studies of other populations. Further research is needed to investigate possible explanations for the higher observed BP-3 levels, such as occupational or California-specific exposures.