Seasonality of retinal detachment incidence and its associations with climate: an 11-year nationwide population-based study

This study aimed to examine the seasonal variability of retinal detachment (RD) in Taiwan by using an 11-yr nationwide population database. This study also investigated the association of weather conditions, i.e., ambient temperature, relative humidity, rainfall, monthly hours of sunshine, and atmospheric pressure, with RD. Data were retrospectively collected from the Taiwan National Health Insurance Research Database. The study sample included 23 718 RD hospitalizations between January 1999 and December 2009. The incidence rate of RD/100 000 people over the 132 months was computed according to sex and age groupings of <20, 20-39, 40-59, and ≥60 yrs. Then, the association between climatic factors and the monthly RD incidence rate was examined. The ARIMA (autoregressive integrated moving average) method was also employed to test the seasonality of RD incidence rates and their association with climatic factors. The annual RD incidence rates were between 7.8 and 10.8 cases/100 000 people during the study period. A fairly similar seasonal pattern of monthly RD incidence rates was apparent for males and females and males and females combined. Rates were highest August through October, decreasing in November, and lowest in February. After adjusting for time, trend, and month, the ARIMA regression models for the male, female, and males and females combined consistently revealed the monthly RD incidence rate was significantly and positively associated with ambient temperature, but negatively associated with atmospheric pressure. The authors conclude that the monthly RD incidence rates were significantly associated with seasonality. The monthly RD incidence rates were positively associated with ambient temperature and negatively associated with atmospheric pressure.     

SEASONALITY OF PNEUMONIA ADMISSIONS AND ITS ASSOCIATION WITH CLIMATE: AN EIGHT-YEAR NATIONWIDE POPULATION-BASED STUDY

The aim of the study was to examine seasonal variability in monthly admissions for community-acquired pneumonia (CAP) in Taiwan. Our study sample comprised 477,541 pneumonia patients in Taiwan between 1998 and 2005, inclusive. Results showed a fairly consistent seasonal pattern of pneumonia admissions, regardless of sex and age, and for the groups combined. Seasonal trends showed a peak in hospitalizations from January through April, followed by a sharp decrease in May and a trough from August through October. The auto-regressive integrated moving average (ARIMA) test found significant seasonality for all age and sex groups and for the whole sample (all p?<?0.001). After adjusting for seasonality, month, and trends, the ARIMA regression models revealed that the monthly pneumonia admissions rate was significantly associated with ambient temperature, for the total sample, for female groups, and for the 65–74 and?≥75 age groups (all p?<?0.01). A 1°C decrease in ambient temperature was associated with roughly a 0.03 increase in monthly pneumonia admissions rate (per 10,000 people) for the entire sample. We conclude the monthly pneumonia admissions rate was significantly associated with seasonality, and was higher in periods with low ambient temperatures. (Author correspondence: henry11111@tmu.edu.tw)     

Seasonal Variation in Ischemic Stroke Incidence and Association with Climate: A Six‐Year Population‐Based Study

Questions about the seasonality of stroke remain controversial. Using a nationwide population‐based dataset, this study presents a time series analysis of seasonal patterns in ischemic stroke occurrence, along with their association with climate in Taiwan. Using data from the Taiwan National Health Insurance Research Database, a total of 168,977 visits to emergency departments between 1998 and 2003 for ischemic stroke were identified for patients ranging between 20 and 84 yrs of age. Monthly stroke incidences were calculated for 72 months, by sex and stroke subtype, and for the age groups 20–54, 55–64, 65–74, and ≥75 yrs per 100,000 of the population. We performed auto‐regressive integrated moving average (ARIMA) analysis to investigate the presence of seasonality and any association with climate for acute ischemic stroke events. We found no significant seasonal variation in the incidence of ischemic stroke for any age or sex groups. Furthermore, after adjusting for seasonality, month, and trend, the ARIMA regression model revealed only associations between ischemic stroke incidence and atmospheric pressure. We conclude that seasonality of ischemic stroke does not exist in Taiwan. Ischemic stroke incidence is, however, significantly related to atmospheric pressure.     

INTERINDIVIDUAL DIFFERENCES IN NEUROBEHAVIORAL PERFORMANCE IN RESPONSE TO INCREASING HOMEOSTATIC SLEEP PRESSURE

Neurobehavioral function deteriorates with increasing homeostatic sleep pressure during wakefulness. It has been claimed that some individuals exhibit a quicker rate of such deterioration than others, thus being more vulnerable than others to the detrimental impact of increasing homeostatic sleep pressure. Evidence supporting the claim, however, has been limited by methodological issues. To overcome these limitations, the current study used a 12-calendar-day, 28-h forced desynchrony (FD) protocol (sleep:wake period?=?1:2) to study individual differences in the rate of change in neurobehavioral performance with increasing homeostatic sleep pressure. Neurobehavioral performance was assessed with a psychomotor vigilance task and a serial addition subtraction task. A significant performance decline on both tasks was revealed within as short as 17?h of wakefulness. The rates of decline of individual performance trajectories were, however, not different from the group average rate. This suggests that individuals are not differentially vulnerable to the detrimental impact of increasing homeostatic sleep pressure. (Author correspondence: xuan.zhou@unisa.edu.au)     

Morningness/Eveningness and Satisfaction With Life in a Polish Sample

Previous studies have provided evidence that eveningness could be related to disadvantageous individual characteristics. The hypothesis that more evening-oriented individuals exhibit lower satisfaction with life has been tested by Randler using a sample of 164 German university students, and this showed that eveningness is associated with lower satisfaction with life (r?=?.177). The aim of the present study was to answer the question of whether or not this relationship is culturally independent, and would exist if a sample from another geographical location and culture had been studied. A sample of 349 residents (149 men) aged between 13 and 59 yrs from two Polish cities completed the Morningness-Eveningness Questionnaire and the Satisfaction with Life Scale. Analysis revealed that morningness was related to greater life satisfaction (r?=?.105), regardless of age and sex. The magnitude of this relationship did not differ significantly between the Polish and the German sample, which suggests that the magnitude and direction of association between morningness/eveningness and satisfaction with life could be independent of culture or geographical location. (Author correspondence: E-mail: konrad.jankowski@psych.uw.edu.pl)     

Effects of Age,Sex, Index Admission,and Predominant Polarity on the Seasonality of Acute Admissions For Bipolar Disorder: A Population-Based Study

Bipolar disorder seasonality has been documented previously, though information on the effect of demographic and clinical variables on seasonal patterns is scant. This study examined effects of age, sex, index admission, and predominant polarity on bipolar disorder seasonality in a nationwide population. An inpatient cohort admitted to hospital exclusively for mental illness was derived from the Taiwan National Health Insurance Research Database for 2002–2007. The authors identified 9619 inpatients with bipolar disorder, who had generated 15 078 acute admission records. An empirical mode decomposition method was used to identify seasonal oscillations in bipolar admission data, and regression and cross-correlation analyses were used to quantify the degree and timing of bipolar admission seasonality. Results for seasonality timing found that manic or mixed episodes peak in spring or summer, and depressive episodes peak in winter. Analysis for degree of seasonality revealed that (1) the polarity of patients' index admission predicted the seasonality of relapse admissions; (2) seasonality was significant in female admissions for depressive episodes and in male admissions for manic episodes; (3) young adults displayed a higher degree of seasonality for acute admissions than middle-aged adults; and (4) patients with predominantly depressive admissions displayed a higher degree of seasonality than patients with predominantly manic admissions. Demographic and clinical variables were found to affect the seasonality of acute admissions for bipolar disorders. These findings highlight the need for research on identification and management of seasonal features in bipolar patients. (Author correspondence: ccyang@physionet.org)     

SEASON OF BIRTH AND SMOKING: FINDINGS FROM THE NORTHERN FINLAND 1966 BIRTH COHORT

A season of birth effect in addictive disorders has scarcely been studied. As smoking is known to be a highly addictive behavior, we examined whether there exists an association between season of birth and smoking habits among the general population in the Northern Finland 1966 Birth Cohort (NFBC, n?=?8,319). The birth month of each cohort member was categorized into one of the four seasons: spring (March–May), summer (June–August), autumn (September–November), or winter (December–February). Smoking habits of the cohort members were assessed by a postal questionnaire at the age of 31 yrs. Those who reported that they regularly smoked 11 or more cigarettes/day were regarded as heavy smokers. The association between season of birth and smoking was assessed with a logistic regression analysis: first, after controlling for early pregnancy-related and perinatal characteristics (Model 1) and second, after controlling for cohort members' hospital-treated psychiatric disorders, suicide attempts, adult educational level, and marital status (Model 2). Compared to males born in winter, the likelihood for heavy daily smoking was significantly increased, up to 1.3-fold, among males born in the autumn in both logistic regression models. However, among females the likelihood for heavy smoking was statistically significantly elevated among those born during any season other than winter. Season of birth may modify the development of dopaminergic or other neurotransmitter systems divergently among males and females. Altered expression of dopaminergic genes due to environmental climatic factors could explain the association between season of birth and heavy smoking. (Author correspondence: kaisa.riala@oulu.fi).     

Associations Between Chronotypes,Psychopathology, and Personality Among Incoming College Students

Chronotye is associated with age, sex, personality, and parental monitoring during childhood. The evening type is associated with poor school performance, sleep problems, anxious/depressive symptoms, tobacco smoking, caffeine consumption, alcohol drinking, and suicidality in adolescents. The present study tested the relationships between chronotype and a wide range of psychopathology and personality traits among 2919 incoming undergraduate students. Each participant completed a self-administered questionnaire that included demographics, plus the Morningness-Eveningness (M-E) scale, Brief Symptom Rating Scale (BSRS), Tridimensional Personality Questionnaire, and Maudesley Personality Inventory. The t-score distribution of the M-E scale was used to form the morning (t-score >60, n?=?419), evening (t-score <40, n?=?371), and intermediate (40?≤?t-score?≤?60, n?=?2129) groups. Multivariable regression was employed for data analysis. For males, the evening type scored higher on all subscales of the BSRS than the morning type, except phobic anxiety. For females, the evening type had higher scores than the other two types on all subscales, except in obsession/compulsion and phobic anxiety, where the evening type only scored higher than the intermediate type. The evening type of both sexes also scored higher than the morning type in novelty seeking, harm avoidance, and neurotic personality characteristics, but lower than the morning type in extraversion and social desirability. In reward dependence, the evening type scored lowest for males, but there was no difference for females. The findings of the evening type being associated with possible psychopathology and certain types of personality have public health implications, that is, chronotype needs to be taken into account in the development of mental health prevention programs and assessment of and intervention for mental problems in young adults. (Author correspondence: gaushufe@ntu.edu.tw)     

Prolonged Seasonality of Respiratory Syncytial Virus Infection among Preterm Infants in a Subtropical Climate

Objective

There is limited epidemiological data on the seasonality of respiratory syncytial virus (RSV) infection in subtropical climates, such as in Taiwan. This study aimed to assess RSV seasonality among children ≤24 months of age in Taiwan. We also assessed factors (gestational age [GA], chronologic age [CA], and bronchopulmonary dysplasia [BPD]) associated with RSV-associated hospitalization in preterm infants to confirm the appropriateness of the novel Taiwanese RSV prophylactic policy.

Study Design

From January 2000 to August 2010, 3572 children aged ≤24-months were admitted to Taipei Mackay Memorial Hospital due to RSV infection. The monthly RSV-associated hospitalization rate among children aged ≤24 months was retrospectively reviewed. Among these children, 378 were born preterm. The associations between GA, CA, and BPD and the incidence of RSV-associated hospitalization in the preterm infants were assessed.

Results

In children aged ≤24 months, the monthly distribution of RSV-associated hospitalization rates revealed a prolonged RSV season with a duration of 10 months. Infants with GAs ≤32 weeks and those who had BPD had the highest rates of RSV hospitalization (P<0.001). Preterm infants were most vulnerable to RSV infection within CA 9 months.

Conclusions

Given that Taiwan has a prolonged (10-month) RSV season, the American Academy of Pediatrics'' recommendations for RSV prophylaxis are not directly applicable. The current Taiwanese guidelines for RSV prophylaxis, which specify palivizumab injection (a total six doses until CA 8–9 months) for preterm infants (those born before 28^6/7 weeks GA or before 35^6/7 weeks GA with BPD), are appropriate. This prophylaxis strategy may be applicable to other countries/regions with subtropical climates.     

Birth seasonality and offspring production in threatened neotropical primates related to climate

Given the threatened status of many primate species, the impacts of global warming on primate reproduction and, consequently, population growth should be of concern. We examined relations between climatic variability and birth seasonality, offspring production, and infant sex ratios in two ateline primates, northern muriquis, and woolly monkeys. In both species, the annual birth season was delayed by dry conditions and El Niño years, and delayed birth seasons were linked to lower birth rates. Additionally, increased mean annual temperatures were associated with lower birth rates for northern muriquis. Offspring sex ratios varied with climatic conditions in both species, but in different ways: directly in woolly monkeys and indirectly in northern muriquis. Woolly monkeys displayed an increase in the proportion of males among offspring in association with El Niño events, whereas in northern muriquis, increases in the proportion of males among offspring were associated with delayed onset of the birth season, which itself was related, although weakly, to warm, dry conditions. These results illustrate that global warming, increased drought frequency, and changes in the frequency of El Niño events could limit primate reproductive output, threatening the persistence and recovery of ateline primate populations.     

The Validity of Temperature-Sensitive Ingestible Capsules for Measuring Core Body Temperature in Laboratory Protocols

The human core body temperature (CBT) rhythm is tightly coupled to an endogenous circadian pacemaker located in the suprachiasmatic nucleus of the anterior hypothalamus. The standard method for assessing the status of this pacemaker is by continuous sampling of CBT using rectal thermometry. This research sought to validate the use of ingestible, temperature-sensitive capsules to measure CBT as an alternative to rectal thermometry. Participants were 11 young adult males who had volunteered to complete a laboratory protocol that extended across 12 consecutive days. A total of 87 functional capsules were ingested and eliminated by participants during the laboratory internment. Core body temperature samples were collected in 1-min epochs and compared to paired samples collected concurrently via rectal thermistors. Agreement between samples that were collected using ingestible sensors and rectal thermistors was assessed using the gold-standard limits of agreement method. Across all valid paired samples collected during the study (n?=?120,126), the mean difference was 0.06°C, whereas the 95% CI (confidence interval) for differences was less than ±0.35°C. Despite the overall acceptable limits of agreement, systematic measurement bias was noted across the initial 5?h of sensor-transit periods and attributed to temperature gradations across the alimentary canal. (Author correspondence: david.darwent@unisa.edu.au)     

Environmental influences on the sexual dimorphism in body size of western bobcats

Sexual size dimorphism might be influenced by environmental constraints on sexual selection or by intraspecific competition between males and females. We studied bobcats (Lynx rufus) in collections of museum specimens from western North America to examine these hypotheses. Structural body size was estimated from several measurements of the skull, ln-transformed and indexed through principal components analysis. Sexual dimorphism in body size was estimated from the difference in size index of males and females, and compared to geographic and climatic variables associated with biotic provinces (ecoregions). Of several climatic variables that were associated with bobcat body size, only seasonality of climate was associated with sexual dimorphism. Sexual size dimorphism, longitude, elevation, and seasonality were intercorrelated. As longitude decreased (moving inland from west-coastal ecoregions), sexual dimorphism decreased with the increased elevation and seasonality of continental climates of the Rocky Mountains. We suggest that increased seasonality and the need for fasting endurance by females may place constraints on the degree of sexual dimorphism in bobcats. Sexual dimorphism of body size and sexual size dimorphism of trophic structures (teeth) exhibited a strong positive association over geography, thus indirectly supporting the hypothesis that intrasexual competition for prey could account for the geographic variation in sexual size dimorphism. Thus, both environmental constraints on sexual selection of body size and intersexual competition were supported as possible explanations of the degree of sexual size dimorphism that occurs in populations of bobcats.     

WORK HOURS AND SLEEP/WAKE BEHAVIOR OF AUSTRALIAN HOSPITAL DOCTORS

The objective of the study was to describe the work and sleep patterns of doctors working in Australian hospitals. Specifically, the aim was to examine the influence of work-related factors, such as hospital type, seniority, and specialty on work hours and their impact on sleep. A total of 635 work periods from 78 doctors were analyzed together with associated sleep history. Work and sleep diary information was validated against an objective measure of sleep/wake activity to provide the first comprehensive database linking work and sleep for individual hospital doctors in Australia. Doctors in large and small facilities had fewer days without work than those doctors working in medium-sized facilities. There were no significant differences in the total hours worked across these three categories of seniority; however, mid-career and senior doctors worked more overnight and weekend on-call periods than junior doctors. With respect to sleep, although higher work hours were related to less sleep, short sleeps (< 5 h in the 24 h prior to starting work) were observed at all levels of prior work history (including no work). In this population of Australian hospital doctors, total hours worked do impact sleep, but the pattern of work, together with other nonwork factors are also important mediators. (Author correspondence: sally.ferguson@unisa.edu.au)     

CONTRIBUTION OF CORE BODY TEMPERATURE,PRIOR WAKE TIME,AND SLEEP STAGES TO COGNITIVE THROUGHPUT PERFORMANCE DURING FORCED DESYNCHRONY

Shiftworkers are often required to sleep at inappropriate phases of their circadian timekeeping system, with implications for the dynamics of ultradian sleep stages. The independent effects of these changes on cognitive throughput performance are not well understood. This is because the effects of sleep on performance are usually confounded with circadian factors that cannot be controlled under normal day/night conditions. The aim of this study was to assess the contribution of prior wake, core body temperature, and sleep stages to cognitive throughput performance under conditions of forced desynchrony (FD). A total of 11 healthy young adult males resided in a sleep laboratory in which day/night zeitgebers were eliminated and ambient room temperature, lighting levels, and behavior were controlled. The protocol included 2 training days, a baseline day, and 7?×?28-h FD periods. Each FD period consisted of an 18.7-h wake period followed by a 9.3-h rest period. Sleep was assessed using standard polysomnography. Core body temperature and physical activity were assessed continuously in 1-min epochs. Cognitive throughput was measured by a 5-min serial addition and subtraction (SAS) task and a 90-s digit symbol substitution (DSS) task. These were administered in test sessions scheduled every 2.5?h across the wake periods of each FD period. On average, sleep periods had a mean (± standard deviation) duration of 8.5 (±1.2) h in which participants obtained 7.6 (±1.4) h of total sleep time. This included 4.2 (±1.2) h of stage 1 and stage 2 sleep (S1–S2 sleep), 1.6 (±0.6) h of slow-wave sleep (SWS), and 1.8 (±0.6) h of rapid eye movement (REM) sleep. A mixed-model analysis with five covariates indicated significant fixed effects on cognitive throughput for circadian phase, prior wake time, and amount of REM sleep. Significant effects for S1–S2 sleep and SWS were not found. The results demonstrate that variations in core body temperature, time awake, and amount of REM sleep are associated with changes in cognitive throughput performance. The absence of significant effect for SWS may be attributable to the truncated range of sleep period durations sampled in this study. However, because the mean and variance for SWS were similar to REM sleep, these results suggest that cognitive throughput may be more sensitive to variations in REM sleep than SWS. (Author correspondence: david.darwent@unisa.edu.au)     

INFLUENCE OF SEASONALITY ON CIRCADIAN MOTOR ACTIVITY RHYTHM IN COMMON MARMOSETS DURING PUBERTY

The effect of puberty on circadian rhythmicity in nonhuman primates has been little studied, even though it has been demonstrated that puberty-related changes in circadian activity rhythm occur in a number of species, including humans. To characterize the motor activity rhythm during puberty in common marmosets (Callithrix jacchus), six animals was continuously monitored by actimeters between their 5th and 12th months of age. The animals were housed with their families in outdoor cages under seminatural conditions. Onset of puberty was determined from fecal estrogen and progesterone levels in females and androgen levels in males. The spectral power of the circadian component stabilized later in the last two animals to enter puberty. The bimodal characteristic of the active phase in this species became progressively more apparent over the course of the months in which the mean temperature was highest, irrespective of the animal's age. Although the onset of activity advanced after entry into puberty, this parameter showed a strong correlation with sunrise, indicating that seasonality influences this variable. Neither age nor climatic factors included in the regression model influenced the differences in phase angles between sunrise and onset of activity, and between sunset and offset of activity. Total activity was the only parameter influenced by age in the regression model, showing an increase after entry into puberty. Despite the evidence of pubertal influence on both the circadian component and total activity, under seminatural conditions seasonal factors may have a more important effect on motor activity rhythm in common marmosets. (Author correspondence: E-mail: carolina@cb.ufrn.br)     

Multiple Sclerosis Incidence Associated with the Soil Lead and Arsenic Concentrations in Taiwan

Background

Few studies in the world have assessed the incidence of multiple sclerosis (MS) with soil heavy metal concentrations. We explored the association of soil heavy metal factors and the MS incidence in Taiwan.

Methods

There were 1240 new MS cases from the National Health Insurance Research Database and were verified with serious disabling disease certificates, 1997–2008. Soil heavy metal factors records included arsenic, mercury, cadmium, chromium, copper, nickel, lead and zinc in Taiwan from 1986 to 2002. Spatial regression was used to reveal the association of soil heavy metals and age- and gender-standardized incidence ratios for townships by controlling sunlight exposure hours, smoking prevalence and spatial autocorrelation.

Results

The lead (Pb) concentration in the soil positively correlated with the township incidence; on the other hand, the arsenic (As) concentration in soil negatively correlated with the township incidence and when found together controlled each other. The positive correlation of lead (Pb) predominated in males, whereas the negative correlation of arsenic (As) in soil predominated in females.

Conclusions

We conclude that exposure to lead (Pb) in soil positive associated with incidence of MS in Taiwan, especially in males. Exposure to arsenic (As) in soil negative associated with MS in Taiwan, especially in females.     

SEASONAL VARIATION OF NEONATAL TRANSIENT HYPERTHYROTROPINEMIA IN TEHRAN PROVINCE, 1998–2005

Seasonal aggregation and the monthly rate of neonatal transient hyperthyrotropinemia (THT) were assessed. From November 1998 to April 2005, neonates of gestational age ≥37 wks, birth weight 2500–4000?g, birth length 45–55?cm, and 1st min Apgar score >3, who had thyrotropin (TSH) ≥20 mU/L in their cord dried-blood specimen, but without congenital hypothyroidism, were enrolled in the study. The recall rate equals the rate of THT occurrence in this study. Of 47,945 neonates, 555 had THT (recall rate: 1.2%). The aggregated seasonal recall rate (recall for further assessment to rule out congenital hypothyroidism) was significantly higher in winter (January, February, and March) than the other seasons (p < .0001). Winter had higher recall rate in each year as compared to other seasons, but the overall rate of recalls decreased in 2001 and 2002. Excluding the first 6 months (due to erratic variations), the remaining 72 months revealed a relatively sinusoidal pattern in monthly recall rates; indeed, there was an initial 11-month high recall rates (1.7%), followed by a 33-month decrease (0.7%), a 19-month increase (1.9%), and a final 9-month decrease (0.8%). The recall rate of each of these time intervals was significantly different from that of the next time interval (p < .0001). The monthly recall rates were best fitted to cubic curve estimation and then autoregressive integrated moving average (ARIMA) (0, 1, 1) models. THT occurs significantly more in winter than in other seasons, and this suggests a possible role for time-varying factor(s) contributing to its seasonal preponderance. (Author correspondence: E-mail: arash_ordookhani@yahoo.com)     

Environmental limits to the distribution of Scaevola plumieri along the South African coast

Abstract. Scaevola plumieri is an important pioneer on many tropical and subtropical sand dunes, forming a large perennial subterranean plant with only the tips of the branches emerging above accreting sand. In South Africa it is the dominant pioneer on sandy beaches along the east coast, less abundant on the south coast and absent from the southwest and west coasts. Transpiration rates (E) of S. plumieri are predictably related to atmospheric vapour pressure deficit under a wide range of conditions and can therefore be predicted from measurement of ambient temperature and relative humidity. Scaling measurements of E at the leaf level to the canopy level has been demonstrated previously. Using a geographic information system, digital maps of regional climatic variables were used to calculate digital maps of potential transpiration from mean monthly temperature and relative humidity values, effectively scaling canopy level transpiration rates to a regional level. Monthly potential transpiration was subtracted from the monthly median rainfall to produce a map of mean monthly water balance. Seasonal growth was correlated with seasonal water balance. Localities along the coast with water deficits in summer corresponded with the recorded absence of S. plumieri, which grows and reproduces most actively in the summer months. This suggests that reduced water availability during the summer growth period limits the distribution of S. plumieri along the southwest coast, where water deficits develop in summer. Temperature is also important in limiting the distribution of S. plumieri on the southwest coast of South Africa through its effects on the growth and phenology of the plant.     

OBESITY AND HIGH BLOOD PRESSURE OF 12-HOUR NIGHT SHIFT FEMALE CLEAN-ROOM WORKERS

The 12?h shift schedule is widely used in clean rooms for electronic semiconductor production in Taiwan. This study investigated the associations of obesity and metabolic syndrome (MetS) components among women working in a semiconductor manufacturing factory in North Taiwan. Workers were divided into four groups according to their work schedules and duties (i.e., office workers, day workers, fixed 12?h day shift, and fixed 12?h night shiftworkers). The subjects comprised 1838 women who voluntarily attended a health examination between August 2006 and November 2006. Their mean (±SD) age was 33.6 (±7.1) yrs and their mean duration of work was 7.4 (±5.2) yrs. Each subject's health-related behaviors, body mass index, and MetS components were measured and analyzed using multivariate logistic regression. Obesity and MetS were defined according to World Health Organization criteria for Asian populations and the National Cholesterol Educational Program and Adult Treatment Panel III Guidelines, respectively. The results showed that women working in the clean room on fixed 12?h night shifts had significantly elevated odds ratios for obesity (OR, 2.7; 95% CI, 1.6–4.5), central obesity (OR, 2.9; 95% CI, 1.7–5.1), and high blood pressure (OR, 2.3; 95% CI, 1.2–4.4) compared to female office workers; these results persisted after adjusting for age, smoking, drinking, education, and duration of work. We did not find any significant differences in triglyceride and high-density lipoprotein cholesterol among women working different schedules. We conclude that working fixed 12?h night shifts was associated with an increased odds ratio for obesity, central obesity, and high blood pressure among clean-room women workers. Weight reduction and blood pressure control programs should be implemented in the workplace for women working fixed 12?h night shifts. (Author correspondence: m006671@ms.skh.org.tw)     

Clinical Application of a Novel Automatic Algorithm for Actigraphy-Based Activity and Rest Period Identification to Accurately Determine Awake and Asleep Ambulatory Blood Pressure Parameters and Cardiovascular Risk

This paper reports the results of a study designed to determine whether there are statistically significant differences between the values of ambulatory blood pressure monitoring (ABPM) parameters obtained using different methods—fixed schedule, diary, and automatic algorithm based on actigraphy—of defining the main activity and rest periods, and to determine the clinical relevance of such differences. We studied 233 patients (98 men/135 women), 61.29?±?.83 yrs of age (mean?±?SD). Statistical methods were used to measure agreement in the diagnosis and classification of subjects within the context of ABPM and cardiovascular disease risk assessment. The results show that there are statistically significant differences both at the group and individual levels. Those at the individual level have clinically significant implications, as they can result in a different classification, and, therefore, different diagnosis and treatment for individual subjects. The use of an automatic algorithm based on actigraphy can lead to better individual treatment by correcting the accuracy problems associated with the fixed schedule on patients whose actual activity/rest routine differs from the fixed schedule assumed, and it also overcomes the limitations and reliability issues associated with the use of diaries. (Author correspondence: cristina.crespo@oit.edu)