Evidence-Based Diabetes Management
December 2014
Volume 20
Issue SP18

New Research Shows Employers Need Strategies to Help Night Shift Workers Avoid Diabetes


New research into the link between shift work and type 2 diabetes mellitus (T2DM) further quantifies a well-established but underappreciated fact: irregular hours significantly reduce employee well-being and raise healthcare costs.

While some employers have begun taking steps to mitigate the damage, reports on companies eliminating nonessential shift work have been scarce, and most employers have yet to address the issue despite its enormous impact on the 16 million Americans who regularly work at odd times.1

A growing body of research shows that working nights—or worse, rotating shifts—increases the risk of obesity, insomnia, hypertension, stomach ulcers, depression, workplace injury, tobacco use, heart disease, and, diabetes. “The health risks are big enough that all people should consider them before taking on shift work,” said Frank Hu, MD, PhD, a professor of nutrition and epidemiology at the Harvard School of Public Health, in an interview with Evidence-Based Diabetes Management. “People who are in poor health or at risk of developing a related disease, especially diabetes, should probably avoid shift work if they can. Those people who do take it should pay extra attention to diet, exercise, and sleep. They should also get screened regularly for signs of diabetes and other health problems.”

Hu coauthored a paper that analyzed the ties between shift work and diabetes in 177,000 nurses who participated in a pair of long-term general health studies. Published in PLoS Medicine, the paper reported that women who worked rotating night shifts for 1 year or 2 years were 5% more likely to develop diabetes over the following 20 years than women who only worked days.1

Women who spent more time working rotating night shifts fared much, much worse. A decade or two of rotating shift work was associated with a 40% increase in diabetes risk, and any more than 20 years was associated with a 60% greater risk.1 The newest research on the links between shift work and diabetes aggregated data from Hu’s paper and 11 other international studies, in an effort to better quantify and to conduct analysis on various subgroups.

The meta-study, which was published this past summer in Occupational & Environmental Medicine, found that any amount of time spent doing shift work was associated with a 9% greater risk of diabetes (95% CI, 1.05-1.12; P = .014). The study’s major finding was that it identified a more significant correlation between shift work and diabetes in men than in women. Multivariate

analysis suggested that men with any exposure to shift work were 37% more likely to develop diabetes than men who worked days (95% CI, 1.20-1.56).2

Moreover, rotating shifts appeared more hazardous than steady night work: the meta-study identified a 42% increase in diabetes risk due to rotating shifts, among both genders (95% CI, 1.19-1.69). And diabetes is only one of many health risks associated with working during odd hours. Several studies have found significant associations between shift work and various forms of cancer. A much-cited paper from the Journal of the National Cancer Institute, for example, found that steady night work was associated with a 60% increase in the risk of breast cancer.3

An even greater body of evidence suggests that shift work increases the risk of cardiovascular disease. A large meta-study from 1999 concluded that shift workers faced a 40% greater risk of cardiovascular disease than daytime workers.4 Ulcers? Nearly quadruple the risk.5 Metabolic syndrome? Up to a 5-fold increase.6 Hypertension? 81% more common in African American female shift workers.7 Depression? Probably.8 “Shift work fundamentally disrupts the body’s efforts to rest and repair itself, so it’s hardly surprising that it produces a wide range of negative biological effects in many people,” Hu said. “But the effects are not only biological. Shift work affects important behaviors. It causes people to eat worse, exercise less, and socialize with fewer people. All of those behaviors have biological effects of their own, and, again, they’re all negative.”

Yet even as the evidence of shift work’s toll continues to grow, the number of people working nights may also be on the rise. Some shift work, of course, is indisputably necessary. Police departments and hospitals must operate at night. The rationale for other shift work, however, is purely economic. A 3-shift operation generates 3 times the return on capital as a 1-shift operation. Truckers fight less traffic at night. Overseas clients expect suppliers to work ontheir hours.

Economics drives employee decisions as well. Shift work often provides a huge premium over available work, particularly for unskilled employees, or it may be a necessary stepping-stone to day work that’s reserved for senior employees. Unfortunately, according to many who study shift work, employers and employees often make bad economic decisions because they do not fully understand the true costs that odd hours impose on the body.

Research from Circadian, a Massachusetts-based company that helps employers optimize their off-hour operations, indicates that the total cost associated with shift work averages more than $10,000 per employee per year.9 That figure accounts for lower productivity, higher error rates, increased turnover, inflated absenteeism, and several other factors. Increased health spending alone accounts for a significant percentage of the total. Indeed, shift workers account for 10% of all Americans with health insurance but 17% of healthcare spending.9

Most operations with any significant number of shift workers bear that cost directly because they self-insure. Smaller companies that purchase coverage rarely pay an explicit premium for shift workers. However, high claims from shift workers in one year influence the next year’s rates. Employers, in otherwords, have a big financial incentive to mitigate the costs of shift work, but Circadian’s research indicates that most of them take no systematic steps.

Many logical strategies for mitigating those dangers aren’t even legal. For example, a company that saw the diabetes meta-study and tried to save employees from decades of chronic illness by assigning women and other low-risk candidates to shift work would risk lawsuits, union action, government intervention, and terrible publicity. Considering that research and anecdotal experience both indicate that some people naturally tolerate shift work much better than others, such restrictions significantly limit the potential efficacy of harm-reduction efforts. Still, they exist. So employers who want to minimize the economic and human toll of shift work must focus on self-help for the employees who land in the job.

At companies where most people work the usual day shift, logistical difficulties often minimize the benefit shift workers receive from general health initiatives. Nutrition classes that begin at noon are useless to them. The fitness trail in the woods behind the parking lot is no fun to walk at night. And the healthy options in the cafeteria do nothing for people who arrive after it has closed.

Still, companies have options.

Viridian Health Management, a Phoenix-based population health management company that helps many large companies maximize employee wellness, advises clients to inform shift workers about the associated risks and to remind them periodically.

“Many companies hesitate to tell workers about any job-related risks they’re not legally obligated to disclose, which is self-defeating. You can’t expect people to work hard to prevent serious health problems if they don’t know they’re at risk in the first place,” Viridian’s chief medical officer, Eric Dinenberg, MD, MPH, told EBDM. “At the very least, employers with shift workers should communicate the facts, outline some basic strategies for coping, and stress the need for regular screening that can spot problems early.

But given the stakes involved—once a person develops diabetes, healthcare costs double—employers should do much more,” Dinenberg added.

Dinenberg believes that employers need to include screenings for health risk factors for diabetes and other chronic conditions that reach third-shift workers. He also urges all companies to offer all workers on all shifts regular opportunities to participate in a diabetes prevention program that conforms to CDC guidelines. Research has found that such programs reduce the risk of a pre-diabetic individual developing diabetes by more than 50%.10 Better still, program costs are moderate. Groups meet once a week for 16 weeks and once a month for another 6 months. At each meeting, a lifestyle coach helps participants develop strategies for eating better, exercising more, and identifying emotions and situations that can get them off track.11

The facilitator doesn’t have to be a costly healthcare professional. Research shows that diabetes prevention programs facilitated by lay educators without any clinical background are as effective as programs facilitated by clinically trained professionals.12 Motivation is important, however, and forward-thinking employers use incentives to encourage employee participation, Dinenberg said.

Given the size of the problem—86 million American adults now qualify as prediabetic13—nearly all employers have reason to consider such programs, but they’re relatively rare among companies with large numbers of shift workers (and other companies as well), despite the economic incentives.

Wellness programs aimed at shift workers often pay for themselves (or even generate automatic profits) because many health insurers offer automatic discounts for workers who attend them. Looking forward, the financial incentives could grow larger still if workers’ compensation insurers were to offer incentives to employers who get staff to complete these programs. Discounts on workers’ compensation policies are not currently given, insurers told EBDM.

Sleepy shift workers have significantly more accidents on the job than people who work days,14 and the health complications they help to cause make problems worse. Studies have shown that obesity and diabetes are both associated with more errors in the workplace. Effective wellness programs, therefore, would reduce workers’ compensation claims as well as traditional

health costs.

Employees, naturally, face some financial incentives of their own. More trips to the doctor and the drugstore translate into larger annual co-payments. Employers cannot legally increase those incentives by making shift workers contribute more to their healthcare policies than comparable day workers or by increasing their co-pay rates. They can, on the other hand, provide some discounts to employees who reach certain health targets or complete wellness programs. (This is actually a bit of a legal gray area, and laws vary among the states, but employers are experimenting.15)

Employers can also address the general effects of shift work directly, rather than address the specific conditions that odd hours can trigger. “There are steps that can produce significant benefits without any conscious behavioral changes from anyone,” Circadian chairman and chief executive officer Martin Moore-Ede, MD, PhD, told EBDM. “Some shift schedules are dramatically better for workers than others, and changes to the office environment, particularly the lighting, can also help workers adapt to the unusual hours.”

A comprehensive strategy that combines environmental improvements with worker training can generally reduce the extra costs associated with shift work by about 50%—and greatly improve the health and happiness of workers. “Workers tend to be skeptical when they start the training, but once they begin trying the strategies and getting better rest, they become very enthusiastic,”

Moore-Ede said. “That’s not to say that any combination of strategies can fully control our internal clocks or eliminate the practical difficulties of working when everyone else sleeps. They can, however, produce dramatic benefits in terms of employee health, employee happiness, and the bottom line.”

“Workers tend to be skeptical when they start the training, but once they begin trying the strategies and getting better rest, they become very enthusiastic,” Moore-Ede said. “That’s not to say that any combination of strategies can fully control our internal clocks or eliminate the practical difficulties of working when everyone else sleeps. They can, however, produce dramatic benefits in terms of employee health, employee happiness, and the bottom line.”References

1. Pan A, Schernhammer ES, Sun Q, Hu FB. Rotating night shift work and risk of type 2 diabetes: two prospective cohort studies in women. PLoS Med. 2011;8(12):e1001141.

2. Gan Y, Yang C1, Tong X, et al. Shift work and diabetes mellitus: a meta-analysis of observational studies [published online July 16, 2014]. Occup Environ Med. doi:10.1136/oemed-2014-102150.

3. Davis S, Mirick DK, Stevens RG. Night shift work, light at night, and risk of breast cancer. J Natl Cancer Inst. 2001;93(20):1557-1562.

4. Bøggild H, Knutsson A. Shift work, risk factors and cardiovascular disease. Scand J Work Environ Health. 1999;25(2):85-99.

5. Pietroiusti A, Forlini A, Magrini A, et al. Shift work increases the frequency of duodenal ulcer in H pylori infected workers. Occup Environ Med. 2006;63(11):773-775.

6. Pietroiusti A, Neri A, Somma G, et al. Incidence of metabolic syndrome among night-shift healthcare workers. Occup Environ Med. 2010;67:54-57.

7. Lieu SJ, Curhan GC, Schernhammer ES, Forman JP. Rotating night shift work and disparate hypertension risk in African-Americans. J Hypertens. 2012;30(1):61-66.

8. Rotating shift workers have lower levels of serotonin. ScienceDaily website. Published August 5, 2007. Accessed

September 26, 2014.

9. Identifying the excess costs in the average shiftwork operation. Circadian website. Accessed September 26, 2014.

10. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346:393-403.

11. National diabetes prevention program. CDC website. Reviewed March 13, 2014. Accessed September 26, 2014. 12. Ali MK, Echouffo-Tcheugui J, Williamson DF. How effective were lifestyle interventions in real-world settings that were modeled on the Diabetes Prevention Program? Health Aff (Millwood). 2012;31(1):67-75.

13. More than 29 million Americans have diabetes; 1 in 4 doesn’t know [press release]. CDC website. Atlanta, GA; June 10, 2014.

14. Rajaratnam SM, Howard ME, Grunstein RR. Sleep loss and circadian disruption in shift work: health burden and management. Med J Aust. 2013;199(8):S11-S15.

15. Hand L. Employee wellness programs prod workers to adopt healthy lifestyles. Harvard School of Public Health website. winter09healthincentives/. Published 2009. Accessed September 26, 2014.

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