Exposure-lag-response association between sunlight and schizophrenia in Ningbo, China

Artificial light at night, MRI-based measures of brain iron deposition and incidence of multiple mental disorders

BACKGROUND

Epidemiologic evidence on whether iron accumulation in brain modified the association between artificial light at night (ALAN) and incident mental disorders is lacking. The authors aims to investigate modification of brain iron deposition on the associations of ALAN with multiple mental disorders in the middle-aged and older adults.

METHODS

This prospective study used data from the UK Biobank. ALAN was drawn from satellite datasets. Susceptibility-weighted magnetic resonance imaging was used to ascertain iron content of each brain region. T2* signal loss was used as indices of iron deposition. The main outcomes are impacts of ALAN exposure on onset of wide spectrum of physician-diagnosed mental disorders, which was estimated by time-varying Cox proportional hazard model. The authors further conducted stratified analyses by levels of iron brain deposition to examine the potential modifying effects.

RESULTS

Among 298,283 participants followed for a median of 10.91 years, higher ALAN exposure was associated with increased risk of mental disorders. An IQR (11.37 nW/cm2/sr) increase in annual levels of ALAN was associated with an HR of 1.050 (95 % CI: 1.034,1.066) for any mental disorder, 1.076 (95 % CI: 1.053,1.099) for substance use disorder, and 1.036 (95 % CI: 1.004,1.069) for depression disorder in fully adjusted models. The exposure-response curves showed steeper trends at lower ALAN levels and a plateau at higher exposures. The associations were stronger in participants with high iron deposition in left hippocampus, left accumbens and left pallidum.

CONCLUSIONS

ALAN was associated with multiple mental disorders in the middle-aged and older adults, and the findings indicated stricter standards of ALAN is needed and targeted preventive measures are warranted, especially with high brain iron deposition.

Seasonal peak and the role of local weather in schizophrenia occurrence: A global analysis of epidemiological evidence

BACKGROUND

Many studies have shown that the onset of schizophrenia peaked in certain months within a year and the local weather conditions could affect the morbidity risk of schizophrenia. This study aimed to conduct a systematic analysis of schizophrenia seasonality in different countries of the world and to explore the effects of weather factors globally.

METHODS

We searched three databases (PubMed, Web of Science, and China National Knowledge Infrastructure) for eligible studies published up to September 2022. Schizophrenia seasonality was compared between hemispheres and within China. A meta-analysis was conducted to pool excess risk (ER, absolute percentage increase in risk) of the onset of schizophrenia associated with various weather factors including temperature (an increase or decrease of temperature as a reflection of high or low temperature; heatwave; temperature variation), precipitation, etc. RESULTS: We identified 84 relevant articles from 22 countries, mainly in China. The seasonality analysis found that the onset of schizophrenia mostly peaked in the cold season in the southern hemisphere but in the warm season in the northern hemisphere. Interestingly in China, schizophrenia seasonality presented two peaks, respectively in the late cold and warm seasons. The meta-analysis further revealed an increased risk of schizophrenia after short-term exposure to high temperature [ER%: 0.45 % (95 % confidence interval (CI): 0.14 % to 0.76 %)], low temperature [ER%: 0.52 % (95%CI: 0.29 % to 0.75 %)], heatwave [ER%: 7.26 % (95%CI: 4.45 % to 10.14 %)], temperature variation [ER%: 1.02 % (95%CI: 0.55 % to 1.50 %)], extreme precipitation [ER%: 3.96 % (95%CI: 2.29 % to 5.67 %)]. The effect of other weather factors such as sunlight on schizophrenia was scarcely investigated with inconsistent findings.

CONCLUSION

This study provided evidence of intra- and inter-country variations in schizophrenia seasonality, especially the double-peak seasons in China. Exposure to local weather conditions mainly temperature changes and precipitation could affect the onset risk of schizophrenia.

Association Between Sunlight Exposure and Mental Health: Evidence from a Special Population Without Sunlight in Work

Purpose

In recent years, mental health problems have become the most serious social problems worldwide. Past studies have proposed that some links exist between sunlight and mental health; however, relevant studies examining low-dose sunlight exposure populations are lacking. We conducted a study among a group of operating room nurses (ORNs) who work long hours in operating rooms and have limited sunlight exposure. We aim to add to and refine previous researches on the association between mental health and sunlight exposure in community population.

Patients and Methods

A total of 787 ORNs were interviewed and analyzed. Mental health, sunlight exposure duration, sociodemographic and work-related variables, and chronic diseases were evaluated. The Kessler 10 scale (K10) was used to assess participants' mental health status, and their sunlight exposure duration was assessed using their self-reports. Multiple linear regression analysis was adopted to examine the association between sunlight exposure and mental health.

Results

The average K10 score of ORNs was 25.41. ORNs exhibit poorer mental health than other populations. Poor mental health was negatively associated with greater sunlight exposure hours per day (β=-0.378) and sleep regularity (β=-3.341). Poor mental health was positively associated with chronic disease (β=3.514).

Conclusion

This study indicated that the positive association between sunlight exposure and mental health existed. Appropriate enhancement of sunlight exposure will be beneficial to mental health. Hospitals, related organizations and individuals should pay greater attention to ORNs' mental health and sunlight exposure conditions. More policy recommendations as well as building structure recommendations should be proposed.

Sunshine duration and risks of schizophrenia hospitalizations in main urban area: Do built environments modify the association?

BACKGROUND

Although studies have explored the relationship between sunshine duration and schizophrenia, the evidence was ambiguous. Different built environments may alter the effect of sunlight on schizophrenia, thus the purpose of this study was to investigate the effects of built environments on the sunshine duration-schizophrenia association.

MATERIALS AND METHODS

Daily schizophrenia hospitalizations data during 2017-2020 in Hefei's main urban area, China, and corresponding meteorological factors as well as ambient pollutants were collected. The impact of sunshine duration on schizophrenia admissions in urban areas was investigated using a generalized additive model combined with a distributed lagged nonlinear model. Additionally, the various modifying effects of different Building Density, Building Height, Normalized Vegetation Index, and Nighttime Light were also explored between sunshine duration and schizophrenia.

RESULTS

We observed that inadequate sunshine duration (<5.3 h) was associated with an increase in schizophrenia hospital admissions, with a maximum relative risk of 1.382 (95 % confidence interval (CI): 1.069-1.786) at 2.9 h. In turn, adequate sunshine duration reduced the risk of schizophrenia hospitalizations. Subgroup analyses indicated females and old patients were particularly vulnerable. In the case of insufficient sunshine duration, significant positive effects were noticed on schizophrenia risk at High-Building Density and High-Nighttime Light. Higher NDVI as well as Building Height were found to be associated with lower risks of schizophrenia.

CONCLUSIONS

Given that sunshine duration in various built environments might lead to distinct effects on schizophrenia hospitalizations. Our findings assist in identifying vulnerable populations that reside in particular areas, thus suggesting policymakers provide advice to mitigate the onset of schizophrenia by allocating healthcare resources rationally and avoiding adverse exposures to vulnerable populations timely.

The role of extreme high humidex in depression in chongqing, China: A time series-analysis

As global climate change intensifies, people are paying increasing attention to the impact of temperature changes on adverse mental health outcomes, especially depression. While increasing attention has been paid to the effect of temperature, there is little research on the effect of humidity. We aimed to investigate the association between humidex, an index combining temperature and humidity to reflect perceived temperature, and outpatient visits for depression from 2014 to 2019 in Chongqing, the largest and one of the most hot and humid cities of China. We also aimed to further identify susceptible subgroups. A distributed lag non-linear model (DLNM) was used to explore the concentration-response relationship between humidex and depression outpatient visits. Hierarchical analysis was carried out by age and gender. A total of 155,436 visits for depression were collected from 2014 to 2019 (2191 days). We found that depression outpatient visits were significantly associated with extremely high humidex (≥40). The significant positive single-lag day effect existed at lag 0 (RR = 1.029, 95%CI: 1.000-1.059) to lag 2 (RR = 1.01, 95%CI: 1.004-1.028), and lag 12 (RR = 1.013, 95%CI: 1.002-1.024). The significant cumulative adverse effects lasted from lag 01 to lag 014. Hierarchical analyses showed that females and the elderly (≥60 years) appeared to be more susceptible to extremely high humidex. The attributable numbers (AN) and fraction (AF) of extremely high humidex on depression outpatients were 1709 and 1.10%, respectively. Extremely high humidex can potentially increase the risk of depression, especially in females and the elderly. More protective measures should be taken in vulnerable populations.

Seasonality of brain function: role in psychiatric disorders

Seasonality patterns are reported in various psychiatric disorders. The current paper summarizes findings on brain adaptations associated with seasonal changes, factors that contribute to individual differences and their implications for psychiatric disorders. Changes in circadian rhythms are likely to prominently mediate these seasonal effects since light strongly entrains the internal clock modifying brain function. Inability of circadian rhythms to accommodate to seasonal changes might increase the risk for mood and behavior problems as well as worse clinical outcomes in psychiatric disorders. Understanding the mechanisms that account for inter-individual variations in seasonality is relevant to the development of individualized prevention and treatment for psychiatric disorders. Despite promising findings, seasonal effects are still understudied and only controlled as a covariate in most brain research. Rigorous neuroimaging studies with thoughtful experimental designs, powered sample sizes and high temporal resolution alongside deep characterization of the environment are needed to better understand the seasonal adaptions of the human brain as a function of age, sex, and geographic latitude and to investigate the mechanisms underlying the alterations in seasonal adaptation in psychiatric disorders.

Association between short-term exposure to extreme humidity and painful diabetic neuropathy: a case-crossover analysis

Painful diabetic neuropathy (PDN) is a common complication of diabetes mellitus, which reduces the quality of life. However, the association between PDN and environmental factors, especially ambient humidity, remains unclear. Therefore, this study investigated the impact of extreme humidity events on PDN. Data on PDN-related hospital admissions to two tertiary hospitals in Hefei, China (2014-2019) were obtained. A distributed lag non-linear model with a case-crossover design was used to quantitatively estimate the effects of ambient humidity on PDN, and the results were stratified by sex and age. The 1st, 10th, 90th, and 99th percentiles of relative humidity (RHU) were defined as extreme humidity, and the average relative humidity (74.94%) was set as the reference value. Non-linear exposure-response curves between the RHU and PDN cases were obtained. Extreme humidity (92%) had a significant effect on PDN with a relative risk (RR) of 1.13 (95% confidence interval (CI): 1.01-1.26) on a particular day, which increased with the RHU (RR: 1.21, 95% CI: 1.02-1.45 at 98% extreme humidity). Stratification analysis showed that women (RR: 1.38, 95% CI: 1.07-1.77) and patients aged < 65 years (RR: 1.26, 95% CI: 1.01-1.57) were highly susceptible to this effect on the same day. The results suggest that extreme humidity is a crucial trigger for PDN onset in diabetes patients. Furthermore, the effects vary with sex and age. This study provides detailed evidence of the adverse effects of extreme weather on diabetes patients.

Explainable Gated Recurrent Unit to explore the effect of co-exposure to multiple air pollutants and meteorological conditions on mental health outcomes

Mental health conditions have the potential to be worsened by air pollution or other climate-sensitive factors. Few studies have empirically examined those associations when we faced to co-exposures, as well as interaction effects. There would be an urgent need to use deep learning to handle complex co-exposures that might interact in multiple ways, and the model performance reinforced by SHapely Additive exPlanations (SHAP) enabled our predictions interpretable and hence actionable. Here, to evaluate the mixed effect of short-term co-exposure, we conducted a time-series analysis using approximately 1.47 million hospital outpatient visits of mental disorders (i.e., depressive disorder-DD, Schizophrenia-SP, Anxiety Disorder-AD, Bipolar Disorder-BD, Attention Deficit and Hyperactivity Disorder-ADHD, Autism Spectrum Disorder-ASD), with matched meteorological observations from 2015 through 2019 in Nanjing, China. The global insights of gated recurrent unit model revealed that most of input features with similar effect size caused the illness risk of SP and ASD increase, and most markedly, 73% of relative humidity, 44.6 µg/m³ of NO₂, and 14.1 µg/m³ of SO₂ at 5-year average level associated with 2.27, 1.14, and 1.29 visits increase for DD, SP, and AD, respectively. Both synergic and antagonistic effect among informative paired-features were distinguished from local feature dependence. Interestingly, variation tendencies of excessive visits of bipolar disorder when atmospheric pressure, PM_2.5, and O₃ interacted with one another were inconsistent. Our results provided added qualitative and quantitative support for the conclusion that short-term co-exposure to ambient air pollutants and meteorological conditions posed threats to human mental health.

Short-term effects of extreme meteorological factors on daily outpatient visits for anxiety in Suzhou, Anhui Province, China: a time series study

Anxiety disorders are a major public health concern in China. Previous studies have provided evidence for associations between ambient temperature and anxiety outpatient visits, but no studies have examined short-term effects of other meteorological factors such as sunshine duration, wind speed, and precipitation on increased anxiety outpatient visits. We aimed to assess the association between climatic factors and outpatient visits for anxiety in Suzhou, a city with a temperate climate in Anhui Province, China. Daily anxiety outpatient visits, meteorological factors, and air pollutants from 2017 to 2019 were collected. A quasi-Poisson generalized linear regression model combined with distributed lag non-linear model (DLNM) was used to quantify the effects of extreme meteorological factors (sunshine duration, wind speed, and precipitation) on anxiety outpatient visits. All effects were presented as relative risk (RR), with the 90th and 10th percentiles of meteorological factors compared to the median. Subgroup analyses by age and gender were performed to identify susceptible subgroups. A total of 11,323 anxiety outpatient visits were reported. Extremely low sunshine duration and low and high wind speed increased the risk of anxiety outpatient visits. The strongest cumulative effects occurred at lag 0-14 days, and the corresponding RRs of extremely low sunshine duration and low and high wind speed were 1.417 (95% CI: 1.056-1.901), 1.529 (95% CI: 1.028-2.275), and 1.396 (95% CI: 1.007-1.935), respectively. Subgroup analyses showed that males and people aged ≥45 years appeared to be more susceptible to the cumulative effects of extremely low sunshine duration. In addition, the adverse effects of extreme wind speed were more pronounced in the cold season. This study provides evidence that extreme climatic factors have a lagged effect on anxiety outpatient visits. In the context of climate change, these findings may help develop weather-based early warning systems to minimize the effects of extreme meteorological factors on anxiety.

Effects of sunshine duration on daily outpatient visits for depression in Suzhou, Anhui Province, China

Previous epidemiological studies have reported seasonal variation patterns of depression symptoms, which may be influenced by bad weather conditions, such as a lack of sunlight. However, evidence on the acute effects of sunshine duration on outpatient visits for depression is limited, especially in developing countries, and the results are inconsistent. We collected daily outpatient visits for depression from the local mental health centre in Suzhou, Anhui Province, China, during 2017-2019. We defined the 5th and 95th sunshine percentiles as short and long sunshine durations, respectively. A quasi-Poisson generalized linear regression model combined with a distributed lag nonlinear model was used to quantitatively assess the effects of short and long sunshine durations on outpatient visits for depression. Stratified analyses were further performed by gender, age and number of visits to identify vulnerable populations. A total of 26,343 depression cases were collected during the study period. An approximate U-shaped exposure-response association was observed between sunshine duration and depression outpatient visits. The cumulative estimated relative risks (RRs) for short and long sunshine durations at lag 0-21 days were 1.53 [95% confidence intervals (CI): 1.14, 2.06] and 1.13 (95% CI: 0.88, 1.44), respectively. Moreover, a short sunshine duration was associated with a greater disease burden than a long sunshine duration, with attributable fractions (AFs) of 16.64% (95% CI: 7.8%, 23.89%) and 2.24% (95% CI: -2.65%, 5.74%), respectively. Subgroup analysis showed that males, people aged less than 45 years and first-visit cases may be more susceptible to a lack of sunlight. For a long sunshine duration, no statistically significant associations were found in any population groups. Our study found that a short sunshine duration was associated with an increased risk of depression. The government, medical institutions, family members and patients themselves should fully recognize the important role of sunlight and take active measures to prevent depression.

Climatic exposures in childhood and the risk of schizophrenia from childhood to early adulthood

BACKGROUND

Season of birth is a risk factor of schizophrenia, and it is possible that cumulative exposure to climatic factors during childhood affects the risk of schizophrenia. We conducted a cohort study among 365,482 persons born in Finland in 1990-1995 to examine associations of 10-year cumulative exposure to global solar radiation and ambient temperature in childhood with schizophrenia.

METHODS

Data on schizophrenia diagnoses and sociodemographic factors from the Finnish population register and health care register were linked to daily meteorological data using residential information. The study population was followed from age 10 until the first schizophrenia diagnosis, death, emigration or December 31, 2017, whichever came first. Hazard ratios (HR) for the risk of schizophrenia were estimated using Cox proportional hazards model.

RESULTS

Compared to the lowest quintile of global solar radiation or ambient temperature, growing up in the second highest quintile (Q4) was associated with greater risk of schizophrenia. These hazard ratios were attenuated after adjustment for parental mental disorder, parental education, parental income, area-level socioeconomic characteristics and urbanicity (HR = 1.29, 95 % CI 1.06-1.58 for radiation; HR = 1.24, 95 % CI, 1.02-1.52 for temperature). Continuous linear terms evaluated in secondary models suggested a greater risk of schizophrenia at greater childhood exposure to global radiation and ambient temperature, but these associations did not remain in fully adjusted models.

CONCLUSIONS

We found no consistent evidence that cumulative exposure to sunlight and ambient temperature in childhood is associated with the risk of developing schizophrenia. Studies in other populations residing in different latitudes are needed.

Identifying joint impacts of sun radiation, temperature, humidity, and rain duration on triggering mental disorders using a high-resolution weather monitoring system

BACKGROUND

Mental disorders (MDs) are behavioral or mental patterns that cause significant distress or impairment of personal functioning. Previously, temperature has been linked to MDs, but most studies suffered from exposure misclassification due to limited monitoring sites. We aimed to assess whether multiple meteorological factors could jointly trigger MD-related emergency department (ED) visits in warm season, using a highly dense weather monitoring system.

METHODS

We conducted a time-stratified, case-crossover study. MDs-related ED visits (primary diagnosis) from May-October 2017-2018 were obtained from New York State (NYS) discharge database. We obtained solar radiation (SR), relative humidity (RH), temperature, heat index (HI), and rainfall from Mesonet, a real-time monitoring system spaced about 17 miles (126 stations) across NYS. We used conditional logistic regression to assess the weather-MD associations.

RESULTS

For each interquartile range (IQR) increase, both SR (excess risk (ER): 4.9%, 95% CI: 3.2-6.7%) and RH (ER: 4.0%, 95% CI: 2.6-5.4%) showed the largest risk for MD-related ED visits at lag 0-9 days. While temperature presented a short-term risk (highest ER at lag 0-2 days: 3.7%, 95% CI: 2.5-4.9%), HI increased risk over a two-week period (ER range: 3.7-4.5%), and rainfall hours showed an inverse association with MDs (ER: -0.5%, 95% CI: 0.9-(-0.1)%). Additionally, we observed stronger association of SR, RH, temperature, and HI in September and October. Combination of high SR, RH, and temperature displayed the largest increase in MDs (ER: 7.49%, 95% CI: 3.95-11.15%). The weather-MD association was stronger for psychoactive substance usage, mood disorders, adult behavior disorders, males, Hispanics, African Americans, individuals aged 46-65, or Medicare patients.

CONCLUSIONS

Hot and humid weather, especially the joint effect of high sun radiation, temperature and relative humidity showed the highest risk of MD diseases. We found stronger weather-MD associations in summer transitional months, males, and minority groups. These findings also need further confirmation.

Association between air pollution and hospital admissions for chronic respiratory disease in people aged over 65 years: a time series analysis in Ningbo, China, 2015-2017

PURPOSE

To provide essential information of environmental triggers leading to CRD.

METHODS

We investigated the short-term effects of ambient air pollutants on CRD-related hospitalizations in people aged ≥ 65 years in Ningbo. Data on 23,610 cases of CRD requiring hospitalization were collected from January 2015 to August 2017. After adjusting for temporal trends, seasonality, meteorological conditions, day of week (DOW), and public holidays, we used generalized additive Poisson distribution models to calculate the excess risks (ERs) and 95% confidence intervals (95% CIs) of CRD related hospitalizations.

RESULTS

Our results showed that fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO) were associated with CRD-related hospitalizations in people aged ≥ 65 years. We observed that each 10 μg/m³ increase (except for each 0.1 mg/m³ increase in CO) in the concentration of air pollutants, the percentage of CRD-related hospitalizations due to PM_2.5, PM₁₀, and SO₂ exposure at lag 07, NO₂ exposure at lag 03, and CO exposure at lag 0 increased by 2.13% (95% CI: 0.55%, 3.74%), 1.76% (95% CI: 0.70%, 2.83%), 8.24% (95% CI: 0.92%, 16.09%), 2.16% (95% CI: 0.26%, 4.05%), and 1.19% (95% CI: 0.26%, 2.12%), respectively. In addition, we found stronger effects of particulate matter in 75-84 years age group, on warmer days, and in asthmatics.

CONCLUSION

In conclusion, air pollution may have adverse effects on CRD-related hospitalizations among people aged ≥ 65 years in Ningbo. Therefore, public health measures should be taken to improve air quality.

Investigating the association between temperature and hospital admissions for major psychiatric diseases: A study in Greece

Evidence has emerged regarding the role of seasonality and several meteorological parameters on bipolar disorder, schizophrenia and depression. We investigated the relationship between ambient and apparent temperature and hospital admissions of major psychiatric diseases in a psychiatric clinic of a General Hospital situated in Northern Greece during 2013-19. Temperature data was provided by the National Observatory of Athens and diagnosis for psychotic, schizophrenic, manic and bipolar and unipolar depression were retrieved from medical records. A total of 783 admissions were recorded. Poisson regression models adjusted for time trends were applied to analyze the impact of temperature on monthly admissions. A summer peak was observed for the bipolar disorder, irrespectively of substance/alcohol use status. Seasonality emerged also for psychotic and schizophrenic patients with a through in winter. An increase of 1 °C in either ambient or apparent temperature was associated with an increase 1-2% in the monthly admissions in most outcomes under investigation. Alcohol and drug abuse did not modify this effect. Although our results indicate effects of temperature on psychiatric admissions, they are not consistent across subgroups populations and need to be replicated by other methodologically superior studies.

Exposure-lag-response associations between extreme environmental conditions and primary Sjögren's syndrome

INTRODUCTION

Patients with primary Sjögren's syndrome (pSS) reportedly believe that their symptoms worsen on extreme weather days due to variations in environmental conditions. However, few studies have assessed the acute effects of environmental exposure on the onset of pSS. This study aimed to evaluate the exposure-response relationship between extreme environmental conditions and pSS outpatient visits.

METHOD

We obtained data on pSS outpatient visits from two provincial general hospitals in Hefei, China, during 2014-2019. A distributed lag non-linear model was used to estimate the exposure-lag-response relationship between environmental variables and pSS.

RESULTS

We detected significant and non-linear associations between extreme environments and pSS. The estimated relative risk (RR) for a lag of 3 days was 1.11 (95% CI: 1.03 to 1.19) for extreme cold and for a lag of 21 days was 1.07 (95% CI: 1.01 to 1.12) for extreme dampness. Long sunshine duration was positively correlated with pSS (lag 11, 1.05, 95% CI: 1.01 to 1.08). Moreover, female patients were more susceptible to these effects. Patients older than 65 years old were more vulnerable to frigid environments (lag 3, RR = 1.30, 95% CI: 1.09 to 1.54), while younger patients were more vulnerable to extreme dampness (lag 21, RR = 1.10, 95% CI: 1.03 to 1.16). Extreme cold and high humidity were negatively correlated with the same-day outpatient visits.

CONCLUSIONS

Our findings suggest a potential relationship between exposure to extreme environmental conditions and increased risk of pSS outpatient visits. We therefore suggest that policymakers and doctors aim to further our understanding of environmental effects on pSS and adopt adequate measures to alleviate pSS symptoms. Key Points • Extreme cold, extreme dampness, and long sunshine duration increased the risk of pSS outpatient visits, especially for females. • Young pSS patients are more susceptible to a rise in humidity. • Elderly pSS patients are more sensitive to extreme cold weather.

Exposure-lag-response associations between weather conditions and ankylosing spondylitis: a time series study

Background

Patients with ankylosing spondylitis (AS) have reported that their pain becomes worse when the local weather changes. However, there is limited evidence verifying the short-term associations between meteorological factors and outpatient visits for patients with AS. Therefore, this study evaluates this possible association.

Methods

Meteorological data and data on daily AS outpatient visits to a general hospital in Hefei, China, from 2014 to 2019 were collected and analysed. Distributed lag nonlinear models and Poisson regression models were employed to determine the association between weather conditions and outpatient visits; the results were also stratified by gender and age.

Results

High relative humidity is significantly associated with all patient visits in lag 1 (RR = 1.113, 95% CI 1.021 to 1.213) and lag 7 days (RR = 1.115, 95% CI 1.014 to 1.227). A low relative risk to the nadir is observed in lag 4 days (RR = 0.920, 95% CI 0.862 to 0.983). Male and young patients (< 65 years) are more vulnerable to damp weather, and elderly people (≥ 65 years) are significantly affected by high temperatures in lag 7 days (RR = 3.004, 95% CI 1.201 to 7.510).

Conclusions

Our findings suggest a potential relationship between exposure to weather conditions and increased risk of AS outpatient visits. These results can aid hospitals in preparing for and managing hospital visits by AS patients when the local weather conditions change.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04523-y.

Association between extreme heat and hospital admissions for cataract patients in Hefei, China

Cataract is the first cause of blindness and the major cause of visual impairment worldwide. Under conditions of global warming, researchers have begun to give attention to the influence of increasing temperature on cataract patients. Our paper aimed to investigate the association between extreme heat and hospital admissions for cataract in Hefei, China. Based on data from the New Rural Cooperative Medical System and National Meteorological Information Center, we used a generalized additive model and a distributed lag nonlinear model to examine the relationship between extreme heat and hospitalizations for cataract, with consideration of cumulative and lagged effects. When current mean temperature was above 28 °C, each 1 °C rise was associated with a 4% decrease in the number of cataract admissions (RR = 0.96, 95% CI = 0.94-0.98). The cumulative relative risk over 11 days of lag was the lowest, which indicated that every 1 °C increase in mean temperature above 28 °C was associated with a 19% decrease in the number of hospital admissions for cataract (RR = 0.81, 95% CI = 0.75-0.88). In subgroup analyses, the negative association between extreme heat and hospital admissions for cataract was stronger among patients who were not admitted to provincial-level hospitals. In conclusion, this paper found that extreme heat was negatively associated with cataract hospitalizations in Hefei, providing useful information for hospitals and policymakers.

Seasonality in schizophrenia-An analysis of a nationwide registry with 110,735 hospital admissions

Background.

Seasonal patterns in hospitalizations have been observed in various psychiatric disorders, however, it is unclear whether they also exist in schizophrenia. Previous studies found mixed results and those reporting the presence of seasonality differ regarding the characteristics of these patterns. Further, they are inconclusive whether sex is an influencing factor. The aim of this study was therefore to examine if seasonal patterns in hospitalizations can be found in schizophrenia, with special regard to a possible influence of sex, by using a large national dataset.

Methods.

Data on all hospital admissions within Austria due to schizophrenia (F20.0–F20.6) for the time period of 2003–2016 were included. Age standardized monthly variation of hospitalization for women and men was analyzed and the level of significance adjusted for multiple testing.

Results.

The database comprised of 110,735 admissions (59.6% men). Significant seasonal variations were found in the total sample with hospitalization peaks in January and June and a trough in December (p < 0.0001). No significant difference in these patterns was found between women and men with schizophrenia (p < 0.0001).

Conclusion.

Our study shows that schizophrenia-related hospitalizations follow a seasonal pattern in both men and women. The distribution of peaks might be influenced by photoperiod changes which trigger worsening of symptoms and lead to exacerbations in schizophrenia. Further research is necessary to identify underlying factors influencing seasonal patterns and to assess whether a subgroup of patients with schizophrenia is especially vulnerable to the impact of seasonal variations.