Healthy Diet and Reduction of Chronic Disease Risks of Night Shift Workers

Association Between Consumption of Foods Containing Vitamin D and All-Cause Mortality in Korea

Sufficient vitamin D levels are reported to be a factor in reducing various chronic diseases and resulting mortality rates. Well-dried mushrooms and blue-backed fish are known to be rich in vitamin D. In this study, the association between mortality rates and the intake of vitamin D-rich foods was confirmed using data from the Korean Genome and Epidemiological Study (KoGES). Among the KoGES database, we followed up a total of 6844 adults who participated in the Ansung-Ansan cohort study recruited from 2001 to 2002 and continued for an average of 16.7 years until 2018. The main findings were analyzed using Cox regression analysis. During follow-up, 439 cases of all-cause mortality, 149 cases of cancer-related mortality, and 91 cases of cardiovascular mortality were confirmed. In the fully adjusted model, the hazard ratio (HR) for all-cause mortality in quartile 3 of mushroom consumption was 0.709 (95% confidence interval [CI], 0.525-0.958) compared with quartile 1. In addition, the HRs for cardiovascular mortality in quartile 3 of mushroom consumption were 0.348 (95% CI, 0.154-0.787) compared with those in quartile 1. The HRs of cardiovascular mortality for quartiles 3 and 4 of fish consumption were 0.442 (95% CI, 0.226-0.865) and 0.533 (95% CI, 0.285-0.998), respectively, compared with quartile 1. In conclusion, moderate consumption of mushrooms was related to decreased risk of all-cause and cardiovascular mortality, while heightened fish consumption was inversely related to cardiovascular mortality.

Association of Night Shifts and Lifestyle Risks With Incident Dementia

BACKGROUND

Little is known about the combined relationship between night shifts and lifestyle risks with incident dementia or their potential interactions. To evaluate the association of night shifts and lifestyle risks with incident dementia and further analyze their interactions.

METHODS

A total of 276 059 participants were included in this study from the UK Biobank cohort. Cox proportional hazards models were used to investigate the combined association of night shifts and lifestyle risks with incident dementia.

RESULTS

Participants with always night shifts and 3 or 4 unhealthy lifestyle factors had the highest risk of incident all-cause dementia (hazard ratio: 3.15, 95% confidence interval [CI]: 1.74-5.69). An additive interaction was found between night shifts and lifestyle risks for incident all-cause dementia (p < .001), with a relative excess risk due to the interaction of 0.14 (95% CI: 0.11-0.45). The attributable proportions of the combined effect on the incidence of all-cause dementia were 22.6% (95% CI: 20.91%-26.75%) for night shift work, 65.0% (95% CI: 63.12%-69.80%) for unhealthy lifestyle factors, and 12.1% (95% CI: 8.67%-18.04%) for their interaction.

CONCLUSIONS

Both night shifts and lifestyle risks were associated with a higher risk of incident dementia. The combined impact was higher than the increase in the risks related to each single factor. Our results indicated that most incident dementia cases might be prevented by a healthy lifestyle, and the benefits would be greater among night shift workers. Further studies are needed to confirm our results and explore the underlying mechanisms.

Rotating night shift work and adherence to unhealthy lifestyle in predicting risk of type 2 diabetes: results from two large US cohorts of female nurses

OBJECTIVES

To prospectively evaluate the joint association of duration of rotating night shift work and lifestyle factors with risk of type 2 diabetes risk, and to quantitatively decompose this joint association to rotating night shift work only, to lifestyle only, and to their interaction.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study (1988-2012) and Nurses' Health Study II (1991-2013).

PARTICIPANTS

143 410 women without type 2 diabetes, cardiovascular disease, or cancer at baseline.

EXPOSURES

Rotating night shift work was defined as at least three night shifts per month in addition to day and evening shifts in that month. Unhealthy lifestyles included current smoking, physical activity levels below 30 minutes per day at moderate to vigorous intensity, diet in the bottom three fifths of the Alternate Healthy Eating Index score, and body mass index of 25 or above.

MAIN OUTCOME MEASURES

Incident cases of type 2 diabetes were identified through self report and validated by a supplementary questionnaire.

RESULTS

During 22-24 years of follow-up, 10 915 cases of incident type 2 diabetes occurred. The multivariable adjusted hazard ratios for type 2 diabetes were 1.31 (95% confidence interval 1.19 to 1.44) per five year increment of duration of rotating night shift work and 2.30 (1.88 to 2.83) per unhealthy lifestyle factor (ever smoking, low diet quality, low physical activity, and overweight or obesity). For the joint association of per five year increment rotating night shift work and per unhealthy lifestyle factor with type 2 diabetes, the hazard ratio was 2.83 (2.15 to 3.73) with a significant additive interaction (P for interaction <0.001). The proportions of the joint association were 17.1% (14.0% to 20.8%) for rotating night shift work alone, 71.2% (66.9% to 75.8%) for unhealthy lifestyle alone, and 11.3% (7.3% to 17.3%) for their additive interaction.

CONCLUSIONS

Among female nurses, both rotating night shift work and unhealthy lifestyle were associated with a higher risk of type 2 diabetes. The excess risk of rotating night shift work combined with unhealthy lifestyle was higher than the addition of risk associated with each individual factor. These findings suggest that most cases of type 2 diabetes could be prevented by adhering to a healthy lifestyle, and the benefits could be greater in rotating night shift workers.