Relative humidity and affective disorders

INTRODUCTION: Looking at specific weather parameters over a period of time prior to hospital admissions may provide evidence of a link between weather conditions and some psychiatric conditions such as affective disorders. We examined the association between relative humidity (as well as other parameters such as sunshine hours, diurnal variations in temperature and rainfall) and psychiatric admissions in North Cheshire, UK. METHOD: The daily numbers of all psychiatric admissions in North Cheshire in a specified year were analysed in relation to meteorological data, which were measured at the meteorological office nearest to the study population. RESULTS: We found a significant inverse relationship (with time lag) between admissions for affective disorders and relative humidity in the week preceding admission. Changes in diurnal variations in temperature, sunshine hours and rainfall a few days before admission were also noted, but the findings did not achieve statistical significance for any diagnostic category. CONCLUSION: The effect of weather parameters on mental health is likely to be influenced by other seasonal factors, as well as non-climatic factors, predominantly social, that may have contributed to the study findings. Psychiatric admissions reflect the behaviour of patients, carers and medical professionals. The complexity of this behaviour and the day-of-the-week periodicity may have confounded variations associated with the weather. (Int J Psych Clin Pract 2002; 6: 147-153 )     

Weather as an effective predictor for occurrence of dengue fever in Taiwan

We evaluated the impacts of weather variability on the occurrence of dengue fever in a major metropolitan city, Kaohsiung, in southern Taiwan using time-series analysis. Autoregressive integrated moving average (ARIMA) models showed that the incidence of dengue fever was negatively associated with monthly temperature deviation (beta=-0.126, p=0.044), and a reverse association was also found with relative humidity (beta=-0.025, p=0.048). Both factors were observed to present their most prominent effects at a time lag of 2 months. Meanwhile, vector density record, a conventional approach often applied as a predictor for outbreak, did not appear to be a good one for diseases occurrence. Weather variability was identified as a meaningful and significant indicator for the increasing occurrence of dengue fever in this study, and it might be feasible to be adopted for predicting the influences of rising average temperature on the occurrence of infectious diseases of such kind at a city level. Further studies should take into account variations of socio-ecological changes and disease transmission patterns to better propose the increasing risk for infectious disease outbreak by applying the conveniently accumulated information of weather variability.     

云南省地方性猝死病区天气因素与饮用水生物性污染相关性分析

目的调查云南省地方性猝死病区饮用水卫生学指标及天气情况，分析天气状况对饮用水水质的影响，进而研究用天气状况作为云南省地方性猝死病情症候群监测指标的可行性。方法连续监测了3个重病区的水质卫生状况及其同期天气情况。以细菌总数和总大肠埃希菌群值超标率和超标程度评价饮用水的微生物污染状况，并对天气状况和水质卫生状况之间的相关性进行统计学分析。结果总体上饮用水细菌总数超标率为72．1％，总大肠埃希菌群值超标率为97．4％。日照情况与水样的总大肠埃希菌群值呈负相关（r=-0．42，P〈0．05或r=-0．36，P〈0．05），温度与水样的总大肠埃希菌群值呈正相关（r=0．39，P〈0．05或r=0．40，P〈0．05）。结论病区居民的饮用水污染程度相当严重，且受天气变化影响较大。饮用水的卫生状况与温度等气象因素相关。     

Weather factor impacts on commuting to work by bicycle

Objective

Quantify the impact of weather conditions on individual decisions to commute to work by bicycle among a diverse panel of adults who commute ≥ 2 miles each way.

Method

Working adults (n = 163) in a northern U.S. state reported transportation mode for four seven-day periods in 2009-2010 that maximized seasonal weather variations. Personal characteristics, trip to work distances, and commuting mode data were linked to location- and time-specific weather data and daylight hours. Analyses focused on effect of weather conditions on reports of commuting by bicycle.

Results

Participants were diverse in age, gender and bicycle use, but were relatively well-educated; they traveled to work by bicycle on 34.5% of the logged commuting days. Modeling indicated that the likelihood of bicycle commuting increased in the absence of rain (odds ratio = 1.91; 95% confidence interval 1.42, 2.57) and with higher temperatures (1.03; 1.02, 1.04), and decreased with snow (0.90; 0.84, 0.98) and wind (0.95; 0.92, 0.97). Independent effects also were found for bicycle commuting distance, gender, and age, but not for daylight hours.

Conclusion

Precipitation, temperature, wind and snow conditions had significant and substantial independent effects on the odds of travel to work by bicycle among a diverse panel of adult bicycle commuters.     

2007—2011年高温对哈尔滨市区人口死亡的影响

目的探讨高温对哈尔滨市区人口死亡的影响。方法分析哈尔滨市近5年来的气候特点,以32~C为临界点,区分“热日”、“非热日”。在此基础上,分析哈尔滨市区2007—2011年夏季（6—8月份）日最高温度与总死亡数、年龄、性别死亡数的关系,并对人121死亡的影响进行探讨。结果哈尔滨夏季最高气温多出现在6月份,最高达37．8℃。当气温超过29℃以上时,死亡数随温度的升高而增加,“热日”与“非热日”死亡数之比为1．23：1（F=6．91,P=0．0303）;老年人对热更敏感。结论哈尔滨的高温天气对人口死亡有显著影响。     

Modeling of air pollution and its relationship with mortality and morbidity in Madrid, Spain

Objective: Evaluation of the association between air pollution and mortality and morbidity is becoming ever more complex owing to changes in inner-city air pollution, marked by decreasing values for all main pollutants save those associated with traffic. This has led to the need for the study of new epidemiological scenarios in which most pollutants are below guideline values. Nonetheless, the health effects are significant. Methods: This report presents the results of a statistically based model for real-time forecasting of mortality and morbidity in Madrid, with meteorological and pollution series serving as inputs. Results and conclusions: Not only did the models perform well with correlation coefficients between predicted and observed values (r = 0.683 for mortality, r = 0.681 for morbidity), but they enabled quantification of the impact of air pollution on mortality and morbidity (with increases ranging from 1.8% to 12% for mortality and from 2.3% to 18% for morbidity for a 25-μg/m³ increase in pollutants). Moreover, attention should be drawn to the observation that the model proved to be easy to implement and operate on a routine basis. Received: 31 August 1998 / Accepted: 3 March 1999     

High temperature effect on daily all-cause mortality in Tunis 2005–2007

BackgroundThe relationship between thermal stress and health has been only marginally investigated in North Africa. This study aimed to estimate the short-term effect of heat on total mortality, in the city of Tunis in 2005–2007, using time series analysis.MethodsThe study period was restricted to the summer season (May–October) and heat effect was assessed using maximum temperature as exposure variable. We estimated the breakpoint above which heat-related mortality begins to increase using a segmented linear regression. A Poisson Generalized Estimating Equations (GEE) model was then used to estimate the impact of heat on daily mortality. Models were adjusted for nitrogen dioxide (NO₂), trend, calendar month, day of the week, the Ramadan period, and holidays.ResultsThe estimated breakpoint was 31.5 °C (standard deviation: 0.9 °C). After adjustment for potential confounders, the daily mortality increased significantly by 2.00% [95% confidence interval: 0.68–3.16] for a 1 °C increase in daily maximum temperature above the breakpoint. An increase of 10 mg/m³ in NO₂ was associated with a significant increase in daily mortality (0.48% [0.08–0.88]).ConclusionThere is an important effect of heat on daily mortality in the city of Tunis. This is the first evaluation of such an association in a North African city with hot and dry summers and a lower middle economy.     

Warm Front Passage on the Previous Day Increased Ischemic Stroke Events

Background and Purpose: The influence of a weather front passage is rarely evaluated on stroke events. We hypothesized that a weather front passage on the stroke onset day or during the previous days may play an important role in the incidence of stroke. Methods: A multicenter retrospective study was conducted to evaluate the frequency of stroke events and their interaction with weather front passages. Consecutive acute stroke patients (n = 3935, 73.5 ± 12.4 years, 1610 females) who were admitted to 7 stroke hospitals in 3 cities from January 2012 to December 2013 were enrolled in this study. Multivariate Poisson regression models involving time lag variables were used to compare the daily rates of stroke events with the day of a weather front passage and the previous 6 days, adjusting for considerable influences of ambient temperature and atmospheric pressure. Results: There were a total of 33 cold fronts and 13 warm fronts that passed over the 3 cities during the study period. The frequency of ischemic stroke significantly increased when a warm front passed on the previous day (risk ratio 1.34, 95% confidence interval 1.07-1.69, P= .016). Conclusions: This study indicated that a weather front passage on the previous days may be associated with the occurrence of stroke.