Influence of Obesity on Heart Rate Variability in Nurses with Age and Shift Type as Moderators

Obesity is a risk factor of cardiovascular disease-related mortality and may be associated with changes in the autonomic nerve activity. Nurses working shifts and caring for patients are under great mental and physical pressure, and research has proven that these can negatively affect the body. The objective of this study was to examine the influence of obesity in nurses on their heart rate variability (HRV) and determine whether age or shift type moderates this influence. A questionnaire survey and HRV measurements were conducted on nurses at a hospital in Taiwan during a routine employee health checkup. HRV analysis was conducted using a noninvasive HRV monitor for five minutes. A total of 242 nurses with a mean age of 28.98 ± 6.56 years were enrolled in this study. An overly large waist circumference (WC) had a negative impact on high frequency (HF), low frequency (LF), and standard deviation of normal-to-normal interval (SDNN), while an overly high body mass index (BMI) had a negative impact on very low frequency (VLF) and SDNN. The interaction term “overly large WC × age” had a negative impact on HF ( β = − 0.21 , p = 0.010 ) and LF ( β = − 0.18 , p = 0.030 ), whereas the interaction term “overly high BMI×age” had a negative impact on HF ( β = − 0.27 , p = 0.001 ), LF ( β = − 0.19 , p = 0.023 ), and VLF ( β = − 0.17 , p = 0.045 ). The interaction terms “overly large WC × shift type” and “overly high BMI × shift type” did not influence any HRV parameters. As age increased, so did the degree to which the HF and LF of nurses with an overly large WC were lower than normal, and so did the degree to which the HF, LF, and VLF of nurses with an overly high BMI were lower than normal.

A GENERALIZATION OF THE SHIFT OPERATOR

Several approaches are known to generalize the shift operator in the complex domain. Specific generalization procedures lead to significantly different operators of the shift type even in one specific area of complex analysis. In this paper, a certain general operator of the shift type is defined. The properties of this operator are studied and the question of the continuity of this definition is considered. The properties of a certain operator to a certain extent re-peat the properties of the previously studied operators of the shift type. This allows us to speak of the possibility of extending the main results on spectral synthesis in the complex domain to convolutional equations of a more general form.

288 Chronotype-dependent impact of napping on sleep behavior in rotating shift workers

Introduction Rotating shift work is known to adversely impact sleep. Napping is one of the strategies that workers can use to mitigate the effect of shift work on their sleep. In this study, we investigated the effect of chronotype on napping behavior in police officers involved in rotating shift work. Methods Actigraphy-based sleep measures and chronotype information was available from 74 police officers (20 women and 54 men; age [mean ± SD]: 32 ± 5.4 years) that participated in a 35-day field study during which they worked morning, evening, and night shifts. A generalized linear mixed model was used to assess the effect of shift type, chronotype, and their interaction on the likelihood to take a nap, adjusted for relevant covariates. In addition, linear mixed models were used to determine the effect of shift type, chronotype, and their interaction on sleep duration with and without taking into account napping duration. Results The likelihood to take a nap was influenced by an interaction between shift type and chronotype (χ2(2) = 11.2, p = 0.004). Earlier chronotype was linked to a lower likelihood to take naps during days with morning shifts and a higher likelihood during days with night shifts. Napping modulated the effect of shift type and chronotype on daily sleep duration, most notably during night shifts: while chronotype was associated with the duration of the main sleep period during night shifts, with the main sleep period being 1.7 h [95% C.I.: 0.6 – 2.8] shorter in the earliest chronotypes compared to the latest chronotypes, this effect was attenuated and no longer significant when napping duration was taken into account (difference in total sleep duration in latest chronotypes vs earliest chronotypes during nights shifts: 0.9 [−0.1 to 1.9] h). Conclusion Napping attenuates the chronotype-dependent effect of atypical work schedules on sleep duration in this population of shift-working police officers. These findings highlight the need to take into account chronotype when assessing the effect of shift work on sleep behavior. Support (if any) The Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRRST) and Fonds de Recherche du Québec–Santé (FRQS).

Examination of refractory discoid lateral meniscus injury

Background: Lateral discoid meniscus (LDM) should be treated and preserved with saucerization and/or suture repair. However, repair of the meniscal hoop structure is sometimes difficult due to displacement or large defects. In this study, we aimed to examine tear patterns based on the Ahn classification in those requiring meniscal repair and those undergoing subtotal meniscectomy. Methods: Twenty-three patients were evaluated (mean age, 27.4 years; mean follow-up period, 2.5 years). The following were evaluated: displacement morphology based on the Ahn classification, site of tear under arthroscopy, morphology, surgical procedure, Lysholm score at final postoperative follow-up, and clinical outcome of meniscus using Barrett’s criteria. Result: There were 16 knees without displacement (saucerization with suture repair, 13 knees; subtotal meniscectomy, 3 knees) and 10 knees with displacement (reduction with suture repair, 3 knees; subtotal meniscectomy, 7 knees). Subtotal meniscectomy was performed more often in cases with dislocation, especially in the central shift type as defined by the Ahn classification. The mean Lysholm score was 65.0 points preoperatively and 95.3 points postoperatively. Twenty-three knees (88%) were postoperatively categorized under the Barrett’s criteria as healing and 3 knees (12%) were categorized as non-healing. The number of non-healing cases that underwent subtotal meniscectomy was relatively small (1 of 10 knees), and the short-term results were not poor. Conclusion: Localized peripheral longitudinal tears tended to be repairable even with displacement, while peripheral tears covering the entire meniscus or with severe defects/tears in the body of the meniscus tended to be difficult to repair, leading to subtotal meniscectomy.

285 Pilot field study of Ambulatory Sleep-Staging in Shift-Working Air Traffic Controllers

Introduction The simplicity of wrist actigraphy for sleep-wake monitoring in the field contributes to its ubiquity in shift-work research. However, devices based solely on recording activity levels are generally not suitable to quantify sleep architecture. This is a limitation as quantifying changes in sleep stages caused by circadian misalignment is important to better assess the consequences of sleep-wake disruption in shift-working populations. This pilot study was conducted to evaluate whether sleep stages vary with respect to different shift types. Methods Six male air traffic controllers aged 48.5±8.4 years (mean±SD) completed the protocol which entailed two ~9-day periods, each with up to 6 workdays. Schedules comprised 1 or 2 early night shifts (19:30–03:30h), followed by an evening shift (15:00–23:00h), day shift (09:00–17:00h), morning shift (06:30–14:30h), and 1 or 2 full night shifts (23:00–7:00h). A portable sleep-staging device (Somno-Art, Paris, France) that monitored activity levels and heart rate was worn on the non-dominant forearm during bedtime and produced estimates of REM and NREM sleep stages with a proprietary algorithm. Total sleep time (TST) and sleep stages were assessed per shift type with mixed-effects models. Results Final analyses were based on 70 sleep periods preceding workdays, standardized to 24 h to account for the different intervals between consecutive shifts. Analyses revealed significant effects of shift type for TST (p=.016), stages N1 (p=.010) and N2 (p=.043), but none for N3 (p=.055) or REM (p=.117) sleep. TST and stage N1 sleep prior to night shifts was shorter than for day, evening, or early night shifts (all p<.05). Participants obtained less stage N2 sleep prior to night shifts than days shifts (p=.049). Conclusion This pilot study suggests variations in TST across shifts were predominantly due to differences in light sleep stages, whereas no significant differences in N3 and REM sleep were observed. Thus, while TST was reduced for night shifts, participants obtained similar durations of the most recuperative stages. These findings highlight the importance of refined monitoring of sleep in field research involving shift-work. Support (if any) Project funded by NAV Canada. Devices lent by the Somno-Art company. A.K. received a postdoctoral fellowship from the Fonds de Recherche en Santé du Québec (FRQS).

Assessment of safety climate status in personnel of Naeen Tile Industries Company in 2019

Introduction: safety occupational safety researchers have always analyzed climate analysis. Climate can be investigated at different organizational levels. The purpose of the present study was to examine the safety climate among Nain tile factory workers and its relationship with having a history of occupational accidents. Materials and Methods: This cross-sectional and descriptive-analytical study was conducted in 2019 among the Nain Tile factory staff. The Nordic Safety Climate Questionnaire (NOSACQ-50) was used to assess the safety climate among workers of the different organizational departments. Out of 252, 142 workers were selected by simple random sampling. Descriptive and analytical statistics were used to analyze the data. The instrument's internal consistency was also calculated by calculating Richardson's coefficient of coefficient 0.942.coefficients were used for analytical analysis. Analyzes were performed in SPSS software version 19 with a significance level of 5%. Results: The reliability coefficient of the whole questionnaire was calculated 0.95 using Cronbach's alpha test. The safety climate score was higher than two in all domains. Safety climate score was significantly correlated with work area and shift type. The highest score of safety climate was in the crusher section as well as in day shift work. There was no significant relationship between safety climate score and other variables of the study. Conclusion: The safety atmosphere score is affected by the day shift and the workplace section. Therefore, it is suggested to modify the job plan and work shifts to improve the prevailing safety climate.

The role of chronic muscle (in)activity on carnosine homeostasis: a study with spinal-cord injured athletes

To examine the role of chronic (in)activity on muscle carnosine (MCarn) and how chronic (in)activity affects MCarn responses to β-alanine supplementation in spinal-cord injured athletes, sixteen male athletes with paraplegia were randomized (2:1 ratio) to receive β-alanine (n=11) or placebo (PL, n=5). They consumed 6.4 g‧d-1 of β-alanine or PL for 28 days. Muscle biopsies of the active deltoid and the inactive vastus lateralis (VL) were taken before and after supplementation. MCarn in the VL was also compared with the VL of a group of individuals without paraplegia (n=15). MCarn was quantified in whole muscle and in pools of individual fibers by High-performance Liquid Chromatography. MCarn was higher in chronically inactive VL vs. well-trained deltoid (32.0±12.0 vs. 20.5±6.1 mmol‧kg-1 DM; p=0.018). MCarn was higher in inactive vs. active VL (32.0±12.0 vs. 21.2±7.5 mmol‧kg-1 DM; p=0.011). In type-I fibers, MCarn was significantly higher in the inactive VL than in the active deltoid (38.3±4.7 vs. 27.3±11.8 mmol‧kg-1 DM, p=0.014). MCarn increased similarly between inactive VL and active deltoid in the β-alanine group (VL: 68.9±55.1%, p=0.0002; deltoid: 90.5±51.4%, p<0.0001), with no changes in the PL group. MCarn content was higher in the inactive VL than in the active deltoid and the active VL, but this is probably a consequence of fiber type shift (type I to type II) that occurs with chronic inactivity. Chronically inactive muscle showed an increase in MCarn after BA supplementation equally to the active muscle, suggesting that carnosine accretion following β-alanine supplementation is not influenced by muscle inactivity.