Diabetes, obesity, CVD-all have been linked to disruption of the day-night rhythm caused by shift work. More facts and some tips for your shift-weary patients, here.
The First National Health and Nutrition Examination Survey (NHANES I) found that hypertension was significantly higher in over 24,000 people aged 32-59 who slept 5 hours or less per night (OR: 2.10; 95% CI 1.58-2.79).(2) This relationship remained significant even after adjusting for obesity and diabetes. Conclusion: Sleep deprivation in healthy individuals can increase blood pressure and sympathetic nervous system activity. A systematic review found “strong evidence” for the link between being overweight and shift work.(3) Some studies have found a link between shift work and increased food consumption, with a preference for carbohydrate-rich foods. Reduced physical activity may also play a role.
Most studies link shift work and metabolic disease. Example: A f5-year study that included 387 female workers in Taiwan found that women who initially had 1 or 2 risk factors for metabolic disease were 4.6 and 12.7 times, respectively, more likely to develop the disorder.(4) Strong evidence exists for the link between shift work and the development of diabetes. Example: A study of 177,000 nurses aged 25-67 years found that those who did rotating shifts for 1 to 2 years had 5% increased risk for T2DM. This risk increased to 20% after 3 to 9 years, 40% after 10 to 19 years, and nearly 60% after 20 years of rotating shifts.(5)
Sleep deprivation associated with shift work may affect hormones involved in circadian rhythm and metabolic processes: Suppression of growth hormone production; suppression of circadian melatonin rhythm; increased ghrelin (which stimulates hunger and reduces fat utilization); decreased leptin (which decreases hunger). Factors associated with shift work may also disrupt circadian rhythm: Changes in light-dark synchronization; frequent snacking; less physical activity; daylight savings time.
Using melatonin and bright lights during the night may help regulate circadian rhythms.Plan sleep schedules and time light exposure: Get at least 7 hours of sleep every 24 hours. Start the main sleep episode right after work. Take 30-minute to 2-hour naps before night shifts. Nap 20 to 30 minutes during the shift to maintain wakefulness, especially in high-risk jobs.
Increase exposure to bright lights during the first half of the shift. Avoid bright lights after the end of the night shift. Keep the bedroom quiet and dark. Keep regular meal and exercise schedules.
The health burden of shift work includes metabolic disorders, obesity, diabetes, hypertension, abdominal obesity, cardiovascular disorders, and increased total cholesterol, triglycerides, and inflammatory markers such as CRP. There is strong evidence linking shift work to being overweight and the development of diabetes. Sleep deprivation associated with shift work may affect hormones involved in circadian rhythm and metabolic processes. Behavioral factors may also play a role. Taking melatonin, using bright lights, planning sleep schedules and timing light exposure during the night may help regulate circadian rhythms.
Shift work is known to cause dangerous disruption in the circadian rhythms that regulate sleeping and waking. Sleep disturbance and associated sleepiness lead to poor concentration, absenteeism, accidents, errors, injuries, and fatalities. Shift work is also linked to metabolic disturbances that lead to chronic disease such as obesity, diabetes and hypertension. The slides above offer evidence for these connections and also some tips for primary care physicians to offer at-risk patients.