Cardiovascular Disease and Occupational Factors

CVD, and specifically heart disease, is a major focus of the NIOSH Fire Fighter Fatality Investigation and Prevention Program. Sudden cardiac death is the most common type of on-duty death for fire fighters. This NIOSH program investigates the on-duty cardiovascular deaths of individual fire fighters to:

1. characterize the individual and occupational risk factors,
2. develop a database for use by internal and external researchers,
3. provide recommendations to fire departments regarding prevention programs, and
4. assist in the development of National Fire Protection Association (NFPA) consensus standards for the fire service.

The fatality reports are widely disseminated to stakeholders and in the peer-reviewed scientific literature. See the NIOSH Topic Page "Fire Fighter Fatality Investigation and Prevention" and the NIOSH document "Preventing Fire Fighter Fatalities Due to Heart Attacks and Other Sudden Cardiovascular Events".

In 1990, the National Football League (NFL) Players Association asked researchers at NIOSH to look at the causes of death among former football players due to concerns with shortened life span and heart disease among retired players. In 1994, NIOSH published research examining death rates and risk factors for former NFL players ¹. At that time the research was based on all deaths that had occurred through 1991. After adding 16 years of data NIOSH published updated research on the topic in the American Journal of Cardiology ². In the most recent study, we included all who played for the NFL for at least five seasons during 1959 to1988. We compared the rate and causes of death among these players to what would be expected among men in the general population to see if there was a difference. When looking at all of the players as a group, we found the risk of dying of heart disease was lower compared to the general population. However, we found some higher risk of death from heart disease among certain players:

• We found players who had a Body Mass Index (BMI) of 30 or more during their playing years had twice the risk of death from heart disease compared to other players. BMI estimates body fat using height and weight. A BMI of 30 or more is considered obese in the general population.
• We found African American players had a 69% higher risk of death from heart disease compared to Caucasian players. We are not sure what caused this difference, but player size and position are not the reason. In general, African Americans have been found to have a higher risk of heart disease compared to Caucasians.
• We found heart disease varied by player position. Defensive linemen had a 42% higher risk of death from heart disease compared to men in the general population. All other positions had a lower chance of dying of heart disease compared to the general population. We are not certain why heart disease was higher among the defensive linemen; this finding was unexpected and needs further study.
• Among the 41 defensive linemen who died of heart disease, 8 deaths were due to cardiomyopathy. Cardiomyopathy is a specific kind of heart disease that causes the heart to enlarge and can lead to heart failure. We anticipated fewer than 2 deaths from cardiomyopathy.

See the NIOSH Science Blog for more information on this topic: http://blogs.cdc.gov/niosh-science-blog/2012/01/30/nfl/

To help address research gaps and better understand potential health risks faced by truck drivers, NIOSH has performed a national survey of truck driver health and injury. Findings from the survey revealed that among the participating long-haul truck drivers

• 69 percent were found to be obese,
• 51 percent smoked, and
• 88 percent reported having a risk factor for chronic disease including CVD such as hypertension, obesity, or smoking ^{3, 4}

See the NIOSH Topic Page "Long-Haul Truck Drivers" for more information.

NIOSH researchers have an ongoing collaboration with the State University of New York at Buffalo to study the effects of policing and occupational stress on early (subclinical) markers of cardiovascular health. Officers complete a 6-hour comprehensive examination that includes questionnaires, physiologic assessments and blood measurements. The goal is the prevention of stress-related disorders. To date, over 400 police officers have participated in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Study ^{5, 6}, and the first follow-up examination is complete. A second follow-up study began in late 2015 and will be completed in 2018. Completion of the second follow-up examination will provide over 12 years of follow-up data.

In 2008 NIOSH scientists reviewed current practices in the collection and analytic treatment of occupational data in population-based CVD studies ^{7, 8}. NIOSH found that that most US federally-funded longitudinal population-based CVD studies collect at least descriptive occupational data, but those data are rarely used in epidemiologic analyses to examine associations between social and environmental risk factors at work and CVD. Collaborations with several CVD research groups have since been established, using NIOSH expertise and existing federal funds to improve the scientific evidence-base linking working conditions and CVD/stroke.

The Reasons for Geographic and Racial Differences in Stroke Study (REGARDS) project is a large population-based prospective study focused on factors of racial and geographic differences in stroke, heart disease, and cognitive decline among a national sample of over 30,000 Caucasian and African American men and women aged 45 and older ⁹. Recently completed analyses generated aggregate and occupation-specific national estimates of heart disease and stroke, as well as biometric and behavioral cardiovascular risk factors among disease-free workers age ≥ 45 years. Several other types of analyses are underway to examine such issues as:

• occupational factors related to cognitive decline
• associations between specific exposures (job strain, shiftwork) and several CVD end-points
• associations between changes in employment status, physical activity, and health outcomes

The Multi-Ethnic Study of Atherosclerosis is a community-based prospective cohort study of more than 6,800 men and women (age: 45-84 years), designed to investigate the development of CVD. At the time of enrollment, the participants reported their main job in life (or current job if they were still working). This enables us to investigate the link between various characteristics of jobs and CVD risks. We have identified that long work hours, blue-collar work, and lack of job control were associated with risk factors for CVD such as hypertension, plaque formation, peripheral artery disease, and dysregulation of stress hormone secretion ¹⁰.

NIOSH researchers also collaborate with many other researchers to investigate workplace risk factors for CVD. For example, NIOSH researchers are collaborating with the Jackson Heart Study, a population-based investigation of risk factors for CVD in 5,300 African American men and women in Jackson, Mississippi. Other studies in which NIOSH investigators have collaborated include

• Adult Health and Behavior Project–Phase 2 (AHAB-II) ¹¹
• Behavioral Risk Factor Surveillance System ¹²
• National Health Interview Survey ¹³