Association between Night-shift Work and Serum 25-hydroxyvitamin D Levels in Japanese Male Indoor Workers: A Cross-sectional Study

Itoh, Hiroaki; Weng, Zuquan; Saito, Hiroyuki; Ogawa, Yasutaka; Nakayama, Kotaro; Hasegawa-Ohira, Masako; Morimoto, Kanehisa; Maki, Syou; Takahashi, Masaya

doi:10.2486/indhealth.ms1271

Cited by 28 publications

(28 citation statements)

References 22 publications

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“…Melatonin suppression, decreased vitamin D levels, or lifestyle disturbances (absent in mice) cannot account for the enhanced cancer risk in animals kept under LD inversion conditions: (1) p53 R270Hª/+ WAPCre mice (FVB background) are melatonin deficient; (2) neither CRD mice nor controls were exposed to sunlight, and we found no difference in 25-hydroxy-vitamin D between groups. This is consistent with a study in night shift workers, which found no difference in vitamin D levels between fixed daytime workers, rotating shift workers without night shift, and rotating shift workers with night shift [22]. (3) Lifestyle factors did not differ (amount of food intake) in the LD inversion mice and the controls or were absent (e.g., breastfeeding, smoking).…”

Section: Discussionsupporting

confidence: 91%

Chronically Alternating Light Cycles Increase Breast Cancer Risk in Mice

et al. 2015

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Although epidemiological studies in shift workers and flight attendants have associated chronic circadian rhythm disturbance (CRD) with increased breast cancer risk, causal evidence for this association is lacking. Several scenarios have been proposed to contribute to the shift work-cancer connection: (1) internal desynchronization, (2) light at night (resulting in melatonin suppression), (3) sleep disruption, (4) lifestyle disturbances, and (5) decreased vitamin D levels due to lack of sunlight. The confounders inherent in human field studies are less problematic in animal studies, which are therefore a good approach to assess the causal relation between circadian disturbance and cancer. However, the experimental conditions of many of these animal studies were far from the reality of human shift workers. For example, some involved xenografts (addressing tumor growth rather than cancer initiation and/or progression), chemically induced tumor models, or continuous bright light exposure, which can lead to suppression of circadian rhythmicity. Here, we have exposed breast cancer-prone p53(R270H/+)WAPCre conditional mutant mice (in a FVB genetic background) to chronic CRD by subjecting them to a weekly alternating light-dark (LD) cycle throughout their life. Animals exposed to the weekly LD inversions showed a decrease in tumor suppression. In addition, these animals showed an increase in body weight. Importantly, this study provides the first experimental proof that CRD increases breast cancer development. Finally, our data suggest internal desynchronization and sleep disturbance as mechanisms linking shift work with cancer development and obesity.

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Section: Discussionsupporting

confidence: 91%

Chronically Alternating Light Cycles Increase Breast Cancer Risk in Mice

et al. 2015

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“…Daily workers were defined as subjects working only on daylight hours (9 a.m. to 5 p.m.), and night-shift workers as subjects working on nocturnal hours at least twice a week. As it was expected, but contrary to the previous Japanese study by Itoh et al (2011), low 25-OH vitamin D serum levels are associated with shift work. We interpret this phenomenon as the effect of a general higher open-air exposure in daily workers.…”

Section: Discussioncontrasting

confidence: 82%

“…In fact, we conducted the current study during the month of April, thus avoiding a confounding factor: at the end of winter, sun radiation in Northern Italy is not able to convert cutaneous vitamin D precursor into the biological active form and cannot attenuate the difference of vitamin D concentration between night and daily workers (Itoh et al, 2011;Hilger et al, 2014). Besides, dairy products are not supplemented with vitamin D, since Italian public health authorities do not recommend it.…”

Section: Discussionmentioning

confidence: 98%

“…Albeit vitamin D deficit and insufficiency are widespread especially in the areas north of 37 N and south of 37 S parallels (Holick, 2007;Seckmeyer et al, 2013), there are only few trials exploring their prevalence in the working population and possible associations between this phenomenon and working shifts (Itoh et al, 2011) or life-style habits in workers (Chao et al, 2013;Sarikaya et al, 2006), leading to controversial findings. For these reasons, we investigated the vitamin D serum levels and the heel bone density in a population of healthy male workers of an engineering factory, focusing upon their role in the maintenance of both skeletal and extraskeletal implications.…”

Section: Introductionmentioning

confidence: 98%

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Shift work and serum 25-OH vitamin D status among factory workers in Northern Italy: Cross-sectional study

Romano

Vigna

Belluigi³

et al. 2015

Chronobiology International

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Low levels of vitamin D are related to muscle weakness, poor balance, and higher risk of falls, and can therefore have a major impact on performance and safety at work. Little knowledge exists on the association between work environment and vitamin D status. This study evaluates vitamin D status in shift workers. In this cross-sectional study, led during early springtime, 96 male shift workers at an engineering factory in Northern Italy, and 100 male daily workers operating nearby, participated. 25-OH vitamin D concentration, anthropometric indexes, fasting glycemia and triglycerides were detected. 51 shift workers underwent anamnesis collection on lifestyle and habits and determination of heel bone mineral density. Vitamin D levels were lower in shift workers than daily ones (13.4 ± 5.3 ng/mL versus 21.9 ± 10.7 ng/mL, p < 0.001). Linear regression analysis adjusted for age, body mass index and smoking habits confirms a statistically significant association between shift work and vitamin D levels (p < 0.0001). An association trend between cigarette smoking and low vitamin D values was found. No significant association was detected between the heel bone mineral density values and vitamin D levels or smoking habits. In conclusion, this cross-sectional study highlights the high prevalence of vitamin D deficit among shift workers compared with daily ones.

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“…Bunun yanında, Itoh ve ark. [19] kapalı ortamda çalışan Japon erkeklerini, gündüz çalışan işçiler ve gece çalışan işçiler ile 25-hidroksivitamin D 3 seviyesi için karşılaştırmala-rına rağmen bu gruplar arasında istatistiksel olarak anlamlı farklılık tespit etmemişlerdir.…”

Section: Gereç Ve Yöntemlerunclassified

Are there any adverse effects of static magnetic field from magnetic resonance imaging devices on bone health of workers?

Gungor

Ök

Akkaya

et al. 2014

Eklem Hastalik Cerrahisi

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Amaç: Bu çalışmada, manyetik rezonans görüntüleme (MRG) cihazlarının oluşturduğu statik manyetik alanın (SMA) MRG çalışanlarının kemik sağlığı üzerindeki etkileri araştırıldı. Gereç ve yöntemler: En az iki yıl boyunca 1.5 Tesla MRG cihazı ile çalışan 14 gönüllü MRG teknisyeni çalışmaya dahil edildi. Cinsiyet ve yaş eşleştirilmesi yapıldıktan sonra aynı kriterler gözetilerek, SMA'ya maruz kalmayan ve kapalı alanda çalışan 14 paramedikal gönüllü personelden kontrol grubu oluşturuldu. Tüm katılımcılara dual-enerji X-ray absopsiyometri (DXA) görüntülemesi uygulandı. Paratiroid hormon, kalsiyum, fosfor, alkalen fosfataz, 25-hidroksivitamin D3, ve 1.25-dihidroksivitamin D3 seviyeleri ölçüldü. Bulgular: MRG teknisyenlerinin vertebra ve femur boynu ortalama kemik mineral içeriği (KMİ) ve ortalama kemik mineral yoğunluğu (KMY) ile birlikte ortalama 25-hidroksivitamin D3 değerleri kontrol grubuna göre anlamlı oranda düşük bulundu (p<0.01). Referans sınırlarda olmasına rağmen MRG teknisyenlerinin kalsiyum düzeyleri, kontrol grubuna kıyasla, daha yüksek olarak tespit edildi (p<0.05). Ölçülen diğer parametrelerde gruplar arası istatistiksel olarak anlamlı bir farklılık görülmedi. Sonuç: Mevcut bilgilerimize göre, MRG cihazlarının oluş-turduğu SMA'nın çalışanların kemik sağlığı üzerinde olumsuz etkilerinin olduğu ilk kez saptandı. Ancak SMA'ya kronik maruziyetin kemik metabolizmasına etkisinin daha iyi anlaşı-labilmesi için çokmerkezli çalışmalara ve hayvan deneylerine gereksinim vardır.Anahtar sözcükler: Kemik yoğunluğu; manyetik alanlar; manyetik rezonans görüntüleme; mesleki etkilenim; vitamin D. Objectives:In this study, we aimed to evaluate the effects of static magnetic field (SMF) from magnetic resonance imaging (MRI) devices on the bone health of MRI workers. Materials and methods: Fourteen volunteer MRI technicians working with 1.5 Tesla MRI units at least for two years were included in the study. An age and sex-matched control group from indoor working 14 volunteer paramedical staff who were not exposed to SMF and met the identical criteria was formed. Dual-energy X-ray absorptiometry (DXA) scanning was performed in all participants. Parathyroid hormone, calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D3, and 1.25-dihydroxyvitamin D3 levels were measured. Results: The mean vertebral and femoral neck bone mineral content (BMC) and bone mineral density (BMD) as well as the mean 25-hydroxyvitamin D3 level of MRI technicians was found to be lower than the control group (p<0.01). Despite presenting within the normal range, the mean calcium level of MRI technicians was higher than the control group (p<0.05). There was no statistically significant difference in other variables between the groups. Conclusion: To the best of our knowledge, adverse effects of SMF from MRI devices on the bone health of MRI workers were detected for the first time. However, further multicenter studies and animal experiments are required to gain a better understanding of the mechanism that how the SMF affects bone health in chronic ...

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Association between Night-shift Work and Serum 25-hydroxyvitamin D Levels in Japanese Male Indoor Workers: A Cross-sectional Study

Cited by 28 publications

References 22 publications

Chronically Alternating Light Cycles Increase Breast Cancer Risk in Mice

Chronically Alternating Light Cycles Increase Breast Cancer Risk in Mice

Shift work and serum 25-OH vitamin D status among factory workers in Northern Italy: Cross-sectional study

Are there any adverse effects of static magnetic field from magnetic resonance imaging devices on bone health of workers?

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