Night shift work and modifiable lifestyle factors

Objectives: Night shift work has been linked to some chronic diseases. Modification of lifestyle by night work may partially contribute to the development of these diseases, nevertheless, so far epidemiological evidence is limited. The aim of the study was to explore association between night shift work and lifestyle factors using data from a cross-sectional study among blue-collar workers employed in industrial plants in Łódź, Poland. Material and Methods: The anonymous questionnaire was self-administered among 605 employees (236 women and 369 men, aged 35 or more) - 434 individuals currently wor­king night shifts. Distribution of the selected lifestyle related factors such as smoking, alcohol drinking, physical activity, body mass index (BMI), number of main meals and the hour of the last meal was compared between current, former, and never night shift workers. Adjusted ORs or predicted means were calculated, as a measure of the associations between night shift work and lifestyle factors, with age, marital status and education included in the models as covariates. Results: Recreational inactivity (defined here as less than one hour per week of recreational physical activity) was associated with current night shift work when compared to never night shift workers (OR = 2.43, 95% CI: 1.13-5.22) among men. Alcohol abstinence and later time of the last meal was associated with night shift work among women. Statistically significant positive relationship between night shift work duration and BMI was observed among men (p = 0.029). Conclusions: This study confirms previous studies reporting lower exercising among night shift workers and tendency to increase body weight. This finding provides important public health implication for the prevention of chronic diseases among night shift workers. Initiatives promoting physical activity addressed in particular to the night shift workers are recommended

Night work and health of nurses and midviwes – A review

Night shift work has been thought to play a role in the etiology of chronic diseases through a disruption of the circadian rhythm, decreased synthesis of melatonin and sleep deprivation. Our aim was to review the epidemiological studies on the association between night shift work and some pathologies in nurses and midwives. We reviewed publications available in the MEDLINE database and published before June 2012, describing the cross-sectional (almost two thirds of all papers) and cohort studies. In total, we identified 26 original papers, including 5 epidemiological studies addressing diseases or disorders of the digestive system, 3 - metabolic syndrome, 2 - diabetes type 2, 9 - cardiovascular diseases and CVD risk factors, 5 - obesity/overweight, 2 - menstrual disorders and 3 - poor pregnancy outcomes. The analysis of the literature indicates that night shift work of nurses and midwives is most strongly associated with a higher risk of obesity/overweight. In each of the five studies, which we identified this association was observed (confirmed by the statistical significance of the results), also after adjustment for confounders. The results for diabetes type 2 and disorders of the menstrual cycle are also suggestive. Epidemiological data on the other disorders or pathologies discussed in this article seem to be less certain - their results are inconsistent or their number is too small to draw definite conclusions. Further epidemiological studies of nurses and midwives working on night shifts and prospective observations in particular are recommended to find out whether potential association between the night work and discussed health issues is causal. Med Pr 2013;64(3):397–41

Night shift work and prolactin as a breast cancer risk factor

Prolactin - a hormone secreted in a circadian rhythm acts as a regulator of growth and development of the mammary glands. It has been observed that working at night increases breast cancer risk in women. Night shift work, probably carcinogenic to humans (Group 2A IARC), can disrupt a circadian rhythm, and thus potentially alter the rhythm of prolactin secretion. The aim of our work was to review epidemiological evidence on the association between prolactin and the risk of breast cancer and the influence of work at night on prolactin secretion. Search was done in the Medline database by keywords (shift work, work at night, risk of breast cancer and prolactin). The increased proliferation of breast cells activated by prolactin can promote the development of cancer. The results of the largest epidemiological prospective studies suggest the association between prolactin levels and the risk of breast cancer in women. So far, only seven studies have investigated the association between work at night and prolactin secretion. In three studies lower concentrations of prolactin have been observed in night shift workers. No relationship between the night shift work duration and prolactin level in women have been reported. Night shift work can modify the profile of prolactin secretion in night workers, probably decreasing the secretion of this hormone at night. It is therefore unlikely that prolactin plays an important role in the development of breast cancer in women working at night. This conclusion is based on the results of a few epidemiological studies. Med Pr 2013;64(2):245–25

Cigarette smoking and mammographic breast density among Polish women

ObjectivesHigh mammographic breast density (MBD) is one of the strongest breast cancer risk factors. The results of some epidemiological studies suggest that one of the lifestyle factors likely altering breast density is cigarette smoking. The aim of this study was to assess the association between active smoking, considering in detail the duration and intensity of smoking, and MBD among Polish women.Material and MethodsA cross-sectional study included 467 women aged 40–60 years who underwent screening mammography in Łódź, Poland. Volumetric mammographic density, fibroglandular tissue volume and non-fibroglandular tissue volume were determined based on the analysis of mammographic image (in the “for processing” format) using Volpara Imaging Software. Current and lifetime intensity of cigarette smoking was assessed based on the data from interviews. Linear and logistic regressions were fitted with estimated MBD parameters as the outcomes, and life-long smoking duration and intensity as the determinants, adjusted for major confounders.ResultsThe former smokers had a significantly lower volumetric mammographic density compared to the non-smokers in the crude analysis (p = 0.022). However, the associations became insignificant after adjustments for important confounding factors. The analyses adjusted for important confounders revealed an inverse statistically significant association between the number of pack-years and volumetric mammographic density among the current smokers (p = 0.048).ConclusionsThe observed result is consistent with the majority of previous studies that analyzed the associations between mammographic density and life-long smoking duration

The association between night shift work and nutrition patterns among nurses: a literature review

The shift work system may affect the temporal distribution of eating and diet quality. The paper aimed at reviewing a body of research examining the associations between night shift work and dietary habits among nurses. Data from the PubMed and Google Schoolar databases, as well as references lists in selected papers were searched. The authors used the following keywords: nurses, shift work, diet, nutrition. Papers published in English or Polish were selected for the review, and as many as 19 papers published in 2000−2017 were eventually identified. The studies varied greatly with respect to the study size, subjects’ age and the duration of night shift work. The major problem was the heterogeneity of the tools used for dietary assessment. Self-administered questionnaires were used and analyses were rarely adjusted for confounders. Alcohol consumption was the most frequently analyzed aspect (N = 8 studies), followed by the total energy (N = 7), protein, fat (N = 6), and carbohydrate intake, coffee and fruit consumption (N = 5). The results showed quite a consistent association of night work with higher coffee (caffeine) consumption, as well as lower alcohol, and fruit and vegetables consumption. Few studies also reported more frequent snacks consumption, later time of the last meal, eating at night, meals irregularity, and a poorer diet quality among night shift nurses when compared to the reference. The review showed some poor nutritional habits among nurses working night shifts. However, the topic warrants further attention, owing to the relatively small number of the studies performed so far, and their numerous methodological limitations. Med Pr. 2019;70(3):363–7

Cadmium and volumetric mammographic density: A cross-sectional study in Polish women.

INTRODUCTION:Cadmium (Cd) is a heavy metal, which is widespread in the environment and has been hypothesized to be a metalloestrogen and a breast cancer risk factor. Mammographic density (MD) reflects the composition of the breast and was proposed to be used as a surrogate marker for breast cancer. The aim of our study was to investigate association between cadmium concentration in urine and mammographic density. METHODS:A cross-sectional study included 517 women aged 40-60 years who underwent screening mammography in Łódź, Poland. Data were collected through personal interviews and anthropometric measurements. Spot morning urine samples were obtained. The examination of the breasts included both craniocaudal and mediolateral oblique views. Raw data ("for processing") generated by the digital mammography system were analysed using Volpara Imaging Software, The volumetric breast density(%) and fibrograndular tissue volume(cm3) were determined. Cadmium concentration in urine was analysed using the standard ICP-MS method. RESULTS:After adjusting for key confounders including age, BMI, family breast cancer, mammographic device, season of the year of mammography, and age at menarche, an inverse association of Cd and volumetric breast density was found, which was attenuated after further adjustment for smoking. Associations of Cd with dense volume were null. CONCLUSIONS:These findings suggest that Cd is not positively associated with breast density, a strong marker of breast cancer risk, when examined in a cross-sectional fashion

Ionizing radiation and volumetric mammographic density

Objectives Mammographic density (MD) refers to the percentage of dense tissue of an entire breast and was proposed to be used as a surrogate marker for breast cancer. High-dose ionizing radiation (IR) has been recognized as a breast cancer risk factor. The aim of our study was to investigate association between lifetime low dose ionizing radiation (LDIR) and MD. Material and Methods A cross-sectional study included 467 women aged 40–60 years who underwent screening mammography in Łódź, Poland. The digital mammography examination of the breasts included both craniocaudal and mediolateral oblique views. The volumetric breast density (VBD) (%) and fibrograndular tissue volume (FG) (cm3) were determined based on the analysis of mammographic image (“for processing”) using Volpara Imaging Software. The exposure to IR was estimated for each individual, based on the data from interviews about diagnostic or therapeutic medical procedures performed in the area of the neck, chest, abdomen and spine, which involved X-rays and γ rays and the data about the doses derived from literature. Linear and logistic regression were fitted with VBD and FG as the outcomes and organ breast dose, effective dose and number of mammographies as the determinants, adjusted for major confounders. Results The analyses showed no association between VBD or FG and the breast organ dose or the effective dose. The only significant finding observed concerned the association between the number of mammographies and the FG volume with β coefficient: 0.028 (95% CI: 0.012–0.043), and predicted mean FG volume >13.4 cm3 among the women with >3 mammographies when compared to those with none. Conclusions This study does not, in general, provide support for the positive association between LDIR and MD. The weak association of the FG volume with the number of mammographies warrants further verification in larger independent studies