Re: Aircraft noise and cardiovascular disease near Heathrow airport in London: small area study
Upon reading this article, we would like to expand upon the point made by Dr Jan Coebergh about the ‘shift-work’ at Heathrow acting as a confounding variable for this research from a more personal view. Both of the primary respondent’s parents work in Heathrow airport.
“My mother works part-time in the terminal and my father full-time (before the addition of over-time hours) as an engineer. We also live under a flight path leading to Heathrow. As I progress further through my medical degree I am becoming increasingly aware of the dangers of shift work upon an individual’s health - for the purpose of this response I will focus on my father as an example.
My father left school at the age of sixteen, became an engineer apprentice and has worked at Heathrow ever since (coming up to 37 years). Throughout my life I have been aware of the long hours, often including ‘double shifts’ (16 hours) and ‘overtime’ that my father and his colleagues work to allow the airport to run through the night. While over-time and ‘double shifts’ are optional, my understanding of it is that these shifts are highly sort after by the employees and contribute to a significant amount of time spent at work.”
This has various implications for workers’ health. Sleeping patterns are difficult to establish, there is an irregular pattern to the shifts with little time between to adjust to new work patterns and the jump from ‘earlies’ to ‘lates’ occurring on a weekly basis. Factors which have a negative impact on establishing a regular sleeping pattern and limit the amount of sleep include living under a flight path. Lack of sleep has been associated with cardiovascular risk factors [1-4] and associated with all-cause mortality [5], with one study already mentioned by Dr Jan Coebergh attributing shift-work to cardiovascular events [6]. As well as sleeping patterns, other health-behaviours, such as healthy eating and exercise also become a challenge. Further challenges include poorly established meal time breaks, working through meal-times and irregularity of shift work creating difficulty in partaking in regular recreational activities as many of these are aimed at 9-5 workers. Both of these factors should also be considered as cofounding variables when considering shift workers as a cohort as both have an impact on risk of cardiovascular disease [7,8].
Arguably, engineering at the airport is similar in many ways to working in a hospital. Engineers must be alert and in control at all times for the safety of thousands of passengers a day and are held accountable and responsible for their actions, often needing to attend courses with exams to keep the standard of work high. This creates a high stress environment, and anecdotal evidence suggests many ground staff need time off to allow them to cope (a pattern that might be assumed to be universal among all classes of airport staff given the highly stressful environment!). Uncontrollable factors such as weather can account for the airport grinding to a halt, resulting in managing thousands of stranded and very unhappy passengers. Stress, while the relationship is not well understood, is also linked to cardiovascular disease [9].
While we have used a very particular example, this highlights the importance of accounting for such confounding variables in this study. Many of the workers at Heathrow live within the boroughs and districts described in the study and will have lifestyle factors specific to them as a cohort of individuals as discussed above.
References:
1. Sabanayagam C, Shanka A. Sleep duration and cardiovascular disease: results from the National Health Survey. Sleep. 2010;33:1037–1042. [PMC free article] [PubMed]
2. Ikehara S, Iso H, Date C, et al. Association of sleep duration with mortality from cardiovascular disease and other causes for Japanese men and women: the JACC study. Sleep. 2009;32:295–301.[PMC free article] [PubMed]
3. Amagai Y, Ishikawa S, Gotoh T, Kayaba K, Nakamura Y, Kajii E. Sleep duration and incidence of cardiovascular events in a Japanese population: the Jichi Medical School cohort study. J Epidemiol.2010;20:106–110. [PubMed]
4. Ayas NT, White DP, Manson JE, et al. A prospective study of sleep duration and coronary heart disease in women. Arch Inter Med. 2003;163:205–209
5. F Cappuccio, L D’Elia, P Strazzullo, M Miller (2010) Sleep Duration and All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies American Academy of Sleep Medicine v.33 Issue: 05
6. M Vyas, A Garg, A Iansavichus, J Costella, A Donner, L Laugsand, I Janszky, M Mrkobrada, G Parraga, D Hackam (2012) Shift work and vascular events: systematic review and meta-analysis BMJ 345:e4800
7. Kromhout D. (2001) Diet and cardiovascular disease J Nutr Health Aging. 5(3):144-9
8. P. Thomas et al (2003) Exercise and Physical Activity in the prevention and treatment of atherosclerotic cardiovascular disease American Heart Association 107: 3109-3116 available online : http://circ.ahajournals.org/content/107/24/3109.short last accessed 19/10/2013
9. A Steptoe and M Kivimäki (2012) Stress and Cardiovascular disease Nature Reviews Cardiology 9, 360-370
Competing interests:
No competing interests
21 October 2013
Amy Bannerman
Medical Student
Stephanie F. Smith (Medical Student, University of Cambridge), Nicholas D. Gollop (Academic FY2 Doctor, Norfolk and Norwich University Hospital)
Cardiff University School of Medicine
Cochrane Medical Education Centre, Heath Park, Cardiff CF14 4YU
Rapid Response:
Re: Aircraft noise and cardiovascular disease near Heathrow airport in London: small area study
Upon reading this article, we would like to expand upon the point made by Dr Jan Coebergh about the ‘shift-work’ at Heathrow acting as a confounding variable for this research from a more personal view. Both of the primary respondent’s parents work in Heathrow airport.
“My mother works part-time in the terminal and my father full-time (before the addition of over-time hours) as an engineer. We also live under a flight path leading to Heathrow. As I progress further through my medical degree I am becoming increasingly aware of the dangers of shift work upon an individual’s health - for the purpose of this response I will focus on my father as an example.
My father left school at the age of sixteen, became an engineer apprentice and has worked at Heathrow ever since (coming up to 37 years). Throughout my life I have been aware of the long hours, often including ‘double shifts’ (16 hours) and ‘overtime’ that my father and his colleagues work to allow the airport to run through the night. While over-time and ‘double shifts’ are optional, my understanding of it is that these shifts are highly sort after by the employees and contribute to a significant amount of time spent at work.”
This has various implications for workers’ health. Sleeping patterns are difficult to establish, there is an irregular pattern to the shifts with little time between to adjust to new work patterns and the jump from ‘earlies’ to ‘lates’ occurring on a weekly basis. Factors which have a negative impact on establishing a regular sleeping pattern and limit the amount of sleep include living under a flight path. Lack of sleep has been associated with cardiovascular risk factors [1-4] and associated with all-cause mortality [5], with one study already mentioned by Dr Jan Coebergh attributing shift-work to cardiovascular events [6]. As well as sleeping patterns, other health-behaviours, such as healthy eating and exercise also become a challenge. Further challenges include poorly established meal time breaks, working through meal-times and irregularity of shift work creating difficulty in partaking in regular recreational activities as many of these are aimed at 9-5 workers. Both of these factors should also be considered as cofounding variables when considering shift workers as a cohort as both have an impact on risk of cardiovascular disease [7,8].
Arguably, engineering at the airport is similar in many ways to working in a hospital. Engineers must be alert and in control at all times for the safety of thousands of passengers a day and are held accountable and responsible for their actions, often needing to attend courses with exams to keep the standard of work high. This creates a high stress environment, and anecdotal evidence suggests many ground staff need time off to allow them to cope (a pattern that might be assumed to be universal among all classes of airport staff given the highly stressful environment!). Uncontrollable factors such as weather can account for the airport grinding to a halt, resulting in managing thousands of stranded and very unhappy passengers. Stress, while the relationship is not well understood, is also linked to cardiovascular disease [9].
While we have used a very particular example, this highlights the importance of accounting for such confounding variables in this study. Many of the workers at Heathrow live within the boroughs and districts described in the study and will have lifestyle factors specific to them as a cohort of individuals as discussed above.
References:
1. Sabanayagam C, Shanka A. Sleep duration and cardiovascular disease: results from the National Health Survey. Sleep. 2010;33:1037–1042. [PMC free article] [PubMed]
2. Ikehara S, Iso H, Date C, et al. Association of sleep duration with mortality from cardiovascular disease and other causes for Japanese men and women: the JACC study. Sleep. 2009;32:295–301.[PMC free article] [PubMed]
3. Amagai Y, Ishikawa S, Gotoh T, Kayaba K, Nakamura Y, Kajii E. Sleep duration and incidence of cardiovascular events in a Japanese population: the Jichi Medical School cohort study. J Epidemiol.2010;20:106–110. [PubMed]
4. Ayas NT, White DP, Manson JE, et al. A prospective study of sleep duration and coronary heart disease in women. Arch Inter Med. 2003;163:205–209
5. F Cappuccio, L D’Elia, P Strazzullo, M Miller (2010) Sleep Duration and All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies American Academy of Sleep Medicine v.33 Issue: 05
6. M Vyas, A Garg, A Iansavichus, J Costella, A Donner, L Laugsand, I Janszky, M Mrkobrada, G Parraga, D Hackam (2012) Shift work and vascular events: systematic review and meta-analysis BMJ 345:e4800
7. Kromhout D. (2001) Diet and cardiovascular disease J Nutr Health Aging. 5(3):144-9
8. P. Thomas et al (2003) Exercise and Physical Activity in the prevention and treatment of atherosclerotic cardiovascular disease American Heart Association 107: 3109-3116 available online : http://circ.ahajournals.org/content/107/24/3109.short last accessed 19/10/2013
9. A Steptoe and M Kivimäki (2012) Stress and Cardiovascular disease Nature Reviews Cardiology 9, 360-370
Competing interests: No competing interests